Computer Operating System Notes PDF Download
OPERATING SYSTEM
An
Operating System (OS) can be defined as the system software that helps in
managing the resources of a computer as well as provides a platform for the
application programs running in the computer. In other words, the operating
system acts as an interface b/w the computer and its application programs. Some
of the popular operating systems include MS DOS, MS Windows and UNIX.
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Types of Operating Systems
Depending
on the characteristics of operating system, they can be categorized into the
following types :
·
Batch operating system : This is the earliest operating system, where only
one program is allowed to run at one time. We cannot modify any data used by the program
while it is being run. If an error is encountered, it means starting the
program from scratch all over again. A popular batch operating system is MS
DOS.
·
Interactive operating system : This operating system comes after
the batch operating system, where also only one program can run at one time.
However, here, modification and entry of data are allowed while the program is
running. An example of an interactive operating system is Multics (Multiplexed Information and
Computing Service).
·
Multiuser operating system : A multiuser operating system allows
more than one user to use a computer system either at the same time or at
different times. Example of multiuser operating systems include Linux and Windows 2000.
·
Multi-tasking operating system : a multi-tasking operating system
allows more than one program to run at the same time. Examples of multi-tasking
operating systems include Unix and Windows 2000.
·
Multithreading Operating System : A multithreading operating system
allows the running of different parts of a program at the same time. Examples
of multithreading operating system include UNIX and LINUX.
MS DOS Operating System
MS-DOS stands
for Microsoft Disk Operating System) is an operating
system for x86-based personal
computers mostly developed by Microsoft.
Collectively, MS-DOS, its rebranding as IBM
PC DOS, and some operating systems attempting to be compatible with
MS-DOS, are sometimes referred to as "DOS" (which is also the generic
acronym for disk operating system). MS-DOS was the main operating
system for IBM PC compatible personal computers during
the 1980s, from which point it was gradually superseded by operating systems
offering a graphical user interface (GUI),
in various generations of the graphical Microsoft
Windows operating system.
IBM licensed and re-released it in 1981, as PC DOS 1.0
for use in its PCs. Although MS-DOS and PC DOS were initially developed in
parallel by Microsoft and IBM, the two products diverged after twelve years, in
1993, with recognizable differences in compatibility, syntax, and capabilities.
During its lifetime, several competing products were
released for the x86 platform, and MS-DOS went through
eight versions, until development ceased in 2000.[6] Initially,
MS-DOS was targeted at Intel
8086 processors running on computer hardware using floppy
disks to store and access not only the operating system, but
application software and user data as well. Progressive version releases
delivered support for other mass storage media in ever greater sizes and
formats, along with added feature support for newer processors and rapidly
evolving computer architectures. Ultimately, it was the key product in
Microsoft's development from a programming language company to a diverse
software development firm, providing the company with essential revenue and
marketing resources. It was also the underlying basic operating system on which
early versions of Windows ran as a GUI. It is a flexible operating system, and
consumes negligible installation space.
List of all DOS Commands.
1) Date Command
This command is used to change or/and
display current system date.
C:\>DATE /t
Sun 03/04/2012
C:\>DATE
The current date is: Sun 03/04/2012
Enter the new date: (mm-dd-yy) 04-05-2013
2) TIME Command
This command is used to change or/and
display current system time.
C:\>TIME /t
02:48 AM
C:\>TIME
The current time is: 2:48:47.32
Enter the new time: 06:10:00
3) VER Command
This command is used to display the
window's version.
C:\>ver
Microsoft Windows [Version 6.1.7600]
4) VOL Command
This command is used to display the
disk volume level or serial number.
C:\>vol d:
Volume in drive D is SOFTWARE
Volume Serial Number is 147C-DA89
5) LABEL Command
This command is used to create, update
and delete the serial number of particular disk.
C:\>LABEL D:
Volume in drive D: is SOFTWARE
Volume Serial Number is 147C-DA89
Volume label (32 characters, ENTER for none)? IMP_DOCUMENTS
6) ECHO Command
This command is used to display message on command
screen, and also turn on/off command-echoing.
Command syntax is :
C:\> ECHO [ON|OFF]
C:\> ECHO [MESSAGE]
C:\>ECHO "https://www.includehelp.com"
"https://www.includehelp.com"
C:\>ECHO OFF
DATE/T
Sun 03/04/2012
ECHO ON
C:\>
7) PROMPT Command
This command is used to change the command prompt.
Switches:
$A - & (Ampersand)
$B - | (pipe)
$C - ( (Left parenthesis)
$D - Current date
$E - Escape code (ASCII code 27)
$F - ) (Right parenthesis)
$G - > (greater-than sign)
$H - Backspace (erases
previous character)
$L - < (less-than sign)
$N - Current drive
$P - Current drive and path
$Q - = (equal sign)
$S - (space)
$T - Current time
$$ - $ dollar sign
C:\>prompt "includehelp.com"
"includehelp.com"DATE/t
Sun 03/04/2012
"includehelp.com"PROMPT $p$g
C:\>
8) TITLE Command
This command is used to change the title of MS DOS
screen.
C:\>TITLE includehelp.com
9) MKDIR/MD Command
MKDIR/MD command is used to
create directory in particular drive.
Command syntax is :
C:\> MKDIR [drive]:\[Directory_Name]
C:\> MKDIR [Directory_Name]
* If you do not enter path [drive or directory],
directory will make in current working drive/directory.
1. C:\>MKDIR D:\Tutorial
2. C:\>MKDIR Tutorial
3. C:\>MKDIR D:\Folder1\Folder2\Folder3
Explanation
1. Directory will create into D: drive
2. Directory will create into C: drive.
3. You can also create directories using sub-direcories, here 3 directories will be created . Folder1 will be created in D: drive then Folder2 will be in Folder1 and Folder3 will be in Folder2.
2. Directory will create into C: drive.
3. You can also create directories using sub-direcories, here 3 directories will be created . Folder1 will be created in D: drive then Folder2 will be in Folder1 and Folder3 will be in Folder2.
10) CHDIR/CD Command
CHDIR/CD command is used to
change current working direcory.
Command syntax is :
C:\> CHDIR [drive]:\[Directory_Name]
C:\> CHDIR [Directory_Name]
11) CD..
and CD\ Command
CD.. command is used to exit from
current working directory.
CD\ command is used to exit from all directories and reaches to current drive.
CD\ command is used to exit from all directories and reaches to current drive.
Command syntax is :
[Current_working_drive\direcotries..\> CD..
[Current_working_drive\direcotries..\> CD\
1. C:\>d:
2. d:\>cd tutorial
3. d:\Tutorial>cd..
