BEd Notes
Operating system (OS)
An operating system (OS) is
software that manages computer hardware and software resources and provides
common services for computer programs. The operating system is an essential
component of the system software in a computer system. Application programs
usually require an operating system to function.
An operating system (OS) is software that manages
computer hardware and software
resources and provides common services for computer
programs. The operating system is an essential component of the system
software in a computer system. Application programs usually require an
operating system to function.
Time-sharing
operating systems schedule tasks for efficient use of the system and may also
include accounting software for cost allocation of processor time, mass
storage, printing, and other resources.
For hardware functions such as input and output
and memory allocation, the operating system
acts as an intermediary between programs and the computer hardware, although
the application code is usually executed directly by the hardware and
frequently makes system calls to an OS function or be
interrupted by it. Operating systems are found on many devices that contain a
computer—from cellular phones and video game consoles to web servers
and supercomputers.
Examples of popular modern operating systems
include Android, BlackBerry 10,
BSD, Chrome OS,
iOS, Linux, OS X, QNX, Microsoft
Windows,[3]
Windows Phone,
and z/OS.
The first eight of these examples share roots in UNIX.
Types of operating systems
Single- and multi-tasking
A single-tasking system can only run one program at a
time, while a multi-tasking operating system allows more
than one program to be running in concurrency. This is achieved by time-sharing, dividing
the available processor time between multiple processes which are each
interrupted repeatedly in time-slices by a task scheduling subsystem of the
operating system. Multi-tasking may be characterized in pre-emptive and
co-operative types. In pre-emptive multitasking, the operating system slices
the CPU time and dedicates a slot to each of the programs. Unix-like operating
systems, e.g., Solaris, Linux, as well as AmigaOS support
pre-emptive multitasking. Cooperative multitasking is achieved by relying on
each process to provide time to the other processes in a defined manner. 16-bit versions of
Microsoft Windows used cooperative multi-tasking. 32-bit versions of
both Windows NT and Win9x, used pre-emptive multi-tasking. Mac OS prior to OS X
also used to support cooperative multitasking
The GNU Project was started
by activist and programmer Richard
Stallman with the goal of creating a complete free
software replacement to the proprietary UNIX operating
system. While the project was highly successful in duplicating the
functionality of various parts of UNIX, development of the GNU Hurd kernel
proved to be unproductive. In 1991, Finnish computer science student Linus
Torvalds, with cooperation from volunteers collaborating over the
Internet, released the first version of the Linux kernel. It was
soon merged with the GNU user space components
and system software to form a complete operating
system. Since then, the combination of the two major components has usually
been referred to as simply "Linux" by the software industry, a naming
convention that Stallman and the Free Software Foundation remain
opposed to, preferring the name GNU/Linux. The Berkeley Software Distribution,
known as BSD, is the UNIX derivative distributed by the University
of California, Berkeley, starting in the 1970s. Freely distributed and ported to many
minicomputers, it eventually also gained a following for use on PCs, mainly as FreeBSD, NetBSD and OpenBSD.
Examples of operating systems
Unix and Unix-like operating
systems
Main article: Unix
Unix was originally written in assembly
language.[8] Ken Thompson wrote B, mainly based on BCPL, based on
his experience in the MULTICS project. B was replaced by C, and Unix, rewritten in C,
developed into a large, complex family of inter-related operating systems which
have been influential in every modern operating system (see History).
The Unix-like family is a
diverse group of operating systems, with several major sub-categories including
System V, BSD, and Linux. The name
"UNIX" is a
trademark of The Open Group which licenses it for use
with any operating system that has been shown to conform to their definitions.
"UNIX-like" is commonly used to refer to the large set of operating
systems which resemble the original UNIX.
Unix-like systems run on a wide variety of computer architectures. They are used heavily for servers in business, as well as workstations in academic
and engineering environments. Free UNIX
variants, such as Linux and BSD, are
popular in these areas.
Four operating systems are certified by The Open
Group (holder of the Unix trademark) as Unix. HP's HP-UX and IBM's AIX are both descendants of the original System V Unix
and are designed to run only on their respective vendor's hardware. In
contrast, Sun Microsystems's Solaris Operating System can run on
multiple types of hardware, including x86 and Sparc servers,
and PCs. Apple's OS X, a
replacement for Apple's earlier (non-Unix) Mac OS, is a hybrid
kernel-based BSD variant derived from NeXTSTEP, Mach, and FreeBSD.
Unix interoperability was sought by establishing the POSIX standard.
The POSIX standard can be applied to any operating system, although it was
originally created for various Unix variants.
BSD and its descendants
Main article: Berkeley Software Distribution
A subgroup of the Unix family is the Berkeley Software Distribution family,
which includes FreeBSD, NetBSD, and OpenBSD. These
operating systems are most commonly found on webservers, although
they can also function as a personal computer OS. The Internet owes much of its
existence to BSD, as many of the protocols now commonly used by computers to
connect, send and receive data over a network were widely implemented and
refined in BSD. The World Wide Web was also first demonstrated
on a number of computers running an OS based on BSD called NextStep.
BSD has its roots in Unix. In 1974, University of California,
Berkeley installed its first Unix system. Over time, students and
staff in the computer science department there began adding new programs to
make things easier, such as text editors. When Berkeley received new VAX computers
in 1978 with Unix installed, the school's undergraduates modified Unix even
more in order to take advantage of the computer's hardware possibilities. The Defense Advanced Research
Projects Agency of the US Department of Defense took
interest, and decided to fund the project. Many schools, corporations, and
government organizations took notice and started to use Berkeley's version of
Unix instead of the official one distributed by AT&T.
Steve Jobs, upon leaving Apple Inc. in
1985, formed NeXT Inc., a company
that manufactured high-end computers running on a variation of BSD called NeXTSTEP. One of
these computers was used by Tim
Berners-Lee as the first webserver to create the World Wide Web.
Developers like Keith Bostic encouraged
the project to replace any non-free code that originated with Bell Labs. Once
this was done, however, AT&T sued. Eventually, after two years of legal
disputes, the BSD project came out ahead and spawned a number of free
derivatives, such as FreeBSD and NetBSD.
OS X
Main article: OS X
The standard user interface of OS X
OS X (formerly "Mac OS X") is a line of open core graphical
operating systems developed, marketed, and sold by Apple Inc., the latest
of which is pre-loaded on all currently shipping Macintosh computers.
OS X is the successor to the original Mac OS, which had
been Apple's primary operating system since 1984. Unlike its predecessor, OS X
is a UNIX operating
system built on technology that had been developed at NeXT through the
second half of the 1980s and up until Apple purchased the company in early
1997. The operating system was first released in 1999 as Mac OS X Server 1.0, with a desktop-oriented
version (Mac OS X v10.0 "Cheetah") following
in March 2001. Since then, six more distinct "client" and "server"
editions of OS X have been released, until the two were merged in OS X 10.7
"Lion". Releases of OS X v10.0 through v10.8 are named after big cats. Starting
with v10.9, "Mavericks", OS X versions are named after inspirational
places in California.[9] OS X 10.10
"Yosemite", the most recent version, was announced and released on
June 2, 2014 at the WWDC 2014.
Prior to its merging with OS X, the server edition – OS X Server – was architecturally identical to its desktop
counterpart and usually ran on Apple's line of Macintosh server hardware. OS X Server
included work group management and administration software tools that provide
simplified access to key network
services, including a mail transfer agent, a Samba server, an LDAP server, a domain name server, and others. With Mac OS X v10.7
Lion, all server aspects of Mac OS X Server have been
integrated into the client version and the product re-branded as "OS
X" (dropping "Mac" from the name). The server tools are now
offered as an application.[10]
Linux and GNU
Android, a popular mobile operating
system using the Linux kernel
The GNU project is a collaboration of many programmers
who envisioned to create a free and open operating system that was similar to
Unix but with new code licensed on the open-source license model. It was started in 1983
by Richard Stallman, and is responsible for many
components of most Linux variants. Thousands of pieces of software for
virtually every operating system are licensed under the GNU General Public License. Meanwhile,
the Linux kernel originated in 1991 as a side project of Linus
Torvalds, while a university student in Finland. He posted
information about his project on a newsgroup for computer students and
programmers, and received support and assistance from volunteers who succeeded
in creating a complete and functional kernel. GNU programmers joint the effort
and both groups worked to integrate the finished GNU parts with the Linux
kernel to create a complete operating system.
Linux is
Unix-like, but was developed without any Unix code, unlike BSD and its
variants. Because of its open license model, the Linux kernel code is
available for study and modification, which resulted in its use on a wide range
of computing machinery from supercomputers to smart-watches. Although estimates
suggest that Linux and GNU software are used on only 1.82% of all personal computers,[11][12] it has been
widely adopted for use in servers[13] and
embedded systems[14] such as
cell phones. GNU/Linux has superseded Unix on many platforms and is used on the
ten most powerful supercomputers in the world.[15] The Linux
kernel is used in some popular distributions, such as Red Hat, Debian, Ubuntu, Linux Mint and Google's Android.
Google Chromium OS
Main article: Google Chromium OS
Chromium is an operating system based on the Linux kernel
and designed by Google. Since Chromium OS targets
computer users who spend most of their time on the Internet, it is mainly a web browser with
limited ability to run local applications, though it has a built-in file
manager and media player. Instead, it relies on Internet applications (or Web apps) used in
the web browser to accomplish tasks such as word processing.[16] Chromium OS
differs from Chrome OS in that Chromium is open-source and used primarily by
developers whereas Chrome OS is the operating system shipped out in
Chromebooks.[17]
Microsoft Windows
Main article: Microsoft
Windows
Microsoft Windows is a family of proprietary operating systems designed by
Microsoft Corporation and primarily targeted to
Intel architecture based computers, with an estimated 88.9 percent total usage
share on Web connected computers.[12][18][19][20] The newest
version is Windows 8.1 for workstations and Windows Server 2012 R2 for servers. Windows 7
recently overtook Windows XP as most used OS.[21][22][23]
Microsoft Windows originated in 1985 as an operating environment running on top of MS-DOS, which was
the standard operating system shipped on most Intel architecture personal
computers at the time. In 1995, Windows 95 was
released which only used MS-DOS as a bootstrap. For backwards compatibility,
Win9x could run real-mode MS-DOS[24][25] and 16 bits
Windows 3.x[26] drivers. Windows ME, released
in 2000, was the last version in the Win9x family. Later versions have all been
based on the Windows NT kernel. Current client versions of
Windows run on IA-32, x86-64 and 32-bit ARM microprocessors.[27] In addition
Itanium is still
supported in older server version Windows Server 2008 R2. In the past, Windows NT
supported additional architectures.
