1.
RT-11
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RT-11 is a discontinued small, single-user real-time operating system for the Digital Equipment Corporation PDP-11 family of 16-bit computers. RT-11 was first implemented in 1970 and was used for real-time systems, process control. RT-11 systems did not support preemptive multitasking, but most versions could run multiple simultaneous applications, all variants of the monitors provided a background job. The FB, XM and ZM monitors also provided a foreground job and these tasks had fixed priorities, with the background job lowest and the foreground job highest. It was possible to switch jobs from the system console user interface, and SYSGEN could generate a monitor that provided a single background job. RT-11 was written in assembly language, developers documentation included a kernel listing that included comments. In RT-11, device drivers were loadable, except that prior to V4.0 the device driver for the device was built into the kernel at configuration time. Because RT-11 was commonly used for control and data acquisition. A third-party favorite was the Tektronix 4010 family, the Keyboard Monitor interpreted commands issued by the user and would invoke various utilities with Command String Interpreter forms of the commands. RT-11 command language had many features that can be later in DOS line of operating systems which heavily borrowed from RT-11. The CSI form expected input and output filenames and options in a precise order, the command-line switches were separated by / sign rather than - used in Unix-like operating systems. All commands had full form and a one to which it could be contracted. For example, RENAME command could be contracted to REN, batch files and the batch processor could be used to issue a series of commands with some rudimentary control flow. In later releases of RT-11, it was possible to invoke a series of using a. COM command file. Even later, it was possible to execute a series of commands with great control through use of the Indirect Command File Processor, files with the extension. SAV were a sort of executables. The SAVE command, along with GET, START, REENTER, EXAMINE, some commands and utilities were later borrowed in DOS-line of operating systems. These commands include DIR, COPY, RENAME, ASSIGN, CLS, DELETE, TYPE, HELP, FORMAT command was used for physical disk formatting, although it was not capable of creating file system, for which purpose INIT command was used. Most commands supported use of wildcards in file names, physical device names were specified in the form dd, where dd was a two-character alphabetic device name and the optional n was the unit number
2.
VT100
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The VT100 is a video terminal, introduced in August 1978 by Digital Equipment Corporation. This led to rapid uptake of the ANSI standard, becoming the de facto standard for terminal emulators, the VT100s, especially the VT102, was extremely successful in the market, and made DEC the leading terminal vendor. The VT100 series was replaced by the VT200 series starting in 1983, ultimately, over six million terminals in the VT series would be sold, based largely on the success of the VT100s. DECs first successful video terminal was the VT50, introduced in 1974, the VT52 featured a text display with 80 columns and 24 rows, bidirectional scrolling, and a custom control language that allowed the cursor to be moved about the screen. The VT100 was introduced in August 1978, replacing the VT50/VT52 family, like the earlier models, it communicated with its host system over serial lines at a speed selectable between 50 and 19,200 bit/s. Basic improvements on the VT52 included a 132 column mode, and a variety of graphic renditions including blinking, bolding, reverse video, the VT100 also introduced an additional box-drawing character set containing various pseudographics that allowed the drawing of on-screen forms. All setup of the VT100 was accomplished using interactive displays presented on the screen, maintainability was also significantly improved since a VT100 could be disassembled quickly without use of tools. The major change within the system was the control system, unlike the VT50/52s proprietary language, the VT100 were based on the emerging ANSI X3.64 standard for command codes. At the time, computer vendors suggested that the standard was beyond the state of the art, the introduction of low-cost microprocessors and the ever-falling cost of computer memory addressed these problems, and the VT100 used the new Intel 8080 as its internal driver. In addition, the VT100 provided backwards compatibility for VT52 users, in 1983, the VT100 was replaced by the more-powerful VT200 series terminals such as the VT220. The VT100 was the first of Digitals terminals to be based on an industry-standard microprocessor, options could be added to the terminal to support an external printer, additional graphic renditions, and more memory. The later option, known as Advanced Video Option or AVO, the VT100 became a platform on which Digital constructed related products. The VT101 and VT102 were cost-reduced, non-expandable follow-on versions, the VT101 was essentially a base-model VT100, while the VT102 came standard with the AVO and serial printer port options pre-installed. The VT105 contained a simple graphics subsystem known as waveform graphics which was compatible with same system in the earlier VT55. This system allowed two mathematical functions to be drawn to the screen on top of the text display, allowing text and graphics to be mixed to produce charts. The VT100 form factor left significant room in the case for expansion, the VT180 added a single-board microcomputer using a Zilog Z80 to run CP/M. The VT278 added a PDP-8 processor, allowing the terminal to run Digitals WPS-8 word processing software, notes DEC video terminal history VT100 user guide VT100 Series Technical Manual ECMA-48 The DEC category at the Terminals Wiki
3.