4. d:\>cd
folder1\folder2\folder3
5. d:\Folder1\Folder2\Folder3>cd\
6. d:\>cd folder1\folder2
7. d:\Folder1\Folder2>cd\
8. d:\>
Explanation
1: Change current drive C: to D: drive.
2: Open tutorial directory .
3: Current working dir. is"D:\tutorial> ", CD.. - exit from tutorial directory.
4: Open folder3 directory. (folder3 exits in "D:\folder1\folder2" No need to write D:\ because current working directory is D:).
5: Current working directory is "folder3". CD\ - exit from all directories.
6: Open folder2 directory .(folder2 is exists in "D:\folder1").
7: Current working directory is "folder2". CD\ - exit from all directories.
2: Open tutorial directory .
3: Current working dir. is"D:\tutorial> ", CD.. - exit from tutorial directory.
4: Open folder3 directory. (folder3 exits in "D:\folder1\folder2" No need to write D:\ because current working directory is D:).
5: Current working directory is "folder3". CD\ - exit from all directories.
6: Open folder2 directory .(folder2 is exists in "D:\folder1").
7: Current working directory is "folder2". CD\ - exit from all directories.
12) COPY
CON
COPY CON command is used to
create a text file.
Command syntax is :
C:\>COPY CON [file_name]
Your text will goes here....
^Z (CTRL+Z) OR F6 .. (to save file)
C:\>COPY CON about_us.txt
includehelp.com provides online tutorials .
^Z
C:\>
13) TYPE Command
TYPE command is used to
display file.
Command syntax is :
C:\> TYPE [FILE_PATH]
C:\>TYPE about_us.txt
includehelp.com provides online tutorials .
C:\>
14) EDIT Command
EDIT command is used to
open DOS Editor to create,display, modify files.
Switches
/B - To open black and white mode.
/R - To open file in read only mode.
Switches
/B - To open black and white mode.
/R - To open file in read only mode.
Command syntax is :
C:\>EDIT [/B|/R] [FILE_PATH]
1. C:\>Edit
2. C:\>Edit/B about_us.txt
3. C:\>Edit/R about_us.txt
4. C:\>Edit about_us.txt
Explanation
1: Opens DOS Editor.
2: Opens about_us.txt file in black and white dos editor.
3: Opens about_us.txt file in read only mode.
4: Open about_us.txt file in colored screen.
2: Opens about_us.txt file in black and white dos editor.
3: Opens about_us.txt file in read only mode.
4: Open about_us.txt file in colored screen.
15) DIR Command
DIR command is used to
displays a list of files and subdirectories in a directory.
Switches
/A Attribute wise filtering ..
R : Read only files.
D : Directories only.
H : Hidden items only.
S : System files only.
-D: Files only
/B Uses bare format (no heading
information or summary).
/C Display the thousand separator
in file sizes. This is the default.
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Use /-C to disable display of
separator.
/D Same as wide but files are
list sorted by column.
/L Uses lowercase.
/N New long list format where
filenames are on the far right.
/O List by files in sorted
order.)
S: Size wise sorting.
N: Name wise.
D: Date wise.
E: Extension wise sorting.
/P Pauses after each screenful of
information.
/Q Display the owner of the file.
/S Displays files in specified
directory and all subdirectories.
/T Control what time field
displayed or used for sorting
timefield C Creation,
A Last Access,
W Last Written
/W Uses wide list format.
Command syntax is :
DIR [drive:][path][filename] [/A[[:]attributes]] [/B] [/C] [/D] [/L]...
DIR [drive:][path][filename] [/A[[:]attributes]] [/B] [/C] [/D] [/L]...
1) C:\> DIR D:
(display all directories
and files of d: drive).
2) Using "A" attribute:-
C:\> DIR/AD D:
(display direcotries
(folders) only of d: drive).
C:\> DIR/A-D D:
(display only files of d:
drive).
C:\> DIR/AH D:
(display all hidden items
of d: drive).
3) C:\> DIR/A-D/AR D:
(display all files(only)
with read only property).
Using wild characters:
1) To find all .txt (text) file from d:\folder1
C:\>DIR D:\folder1\*.txt
2) To display all .docx (ms word files) starting with "A" filename.
C:\>DIR D:\folder1\A*.docx
3) To display all files of E: drive starting with "A" but third character of file name must be "C" (of any type/extension).
C:\>DIR D:\A?C*.*
4) To display all files with all extenstions of E:\.
C:\>DIR E:\*.*
1) To find all .txt (text) file from d:\folder1
C:\>DIR D:\folder1\*.txt
2) To display all .docx (ms word files) starting with "A" filename.
C:\>DIR D:\folder1\A*.docx
3) To display all files of E: drive starting with "A" but third character of file name must be "C" (of any type/extension).
C:\>DIR D:\A?C*.*
4) To display all files with all extenstions of E:\.
C:\>DIR E:\*.*
16) TREE Command
This command is used to display files and sub
directories of particular directory.
Switches
F : Displays the name of the files in each folder.
A : Use ASCII instead of extended characters.
Switches
F : Displays the name of the files in each folder.
A : Use ASCII instead of extended characters.
Command syntax is :
C:\>TREE/[SWITCH] [DRIVE:]\[DIRECTORY]
C:\>TREE D:\test
Folder PATH listing for volume iHelp's
Personal Data
Volume serial number is 00000002 147C:DA89
D:\TEST
├───folder1
├───folder2
│ └───SubFolder1
│ ├───SubFolderA
│ └───SubFolderB
└───folder3
C:\>
C:\>TREE/F D:\test
Folder PATH listing for volume iHelp's
Personal Data
Volume serial number is 00000002 147C:DA89
D:\TEST
│ file1.txt
│ file2.txt
│
├───folder1
├───folder2
│ │ file-A.txt
│ │ file-B.txt
│ │
│ └───SubFolder1
│ │ t.txt
│ │
│ ├───SubFolderA
│ └───SubFolderB
└───folder3
C:\>
17) DEL/ERASE Command
DEL/ERASE command is used
to delete one or more than one file at a time.
Command syntax is :
C:\> Del [/Switch] [File Path]
Following switches can be use with this
command.
1. /P : Display the
confirmation message.
2. /F : Force deleting
of read only files.
3. /A : Select file to
delete based on attributes :
o
S : System files
o
R : read only files
o
H : Hidden files
o
A : ready for archiving
C:\>ERASE/P D:\includehelp.txt
D:\includehelp.txt, Delete (Y/N)? y
Explanation : above command will delete
includehelp.txt file from D:\ drive, with confirmation message
"D:\includehelp.txt, Delete (Y/N) ? " Press Y to delete..