Server editions of Windows are widely used. In recent
years, Microsoft has expended significant capital in an effort to promote the
use of Windows as a server operating system. However, Windows' usage on
servers is not as widespread as on personal computers, as Windows competes
against Linux and BSD for server market share.[28][29]The first PC that used windows operating
system was the IBM Personal System/2.
Other
There have been many operating systems that were
significant in their day but are no longer so, such as AmigaOS; OS/2 from IBM
and Microsoft; Mac OS, the non-Unix precursor to
Apple's Mac OS X; BeOS; XTS-300; RISC OS; MorphOS; Haiku; BareMetal and FreeMint. Some are
still used in niche markets and continue to be developed as minority platforms
for enthusiast communities and specialist applications. OpenVMS formerly
from DEC, is still under active
development by Hewlett-Packard. Yet other operating systems
are used almost exclusively in academia, for operating systems education or to
do research on operating system concepts. A typical example of a system that
fulfills both roles is MINIX, while for example Singularity is used
purely for research.
Other operating systems have failed to win significant
market share, but have introduced innovations that have influenced mainstream
operating systems, not least Bell Labs' Plan 9.
Components
The components of an operating system all exist in order
to make the different parts of a computer work together. All user software
needs to go through the operating system in order to use any of the hardware,
whether it be as simple as a mouse or keyboard or as complex as an Internet
component.
Kernel
A kernel connects the application software to the
hardware of a computer.
Main article: Kernel (computing)
With the aid of the firmware and device
drivers, the kernel provides the most basic level of control
over all of the computer's hardware devices. It manages memory access for
programs in the RAM, it
determines which programs get access to which hardware resources, it sets up or
resets the CPU's operating states for optimal operation at all times, and it
organizes the data for long-term non-volatile storage with file systems on such
media as disks, tapes, flash memory, etc.
Program execution
Main article: Process (computing)
The operating system provides an interface between an
application program and the computer hardware, so that an application program
can interact with the hardware only by obeying rules and procedures programmed
into the operating system. The operating system is also a set of services which
simplify development and execution of application programs. Executing an
application program involves the creation of a process by the operating system kernel which assigns memory space
and other resources, establishes a priority for the process in multi-tasking
systems, loads program binary code into memory, and initiates execution of the
application program which then interacts with the user and with hardware
devices.
Interrupts
Main article: Interrupt
Interrupts are central to operating
systems, as they provide an efficient way for the operating system to interact
with and react to its environment. The alternative — having the operating
system "watch" the various sources of input for events (polling) that
require action — can be found in older systems with very small stacks (50 or 60
bytes) but is unusual in modern systems with large stacks. Interrupt-based
programming is directly supported by most modern CPUs. Interrupts provide a
computer with a way of automatically saving local register contexts, and
running specific code in response to events. Even very basic computers support
hardware interrupts, and allow the programmer to specify code which may be run
when that event takes place.
When an interrupt is received, the computer's hardware
automatically suspends whatever program is currently running, saves its status,
and runs computer code previously associated with the interrupt; this is
analogous to placing a bookmark in a book in response to a phone call. In
modern operating systems, interrupts are handled by the operating system's kernel. Interrupts may come from
either the computer's hardware or the running program.
When a hardware device triggers an interrupt, the
operating system's kernel decides how to deal with this event, generally by
running some processing code. The amount of code being run depends on the
priority of the interrupt (for example: a person usually responds to a smoke
detector alarm before answering the phone). The processing of hardware
interrupts is a task that is usually delegated to software called a device
driver, which may be part of the operating system's kernel,
part of another program, or both. Device drivers may then relay information to
a running program by various means.
A program may also trigger an interrupt to the operating
system. If a program wishes to access hardware, for example, it may interrupt
the operating system's kernel, which causes control to be passed back to the
kernel. The kernel then processes the request. If a program wishes additional
resources (or wishes to shed resources) such as memory, it triggers an
interrupt to get the kernel's attention.
Modes
Privilege rings for the x86 available
in protected mode. Operating systems determine
which processes run in each mode.
Modern CPUs support multiple modes of operation. CPUs with this
capability use at least two modes: protected
mode and supervisor
mode. The supervisor mode is used by the operating system's
kernel for low level tasks that need unrestricted access to hardware, such as
controlling how memory is written and erased, and communication with devices
like graphics cards. Protected mode, in contrast, is used for almost everything
else. Applications operate within protected mode, and can only use hardware by
communicating with the kernel, which controls everything in supervisor mode. CPUs might have
other modes similar to protected mode as well, such as the virtual modes in
order to emulate older processor types, such as 16-bit processors on a 32-bit
one, or 32-bit processors on a 64-bit one.
When a computer first starts up, it is automatically
running in supervisor mode. The first few programs to
run on the computer, being the BIOS or EFI, bootloader, and the
operating system have unlimited access to hardware – and this is required
because, by definition, initializing a protected environment can only be done
outside of one. However, when the operating system passes control to another
program, it can place the CPU into protected
mode.
In protected
mode, programs may have access to a more limited set of the
CPU's instructions. A user program may leave protected
mode only by triggering an interrupt, causing control to be
passed back to the kernel. In this way the operating
system can maintain exclusive control over things like access to hardware and
memory.
The term "protected mode resource" generally
refers to one or more CPU registers, which contain information that the running
program isn't allowed to alter. Attempts to alter these resources generally
causes a switch to supervisor mode, where the operating system can deal with
the illegal operation the program was attempting (for example, by killing the
program).
Memory management
Main article: Memory
management
Among other things, a multiprogramming operating system kernel must be responsible for
managing all system memory which is currently in use by programs. This ensures
that a program does not interfere with memory already in use by another
program. Since programs time share, each program must have independent access
to memory.
Cooperative memory management, used by many early
operating systems, assumes that all programs make voluntary use of the kernel's memory manager, and do not
exceed their allocated memory. This system of memory management is almost never
seen any more, since programs often contain bugs which can cause them to exceed
their allocated memory. If a program fails, it may cause memory used by one or
more other programs to be affected or overwritten. Malicious programs or
viruses may purposefully alter another program's memory, or may affect the
operation of the operating system itself. With cooperative memory management,
it takes only one misbehaved program to crash the system.
Memory protection enables the kernel to limit a process' access to
the computer's memory. Various methods of memory protection exist, including memory segmentation and paging. All
methods require some level of hardware support (such as the 80286 MMU), which
doesn't exist in all computers.
In both segmentation and paging, certain protected
mode registers specify to the CPU what memory address it
should allow a running program to access. Attempts to access other addresses
trigger an interrupt which cause the CPU to re-enter supervisor
mode, placing the kernel in charge. This is called a segmentation violation or Seg-V for short, and since
it is both difficult to assign a meaningful result to such an operation, and
because it is usually a sign of a misbehaving program, the kernel generally resorts to
terminating the offending program, and reports the error.
Windows versions 3.1 through ME had some level of memory
protection, but programs could easily circumvent the need to use it. A general protection fault would be
produced, indicating a segmentation violation had occurred; however, the system
would often crash anyway.
Virtual memory
Main article: Virtual
memory
Further information: Page fault
Many operating systems can "trick" programs into
using memory scattered around the hard disk and RAM as if it is one continuous
chunk of memory, called virtual memory.
The use of virtual memory addressing (such as paging or
segmentation) means that the kernel can choose what memory each program may use
at any given time, allowing the operating system to use the same memory
locations for multiple tasks.
If a program tries to access memory that isn't in its
current range of accessible memory, but nonetheless has been allocated to it,
the kernel is interrupted in the same way as it would if the program were to
exceed its allocated memory. (See section on memory management.) Under UNIX
this kind of interrupt is referred to as a page fault.
When the kernel detects a page fault it generally adjusts
the virtual memory range of the program which triggered it, granting it access
to the memory requested. This gives the kernel discretionary power over where a
particular application's memory is stored, or even whether or not it has
actually been allocated yet.
In modern operating systems, memory which is accessed
less frequently can be temporarily stored on disk or other media to make that
space available for use by other programs. This is called swapping, as an area
of memory can be used by multiple programs, and what that memory area contains
can be swapped or exchanged on demand.
"Virtual memory" provides the programmer or the
user with the perception that there is a much larger amount of RAM in the
computer than is really there.[30]
Multitasking
Multitasking refers to the running of multiple
independent computer programs on the same computer; giving the appearance that
it is performing the tasks at the same time. Since most computers can do at
most one or two things at one time, this is generally done via time-sharing,
which means that each program uses a share of the computer's time to execute.
An operating system kernel contains a scheduling program which determines how
much time each process spends executing, and in which order execution control
should be passed to programs. Control is passed to a process by the kernel,
which allows the program access to the CPU and memory. Later, control is returned to the
kernel through some mechanism, so that another program may be allowed to use
the CPU. This so-called passing of control between the kernel and applications
is called a context switch.
An early model which governed the allocation of time to
programs was called cooperative multitasking. In this
model, when control is passed to a program by the kernel, it may execute for as
long as it wants before explicitly returning control to the kernel. This means
that a malicious or malfunctioning program may not only prevent any other
programs from using the CPU, but it can hang the entire system if it enters an infinite
loop.
Modern operating systems extend the concepts of
application preemption to device drivers and kernel code, so that the operating
system has preemptive control over internal run-times as well.
The philosophy governing preemptive multitasking is that of ensuring that all
programs are given regular time on the CPU. This implies that all programs must
be limited in how much time they are allowed to spend on the CPU without being
interrupted. To accomplish this, modern operating system kernels make use of a
timed interrupt. A protected mode timer is set by the kernel
which triggers a return to supervisor mode after the specified time has
elapsed. (See above sections on Interrupts and Dual Mode Operation.)
On many single user operating systems cooperative
multitasking is perfectly adequate, as home computers generally run a small
number of well tested programs. The AmigaOS is an
exception, having pre-emptive multitasking from its very first version. Windows NT was the
first version of Microsoft Windows which enforced preemptive
multitasking, but it didn't reach the home user market until Windows XP (since Windows NT was
targeted at professionals).
Disk access and file systems
Main article: Virtual file system
Filesystems allow users and programs to organize and sort
files on a computer, often through the use of directories (or
"folders")
Access to data stored on disks is a central feature of
all operating systems. Computers store data on disks using files, which are
structured in specific ways in order to allow for faster access, higher
reliability, and to make better use out of the drive's available space. The
specific way in which files are stored on a disk is called a file system, and
enables files to have names and attributes. It also allows them to be stored in
a hierarchy of directories or folders arranged in a directory
tree.
Early operating systems generally supported a single type
of disk drive and only one kind of file system. Early file systems were limited
in their capacity, speed, and in the kinds of file names and directory
structures they could use. These limitations often reflected limitations in the
operating systems they were designed for, making it very difficult for an
operating system to support more than one file system.