Computing
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Computing is any goal-oriented activity requiring, benefiting from, or creating a mathematical sequence of steps known as an algorithm — e. g. through computers. The field of computing includes computer engineering, software engineering, computer science, information systems, the ACM Computing Curricula 2005 defined computing as follows, In a general way, we can define computing to mean any goal-oriented activity requiring, benefiting from, or creating computers. For example, an information systems specialist will view computing somewhat differently from a software engineer, regardless of the context, doing computing well can be complicated and difficult. Because society needs people to do computing well, we must think of computing not only as a profession, the fundamental question underlying all computing is What can be automated. The term computing is also synonymous with counting and calculating, in earlier times, it was used in reference to the action performed by mechanical computing machines, and before that, to human computers. Computing is intimately tied to the representation of numbers, but long before abstractions like the number arose, there were mathematical concepts to serve the purposes of civilization. These concepts include one-to-one correspondence, comparison to a standard, the earliest known tool for use in computation was the abacus, and it was thought to have been invented in Babylon circa 2400 BC. Its original style of usage was by lines drawn in sand with pebbles, abaci, of a more modern design, are still used as calculation tools today. This was the first known computer and most advanced system of calculation known to date - preceding Greek methods by 2,000 years. The first recorded idea of using electronics for computing was the 1931 paper The Use of Thyratrons for High Speed Automatic Counting of Physical Phenomena by C. E. Wynn-Williams. Claude Shannons 1938 paper A Symbolic Analysis of Relay and Switching Circuits then introduced the idea of using electronics for Boolean algebraic operations, a computer is a machine that manipulates data according to a set of instructions called a computer program. The program has a form that the computer can use directly to execute the instructions. The same program in its source code form, enables a programmer to study. Because the instructions can be carried out in different types of computers, the execution process carries out the instructions in a computer program. Instructions express the computations performed by the computer and they trigger sequences of simple actions on the executing machine. Those actions produce effects according to the semantics of the instructions, computer software or just software, is a collection of computer programs and related data that provides the instructions for telling a computer what to do and how to do it. Software refers to one or more programs and data held in the storage of the computer for some purposes. In other words, software is a set of programs, procedures, algorithms, program software performs the function of the program it implements, either by directly providing instructions to the computer hardware or by serving as input to another piece of software
4.