1) C:\> Del MyFile.Txt
2) C:\> Del/AH *.jpg
3) C:\> Del
D:\Ram\Shyam\F1.Doc
Explanation
1) Delete MyFile.txt from C drive.
2) Delete all hidden files with extension .jpg( JPEG image files).
3) Delete F1.Doc from D:\Ram\Shyam folder..
2) Delete all hidden files with extension .jpg( JPEG image files).
3) Delete F1.Doc from D:\Ram\Shyam folder..
18) RM/RMDIR Command
This command is used to removes (deletes) a
directory (folder).
Command syntax is :
C:\> RD [/Switch] [Path]
Following switches can be use with this
command.
- /S :
Removes all directories and files in the specified directory in addition
to the directory itself. Used to remove a directory tree.
- /Q :
Quiet mode, do not ask if ok to remove a directory tree with /S.
1. C:\>TREE d:\examples
2. Folder PATH listing for
volume Mike's Personal Data
3. Volume serial number is
00000002 147C:DA89
4. D:\EXAMPLES
5. ├───include
6. │ └───Debug
7. └───loop_Ex
8. C:\>RD/S d:\examples
9. d:\examples, Are you sure
(Y/N)? y
10. C:\>
Explanation
1. Command to display d:\examples directory.
8. Command to delete d:\examples directory.
9. Confirmation message to delete ...
8. Command to delete d:\examples directory.
9. Confirmation message to delete ...
19) SHUTDOWN Command
Shutdown command is used
to shuts down the window.
Switches
/S Shuts down the window. /F Forcely shut down the
window. /C Display dialog with comment and then shutdown. /T Shutdown time in
XX seconds. /A Abort the shutdown command. /I To display GUI window for remote
shutdown.
1) C:\> SHUTDOWN -S
2) C:\> SHUTDOWN -F
3) C:\> SHUTDOWN -S -C "Windows is shutting down due to
virus.."
4) C:\> SHUTDOWN -S -T 30
5) C:\> SHUTDOWN -A
6) C:\> SHUTDOWN -I
MS Windows Operating System
Microsoft Windows, commonly referred to as Windows,
is a group of several proprietary graphical operating
system families, all of which are developed and marketed by Microsoft. Each
family caters to a certain sector of the computing industry. Active Microsoft
Windows families include Windows
NT and Windows
IoT; these may encompass subfamilies, e.g. Windows
Server or Windows Embedded Compact (Windows
CE). Defunct Microsoft Windows families include Windows
9x, Windows
Mobile and Windows
Phone.
Microsoft introduced an operating environment named Windows on
November 20, 1985, as a graphical operating system shell for MS-DOS in
response to the growing interest in graphical user interfaces (GUIs). Microsoft
Windows came to dominate the world's personal
computer (PC) market with over 90% market share,
overtaking Mac OS, which had been introduced in 1984. Apple came
to see Windows as an unfair encroachment on their innovation in GUI development
as implemented on products such as the Lisa and Macintosh (eventually
settled in court in Microsoft's favor in 1993). On PCs, Windows is still the
most popular operating system. However, in 2014, Microsoft admitted losing the
majority of the overall operating system market to Android, because of the massive
growth in sales of Android smartphones. In
2014, the number of Windows devices sold was less than 25% that of Android
devices sold. This comparison, however, may not be fully relevant, as the two
operating systems traditionally target different platforms. Still, numbers for
server use of Windows (that are comparable to competitors) show one third
market share, similar to that for end user use.
As of February 2020, the most recent version of Windows for
PCs, tablets and embedded
devices is Windows
10. The most recent version for server computers is Windows
Server, version 1909. A specialized version of Windows also
runs on the Xbox One video game console.
Microsoft, the
developer of Windows, has registered several trademarks, each of which denote a
family of Windows operating systems that target a specific sector of the
computing industry. As of 2014, the following Windows families were being
actively developed:
·
Windows
NT: Started as a family of operating systems with Windows
NT 3.1, an operating system for server computers and workstations. It now
consists of three operating system subfamilies that are released almost at the
same time and share the same kernel:
o Windows:
The operating system for mainstream personal computers, tablets and smartphones. The
latest version is Windows 10. The main competitor of this family is macOS by Apple for
personal computers and Android for mobile devices
(c.f. Usage share of operating systems
§ Market share by category).
o Windows
Server: The operating system for server computers. The latest version
is Windows Server 2019. Unlike its client sibling, it
has adopted a strong naming scheme. The main competitor of this family is Linux.
(c.f. Usage share of operating systems
§ Market share by category)
o Windows
PE: A lightweight version of its Windows sibling, meant to operate
as a live
operating system, used for installing Windows on bare-metal computers
(especially on many computers at once), recovery or troubleshooting purposes.
The latest version is Windows PE 10.
·
Windows
IoT (previously Windows Embedded): Initially, Microsoft
developed Windows CE as a general-purpose operating system
for every device that was too resource-limited to be called a full-fledged
computer. Eventually, however, Windows CE was renamed Windows Embedded Compact
and was folded under Windows Compact trademark which also consists of Windows Embedded Industry, Windows
Embedded Professional, Windows Embedded Standard, Windows Embedded Handheld and Windows Embedded Automotive.[7]
The following Windows families are no longer being developed:
·
Windows
9x: An operating system that targeted consumers market.
Discontinued because of suboptimal performance.[citation needed] (PC World called
its last version, Windows Me, one of the worst products of all time.)
Microsoft now caters to the consumer market with Windows NT.
·
Windows
Mobile: The predecessor to Windows Phone, it was a mobile phone
operating system. The first version was called Pocket PC
2000; the third version, Windows Mobile 2003 is the first version to
adopt the Windows Mobile trademark. The last version is Windows Mobile 6.5.
·
Windows
Phone: An operating system sold only to manufacturers of smartphones.
The first version was Windows
Phone 7, followed by Windows
Phone 8, and Windows
Phone 8.1. It was succeeded by Windows
10 Mobile, that is now also discontinued.
The term Windows collectively describes any or
all of several generations of Microsoft operating
system products. These products are generally categorized as
follows:
Early versions
The history of Windows dates back to 1981, when Microsoft
started work on a program called "Interface Manager". It was
announced in November 1983 (after the Apple
Lisa, but before the Macintosh) under
the name "Windows", but Windows
1.0 was not released until November 1985.[9] Windows
1.0 was to compete with Apple's
operating system, but achieved little popularity. Windows 1.0 is not a complete
operating system; rather, it extends MS-DOS. The
shell of Windows 1.0 is a program known as the MS-DOS
Executive. Components included Calculator, Calendar, Cardfile, Clipboard
viewer, Clock, Control Panel, Notepad, Paint, Reversi, Terminal and Write. Windows
1.0 does not allow overlapping windows. Instead all windows are tiled. Only modal dialog boxes may appear over other windows.