While many simpler operating systems support a limited
range of options for accessing storage systems, operating systems like UNIX and Linux support a
technology known as a virtual file system or VFS. An operating system
such as UNIX supports a wide array of storage devices, regardless of their
design or file systems, allowing them to be accessed
through a common application programming
interface (API). This makes it unnecessary for programs to have
any knowledge about the device they are accessing. A VFS allows the operating
system to provide programs with access to an unlimited number of devices with
an infinite variety of file systems installed on them, through the use of
specific device drivers and file system drivers.
A connected storage device, such as a hard drive, is
accessed through a device driver. The device driver
understands the specific language of the drive and is able to translate that
language into a standard language used by the operating system to access all
disk drives. On UNIX, this is the language of block
devices.
When the kernel has an appropriate device driver in
place, it can then access the contents of the disk drive in raw format, which
may contain one or more file systems. A file system driver is used to translate
the commands used to access each specific file system into a standard set of
commands that the operating system can use to talk to all file systems.
Programs can then deal with these file systems on the basis of filenames, and
directories/folders, contained within a hierarchical structure. They can
create, delete, open, and close files, as well as gather various information
about them, including access permissions, size, free space, and creation and
modification dates.
Various differences between file systems make supporting
all file systems difficult. Allowed characters in file names, case
sensitivity, and the presence of various kinds of file
attributes makes the implementation of a single interface for every
file system a daunting task. Operating systems tend to recommend using (and so
support natively) file systems specifically designed for them; for example, NTFS in Windows
and ext3 and ReiserFS in Linux.
However, in practice, third party drives are usually available to give support
for the most widely used file systems in most general-purpose operating systems
(for example, NTFS is available in Linux through NTFS-3g, and ext2/3
and ReiserFS are available in Windows through third-party software).
Support for file systems is highly varied among modern
operating systems, although there are several common file systems which almost
all operating systems include support and drivers for. Operating systems vary on
file system support and on the disk formats they may be installed on. Under
Windows, each file system is usually limited in application to certain media;
for example, CDs must use ISO 9660 or UDF, and as of Windows
Vista, NTFS is the only file system which the operating system
can be installed on. It is possible to install Linux onto many types of file
systems. Unlike other operating systems, Linux and UNIX allow any file system
to be used regardless of the media it is stored in, whether it is a hard drive,
a disc (CD, DVD...), a USB flash drive, or even contained within a file located
on another file system.
Device drivers
Main article: Device
driver
A device
driver is a specific type of computer software developed to
allow interaction with hardware devices. Typically this constitutes an
interface for communicating with the device, through the specific computer bus
or communications subsystem that the hardware is connected to, providing
commands to and/or receiving data from the device, and on the other end, the
requisite interfaces to the operating system and software applications. It is a
specialized hardware-dependent computer program which is also operating system
specific that enables another program, typically an operating system or applications
software package or computer program running under the operating system kernel,
to interact transparently with a hardware device, and usually provides the
requisite interrupt handling necessary for any necessary asynchronous
time-dependent hardware interfacing needs.
The key design goal of device drivers is abstraction. Every
model of hardware (even within the same class of device) is different. Newer
models also are released by manufacturers that provide more reliable or better
performance and these newer models are often controlled differently. Computers
and their operating systems cannot be expected to know how to control every
device, both now and in the future. To solve this problem, operating systems
essentially dictate how every type of device should be controlled. The function
of the device driver is then to translate these operating system mandated
function calls into device specific calls. In theory a new device, which is
controlled in a new manner, should function correctly if a suitable driver is
available. This new driver ensures that the device appears to operate as usual
from the operating system's point of view.
Under versions of Windows before Vista and versions of
Linux before 2.6, all driver execution was co-operative, meaning that if a
driver entered an infinite loop it would freeze the system. More recent
revisions of these operating systems incorporate kernel preemption, where the
kernel interrupts the driver to give it tasks, and then separates itself from
the process until it receives a response from the device driver, or gives it
more tasks to do.
Networking
Main article: Computer
network
Currently most operating systems support a variety of
networking protocols, hardware, and applications for using them. This means
that computers running dissimilar operating systems can participate in a common
network for sharing resources such as
computing, files, printers, and
scanners using either wired or wireless connections. Networks can essentially
allow a computer's operating system to access the resources of a remote
computer to support the same functions as it could if those resources were
connected directly to the local computer. This includes everything from simple
communication, to using networked file systems or even sharing another
computer's graphics or sound hardware. Some network services allow the
resources of a computer to be accessed transparently, such as SSH which
allows networked users direct access to a computer's command line interface.
Client/server networking allows a program on a computer,
called a client, to connect via a network to another computer, called a server.
Servers offer (or host) various services to other network computers and users.
These services are usually provided through ports or numbered access points
beyond the server's network address. Each port number is usually
associated with a maximum of one running program, which is responsible for
handling requests to that port. A daemon, being a user program, can in turn
access the local hardware resources of that computer by passing requests to the
operating system kernel.
Many operating systems support one or more
vendor-specific or open networking protocols as well, for example, SNA on IBM systems, DECnet on systems
from Digital Equipment Corporation, and
Microsoft-specific protocols (SMB) on Windows. Specific protocols for specific tasks
may also be supported such as NFS for file
access. Protocols like ESound, or esd can be easily
extended over the network to provide sound from local applications, on a remote
system's sound hardware.
Security
Main article: Computer
security
A computer being secure depends on a number of
technologies working properly. A modern operating system provides access to a
number of resources, which are available to software running on the system, and
to external devices like networks via the kernel.
The operating system must be capable of distinguishing
between requests which should be allowed to be processed, and others which
should not be processed. While some systems may simply distinguish between
"privileged" and "non-privileged", systems commonly have a
form of requester identity, such as a user name. To establish identity
there may be a process of authentication. Often a username must be
quoted, and each username may have a password. Other methods of authentication,
such as magnetic cards or biometric data, might be used instead. In some cases,
especially connections from the network, resources may be accessed with no
authentication at all (such as reading files over a network share). Also
covered by the concept of requester identity is authorization;
the particular services and resources accessible by the requester once logged
into a system are tied to either the requester's user account or to the variously
configured groups of users to which the requester belongs.
In addition to the allow or disallow model of security, a
system with a high level of security also offers auditing options. These would
allow tracking of requests for access to resources (such as, "who has been
reading this file?"). Internal security, or security from an already
running program is only possible if all possibly harmful requests must be
carried out through interrupts to the operating system kernel. If programs can
directly access hardware and resources, they cannot be secured.
External security involves a request from outside the
computer, such as a login at a connected console or some kind of network
connection. External requests are often passed through device drivers to the
operating system's kernel, where they can be passed onto applications, or
carried out directly. Security of operating systems has long been a concern
because of highly sensitive data held on computers, both of a commercial and
military nature. The United States Government Department of Defense (DoD)
created the Trusted Computer System
Evaluation Criteria (TCSEC) which is a standard that sets basic
requirements for assessing the effectiveness of security. This became of vital
importance to operating system makers, because the TCSEC was used to evaluate,
classify and select trusted operating systems being
considered for the processing, storage and retrieval of sensitive or classified information.
Network services include offerings such as file sharing,
print services, email, web sites, and file transfer protocols (FTP), most of which can have
compromised security. At the front line of security are hardware devices known
as firewalls or intrusion
detection/prevention systems. At the operating system level, there are a number
of software firewalls available, as well as intrusion detection/prevention
systems. Most modern operating systems include a software firewall, which is
enabled by default. A software firewall can be configured to allow or deny
network traffic to or from a service or application running on the operating
system. Therefore, one can install and be running an insecure service, such as
Telnet or FTP, and not have to be threatened by a security breach because the
firewall would deny all traffic trying to connect to the service on that port.
An alternative strategy, and the only sandbox strategy available in systems
that do not meet the Popek and Goldberg
virtualization requirements, is where the operating system is not running user
programs as native code, but instead either emulates a processor
or provides a host for a p-code based
system such as Java.
Internal security is especially relevant for multi-user
systems; it allows each user of the system to have private files that the other
users cannot tamper with or read. Internal security is also vital if auditing
is to be of any use, since a program can potentially bypass the operating
system, inclusive of bypassing auditing.
User interface
A screenshot of the Bourne Again Shell command line. Each command is
typed out after the 'prompt', and then its output appears below, working its
way down the screen. The current command prompt is at the bottom.
Main article: Operating system user
interface
Every computer that is to be operated by an individual
requires a user interface. The user interface is
usually referred to as a shell and is essential if human interaction is to be
supported. The user interface views the directory structure and requests services from
the operating system that will acquire data from input
hardware devices, such as a keyboard, mouse or credit card
reader, and requests operating system services to display prompts, status
messages and such on output
hardware devices, such as a video
monitor or printer. The two most common forms of
a user interface have historically been the command-line interface, where computer commands are
typed out line-by-line, and the graphical user interface, where a
visual environment (most commonly a WIMP) is present.
Graphical user interfaces
A screenshot of the KDE Plasma Desktop graphical user interface.
Programs take the form of images on the screen, and the files, folders
(directories), and applications take the form of icons and symbols. A mouse is
used to navigate the computer.
Most of the modern computer systems support graphical user interfaces (GUI), and
often include them. In some computer systems, such as the original
implementation of Mac OS, the GUI is integrated into
the kernel.
While technically a graphical user interface is not an
operating system service, incorporating support for one into the operating
system kernel can allow the GUI to be more responsive by reducing the number of
context switches required for the GUI to
perform its output functions. Other operating systems are modular, separating the graphics
subsystem from the kernel and the Operating System. In the 1980s UNIX, VMS and
many others had operating systems that were built this way. Linux and Mac OS X
are also built this way. Modern releases of Microsoft Windows such as Windows
Vista implement a graphics subsystem that is mostly in
user-space; however the graphics drawing routines of versions between Windows NT
4.0 and Windows Server 2003 exist mostly in kernel space.
Windows 9x had very
little distinction between the interface and the kernel.
Many computer operating systems allow the user to install
or create any user interface they desire. The X Window
System in conjunction with GNOME or KDE Plasma Desktop is a commonly found setup on
most Unix and Unix-like (BSD, Linux, Solaris)
systems. A number of Windows shell replacements have been
released for Microsoft Windows, which offer alternatives to the included Windows
shell, but the shell itself cannot be separated from Windows.
Numerous Unix-based GUIs have existed over time, most
derived from X11. Competition among the various vendors of Unix (HP, IBM, Sun)
led to much fragmentation, though an effort to standardize in the 1990s to COSE and CDE failed for various reasons,
and were eventually eclipsed by the widespread adoption of GNOME and K Desktop Environment. Prior to free
software-based toolkits and desktop environments, Motif was the
prevalent toolkit/desktop combination (and was the basis upon which CDE was
developed).