OpenVMS
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OpenVMS is a computer operating system for use in general-purpose computing. It is the successor to the VMS Operating System, that was produced by Digital Equipment Corporation, in the 1990s, it was used for the successor series of DEC Alpha systems. OpenVMS also runs on the HP Itanium-based families of computers, as of 2015, a port to the X86-64 architecture is underway. The name VMS is derived from virtual memory system, according to one of its architectural features. OpenVMS is a operating system, but source code listings are available for purchase. OpenVMS is a multi-user, multiprocessing virtual memory-based operating system designed for use in time sharing, batch processing, when process priorities are suitably adjusted, it may approach real-time operating system characteristics. The system offers high availability through clustering and the ability to distribute the system over multiple physical machines and this allows the system to be tolerant against disasters that may disable individual data-processing facilities. OpenVMS contains a user interface, a feature that was not available on the original VAX-11/VMS system. Versions of VMS running on DEC Alpha workstations in the 1990s supported OpenGL, customers using OpenVMS include banks and financial services, hospitals and healthcare, network information services, and large-scale industrial manufacturers of various products. As of mid-2014, Hewlett Packard licensed the development of OpenVMS exclusively to VMS Software Inc, VMS Software will be responsible for developing OpenVMS, supporting existing hardware and providing roadmap to clients. The company has a team of developers that originally developed the software during DECs ownership. In April 1975, Digital Equipment Corporation embarked on a project, code named Star. A companion software project, code named Starlet, was started in June 1975 to develop a new operating system, based on RSX-11M. These two projects were integrated from the beginning. Gordon Bell was the VP lead on the VAX hardware and its architecture, the Star and Starlet projects culminated in the VAX 11/780 computer and the VAX-11/VMS operating system. The Starlet name survived in VMS as a name of several of the system libraries, including STARLET. OLB. Over the years the name of the product has changed, in 1980 it was renamed, with version 2.0 release, to VAX/VMS. g. The smallest MicroVAX2000 had a 40MB RD32 hard disk and a maximum of 6MB of RAM, microVMS kits were released for VAX/VMS4.4 to 4.7 on TK50 tapes and RX50 floppy disks, but discontinued with VAX/VMS5.0
5.
CP/M
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Initially confined to single-tasking on 8-bit processors and no more than 64 kilobytes of memory, later versions of CP/M added multi-user variations and were migrated to 16-bit processors. The combination of CP/M and S-100 bus computers was loosely patterned on the MITS Altair and this computer platform was widely used in business through the late 1970s and into the mid-1980s. CP/M increased the size for both hardware and software by greatly reducing the amount of programming required to install an application on a new manufacturers computer. An important driver of innovation was the advent of low-cost microcomputers running CP/M, as independent programmers and hackers bought them. CP/M was displaced by MS-DOS soon after the 1981 introduction of the IBM PC, manufacturers of CP/M-compatible systems customized portions of the operating system for their own combination of installed memory, disk drives, and console devices. CP/M would also run on based on the Zilog Z80 processor since the Z80 was compatible with 8080 code. CP/M used the 7-bit ASCII set, the other 128 characters made possible by the 8-bit byte were not standardized. For example, one Kaypro used them for Greek characters, WordStar used the 8th bit as an end-of-word marker. The BIOS and BDOS were memory-resident, while the CCP was memory-resident unless overwritten by an application, a number of transient commands for standard utilities were also provided. The transient commands resided in files with the extension. COM on disk, the BIOS directly controlled hardware components other than the CPU and main memory. It contained functions such as input and output and the reading and writing of disk sectors. The BDOS implemented the CP/M file system and some input/output abstractions on top of the BIOS, the CCP took user commands and either executed them directly or loaded and started an executable file of the given name. Third-party applications for CP/M were also essentially transient commands, the BDOS, CCP and standard transient commands were the same in all installations of a particular revision of CP/M, but the BIOS portion was always adapted to the particular hardware. Adding memory to a computer, for example, meant that the CP/M system had to be reinstalled with an updated BIOS capable of addressing the additional memory, a utility was provided to patch the supplied BIOS, BDOS and CCP to allow them to be run from higher memory. Once installed, the system was stored in reserved areas at the beginning of any disk which would be used to boot the system. On start-up, the bootloader would load the system from the disk in drive A. By modern standards CP/M was primitive, owing to the constraints on program size. With version 1.0 there was no provision for detecting a changed disk, if a user changed disks without manually rereading the disk directory the system would write on the new disk using the old disks directory information, ruining the data stored on the disk
6.