Microsoft sold as included Windows Development libraries with the C development
environment, which included numerous windows samples.[10]
Windows 2.0 was released in December 1987, and was
more popular than its predecessor. It features several improvements to the user
interface and memory management.[11] Windows
2.03 changed the OS from tiled windows to overlapping windows. The result of
this change led to Apple Computer filing a suit against Microsoft alleging
infringement on Apple's copyrights.[12][13] Windows
2.0 also introduced more sophisticated keyboard
shortcuts and could make use of expanded
memory.
Windows 2.1 was released in two different versions: Windows/286 and Windows/386.
Windows/386 uses the virtual
8086 mode of the Intel
80386 to multitask several DOS programs and the paged
memory model to emulate expanded memory using available extended
memory. Windows/286, in spite of its name, runs on both Intel
8086 and Intel
80286 processors. It runs in real mode but
can make use of the high
memory area.[citation needed]
In addition to full Windows-packages, there were runtime-only
versions that shipped with early Windows software from third parties and made
it possible to run their Windows software on MS-DOS and without the full
Windows feature set.
The early versions of Windows are often thought of as graphical
shells, mostly because they ran on top of MS-DOS and use it for file
system services.[14] However,
even the earliest Windows versions already assumed many typical operating
system functions; notably, having their own executable file format and providing their
own device drivers (timer, graphics, printer,
mouse, keyboard and sound). Unlike MS-DOS, Windows allowed users to execute
multiple graphical applications at the same time, through cooperative multitasking. Windows
implemented an elaborate, segment-based, software virtual memory scheme, which
allows it to run applications larger than available memory: code segments
and resources are swapped in and thrown away when
memory became scarce; data segments moved in memory when a given application
had relinquished processor control.
Windows 3.x
Windows 3.0, released in 1990, improved the design,
mostly because of virtual
memory and loadable virtual device drivers (VxDs)
that allow Windows to share arbitrary devices between multi-tasked DOS
applications.[citation needed] Windows
3.0 applications can run in protected
mode, which gives them access to several megabytes of memory without
the obligation to participate in the software virtual memory scheme. They run
inside the same address space, where the segmented memory provides a degree of
protection. Windows 3.0 also featured improvements to the user interface.
Microsoft rewrote critical operations from C into assembly. Windows
3.0 is the first Microsoft Windows version to achieve broad commercial success,
selling 2 million copies in the first six months.[15][16]
Windows 3.1, made generally available on
March 1, 1992, featured a facelift. In August 1993, Windows for Workgroups, a
special version with integrated peer-to-peer networking features and a version
number of 3.11, was released. It was sold along with Windows 3.1. Support for
Windows 3.1 ended on December 31, 2001.[17]
Windows 3.2, released 1994, is an updated version of the Chinese
version of Windows 3.1.[18] The
update was limited to this language version, as it fixed only issues related to
the complex writing system of the Chinese language.[19] Windows
3.2 was generally sold by computer manufacturers with a ten-disk version
of MS-DOS that
also had Simplified Chinese characters in
basic output and some translated utilities.
Windows 9x
The next major consumer-oriented release of Windows, Windows
95, was released on August 24, 1995. While still remaining
MS-DOS-based, Windows 95 introduced support for native 32-bit applications, plug and
play hardware, preemptive
multitasking, long file
names of up to 255 characters, and provided increased stability
over its predecessors. Windows 95 also introduced a redesigned, object oriented user interface, replacing
the previous Program Manager with the Start
menu, taskbar, and Windows
Explorer shell. Windows
95 was a major commercial success for Microsoft; Ina Fried of CNET remarked
that "by the time Windows 95 was finally ushered off the market in 2001,
it had become a fixture on computer desktops around the world."[20] Microsoft
published four OEM Service Releases (OSR) of Windows 95, each of which was
roughly equivalent to a service
pack. The first OSR of Windows 95 was also the first version of
Windows to be bundled with Microsoft's web
browser, Internet
Explorer.[21] Mainstream
support for Windows 95 ended on December 31, 2000, and extended support for
Windows 95 ended on December 31, 2001.[22]
Windows 95 was followed up with the release of Windows
98 on June 25, 1998, which introduced the Windows Driver Model, support for USB composite devices, support for ACPI, hibernation, and support for multi-monitor configurations.
Windows 98 also included integration with Internet Explorer 4 through Active
Desktop and other aspects of the Windows Desktop Update (a series of enhancements
to the Explorer shell which were also made available for Windows 95). In May
1999, Microsoft released Windows 98 Second Edition, an
updated version of Windows 98. Windows 98 SE added Internet Explorer 5.0 and Windows Media Player 6.2 amongst other upgrades.
Mainstream support for Windows 98 ended on June 30, 2002, and extended support
for Windows 98 ended on July 11, 2006.[23]
On September 14, 2000, Microsoft released Windows
Me (Millennium Edition), the last DOS-based version of
Windows. Windows Me incorporated visual interface enhancements from its Windows
NT-based counterpart Windows
2000, had faster boot times than previous versions (which however,
required the removal of the ability to access a real mode DOS
environment, removing compatibility with some older programs),[24] expanded multimedia functionality
(including Windows Media Player 7, Windows Movie Maker, and the Windows Image Acquisition framework
for retrieving images from scanners and digital cameras), additional system
utilities such as System File Protection and System
Restore, and updated home
networking tools.[25] However,
Windows Me was faced with criticism for its speed and instability, along with
hardware compatibility issues and its removal of real mode DOS support. PC World considered
Windows Me to be one of the worst operating systems Microsoft had ever
released, and the 4th worst tech product of all time.[8]
Windows NT
Early
versions (Windows NT 3.1/3.5/3.51/4.0/2000)
In November 1988, a new development team within Microsoft (which
included former Digital Equipment Corporation developers Dave
Cutler and Mark
Lucovsky) began work on a revamped version of IBM and
Microsoft's OS/2 operating system known as "NT OS/2". NT OS/2 was
intended to be a secure, multi-user operating
system with POSIX compatibility and a modular, portable kernel with preemptive
multitasking and support for multiple processor architectures.
However, following the successful release of Windows
3.0, the NT development team decided to rework the project to use
an extended 32-bit port of the Windows
API known as Win32 instead of those of OS/2. Win32 maintained
a similar structure to the Windows APIs (allowing
existing Windows applications to easily be ported to
the platform), but also supported the capabilities of the existing NT kernel.