Graphical user interfaces evolve over time. For example,
Windows has modified its user interface almost every time a new major version
of Windows is released, and the Mac OS GUI changed dramatically with the
introduction of Mac OS X in 1999.[31]
Real-time operating systems
Main article: Real-time operating system
A real-time operating system (RTOS) is an operating
system intended for applications with fixed deadlines (real-time computing). Such applications include
some small embedded systems, automobile engine
controllers, industrial robots, spacecraft, industrial control, and some
large-scale computing systems.
An early example of a large-scale real-time operating
system was Transaction Processing
Facility developed by American
Airlines and IBM for the Sabre Airline Reservations
System.
Embedded systems that have fixed deadlines use a real-time operating system such as VxWorks, PikeOS, eCos, QNX, MontaVista
Linux and RTLinux. Windows CE is a real-time operating system that shares
similar APIs to desktop Windows but shares none of desktop Windows' codebase.[citation needed] Symbian OS also has an
RTOS kernel (EKA2) starting with version 8.0b.
Some embedded systems use operating systems such as Palm OS, BSD, and Linux, although
such operating systems do not support real-time computing.
Operating system development
as a hobby
See also: Hobbyist operating system
development
Operating system development is one of the most
complicated activities in which a computing hobbyist may engage.[citation needed] A hobby
operating system may be classified as one whose code has not been directly
derived from an existing operating system, and has few users and active developers.[32]
In some cases, hobby development is in support of a
"homebrew" computing device, for
example, a simple single-board computer powered by a 6502 microprocessor. Or, development may be for
an architecture already in widespread use. Operating system development may
come from entirely new concepts, or may commence by modeling an existing
operating system. In either case, the hobbyist is his/her own developer, or may
interact with a small and sometimes unstructured group of individuals who have
like interests.
Diversity of operating systems
and portability
Application software is generally written for use on a
specific operating system, and sometimes even for specific hardware.[citation needed] When
porting the application to run on another OS, the functionality required by
that application may be implemented differently by that OS (the names of
functions, meaning of arguments, etc.) requiring the application to be adapted,
changed, or otherwise maintained.
Unix was the first operating system not written in
assembly language, making it very portable to systems different from its
native PDP-11.[33]
This cost in supporting operating systems diversity can
be avoided by instead writing applications against software
platforms like Java or Qt. These
abstractions have already borne the cost of adaptation to specific operating
systems and their system libraries.
Another approach is for operating system vendors to adopt
standards. For example, POSIX and OS abstraction layers provide
commonalities that reduce porting costs.
Netiquette
"Netiquette" is network etiquette, the do's and don'ts of online communication. Netiquette covers both common courtesy online and the informal "rules of the road" of cyberspace. This page provides links to both summary and detail information about Netiquette for your browsing pleasure.
Netiquette
is etiquette on the Internet. Since the Internet changes rapidly, its
netiquette does too, but it's still usually based on the Golden Rule. The need
for a sense of netiquette arises mostly when sending or distributing e-mail, posting on Usenet groups, or chatting. To some extent, the practice of
netiquette depends on understanding how e-mail, the Usenet, chatting, or other
aspects of the Internet actually work or are practiced. So a little preliminary
observation can help. Poor netiquette because you're new is one thing, but such
practices as spam and flaming are another matter.
Stellarium (computer program)
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Stellarium is a free software planetarium, licensed under the terms of the GNU
General Public License,
available for Linux, Windows, and Mac OS X. It uses OpenGL to render a realistic projection of the night sky in real time.
Stellarium was developed by the French programmer Fabien Chéreau, who launched the project in the summer of 2001. Other developers include
Robert Spearman, Johannes Gajdosik, Matthew Gates, Nigel Kerr, and Johan
Meuris, who is responsible for the artwork.
Contents
History
In 2006, Stellarium 0.7.1 won a gold award in the
Education category of the Les Trophées du Libre free
software competition.[2]
A modified version of Stellarium has been used by the MeerKAT project as
a virtual sky display showing where the antennae of the radiotelescope are
pointed.[3]
In December 2011, Stellarium was added as one of the
"featured applications" in the Ubuntu Software Center.[4]
Features
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This section is in a list format that may be better
presented using prose. You can
help by converting this section to prose, if appropriate. Editing
help is available. (January 2013)
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- Sky feature
- Over 600,000 stars from the Hipparcos Catalogue and the Tycho-2 Catalogue
- Extra catalogues with more than 210 million stars
- Asterisms and illustrations of the constellations
- Constellations from ten cultures
- Images of nebulae (full Messier catalogue)
- Realistic Milky Way
- Realistic atmosphere, sunrise and sunset
- Planets of the solar system and their major moons
- Ability to display stars and other celestial objects as seen from reference points other than the Earth (e.g. Saturn, Phobos, comet C/2006 P1 (McNaught) or any other object defined in ssystem.ini)
- Interface
- Zoom
- Time control
- Multilingual interface
- Scripting to record and playback shows
- Fisheye projection for planetarium domes
- Spheric mirror projection for personal domes
- Graphical interface and extensive keyboard control
- Telescope control
- Visualization
- Equatorial and azimuthal grids
- Star twinkling
- Shooting stars
- Eclipse simulation
- Skinnable landscapes
- Spherical panorama projection
- Customisability
- Deep sky objects, landscapes, constellation images, scripts etc. can be added.
Planetarium dome projection
The fisheye and spherical mirror distortion features
allow Stellarium to be projected onto domes. Spherical mirror distortion is
used in projection systems that utilize a digital video
projector and a first surface convex spherical
mirror to project images onto a dome. Such
systems are generally cheaper than traditional planetarium projectors and fish-eye
lens projectors and for that reason are used in budget and
home planetarium setups where projection quality is less important. Several
companies that build and sell digital planetarium systems use Stellarium, such
as e-Planetarium.[5]
VirGO
VirGO is a Stellarium plugin, a visual browser for the European Southern Observatory (ESO)
Science Archive Facility that allows astronomers to browse professional
astronomical data. It is no longer supported or maintained, apparently the last
version is 1.4.5, dated Jan 15th 2010.[6]
Stellarium Mobile
Stellarium Mobile[7] is a fork of Stellarium, developed by
some of the Stellarium team members. It is targeting mobile devices running Symbian, Maemo, Android and iOS. Some of
the mobile optimisations have been integrated to the mainline Stellarium.
Hacker (computer security)
In the computer security context, a hacker is someone who seeks and exploits weaknesses in a computer system or computer network. Hackers
may be motivated by a multitude of reasons, such as profit, protest, challenge.
enjoyment,[1] or to
evaluate those weaknesses to assist in removing them. The subculture that has
evolved around hackers is often referred to as the computer underground and is
now a known community.[2] While
other uses of the word hacker exist
that are related to computer security, such as referring to someone with an
advanced understanding of computers and computer networks,[3] they are rarely used in mainstream context. They
are subject to the longstanding hacker definition controversy about the term's true meaning. In this controversy, the term hacker
is reclaimed by computer programmers who argue that someone who breaks into computers,
whether computer criminal (black hats) or
computer security expert (white hats),[4] is more
appropriately called a cracker instead.[5] Some
white hat hackers claim that they also deserve the title hacker, and
that only black hats should be called "crackers".
Contents
- 1 History
- 2 Classifications
- 2.1 White hat
- 2.2 Black hat
- 2.3 Grey hat
- 2.4 Elite hacker
- 2.5 Script kiddie
- 2.6 Neophyte
- 2.7 Blue hat
- 2.8 Hacktivist
- 2.9 Nation state
- 2.10 Organized crime
- 3 Attacks
- 4 Notable intruders and criminal hackers
- 5 Notable security hackers
- 6 Customs
- 7 Consequences for malicious hacking
- 8 Hacking and the media
- 9 See also
- 10 References
- 11 Further reading
- 12 External links
History
Bruce Sterling traces part of the roots of the computer underground to
the Yippies, a 1960s
counterculture movement that published the Technological Assistance Program
(TAP) newsletter.[citation
needed] TAP was a phone phreaking newsletter that taught techniques for unauthorized
exploration of the telephone network. Many people from the phreaking community
are also active in the hacking community even today, and vice versa.[citation
needed]
Classifications
Several subgroups of the
computer underground with different attitudes use different terms to demarcate
themselves from each other, or try to exclude some specific group with whom
they do not agree.
Eric S. Raymond, author of The New Hacker's Dictionary, advocates that members of
the computer underground should be called crackers. Yet, those people see
themselves as hackers and even try to include the views of Raymond in what they
see as a wider hacker culture, a view that Raymond has harshly rejected.
Instead of a hacker/cracker dichotomy, they emphasize a spectrum of different
categories, such as white hat, grey hat, black hat and script kiddie. In contrast to Raymond, they usually reserve the term cracker
for more malicious activity.
According to Ralph D.
Clifford, a cracker or cracking is to "gain unauthorized
access to a computer in order to commit another crime such as destroying
information contained in that system".[6] These subgroups may also be defined by the legal status
of their activities.[7]
White hat
Main article: White hat
A white hat hacker breaks
security for non-malicious reasons, perhaps to test their own security system
or while working for a security company which makes security software. The term
"white hat" in Internet slang refers to an ethical hacker. This classification also includes individuals who
perform penetration tests and vulnerability assessments within a
contractual agreement. The EC-Council,[8] also known as the International Council of Electronic
Commerce Consultants, is one of those organizations that have developed
certifications, courseware, classes, and online training covering the diverse
arena of ethical hacking.[7]
Black hat
A "black hat" hacker
is a hacker who "violates computer security for little reason beyond
maliciousness or for personal gain" (Moore, 2005).[9] Black hat hackers form the stereotypical, illegal
hacking groups often portrayed in popular culture, and are "the epitome of
all that the public fears in a computer criminal".[10] Black hat hackers break into secure networks to destroy,
modify, or steal data; or to make the network unusable for those who are
authorized to use the network. Black hat hackers are also referred to as the
"crackers" within the security industry and by modern programmers.
Crackers keep the awareness of the vulnerabilities to themselves and do not
notify the general public or the manufacturer for patches to be applied.
Individual freedom and accessibility is promoted over privacy and security.
Once they have gained control over a system, they may apply patches or fixes to
the system only to keep their reigning control. Richard Stallman invented the
definition to express the maliciousness of a criminal hacker versus a white hat
hacker who performs hacking duties to identify places to repair.[11]
Grey hat
Main article: Grey hat
A grey hat hacker lies between
a black hat and a white hat hacker. A grey hat hacker may surf the Internet and
hack into a computer system for the sole purpose of notifying the administrator
that their system has a security defect, for example. They may then offer to
correct the defect for a fee.[10] Grey hat hackers sometimes find the defect of a system
and publish the facts to the world instead of a group of people. Even though
grey hat hackers may not necessarily perform hacking for their personal gain,
unauthorized access to a system can be considered illegal and unethical.