DOS
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None of these systems were officially named DOS, and indeed DOS is a general term for disk operating system. MS-DOS dominated the IBM PC compatible market between 1981 and 1995, and Microsoft Windows, still ran on top of it until about 2001, dozens of other operating systems also use the acronym DOS, including DOS/360 from 1966. Others are Apple DOS, Apple ProDOS, Atari DOS, Commodore DOS, TRSDOS, see List of DOS operating systems § Other operating systems. IBM PC DOS and its predecessor, 86-DOS, resembled Digital Researchs CP/M—the dominant disk operating system for 8-bit Intel 8080, DOS instead ran on Intel 8086 16-bit processors. Starting with MS-DOS1.28 and PC DOS2.0 the operating system incorporated various features inspired by Xenix, when IBM introduced the IBM PC, built with the Intel 8088 microprocessor, they needed an operating system. Seeking an 8088-compatible build of CP/M, IBM initially approached Microsoft CEO Bill Gates, IBM was sent to Digital Research, and a meeting was set up. However, the negotiations for the use of CP/M broke down, Digital Research wished to sell CP/M on a royalty basis, while IBM sought a single license. Digital Research founder Gary Kildall refused, and IBM withdrew, Gates in turn approached Seattle Computer Products. There, programmer Tim Paterson had developed a variant of CP/M-80, the system was initially named QDOS, before being made commercially available as 86-DOS. Microsoft purchased 86-DOS, allegedly for $50,000 and this became Microsoft Disk Operating System, MS-DOS, introduced in 1981. Within a year Microsoft licensed MS-DOS to over 70 other companies, Microsoft later required the use of the MS-DOS name, with the exception of the IBM variant. IBM continued to develop their version, PC DOS, for the IBM PC, Digital Research became aware that an operating system similar to CP/M was being sold by IBM, and threatened legal action. IBM responded by offering an agreement, they would give PC consumers a choice of PC DOS or CP/M-86, side-by-side, CP/M cost almost $200 more than PC DOS, and sales were low. CP/M faded, with MS-DOS and PC DOS becoming the operating system for PCs. Microsoft originally sold MS-DOS only to original equipment manufacturers, one major reason for this was that not all early PCs were 100% IBM PC compatible. DOS was structured such that there was a separation between the specific device driver code and the DOS kernel. Microsoft provided an OEM Adaptation Kit which allowed OEMs to customize the device driver code to their particular system, by the early 1990s, most PCs adhered to IBM PC standards so Microsoft began selling MS-DOS in retail with MS-DOS5.0. In the mid-1980s Microsoft developed a version of DOS
7.
OS/2
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OS/2 is a series of computer operating systems, initially created by Microsoft and IBM, then later developed by IBM exclusively. The name stands for Operating System/2, because it was introduced as part of the generation change release as IBMs Personal System/2 line of second-generation personal computers. The first version of OS/2 was released in December 1987 and newer versions were released until December 2001, OS/2 was intended as a protected mode successor of PC DOS. Because of this heritage, OS/2 shares similarities with Unix, Xenix, IBM discontinued its support for OS/2 on 31 December 2006. Since then, it has been updated, maintained and marketed under the name eComStation, in 2015 it was announced that a new OEM distribution of OS/2 would be released that was to be called ArcaOS. The development of OS/2 began when IBM and Microsoft signed the Joint Development Agreement in August 1985 and it was code-named CP/DOS and it took two years for the first product to be delivered. OS/21.0 was announced in April 1987 and released in December, the original release is textmode-only, and a GUI was introduced with OS/21.1 about a year later. OS/2 features an API for controlling the display and handling keyboard. In addition, development tools include a subset of the video, a task-switcher named Program Selector is available through the Ctrl-Esc hotkey combination, allowing the user to select among multitasked text-mode sessions. Communications and database-oriented extensions were delivered in 1988, as part of OS/21.0 Extended Edition, SNA, X. 25/APPC/LU6.2, LAN Manager, Query Manager, SQL. The promised graphical user interface, Presentation Manager, was introduced with OS/21.1 in October,1988 and it had a similar user interface to Windows 2.1, which was released in May of that year. The Extended Edition of 1.1, sold only through IBM sales channels, introduced distributed database support to IBM database systems, in 1989, Version 1.2 introduced Installable Filesystems and notably the HPFS filesystem. HPFS provided a number of improvements over the older FAT file system, including long filenames, in addition, extended attributes were also added to the FAT file system. The Extended Edition of 1.2 introduced TCP/IP and Ethernet support, OS/2 and Windows-related books of the late 1980s acknowledged the existence of both systems and promoted OS/2 as the system for the future. The collaboration between IBM and Microsoft unravelled in 1990, between the releases of Windows 3.0 and OS/21.3, during this time, Windows 3.0 became a tremendous success, selling millions of copies in its first year. Much of its success was because Windows 3.0 was bundled with most new computers, OS/2, on the other hand, was available only as an expensive stand-alone software package. In addition, OS/2 lacked device drivers for many devices such as printers. Windows, on the hand, supported a much larger variety of hardware
8.