Following its approval by Microsoft's staff, development continued on what was
now Windows NT, the first 32-bit version of Windows. However, IBM objected to
the changes, and ultimately continued OS/2 development on its own.[26][27]
The first release of the resulting operating system, Windows
NT 3.1 (named to associate it with Windows
3.1) was released in July 1993, with versions for desktop workstations and servers. Windows
NT 3.5 was released in September 1994, focusing on performance
improvements and support for Novell's NetWare, and was
followed up by Windows
NT 3.51 in May 1995, which included additional improvements and
support for the PowerPC architecture. Windows
NT 4.0 was released in June 1996, introducing the redesigned
interface of Windows 95 to the NT series. On February 17, 2000,
Microsoft released Windows
2000, a successor to NT 4.0. The Windows NT name was dropped at this
point in order to put a greater focus on the Windows brand.[27]
PDF Download Link https://drive.google.com/open?id=1Jy1_PE5EghbfgDH8qZXCI1WyuP-rEJKc
Windows XP
The next major version of Windows NT, Windows
XP, was released on October 25, 2001. The introduction of Windows
XP aimed to unify the consumer-oriented Windows
9x series with the architecture introduced by Windows NT, a
change which Microsoft promised would provide better performance over its
DOS-based predecessors. Windows XP would also introduce a redesigned user interface
(including an updated Start menu and a "task-oriented" Windows
Explorer), streamlined multimedia and networking features, Internet Explorer 6, integration with
Microsoft's .NET
Passport services, modes to help provide compatibility with
software designed for previous versions of Windows, and Remote Assistance functionality.[28]
At retail, Windows XP was now marketed in two main editions: the "Home" edition was targeted
towards consumers, while the "Professional" edition was targeted
towards business environments and power
users, and included additional security and networking features. Home
and Professional were later accompanied by the "Media Center" edition
(designed for home
theater PCs, with an emphasis on support for DVD playback, TV tuner
cards, DVR functionality, and remote controls), and the "Tablet
PC" edition (designed for mobile devices meeting its specifications for a tablet
computer, with support for stylus pen
input and additional pen-enabled applications).[29][30][31] Mainstream
support for Windows XP ended on April 14, 2009. Extended support ended on April
8, 2014.[32]
After Windows 2000, Microsoft also changed its release schedules
for server operating systems; the server counterpart of Windows XP, Windows Server 2003, was released in April 2003.[27] It
was followed in December 2005, by Windows Server 2003 R2.
Windows
Vista
After a lengthy development process, Windows
Vista was released on November 30, 2006, for volume licensing
and January 30, 2007, for consumers. It contained a number of new features, from a
redesigned shell and user interface to significant technical changes, with a
particular focus on security
features. It was available in a number of different editions, and has
been subject to some criticism, such as
drop of performance, longer boot time, criticism of new UAC, and stricter
license agreement. Vista's server counterpart, Windows Server 2008 was released in early 2008.
Windows 7
On July 22, 2009, Windows 7 and Windows Server 2008 R2 were released as RTM
(release to manufacturing) while the former was released to the public 3 months
later on October 22, 2009. Unlike its predecessor, Windows Vista, which
introduced a large number of new features, Windows
7 was intended to be a more focused, incremental upgrade to the Windows line,
with the goal of being compatible with applications and hardware with which Windows
Vista was already compatible.[33] Windows
7 has multi-touch support, a redesigned Windows
shell with an updated taskbar, a home
networking system called HomeGroup,[34] and
performance improvements.
Windows 8 and
8.1
Windows 8, the successor to Windows 7, was released
generally on October 26, 2012. A number of significant changes were made on
Windows 8, including the introduction of a user interface based around
Microsoft's Metro design language with optimizations
for touch-based devices such as tablets and
all-in-one PCs. These changes include the Start
screen, which uses large tiles that are more convenient for touch
interactions and allow for the display of continually updated information, and
a new class of apps which are designed primarily for use on touch-based
devices. The new Windows version required a minimum resolution of 1024×768
pixels,[35] effectively making it unfit
for netbooks with
800×600-pixel screens.
Other changes include increased integration with cloud
services and other online platforms (such as social networks and
Microsoft's own OneDrive (formerly SkyDrive) and Xbox Live services),
the Windows Store service for software
distribution, and a new variant known as Windows
RT for use on devices that utilize the ARM
architecture.[36][37][38][39][40][41] An
update to Windows 8, called Windows
8.1,[42] was
released on October 17, 2013, and includes features such as new live tile
sizes, deeper OneDrive integration, and many other
revisions. Windows 8 and Windows
8.1 have been subject to some criticism, such as removal of
the Start menu.
Windows 10
On September 30, 2014, Microsoft announced Windows
10 as the successor to Windows 8.1. It was released on July
29, 2015, and addresses shortcomings in the user interface first introduced
with Windows 8. Changes on PC include the return of the Start Menu, a virtual
desktop system, and the ability to run Windows Store apps within
windows on the desktop rather than in full-screen mode. Windows
10 is said to be available to update from qualified Windows 7 with
SP1, Windows 8.1 and Windows
Phone 8.1 devices from the Get Windows 10 Application (for Windows 7, Windows
8.1) or Windows
Update (Windows 7).[43]
In February 2017, Microsoft announced the migration of its
Windows source code repository from Perforce to Git. This
migration involved 3.5 million separate files in a 300 gigabyte
repository.[44] By
May 2017, 90 percent of its engineering team was using Git, in about 8500
commits and 1760 Windows builds per day.[44]
UNIX Operating System
Unixis a family of multitasking, multiuser computer operating
systems that derive from the original AT&T Unix,
development starting in the 1970s at the Bell Labs research
center by Ken Thompson, Dennis
Ritchie, and others.[3]
Initially intended for use inside the Bell
System, AT&T licensed Unix
to outside parties in the late 1970s, leading to a variety of both academic and
commercial Unix variants from vendors including University of California,
Berkeley (BSD), Microsoft (Xenix), IBM (AIX),
and Sun Microsystems (Solaris). In the early 1990s,
AT&T sold its rights in Unix to Novell, which
then sold its Unix business to the Santa Cruz Operation (SCO) in 1995.[4] The
UNIX trademark passed to The Open
Group, a neutral industry consortium, which allows the use of the
mark for certified operating systems that comply with the Single UNIX Specification (SUS).
Unix systems are characterized by a modular
design that is sometimes called the "Unix
philosophy". According to this philosophy, the operating system
should provide a set of simple tools, each of which performs a limited,
well-defined function.[5] A
unified filesystem (the Unix
filesystem) and an inter-process communication mechanism
known as "pipes" serve as the main means of communication,[3] and
a shell scripting and command language (the Unix
shell) is used to combine the tools to perform complex workflows.