Elite hacker
A social status among hackers, elite is used to describe the most
skilled. Newly discovered exploits circulate
among these hackers. Elite groups such as Masters of Deception conferred a
kind of credibility on their members.[12]
Script
kiddie
A script kiddie (also known as a skid or skiddie) is an
unskilled hacker who breaks into computer systems by using automated tools
written by others (usually by other black hat hackers), hence the term script
(i.e. a prearranged plan or set of activities) kiddie (i.e. kid, child—an
individual lacking knowledge and experience, immature),[13] usually with little understanding of the underlying
concept.
Neophyte
A neophyte ("newbie", or
"noob") is someone who is new to hacking or phreaking and has almost
no knowledge or experience of the workings of technology and hacking.[10]
Blue hat
A blue hat hacker is someone outside computer security consulting
firms who is used to bug-test a system prior to its launch, looking for
exploits so they can be closed. Microsoft also uses the term BlueHat to represent a series
of security briefing events.[14][15][16]
Hacktivist
A hacktivist is a hacker who
utilizes technology to publicize a social, ideological, religious or political
message.
Hacktivism can be divided into two main groups:
- Cyberterrorism — Activities involving website defacement or denial-of-service attacks; and,
- Freedom of information — Making information that is not public, or is public in non-machine-readable formats, accessible to the public.
Nation state
Organized
crime
Groups of hackers that carry
out organized criminal activities for profit.[17]
Attacks
Main article: Computer security
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Computer security
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Related security categories
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Threats
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Defenses
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A typical approach in an
attack on Internet-connected system is:
- Network enumeration: Discovering information about the intended target.
- Vulnerability analysis: Identifying potential ways of attack.
- Exploitation: Attempting to compromise the system by employing the vulnerabilities found through the vulnerability analysis.[18]
In order to do so, there are
several recurring tools of the trade and techniques used by computer criminals
and security experts.
Security
exploits
Main article: Exploit (computer security)
A security exploit is a
prepared application that takes advantage of a known weakness.[19] Common examples of security exploits are SQL injection, cross-site scripting and cross-site request forgery which abuse
security holes that may result from substandard programming practice. Other
exploits would be able to be used through File Transfer Protocol (FTP), Hypertext Transfer Protocol (HTTP), PHP, SSH, Telnet and some Web pages. These are
very common in Web site and Web domain hacking.
Techniques
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or sources. Please help improve this section by adding
citations to reliable sources. Unsourced material may be
challenged and removed. (August
2011)
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Vulnerability scanner
A vulnerability scanner is a tool
used to quickly check computers on a network for known weaknesses. Hackers also
commonly use port scanners. These check to see which
ports on a specified computer are "open" or available to access the
computer, and sometimes will detect what program or service is listening on
that port, and its version number. (Firewalls defend computers from
intruders by limiting access to ports and machines, but they can still be
circumvented.)
Finding vulnerabilities
Hackers may
also attempt to find vulnerabilities manually. A common approach is to search
for possible vulnerabilities in the code of the computer system then test them,
sometimes reverse engineering the
software if the code is not provided.
Brute-force attack
Password
guessing. This method is very fast when used to check all short passwords, but
for longer passwords other methods such as the dictionary attack are used,
because of the time a brute-force search takes.
Password cracking
Password cracking is the process of recovering passwords from data that
has been stored in or transmitted by a computer system. Common approaches
include repeatedly trying guesses for the password, trying the most common
passwords by hand, and repeatedly trying passwords from a
"dictionary", or a text file with many passwords.
Packet analyzer
A packet analyzer ("packet sniffer") is an application that
captures data packets, which can be used to capture passwords and other data in
transit over the network.
Spoofing attack (phishing)
A spoofing attack involves one program, system or website that
successfully masquerades as another by falsifying data and is thereby treated
as a trusted system by a user or another program — usually to fool
programs, systems or users into revealing confidential information, such as
user names and passwords.
Rootkit
A rootkit is a program that uses low-level, hard-to-detect methods
to subvert control of an operating system from its legitimate operators.
Rootkits usually obscure their installation and attempt to prevent their
removal through a subversion of standard system security. They may include
replacements for system binaries, making it virtually impossible for them to be
detected by checking process tables.
Social engineering
In the
second stage of the targeting process, hackers often use Social engineering tactics to
get enough information to access the network. They may contact the system
administrator and pose as a user who cannot get access to his or her system.
This technique is portrayed in the 1995 film Hackers, when protagonist
Dade "Zero Cool" Murphy calls a somewhat clueless employee in charge
of security at a television network. Posing as an accountant working for the
same company, Dade tricks the employee into giving him the phone number of a
modem so he can gain access to the company's computer system.
Hackers who
use this technique must have cool personalities, and be familiar with their
target's security practices, in order to trick the system administrator into
giving them information. In some cases, a help-desk employee with limited
security experience will answer the phone and be relatively easy to trick.
Another approach is for the hacker to pose as an angry supervisor, and when
his/her authority is questioned, threaten to fire the help-desk worker. Social
engineering is very effective, because users are the most vulnerable part of an
organization. No security devices or programs can keep an organization safe if
an employee reveals a password to an unauthorized person.
Social
engineering can be broken down into four sub-groups:
·
Intimidation As in the "angry
supervisor" technique above, the hacker convinces the person who answers
the phone that their job is in danger unless they help them. At this point,
many people accept that the hacker is a supervisor and give them the
information they seek.
·
Helpfulness The opposite of intimidation,
helpfulness exploits many people's natural instinct to help others solve
problems. Rather than acting angry, the hacker acts distressed and concerned.
The help desk is the most vulnerable to this type of social engineering, as
(a.) its general purpose is to help people; and (b.) it usually has the authority
to change or reset passwords, which is exactly what the hacker wants.
·
Name-dropping The hacker uses names of
authorized users to convince the person who answers the phone that the hacker
is a legitimate user him or herself. Some of these names, such as those of
webpage owners or company officers, can easily be obtained online. Hackers have
also been known to obtain names by examining discarded documents (so-called "dumpster diving").
·
Technical Using technology is also a
way to get information. A hacker can send a fax or email to a legitimate user,
seeking a response that contains vital information. The hacker may claim that
he or she is involved in law enforcement and needs certain data for an
investigation, or for record-keeping purposes.
Trojan horses
A Trojan horse is a
program that seems to be doing one thing but is actually doing another. It can
be used to set up a back door in a computer system,
enabling the intruder to gain access later. (The name refers to the horse from the Trojan War, with the conceptually similar function of deceiving
defenders into bringing an intruder into a protected area.)
Computer virus
A virus is a self-replicating program that spreads by inserting
copies of itself into other executable code or documents. By doing this, it
behaves similarly to a biological virus, which spreads by inserting
itself into living cells. While some viruses are harmless or mere hoaxes, most
are considered malicious.
Computer worm
Like a
virus, a worm is also a self-replicating
program. It differs from a virus in that (a.) it propagates through computer
networks without user intervention; and (b.) does not need to attach itself to
an existing program. Nonetheless, many people use the terms "virus"
and "worm" interchangeably to describe any self-propagating program.
Keystroke logging
A keylogger is a tool designed to record ("log") every
keystroke on an affected machine for later retrieval, usually to allow the user
of this tool to gain access to confidential information typed on the affected
machine. Some keyloggers use virus-, trojan-, and rootkit-like methods to
conceal themselves. However, some of them are used for legitimate purposes,
even to enhance computer security. For example, a business may maintain a
keylogger on a computer used at a point of sale to detect evidence of employee fraud.
Tools and Procedures
A thorough
examination of hacker tools and procedures may be found in Cengage Learning's
E|CSA certification workbook.[20]
Notable intruders
and criminal hackers
Main article: List of computer criminals
Notable
security hackers
Main article: List of hackers
- Jacob Appelbaum is an advocate, security researcher, and developer for the Tor project. He speaks internationally for usage of Tor by human rights groups and others concerned about Internet anonymity and censorship.
- Rakshit Tandon is an prominent cyber security researcher from India with primary focus on combating online abuse of women and children.
- Eric Corley (also known as Emmanuel Goldstein) is the longstanding publisher of 2600: The Hacker Quarterly. He is also the founder of the Hackers on Planet Earth (HOPE) conferences. He has been part of the hacker community since the late 1970s.
- Ed Cummings (also known as Bernie S) is a longstanding writer for 2600: The Hacker Quarterly. In 1995, he was arrested and charged with possession of technology that could be used for fraudulent purposes, and set legal precedents after being denied both a bail hearing and a speedy trial.
- Dan Kaminsky is a DNS expert who exposed multiple flaws in the protocol and investigated Sony's rootkit security issues in 2005. He has spoken in front of the United States Senate on technology issues.
- Andrew Auernheimer, sentenced to 3 years in prison, is a grey hat hacker whose security group Goatse Security exposed a flaw in AT&T's iPad security.
- Gordon Lyon, known by the handle Fyodor, authored the Nmap Security Scanner as well as many network security books and web sites. He is a founding member of the Honeynet Project and Vice President of Computer Professionals for Social Responsibility.
- Gary McKinnon is a Scottish hacker facing extradition to the United States to face criminal charges. Many people in the UK have called on the authorities to be lenient with McKinnon, who suffers from Asperger syndrome.[21]
- Kevin Mitnick is a computer security consultant and author, formerly the most wanted computer criminal in United States history.[22]
- Rafael Núñez, a.k.a. RaFa, was a notorious hacker who was sought by the Federal Bureau of Investigation in 2001. He has since become a respected computer security consultant and an advocate of children's online safety.
- Meredith L. Patterson is a well-known technologist and biohacker who has presented research with Dan Kaminsky and Len Sassaman at many international security and hacker conferences.
- Len Sassaman was a Belgian computer programmer and technologist who was also a privacy advocate.
- Solar Designer is the pseudonym of the founder of the Openwall Project.
- Michał Zalewski (lcamtuf) is a prominent security researcher.
Customs
The computer underground[1] has produced its own specialized slang, such as 1337speak. Its
members often advocate freedom of information, strongly opposing the principles
of copyright, as well as the rights of free speech and privacy.[citation
needed] Writing software and performing other activities
to support these views is referred to as hacktivism. Some consider illegal cracking ethically justified for
these goals; a common form is website defacement. The
computer underground is frequently compared to the Wild West.[23] It is common for hackers to use aliases to conceal their
identities.