Microsoft Windows
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Microsoft Windows is a metafamily of graphical operating systems developed, marketed, and sold by Microsoft. It consists of families of operating systems, each of which cater to a certain sector of the computing industry with the OS typically associated with IBM PC compatible architecture. Active Windows families include Windows NT, Windows Embedded and Windows Phone, defunct Windows families include Windows 9x, Windows 10 Mobile is an active product, unrelated to the defunct family Windows Mobile. Microsoft introduced an operating environment named Windows on November 20,1985, Microsoft Windows came to dominate the worlds personal computer market with over 90% market share, overtaking Mac OS, which had been introduced in 1984. Apple came to see Windows as an encroachment on their innovation in GUI development as implemented on products such as the Lisa. 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 and this comparison however may not be fully relevant, as the two operating systems traditionally target different platforms. As of September 2016, the most recent version of Windows for PCs, tablets, smartphones, the most recent versions for server computers is Windows Server 2016. A specialized version of Windows runs on the Xbox One 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. It now consists of three operating system subfamilies that are released almost at the time and share the same kernel. Windows, The operating system for personal computers, tablets. The latest version is Windows 10, the main competitor of this family is macOS by Apple Inc. for personal computers and Android for mobile devices. Windows Server, The operating system for server computers, the latest version is Windows Server 2016. Unlike its clients sibling, it has adopted a strong naming scheme, the main competitor of this family is Linux. Windows PE, A lightweight version of its Windows sibling meant to operate as an operating system, used for installing Windows on bare-metal computers. The latest version is Windows PE10.0.10586.0, 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. The following Windows families are no longer being developed, Windows 9x, Microsoft now caters to the consumers market with Windows NT. Windows Mobile, The predecessor to Windows Phone, it was a mobile operating system
9.