Unix distinguishes itself from its predecessors as the
first portable operating system: almost the entire
operating system is written in the C programming language, which
allows Unix to operate on numerous platforms.[6]
Unix was originally meant to be a convenient platform for
programmers developing software to be run on it and on other systems, rather than
for non-programmers.[7][8] The
system grew larger as the operating system started spreading in academic
circles, and as users added their own tools to the system and shared them with
colleagues.[9]
At first, Unix was not designed to be portable[6] or
for multi-tasking.[10] Later,
Unix gradually gained portability, multi-tasking and multi-user capabilities
in a time-sharing configuration. Unix systems are
characterized by various concepts: the use of plain
text for storing data; a hierarchical file
system; treating devices and certain types of inter-process communication (IPC)
as files; and the use of a large number of software
tools, small programs that can be strung together through a command-line interpreter using pipes, as
opposed to using a single monolithic program that includes all of the same
functionality. These concepts are collectively known as the "Unix
philosophy". Brian
Kernighan and Rob Pike summarize
this in The Unix Programming Environment as
"the idea that the power of a system comes more from the relationships
among programs than from the programs themselves".[11]
In an era when a standard computer consisted of a hard disk for
storage and a data terminal for input and
output (I/O), the Unix file model worked quite well, as I/O was
generally linear. In the 1980s, non-blocking
I/O and the set of inter-process communication mechanisms
were augmented with Unix domain sockets, shared
memory, message
queues, and semaphores, as well as network
sockets to support communication with other hosts. As graphical
user interfaces developed, the file model proved inadequate to the task of
handling asynchronous events such as those generated by a mouse.
By the early 1980s, users began seeing Unix as a potential
universal operating system, suitable for computers of all sizes.[12][13] The
Unix environment and the client–server program
model were essential elements in the development of the Internet and
the reshaping of computing as centered in networks rather than in individual computers.
Both Unix and the C programming language were
developed by AT&T and distributed to government and academic institutions,
which led to both being ported to a wider variety of machine families than any
other operating system.
The Unix operating system consists of many libraries and
utilities along with the master control program, the kernel. The kernel provides services to
start and stop programs, handles the file system and
other common "low-level" tasks that most programs share, and
schedules access to avoid conflicts when programs try to access the same
resource or device simultaneously. To mediate such access, the kernel has
special rights, reflected in the distinction of kernel space from user
space, the latter being a priority realm where most application
programs operate.
The origins of Unix date back to the mid-1960s when the Massachusetts Institute of
Technology, Bell Labs, and General
Electric were developing Multics, a time-sharing operating
system for the GE-645 mainframe computer.[14] Multics
featured several innovations, but also presented severe
problems. Frustrated by the size and complexity of Multics, but not by its
goals, individual researchers at Bell Labs started withdrawing from the
project. The last to leave were Ken
Thompson, Dennis
Ritchie, Douglas
McIlroy, and Joe
Ossanna,[10] who
decided to reimplement their experiences in a new project of smaller scale.
This new operating system was initially without organizational backing, and
also without a name.
The new operating system was a single-tasking system.[10] In
1970, the group coined the name Unics for Uniplexed
Information and Computing Service (pronounced "eunuchs"),
as a pun on Multics, which stood for Multiplexed
Information and Computer Services. Brian
Kernighan takes credit for the idea, but adds that "no one can
remember" the origin of the final spelling Unix.[15] Dennis
Ritchie,[10] Doug McIlroy,[1] and Peter G.
Neumann[16] also
credit Kernighan.
The operating system was originally written in assembly
language, but in 1973, Version 4 Unix was rewritten in C.[10] Version
4 Unix, however, still had many PDP-11 dependent
codes, and was not suitable for porting. The first port to another platform was
made five years later (1978) for Interdata 8/32.[17]
Bell Labs produced several versions of Unix that are
collectively referred to as "Research
Unix". In 1975, the first source license for UNIX was
sold to Donald B. Gillies at the University of Illinois at
Urbana–Champaign Department of Computer Science.[18] UIUC
graduate student Greg Chesson, who had worked on the UNIX kernel at Bell Labs,
was instrumental in negotiating the terms of the license.[19]
During the late 1970s and early 1980s, the influence of Unix in
academic circles led to large-scale adoption of Unix (BSD and System V) by
commercial startups, including Sequent, HP-UX, Solaris, AIX, and Xenix. In the late 1980s,
AT&T Unix System Laboratories and Sun
Microsystems developed System V Release 4 (SVR4), which
was subsequently adopted by many commercial Unix vendors.
In the 1990s, Unix and Unix-like systems
grew in popularity and became the operating system of choice for over 90% of the world's top 500
fastest supercomputers,[20] as
BSD and Linux distributions
were developed through collaboration by a worldwide network of programmers. In
2000, Apple released Darwin, also a Unix system, which
became the core of the Mac OS X operating system, which was later renamed macOS.[21]
In the late 1980s, an open operating system standardization
effort now known as POSIX provided a common baseline for all operating
systems; IEEE based
POSIX around the common structure of the major competing variants of the Unix
system, publishing the first POSIX standard in 1988. In the early 1990s, a
separate but very similar effort was started by an industry consortium,
the Common Open Software Environment (COSE)
initiative, which eventually became the Single UNIX Specification (SUS)
administered by The Open
Group. Starting in 1998, the Open Group and IEEE started the Austin
Group, to provide a common definition of POSIX and the Single UNIX
Specification, which, by 2008, had become the Open Group Base Specification.
In 1999, in an effort towards compatibility, several Unix system
vendors agreed on SVR4's Executable and Linkable Format (ELF)
as the standard for binary and object code files. The common format allows
substantial binary compatibility among different Unix systems operating on the
same CPU architecture.
The Filesystem
Hierarchy Standard was created to provide a reference directory
layout for Unix-like operating systems; it has mainly been used in Linux.
The Unix system is composed of several components that were
originally packaged together. By including the development environment,
libraries, documents and the portable, modifiable source code for all of these
components, in addition to the kernel of an operating system,
Unix was a self-contained software system. This was one of the key reasons it
emerged as an important teaching and learning tool and has had such a broad
influence.[according
to whom?]
The inclusion of these components did not make the system
large – the original V7 UNIX distribution, consisting of copies of all of
the compiled binaries plus all of the source code and documentation occupied
less than 10 MB and arrived on a single nine-track magnetic tape. The
printed documentation, typeset from the online sources, was contained in two
volumes.