Hacker
groups and conventions
The computer underground is
supported by regular real-world gatherings called hacker conventions or "hacker cons". These events include SummerCon (Summer), DEF CON, HoHoCon (Christmas), ShmooCon (February), BlackHat, Chaos Communication Congress, AthCon,
Hacker Halted, and HOPE.[citation
needed] Local Hackfest groups organize and compete to
develop their skills to send a team to a prominent convention to compete in
group pentesting, exploit and forensics on a larger scale. Hacker groups became
popular in the early 1980s, providing access to hacking information and
resources and a place to learn from other members. Computer bulletin board systems (BBSs),
such as the Utopias, provided platforms for information-sharing via dial-up
modem. Hackers could also gain credibility by being affiliated with elite
groups.[24]
Consequences
for malicious hacking
India
|
Section
|
Offence
|
Punishment
|
|
65
|
Tampering with computer
source documents – Intentional concealment, destruction or alteration
of source code when the computer source code is required to be kept or
maintained by law for the time being in force
|
Imprisonment up to three years, or/and with fine up to
2 lakh rupees
|
|
66
|
Hacking
|
Imprisonment up to three years, or/and with fine up to
5 lakh rupees
|
Netherlands
- Article 138ab of Wetboek van Strafrecht prohibits computervredebreuk, which is defined as intruding an automated work or a part thereof with intention and against the law. Intrusion is defined as access by means of:
- Defeating security measures
- By technical means
- By false signals or a false cryptographic key
- By the use of stolen usernames and passwords.
Maximum imprisonment is one
year or a fine of the fourth category.[25]
United
States
18 U.S.C. § 1030, more
commonly known as the Computer Fraud and Abuse Act, prohibits
unauthorized access or damage of "protected computers".
"Protected computers" are defined in 18 U.S.C. § 1030(e)(2) as:
- A computer exclusively for the use of a financial institution or the United States Government, or, in the case of a computer not exclusively for such use, used by or for a financial institution or the United States Government and the conduct constituting the offense affects that use by or for the financial institution or the Government.
- A computer which is used in or affecting interstate or foreign commerce or communication, including a computer located outside the United States that is used in a manner that affects interstate or foreign commerce or communication of the United States;
The maximum imprisonment or
fine for violations of the Computer Fraud and Abuse Act depends on the
severity of the violation and the offender's history of violations under the Act.
Hacking and
the media
|
|
This section is in a list format that may be better
presented using prose. You can help by converting
this section to prose, if appropriate. Editing help is available. (August 2008)
|
Hacker
magazines
Main category: Hacker magazines
The most notable
hacker-oriented print publications are Phrack, Hakin9 and 2600: The Hacker Quarterly. While the
information contained in hacker magazines and ezines was often
outdated by the time they were published, they enhanced their contributors'
reputations by documenting their successes.[24]
Hackers in
fiction
See also: List of fictional hackers
Hackers often show an interest
in fictional cyberpunk and cyberculture literature and movies. The adoption of fictional pseudonyms,[26] symbols, values and metaphors from these works is very common.[27]
Copyright
From Wikipedia, the free encyclopedia
"Copyrighting"
and "Copyrights" redirect here. For the use of words to promote or
advertise, see Copywriting. For the Wikipedia policy about copyright issues,
see Wikipedia:Copyrights.
Copyright is a legal right created by the law of a country
that grants the creator of an original work exclusive rights to its use and distribution, usually for a limited
time. The exclusive rights are not absolute; they are limited by limitations and exceptions to copyright law, including fair use.
Copyright
is a form of intellectual
property, applicable to any expressed representation of a
creative work. It is often shared among multiple authors, each of whom holds a
set of rights to use or license the work, and who are commonly referred to as rightsholders.[1] These
rights frequently include reproduction, control over derivative works, distribution, public performance, and "moral rights" such as attribution.[2]
Copyrights
are territorial, which means that they do not extend beyond the
territory of a specific state unless that state is a party to an international
agreement. While many aspects of national copyright laws have been standardized
through international copyright agreements, copyright laws of most countries have some unique features.[3]
Typically,
the duration of copyright is the author's life plus 50 to 100 years
(that is, copyright typically expires 50 to 100 years after the author dies,
depending on the country). Some countries require certain copyright formalities to establishing copyright, but most recognize
copyright in any completed work, without formal registration. Generally,
copyright is enforced as a civil matter, though some jurisdictions do apply criminal sanctions.
Most
jurisdictions recognize copyright limitations, allowing "fair" exceptions
to the creator's exclusivity of copyright and giving users certain rights. The
development of digital media and computer network technologies have prompted
reinterpretation of these exceptions, introduced new difficulties in enforcing
copyright, and inspired additional challenges to copyright law's philosophic
basis. Simultaneously, businesses with great economic dependence upon
copyright, such as those in the music business, have advocated the extension
and expansion of their intellectual property rights and sought additional legal
and technological enforcement.
Contents
- 1 Justification
- 2 History
- 3 Scope
- 4 Obtaining and enforcing copyright
- 4.1 Cost of enforcing copyright
- 4.2 Copyright notices in the United States
- 4.3 "Poor man's copyright"
- 5 Exclusive rights
- 6 Limitations and exceptions to copyright
- 6.1 Idea–expression dichotomy and the merger doctrine
- 6.2 The first-sale doctrine and exhaustion of rights
- 6.3 Fair use and fair dealing
- 6.4 Accessible copies
- 7 Transfer and licensing, and assignment
- 8 Duration
- 9 Copyright infringement
- 10 See also
- 11 References
- 12 Further reading
- 13 External links
Justification
Main article: Philosophy of copyright
The usual justification of
copyright is to enable creators of intellectual wealth to financially support
themselves and give them a motive to continue publishing their creations. With
copyright in place, the author of a book or the photographer of a photograph
can charge users who want to get a copy of their creations and thus support
themselves. Before copyright, authors generally requested a large-sum one-off
payment from the printer of their book before publishing it. Artists could
publish a small subset of their creations and then request payment before they
published more (also see the street performer protocol). With
copyright in place, and assuming efficient enforcement, authors, photographers
and other intellectual workers can publish their creations immediately and wait
for licensing requests from people who want to use or re-publish their works.
Examples of this model for funding photography are Alamy, Corbis, Getty Images, and other stock photography image banks).[citation
needed]
Copyright critics claim copyright law protects corporate interests
while criminalizing legitimate uses, while proponents argue the law is fair and
just, protecting the interest of the creator.[4]
History
Main article: History of copyright law
See also: Statute of Anne, Copyright law
of the United States, International
copyright agreements, Berne Convention for the Protection of Literary and Artistic Works and Agreement on Trade-Related Aspects of Intellectual Property Rights
Copyright came about with the
invention of the printing press and with
wider literacy. As a legal concept, its origins in Britain were from a reaction
to printers' monopolies at the beginning of the 18th century. Charles II of England was
concerned by the unregulated copying of books and passed the Licensing of
the Press Act 1662 by Act of Parliament,[5] which established a register of licensed books and
required a copy to be deposited with the Stationers' Company, essentially continuing the licensing of material
that had long been in effect.
The British Statute of Anne (1710) further alluded to individual rights of the
artist. It began, "Whereas Printers, Booksellers, and other Persons, have
of late frequently taken the Liberty of Printing... Books, and other Writings,
without the Consent of the Authors... to their very great Detriment, and too
often to the Ruin of them and their Families:".[6] A right to benefit financially from the work is
articulated, and court rulings and legislation have recognized a right to
control the work, such as ensuring that the integrity of it is preserved. An
irrevocable right to be recognized as the work's creator appears in some
countries' copyright laws.
Copyright laws allow products
of creative human activities, such as literary and artistic production, to be
preferentially exploited and thus incentivized. Different cultural attitudes,
social organizations, economic models and legal frameworks are seen to account
for why copyright emerged in Europe and not, for example, in Asia. In the Middle Ages in Europe, there was generally a lack of any concept of
literary property due to the general relations of production, the specific
organization of literary production and the role of culture in society. The
latter refers to the tendency of oral societies, such as that of Europe in the
medieval period, to view knowledge as the product and expression of the
collective, rather than to see it as individual property. However, with
copyright laws, intellectual production comes to be seen as a product of an
individual, with attendant rights. The most significant point is that patent
and copyright laws support the expansion of the range of creative human activities
that can be commodified. This parallels the ways in which capitalism led to the commodification of many aspects of social
life that earlier had no monetary or economic value per se.[7]
The Statute of Anne was the first real copyright act, and gave the
publishers rights for a fixed period, after which the copyright expired.[8] Copyright has grown from a legal concept regulating
copying rights in the publishing of books and maps to one with a significant
effect on nearly every modern industry, covering such items as sound
recordings, films, photographs, software, and architectural works.
Prior to the passage of the United States Constitution, several
states passed their own copyright laws between 1783 and 1787, the first being Connecticut.[9] Contemporary scholars and patriots such as Noah Webster, John Trumbull (poet), and Joel Barlow were instrumental in securing the passage of these
statutes.[9]
The Copyright Act of 1790 in the Columbian Centinel.
The Copyright Clause of the United States Constitution (1787)
authorized copyright legislation: "To promote the Progress of Science and
useful Arts, by securing for limited Times to Authors and Inventors the
exclusive Right to their respective Writings and Discoveries." That is, by
guaranteeing them a period of time in which they alone could profit from
their works, they would be enabled and encouraged to invest the time required
to create them, and this would be good for society as a whole. A right to
profit from the work has been the philosophical underpinning for much legislation
extending the duration of copyright, to the life of the creator and beyond, to
their heirs.
The original length of
copyright in the United States was 14 years, and it had to be explicitly
applied for. If the author wished, they could apply for a second 14‑year
monopoly grant, but after that the work entered the public domain, so it could be used and built upon by others.
Thomas Jefferson, who strongly advocated the ability of the public to
share and build upon the works of others, proposed as part of the Bill of
Rights that a short timespan be protected:
Art. 9.
Monopolies may be allowed to persons for their own productions in literature
and their own inventions in the arts for a term not exceeding – years but
for no longer term and no other purpose.[10]
The Pirate Publisher—An International Burlesque that has
the Longest Run on Record, from Puck, 1886, satirizes the then-existing situation where a
publisher could profit by simply stealing newly published works from one
country, and publishing them in another, and vice versa.
Copyright law was enacted
rather late in German states, and the
historian Eckhard Höffner argues that the absence of copyright laws in the
early 19th century encouraged publishing, was profitable for authors, led to a
proliferation of books, enhanced knowledge, and was ultimately an important
factor in the ascendency of Germany as a power during that century.[11]
The 1886 Berne Convention first established recognition of copyrights among sovereign nations, rather than merely bilaterally. Under the Berne
Convention, copyrights for creative works do not have to be asserted or declared, as they are
automatically in force at creation: an author need not "register" or
"apply for" a copyright in countries adhering to the Berne
Convention.[12] As soon as a work is "fixed", that is, written
or recorded on some physical medium, its author is automatically entitled to
all copyrights in the work, and to any derivative works unless and until the
author explicitly disclaims them, or until the copyright expires. The Berne
Convention also resulted in foreign authors being treated equivalently to
domestic authors, in any country signed onto the Convention. The UK signed the
Berne Convention in 1887 but did not implement large parts of it until 100 years
later with the passage of the Copyright, Designs and Patents Act of 1988.