The names and filesystem locations of the Unix components have
changed substantially across the history of the system. Nonetheless, the V7
implementation is considered by many[who?] to
have the canonical early structure:
·
Kernel – source code in /usr/sys,
composed of several sub-components:
o conf –
configuration and machine-dependent parts, including boot code
o dev –
device drivers for control of hardware (and some pseudo-hardware)
o sys –
operating system "kernel", handling memory management, process
scheduling, system calls, etc.
o h –
header files, defining key structures within the system and important
system-specific invariables
·
Development environment –
early versions of Unix contained a development environment sufficient to
recreate the entire system from source code:
o as –
machine-language assembler for the machine
o ld –
linker, for combining object files
o lib –
object-code libraries (installed in /lib or /usr/lib). libc,
the system library with C run-time support, was the primary library, but there
have always been additional libraries for things such as mathematical functions
(libm) or database access. V7 Unix introduced
the first version of the modern "Standard I/O" library stdio as
part of the system library. Later implementations increased the number of
libraries significantly.
o include –
header files for software development, defining standard interfaces and system
invariants
o Other
languages – V7 Unix contained a Fortran-77 compiler, a programmable
arbitrary-precision calculator (bc, dc), and the awk scripting
language; later versions and implementations contain many other language
compilers and toolsets. Early BSD releases included Pascal tools, and many modern Unix
systems also include the GNU Compiler Collection as well as or instead of a
proprietary compiler system.
o Other
tools – including an object-code archive manager (ar),
symbol-table lister (nm), compiler-development tools (e.g. lex & yacc),
and debugging tools.
·
Commands – Unix makes little
distinction between commands (user-level programs) for system operation and
maintenance (e.g. cron), commands of
general utility (e.g. grep), and more general-purpose
applications such as the text formatting and typesetting package. Nonetheless,
some major categories are:
o sh –
the "shell" programmable command-line interpreter, the
primary user interface on Unix before window systems appeared, and even
afterward (within a "command window").
o Utilities –
the core toolkit of the Unix command set, including cp, ls, grep, find and
many others. Subcategories include:
§ User
utilities – environment management tools such as passwd, kill,
and others.
o Document
formatting – Unix systems were used from the outset for document
preparation and typesetting systems, and included many related programs such
as nroff, troff, tbl, eqn, refer,
and pic. Some modern Unix systems also include
packages such as TeX and Ghostscript.
o Graphics –
the plot subsystem provided facilities for producing simple
vector plots in a device-independent format, with device-specific interpreters
to display such files. Modern Unix systems also generally include X11 as
a standard windowing system and GUI, and
many support OpenGL.
o Communications –
early Unix systems contained no inter-system communication, but did include the
inter-user communication programs mail and write.
V7 introduced the early inter-system communication system UUCP, and
systems beginning with BSD release 4.1c included TCP/IP utilities.
·
Documentation –
Unix was the first[citation needed] operating
system to include all of its documentation online in machine-readable form. The
documentation included:
o doc –
longer documents detailing major subsystems, such as the C language and troff
The Unix system had a significant impact on other operating
systems. It achieved its reputation by its interactivity, by providing the
software at a nominal fee for educational use, by running on inexpensive
hardware, and by being easy to adapt and move to different machines. Unix was
originally written in assembly
language, but was soon rewritten in C, a high-level programming language.[23] Although
this followed the lead of Multics and Burroughs, it was Unix that popularized the idea.
Unix had a drastically simplified file model compared to many
contemporary operating systems: treating all kinds of files as simple byte
arrays. The file system hierarchy contained machine services and devices (such
as printers, terminals,
or disk drives), providing a uniform interface, but at the
expense of occasionally requiring additional mechanisms such as ioctl and
mode flags to access features of the hardware that did not fit the simple
"stream of bytes" model. The Plan 9 operating system pushed this model even further and
eliminated the need for additional mechanisms.
Unix also popularized the hierarchical file system with
arbitrarily nested subdirectories, originally introduced by Multics. Other
common operating systems of the era had ways to divide a storage device into
multiple directories or sections, but they had a fixed number of levels, often
only one level. Several major proprietary operating systems eventually added
recursive subdirectory capabilities also patterned after Multics. DEC's RSX-11M's
"group, user" hierarchy evolved into VMS directories, CP/M's
volumes evolved into MS-DOS 2.0+ subdirectories, and HP's MPE group.account
hierarchy and IBM's SSP and OS/400 library
systems were folded into broader POSIX file systems.
Making the command interpreter an ordinary user-level program,
with additional commands provided as separate programs, was another Multics
innovation popularized by Unix. The Unix
shell used the same language for interactive commands as for
scripting (shell scripts – there was no separate job
control language like IBM's JCL). Since the shell and OS commands were "just another
program", the user could choose (or even write) their own shell. New
commands could be added without changing the shell itself. Unix's innovative
command-line syntax for creating modular chains of producer-consumer processes
(pipelines) made a powerful programming paradigm (coroutines) widely available. Many later
command-line interpreters have been inspired by the Unix shell.
A fundamental simplifying assumption of Unix was its focus
on newline-delimited text
for nearly all file formats. There were no "binary" editors in the
original version of Unix – the entire system was configured using textual
shell command scripts. The common denominator in the I/O system was the
byte – unlike "record-based" file systems. The
focus on text for representing nearly everything made Unix pipes especially
useful and encouraged the development of simple, general tools that could be
easily combined to perform more complicated ad hoc tasks. The
focus on text and bytes made the system far more scalable and portable than
other systems. Over time, text-based applications have also proven popular in
application areas, such as printing languages (PostScript, ODF), and at
the application layer of the Internet protocols, e.g., FTP, SMTP, HTTP, SOAP,
and SIP.
Unix popularized a syntax for regular expressions that found widespread use.
The Unix programming interface became the basis for a widely implemented
operating system interface standard (POSIX, see above). The C programming language soon
spread beyond Unix, and is now ubiquitous in systems and applications
programming.
Early Unix developers were important in bringing the concepts
of modularity and reusability into software engineering practice, spawning a
"software tools" movement. Over time, the leading developers of Unix
(and programs that ran on it) established a set of cultural norms for
developing software, norms which became as important and influential as the
technology of Unix itself; this has been termed the Unix
philosophy.
The TCP/IP networking protocols were quickly
implemented on the Unix versions widely used on relatively inexpensive
computers, which contributed to the Internet explosion
of worldwide real-time connectivity, and which formed the basis for
implementations on many other platforms.
The Unix policy of extensive on-line documentation and (for many
years) ready access to all system source code raised programmer expectations,
and contributed to the launch of the free software movement in 1983.
In 1983, Richard
Stallman announced the GNU (short
for "GNU's Not Unix") project, an ambitious effort to create a free
software Unix-like system; "free" in the sense
that everyone who received a copy would be free to use, study, modify, and
redistribute it. The GNU project's own kernel development project, GNU Hurd, had not
yet produced a working kernel, but in 1991 Linus
Torvalds released the kernel Linux as
free software under the GNU General Public License. In
addition to their use in the GNU operating
system, many GNU packages – such as the GNU Compiler Collection (and the rest of the GNU
toolchain), the GNU C library and the GNU core
utilities – have gone on to play central roles in other free Unix
systems as well.
Linux distributions, consisting of the Linux kernel
and large collections of compatible software have become popular both with
individual users and in business. Popular distributions include Red Hat Enterprise Linux, Fedora, SUSE
Linux Enterprise, openSUSE, Debian GNU/Linux, Ubuntu, Linux
Mint, Mandriva Linux, Slackware
Linux, Arch Linux and Gentoo.[24]
A free derivative of BSD Unix, 386BSD, was
released in 1992 and led to the NetBSD and FreeBSD projects.
With the 1994 settlement of a lawsuit brought against the University of
California and Berkeley Software Design Inc. (USL v.
BSDi) by Unix System Laboratories, it was
clarified that Berkeley had the right to distribute BSD Unix for free if it so
desired. Since then, BSD Unix has been developed in several different product
branches, including OpenBSD and DragonFly BSD.
Linux and BSD are increasingly filling the market needs
traditionally served by proprietary Unix operating systems, as well as
expanding into new markets such as the consumer desktop and mobile and embedded
devices. Because of the modular design of the Unix model, sharing components is
relatively common; consequently, most or all Unix and Unix-like systems include
at least some BSD code, and some systems also include GNU utilities in their
distributions.
In a 1999 interview, Dennis Ritchie voiced his opinion that
Linux and BSD operating systems are a continuation of the basis of the Unix
design, and are derivatives of Unix:[25]
I think the Linux phenomenon is quite delightful, because it
draws so strongly on the basis that Unix provided. Linux seems to be the among
the healthiest of the direct Unix derivatives, though there are also the
various BSD systems as well as the more official offerings from the workstation
and mainframe manufacturers.
In the same interview, he states that he views both Unix and
Linux as "the continuation of ideas that were started by Ken and me and
many others, many years ago".[25]
OpenSolaris was the open-source counterpart
to Solaris developed by Sun
Microsystems, which included a CDDL-licensed
kernel and a primarily GNU userland. However, Oracle discontinued the project upon their acquisition of Sun,
which prompted a group of former Sun employees and members of the OpenSolaris
community to fork OpenSolaris into the illumos kernel. As of 2014, illumos
remains the only active open-source System V derivative.
ARPANET[edit]
In May 1975, RFC 681 described
the development of Network Unix by the Center for Advanced
Computation at the University of Illinois at
Urbana–Champaign. The system was said to "present several interesting
capabilities as an ARPANET mini-host". At the time Unix
required a license from Bell
Laboratories that at $20,000(US) was very expensive for non-university users,
while an educational license cost just $150. It was noted that Bell was
"open to suggestions" for an ARPANET-wide license.
Specific features found beneficial were the local processing
facilities, compilers, editors, a document
preparation system, efficient file system and access control, mountable and
unmountable volumes, unified treatment of peripherals as special files, integration of the network control program (NCP) within the Unix file
system, treatment of network connections as
special files that can be accessed through standard Unix I/O calls, closing
of all files on program exit, and the decision to be "desirable to
minimize the amount of code added to the basic Unix kernel".
In October 1993, Novell, the
company that owned the rights to the Unix System V source at the time,
transferred the trademarks of Unix to the X/Open Company
(now The Open Group),[26] and
in 1995 sold the related business operations to Santa Cruz Operation (SCO).[27] Whether
Novell also sold the copyrights to
the actual software was the subject of a federal lawsuit in 2006, SCO v.
Novell, which Novell won. The case was appealed, but on August 30,
2011, the United States Court of Appeals for the Tenth Circuit affirmed the
trial decisions, closing the case.[28] Unix
vendor SCO Group Inc. accused Novell of slander
of title.
The present owner of the trademark UNIX is The
Open Group, an industry standards consortium. Only systems fully compliant with
and certified to the Single UNIX Specification qualify
as "UNIX" (others are called "Unix-like").
By decree of The Open Group, the term "UNIX" refers
more to a class of operating systems than to a specific implementation of an
operating system; those operating systems which meet The Open Group's Single
UNIX Specification should be able to bear the UNIX 98 or UNIX 03 trademarks
today, after the operating system's vendor pays a substantial certification fee
and annual trademark royalties to The Open Group.[29] Systems
that have been licensed to use the UNIX trademark include AIX,[30] EulerOS,[31] HP-UX,[32] Inspur
K-UX,[33] IRIX,[34] Solaris,[35] Tru64
UNIX (formerly "Digital UNIX", or OSF/1) macOS, and
a part of z/OS.[38] Notably,
EulerOS and Inspur K-UX are Linux distributions certified as UNIX 03
compliant.
Sometimes a representation like Un*x, *NIX,
or *N?X is used to indicate all operating systems similar to
Unix. This comes from the use of the asterisk (*) and the question mark
characters as wildcard indicators in many utilities. This notation is also used
to describe other Unix-like systems that have not met the requirements for UNIX
branding from the Open Group.
The Open Group requests that UNIX is always
used as an adjective followed by a generic term such as system to
help avoid the creation of a genericized trademark.
Unix was the original formatting,[disputed discuss] but
the usage of UNIX remains widespread because it was once
typeset in small caps (Unix).
According to Dennis Ritchie, when presenting the original
Unix paper to the third Operating Systems Symposium of the American Association for Computing
Machinery (ACM), "we had a new typesetter and troff had
just been invented and we were intoxicated by being able to produce small
caps".[41] Many
of the operating system's predecessors and contemporaries used all-uppercase lettering,
so many people wrote the name in upper case due to force of habit. It is not an
acronym.
Trademark names can be registered by different entities in
different countries and trademark laws in some countries allow the same
trademark name to be controlled by two different entities if each entity uses
the trademark in easily distinguishable categories. The result is that Unix has
been used as a brand name for various products including bookshelves, ink pens,
bottled glue, diapers, hair driers and food containers.
PDF Download Link https://drive.google.com/open?id=1Jy1_PE5EghbfgDH8qZXCI1WyuP-rEJKc
Several plural forms of Unix are used casually to refer to
multiple brands of Unix and Unix-like systems. Most common is the
conventional Unixes, but Unices, treating Unix as
a Latin noun
of the third declension, is also popular. The pseudo-Anglo-Saxon plural form Unixen is
not common, although occasionally seen. Sun
Microsystems, developer of the Solaris variant, has asserted that the
term Unix is itself plural, referencing its many
implementations.[4