The United States did not sign the Berne Convention until 1989.[13]
The United States and most Latin American countries instead entered into the Buenos Aires Convention in 1910,
which required a copyright notice on the work (such as all rights reserved), and
permitted signatory nations to limit the duration of copyrights to shorter and
renewable terms.[14][15][16] The Universal
Copyright Convention was drafted in 1952 as another less demanding
alternative to the Berne Convention, and ratified by nations such as the Soviet Union and developing nations.
The regulations of the Berne Convention are incorporated into the World Trade Organization's TRIPS agreement (1995), thus giving the Berne Convention
effectively near-global application.[17] The 2002 WIPO Copyright Treaty enacted greater restrictions on the use of
technology to copy works in the nations that ratified it.
Scope
Copyright may apply to a wide
range of creative, intellectual, or artistic forms, or "works".
Specifics vary by jurisdiction, but these can include poems, theses, plays and other literary works, motion
pictures, choreography, musical compositions, sound recordings, paintings, drawings, sculptures, photographs, computer software, radio and television broadcasts, and industrial designs. Graphic designs and industrial designs may have separate or overlapping
laws applied to them in some jurisdictions.[18][19]
Copyright does not cover ideas
and information themselves, only the form or manner in which they are
expressed.[20] For example, the copyright to a Mickey Mouse cartoon restricts others from making copies of the
cartoon or creating derivative works based on Disney's particular anthropomorphic mouse, but does not prohibit the creation of other works
about anthropomorphic mice in general, so long as they are different enough to
not be judged copies of Disney's.[20] Note additionally that Mickey Mouse is not copyrighted
because characters cannot be copyrighted[citation
needed]; rather, Steamboat Willie is copyrighted and Mickey Mouse, as a character in that
copyrighted work, is afforded protection.
In many jurisdictions,
copyright law makes exceptions to these restrictions when the work is copied
for the purpose of commentary or other related uses (See fair use, fair dealing). It should be noted that US copyright does NOT cover
names, title, short phrases or Listings (such as ingredients, recipes, labels,
or formulas).[21] However there are protections available for those areas
copyright does not cover – such as trademarks and patents.
Copyright laws are
standardized somewhat through international conventions such as the Berne Convention and Universal
Copyright Convention. These multilateral treaties have been ratified by
nearly all countries, and international organizations such as the
European Union or World Trade Organization require
their member states to comply with them.
Obtaining
and enforcing copyright
A copyright certificate for proof of the Fermat theorem,
issued by the State Department of Intellectual Property of Ukraine.
Typically, a work must meet minimal standards of
originality in order to qualify for copyright, and the copyright
expires after a set period of time (some jurisdictions may allow this to be
extended). Different countries impose different tests, although generally the
requirements are low; in the United Kingdom there has to be some 'skill, labour, and judgment' that
has gone into it.[22] In Australia and the United Kingdom it has been held that a single
word is insufficient to comprise a copyright work. However, single words or a
short string of words can sometimes be registered as a trademark instead.
Copyright law recognizes the
right of an author based on whether the work actually is an original creation,
rather than based on whether it is unique; two authors may own copyright on two
substantially identical works, if it is determined that the duplication was
coincidental, and neither was copied from the other.
In all countries where the Berne Convention standards apply, copyright is automatic, and need not be
obtained through official registration with any government office. Once an idea
has been reduced to tangible form, for example by securing it in a fixed medium
(such as a drawing, sheet music, photograph, a videotape, or a computer file),
the copyright holder is entitled to enforce his or her exclusive rights.[12] However, while registration isn't needed to exercise
copyright, in jurisdictions where the laws provide for registration, it serves
as prima facie evidence of a valid copyright and enables the copyright
holder to seek statutory
damages and attorney's fees. (In the USA, registering after
an infringement only enables one to receive actual damages and lost profits.)
The original holder of the
copyright may be the employer of the author rather than the author
himself, if the work is a "work for hire".[23] For example, in English law the Copyright, Designs and Patents Act 1988
provides that if a copyrighted work is made by an employee in the course of
that employment, the copyright is automatically owned by the employer which
would be a "Work for Hire."
Copyrights are generally
enforced by the holder in a civil law court, but there are also
criminal infringement statutes in some jurisdictions. While central registries are kept in
some countries which aid in proving claims of ownership, registering does not
necessarily prove ownership, nor does the fact of copying (even without
permission) necessarily prove that copyright was infringed. Criminal sanctions are
generally aimed at serious counterfeiting activity, but are now becoming more
commonplace as copyright collectives such as the RIAA are
increasingly targeting the file sharing home Internet user. Thus far, however, most such cases
against file sharers have been settled out of court. (See: Legal aspects of file sharing)
Cost of
enforcing copyright
In most jurisdictions the
copyright holder must bear the cost of enforcing copyright. This will usually
involve engaging legal representation, administrative and or court costs. These
costs, including time, should be taken into consideration when evaluating the
benefits of enforcing copyright. In light of this, many copyright disputes are
settled by a direct approach to the infringing party in order to settle the
dispute out of court.
Copyright
notices in the United States
A copyright symbol used in copyright notice.
Before 1989, the use of a
copyright notice – consisting of the copyright symbol (©, the letter C inside a circle), the
abbreviation "Copr.", or the word "Copyright", followed by
the year of the first publication of the work and the name of the copyright
holder – was part of U. S. statutory requirements.[24][25] Several years may be noted if the work has gone through
substantial revisions. The proper copyright notice for sound recordings of
musical or other audio works is a sound
recording copyright symbol (℗, the
letter P inside a circle), which indicates a sound recording
copyright, with the letter P indicating a "phonorecord".
Similarly, the phrase All rights reserved was once
required to assert copyright.
In 1989 the United States
enacted the Berne Convention Implementation Act, amending the 1976 Copyright Act
to conform to most of the provisions of the Berne Convention. As a result, the
use of copyright notices has become optional to claim copyright, because the
Berne Convention makes copyright automatic.[26] However, the lack of notice of copyright using these
marks may have consequences in terms of reduced damages in an infringement
lawsuit – using notices of this form may reduce the likelihood of a
defense of "innocent infringement" being successful.[27]
"Poor
man's copyright"
Main article: Poor man's copyright
A widely circulated strategy
to avoid the cost of copyright registration is referred to as the "poor
man's copyright". It proposes that the creator send the work to himself in
a sealed envelope by registered mail, using the postmark to establish the date. This technique has not been
recognized in any published opinions of the United States courts. The United
States Copyright Office makes it clear that the technique is no substitute for
actual registration.[28] The United Kingdom Intellectual Property Office
discusses the technique and notes that the technique (as well as commercial
registries) does not constitute dispositive proof that the work is original nor
who the creator of the work is.[29][30]
Exclusive
rights
Several exclusive rights
typically attach to the holder of a copyright:
- to produce copies or reproductions of the work and to sell those copies (including, typically, electronic copies)
- to import or export the work
- to create derivative works (works that adapt the original work)
- to perform or display the work publicly
- to sell or cede these rights to others
- to transmit or display by radio or video.[31]
The phrase "exclusive
right" means that only the copyright holder is free to exercise those
rights, and others are prohibited from using the work without the holder's
permission. Copyright is sometimes called a "negative right", as it
serves to prohibit certain people (e.g., readers, viewers, or listeners,
and primarily publishers and would be publishers) from doing something they
would otherwise be able to do, rather than permitting people (e.g.,
authors) to do something they would otherwise be unable to do. In this way it
is similar to the unregistered design right in English law and European law. The rights of the copyright holder also permit him/her
to not use or exploit their copyright, for some or all of the term.
There is, however, a critique which rejects this assertion as being based on a philosophical interpretation of copyright law that is not
universally shared. There is also debate on whether copyright should be
considered a property right or a moral right.[32]
Useful
articles
If a pictorial, graphic or
sculptural work is a useful article, it is copyrighted only if its aesthetic
features are separable from its utilitarian features. A useful article is an
article having an intrinsic utilitarian function that is not merely to portray
the appearance of the article or to convey information. They must be separable
from the functional aspect to be copyrighted.[33]
Limitations
and exceptions to copyright
Main article: Limitations
and exceptions to copyright
Idea–expression
dichotomy and the merger doctrine
Main article: Idea–expression divide
The idea–expression divide
differentiates between ideas and expression, and states that copyright protects
only the original expression of ideas, and not the ideas themselves. This
principle, first clarified in the 1879 case of Baker v. Selden, has since been codified by the Copyright Act of 1976 at 17
U.S.C. § 102(b).
The
first-sale doctrine and exhaustion of rights
Copyright law does not
restrict the owner of a copy from reselling legitimately obtained copies of
copyrighted works, provided that those copies were originally produced by or
with the permission of the copyright holder. It is therefore legal, for
example, to resell a copyrighted book or CD. In the United States this is known as the first-sale doctrine, and was
established by the courts to clarify the legality of
reselling books in second-hand bookstores. Some countries may have parallel importation
restrictions that allow the copyright holder to control the aftermarket. This may
mean for example that a copy of a book that does not infringe copyright in the
country where it was printed does infringe copyright in a country into
which it is imported for retailing. The first-sale doctrine is known as exhaustion of rights in other
countries and is a principle which also applies, though somewhat differently,
to patent and trademark rights. It is important to note that the first-sale
doctrine permits the transfer of the particular legitimate copy involved. It
does not permit making or distributing additional copies.
In addition, copyright, in
most cases, does not prohibit one from acts such as modifying, defacing, or
destroying his or her own legitimately obtained copy of a copyrighted work, so
long as duplication is not involved. However, in countries that implement moral rights, a
copyright holder can in some cases successfully prevent the mutilation or
destruction of a work that is publicly visible.
Fair use and
fair dealing
Copyright does not prohibit
all copying or replication. In the United States, the fair use doctrine, codified by the Copyright Act
of 1976 as 17 U.S.C. Section 107, permits some copying and
distribution without permission of the copyright holder or payment to same. The
statute does not clearly define fair use, but instead gives four non-exclusive
factors to consider in a fair use analysis. Those factors are:
- the purpose and character of one's use
- the nature of the copyrighted work
- what amount and proportion of the whole work was taken, and
- the effect of the use upon the potential market for or value of the copyrighted work.[34]
In the United Kingdom and many other Commonwealth countries, a similar notion
of fair dealing was established by the courts or through legislation. The concept is sometimes not well defined; however in Canada, private
copying for personal use has been expressly permitted by statute since 1999. In
Alberta (Education) v. Canadian Copyright Licensing Agency (Access
Copyright), 2012 SCC 37, the Supreme Court of Canada concluded
that limited copying for educational purposes could also be justified under the
fair dealing exemption. In Australia, the fair dealing exceptions under the Copyright
Act 1968 (Cth) are a limited set of circumstances under which copyrighted
material can be legally copied or adapted without the copyright holder's
consent. Fair dealing uses are research and study; review and critique; news
reportage and the giving of professional advice (i.e. legal advice). Under current Australian law it is still a breach of copyright to copy, reproduce or
adapt copyright material for personal or private use without permission from
the copyright owner. Other technical exemptions from infringement may also
apply, such as the temporary reproduction of a work in machine readable form
for a computer.
In the United States the AHRA
(Audio Home Recording Act Codified in
Section 10, 1992) prohibits action against consumers making noncommercial
recordings of music, in return for royalties on both media and devices plus
mandatory copy-control mechanisms on recorders.
Section
1008. Prohibition on certain infringement actions
No action
may be brought under this title alleging infringement of copyright based on the
manufacture, importation, or distribution of a digital audio recording device,
a digital audio recording medium, an analog recording device, or an analog
recording medium, or based on the noncommercial use by a consumer of such a
device or medium for making digital musical recordings or analog musical
recordings.
Later acts amended US
Copyright law so that for certain purposes making 10 copies or more is
construed to be commercial, but there is no general rule permitting such
copying. Indeed making one complete copy of a work, or in many cases using a
portion of it, for commercial purposes will not be considered fair use. The Digital
Millennium Copyright Act prohibits the manufacture, importation, or
distribution of devices whose intended use, or only significant commercial use,
is to bypass an access or copy control put in place by a copyright owner.[18] An appellate court has held that fair use is not a
defense to engaging in such distribution.
Accessible
copies
It is legal in several
countries including the United Kingdom and the United States to produce alternative versions (for example, in large
print or braille) of a copyrighted work to provide improved access to a work
for blind and visually impaired persons without permission from the copyright
holder.[35][36]
Transfer and
licensing, and assignment
See also: Collective rights management, extended collective licensing, Compulsory license and Copyright transfer agreement
A copyright, or aspects of it,
may be assigned or transferred from one party to another.[37] For example, a musician who records an album will often
sign an agreement with a record company in which the musician agrees to
transfer all copyright in the recordings in exchange for royalties and other
considerations. The creator (and original copyright holder) benefits, or
expects to, from production and marketing capabilities far beyond those of the
author. In the digital age of music, music may be copied and distributed at
minimal cost through the Internet, however the record industry attempts to provide promotion and marketing for the
artist and his or her work so it can reach a much larger audience. A copyright
holder need not transfer all rights completely, though many publishers will
insist. Some of the rights may be transferred, or else the copyright holder may
grant another party a non-exclusive license to copy and/or distribute the work
in a particular region or for a specified period of time.
A transfer or licence may have
to meet particular formal requirements in order to be effective,[38] for example under the Australian Copyright Act 1968 the
copyright itself must be expressly transferred in writing. Under the U.S.
Copyright Act, a transfer of ownership in copyright must be memorialized in a
writing signed by the transferor. For that purpose, ownership in copyright
includes exclusive licenses of rights. Thus exclusive licenses, to be
effective, must be granted in a written instrument signed by the grantor. No
special form of transfer or grant is required. A simple document that
identifies the work involved and the rights being granted is sufficient.
Non-exclusive grants (often called non-exclusive licenses) need not be in
writing under U.S. law. They can
be oral or even implied by the behavior of the parties. Transfers of copyright
ownership, including exclusive licenses, may and should be recorded in the U.S.
Copyright Office. (Information on recording transfers is available on the
Office's web site.) While recording is not required to make the grant
effective, it offers important benefits, much like those obtained by recording
a deed in a real estate transaction.
Copyright may also be licensed.[37] Some jurisdictions may provide that certain classes of
copyrighted works be made available under a prescribed statutory license (e.g. musical works in the United States used for radio
broadcast or performance). This is also called a compulsory license, because
under this scheme, anyone who wishes to copy a covered work does not need the
permission of the copyright holder, but instead merely files the proper notice
and pays a set fee established by statute (or by an agency decision under
statutory guidance) for every copy made.[39] Failure to follow the proper procedures would place the
copier at risk of an infringement suit. Because of the difficulty of following
every individual work, copyright collectives or collecting societies and performing
rights organizations (such as ASCAP, BMI, and SESAC) have been
formed to collect royalties for hundreds (thousands and more) works at once.
Though this market solution bypasses the statutory license, the availability of
the statutory fee still helps dictate the price per work collective rights organizations
charge, driving it down to what avoidance of procedural hassle would justify.
Free
licences
There are a large number of free licenses, where users are granted several rights; for example,
those mentioned in the Free Software Definition, Open Source Definition, Debian Free
Software Guidelines or Definition of
Free Cultural Works. Examples of free licences are the GNU General Public License, BSD license and some Creative Commons licenses.
Founded in 2001, by James Boyle, Lawrence Lessig, and Hal Abelson the Creative Commons (CC) is a non-profit organization[40] which aims to facilitate the legal sharing of creative
works. To this end, the organization provides a number of copyright license
options to the public, free of charge. These licenses allow copyright holders
to define conditions under which others may use a work and to specify what
types of use are acceptable.[40]
Terms of use have
traditionally been negotiated on an individual basis between copyright holder
and potential licensee. Therefore, a general CC license outlining which rights
the copyright holder is willing to waive enables the general public to use such
works more freely. Six general types of CC licenses are available. These are
based upon copyright holder stipulations such as whether he or she is willing
to allow modifications to the work, whether he or she permits the creation of
derivative works and whether he or she is willing to permit commercial use of
the work.[41] As of 2009 approximately 130 million individuals had
received such licenses.[41]
Duration
Copyright
term
Expansion of U.S. copyright law (Assuming authors create
their works at age 35 and live for seventy years).
Copyright subsists for a
variety of lengths in different jurisdictions. The length of the term can
depend on several factors, including the type of work (e.g. musical
composition, novel), whether the work has been published, and whether the work was created by an individual or a
corporation. In most of the world, the default length of copyright is the life
of the author plus either 50 or 70 years. In the United States, the term for
most existing works is a fixed number of years after the date of creation or
publication. Under most countries' laws (for example, the United States[42] and the United Kingdom[43]), copyrights expire at the end of the calendar year in
question.
The length and requirements
for copyright duration are subject to change by legislation, and since the
early 20th century there have been a number of adjustments made in various
countries, which can make determining the duration of a given copyright
somewhat difficult. For example, the United States used to require copyrights
to be renewed after 28 years to stay in force, and formerly required a
copyright notice upon first publication to gain coverage. In Italy and France,
there were post-wartime extensions that could increase the term by
approximately 6 years in Italy and up to about 14 in France. Many countries
have extended the length of their copyright terms (sometimes retroactively).
International treaties establish minimum terms for copyrights, but individual
countries may enforce longer terms than those.[44]
In the United States, all
books and other works published before 1923 have expired copyrights and are in
the public domain.[45] In addition, works published before 1964 that did not
have their copyrights renewed 28 years after first publication year also are in
the public domain. Hirtle points out that the great majority of these works
(including 93% of the books) were not renewed after 28 years and are in the
public domain.[46] Books originally published outside the US by
non-Americans are exempt from this renewal requirement, if they are still under
copyright in their home country.
But if the intended
exploitation of the work includes publication (or distribution of derivative
work, such as a film based on a book protected by copyright) outside the U.S.,
the terms of copyright around the world must be considered. If the author has
been dead more than 70 years, the work is in the public domain in most, but not
all, countries.
In 1998, the length of a
copyright in the United States was increased by 20 years under the Copyright Term Extension Act. This
legislation was strongly promoted by corporations which had valuable copyrights
which otherwise would have expired, and has been the subject of substantial
criticism on this point.[47]
As a curiosity, the famous
work Peter Pan, or The Boy Who Wouldn't Grow Up has a
complex – and disputed – story of copyright expiry.[48]
Public
domain
Main article: Public domain
Copyright, like other intellectual property rights, is subject
to a statutorily determined term. Once the term of a copyright has expired, the
formerly copyrighted work enters the public domain and may be freely used or
exploited by anyone. Courts in common law countries, such as the United States
and the United Kingdom, have rejected the doctrine of a common law copyright. Public
domain works should not be confused with works that are publicly available.
Works posted in the internet, for example, are publicly
available, but are not generally in the public domain. Copying such works may
therefore violate the author's copyright.
Copyright
infringement
Main article: Copyright infringement
For a work to be considered to
infringe upon copyright, its use must have occurred in a nation that has
domestic copyright laws and/or adheres to a bilateral treaty or established
international convention such as the Berne Convention or WIPO Copyright Treaty. Improper use of materials outside of legislation
is deemed "unauthorized edition", not copyright infringement.[49]
Copyright infringement most
often occurs to software, film and music. However, infringement upon books and
other text works remains common, especially for educational reasons. Statistics
regarding the effects of copyright infringement are difficult to determine.
Studies have attempted to determine whether there is a monetary loss for
industries affected by copyright infringement by predicting what portion of
pirated works would have been formally purchased if they had not been freely
available.[50] Other reports indicate that copyright infringement does
not have an adverse effect on the entertainment industry, and can have a
positive effect.[51] In particular, a 2014 University study concluded that
free music content, accessed on YouTube, does not necessarily hurt sales,
instead has the potential to increase sales.[52]
Copyright
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Introduction
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The Copyright Act, 1957 came
into effect from January 1958. This Act has been amended five times since
then, i.e., in 1983, 1984, 1992, 1994, 1999 and 2012. The Copyright
(Amendment) Act, 2012 is the most substantial. The main reasons for
amendments to the Copyright Act, 1957 include to bring the Act in conformity
with WCT and WPPT; to protect the Music and Film Industry and address its
concerns; to address the concerns of the physically disabled and to protect
the interests of the author of any work; Incidental changes; to remove
operational facilities; and enforcement of rights. Some of the important
amendments to the Copyright Act in 2012 are extension of copyright protection
in the digital environment such as penalties for circumvention of
technological protection measures and rights management information, and
liability of internet service provider and introduction of statutory licences
for cover versions and broadcasting organizations; ensuring right to receive
royalties for authors, and music composers, exclusive economic and moral
rights to performers, equal membership rights in copyright societies for
authors and other right owners and exception of copyrights for physically
disabled to access any works.
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