ReactOS
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ReactOS is a free and open-source operating system for x86/x64 personal computers intended to be binary-compatible with computer programs and device drivers made for Windows Server 2003. Development began in 1996, as a Windows 95 clone project, ReactOS has been noted as a potential open-source drop-in replacement for Windows and for its information on undocumented Windows APIs. As stated on the website, The main goal of the ReactOS project is to provide an operating system which is binary compatible with Windows. Such that people accustomed to the user interface of Windows would find using ReactOS straightforward. The ultimate goal of ReactOS is to allow you to remove Windows, ReactOS is primarily written in C, with some elements, such as ReactOS File Explorer, written in C++. The project partially implements Windows API functionality and has been ported to the AMD64 processor architecture, around 1996, a group of free and open-source software developers started a project called FreeWin95 to implement a clone of Windows 95. The project stalled in discussions of the design of the system, while FreeWin95 had started out with high expectations, there still had not been any builds released to the public by the end of 1997. As a result, the members, led by coordinator Jason Filby. The revived project sought to duplicate the functionality of Windows NT, in creating the new project, a new name, ReactOS, was chosen. The project began development in February 1998 by creating the basis for a new NT kernel, the name ReactOS was coined during an IRC chat. While the term OS stood for operating system, the term referred to the groups dissatisfaction with –. In 2004, a copyright / license violation of ReactOS GPLed code was found when someone distributed a ReactOS fork under the name Ekush OS, in order to avoid copyright prosecution, ReactOS must be expressively completely distinct and non-derivative from Windows, a goal which needs very careful work. A claim was made on 17 January 2006, by now former developer Hartmut Birr on the ReactOS developers mailing list that ReactOS contained code derived from disassembling Microsoft Windows, the code that Birr disputed involved the function BadStack in syscall. S. as well as other unspecified items. Comparing this function to disassembled binaries from Windows XP, Birr argued that the BadStack function was simply copy-pasted from Windows XP, on 27 January 2006, the developers responsible for maintaining the ReactOS code repository disabled access after a meeting was held to discuss the allegations. When approached by NewsForge, Microsoft declined to comment about the incident, contributions from several active ReactOS developers have been accepted post-audit, and low level cooperation for bug fixes still occurs. In a statement on its website, ReactOS cited differing legal definitions of what constitutes clean-room reverse engineering as a cause for the conflict, consequently, ReactOS clarified that its Intellectual Property Policy Statement requirements on clean room reverse engineering conform to US law. Contributors to its development were not affected by events. In September 2007, with the audit nearing completion, the status was removed from the ReactOS homepage
10.
Command-line interface
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A program which handles the interface is called a command language interpreter or shell. The interface is implemented with a command line shell, which is a program that accepts commands as text input. Command-line interfaces to computer operating systems are widely used by casual computer users. Alternatives to the line include, but are not limited to text user interface menus, keyboard shortcuts. Examples of this include the Windows versions 1,2,3,3.1, and 3.11, DosShell, and Mouse Systems PowerPanel. Command-line interfaces are preferred by more advanced computer users, as they often provide a more concise. Programs with command-line interfaces are generally easier to automate via scripting, a program that implements such a text interface is often called a command-line interpreter, command processor or shell. Under most operating systems, it is possible to replace the shell program with alternatives, examples include 4DOS for DOS, 4OS2 for OS/2. For example, the default Windows GUI is a program named EXPLORER. EXE. These programs are shells, but not CLIs, application programs may also have command line interfaces. When a program is launched from an OS command line shell, interactive command line sessions, After launch, a program may provide an operator with an independent means to enter commands in the form of text. OS inter-process communication, Most operating systems support means of inter-process communication, Command lines from client processes may be redirected to a CLI program by one of these methods. Some applications support only a CLI, presenting a CLI prompt to the user, Some examples of CLI-only applications are, DEBUG Diskpart Ed Edlin Fdisk Ping Some computer programs support both a CLI and a GUI. In some cases, a GUI is simply a wrapper around a separate CLI executable file, in other cases, a program may provide a CLI as an optional alternative to its GUI. CLIs and GUIs often support different functionality, for example, all features of MATLAB, a numerical analysis computer program, are available via the CLI, whereas the MATLAB GUI exposes only a subset of features. The early Sierra games, like the first three Kings Quest games, used commands from a command line to move the character around in the graphic window. Early computer systems often used teleprinter machines as the means of interaction with a human operator, the computer became one end of the human-to-human teleprinter model. So instead of a human communicating with another human over a teleprinter, in time, the actual mechanical teleprinter was replaced by a glass tty, and then by a smart terminal
11.
Shell (computing)
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In computing, a shell is a user interface for access to an operating systems services. In general, operating system shells use either a command-line interface or graphical user interface, depending on a computers role and it is named a shell because it is a layer around the operating system kernel. The design of a shell is also dictated by the employed computer periphery, such as keyboard, pointing device or touchscreen. CLIs are also easier to be operated via refreshable braille display, graphical shells place a low burden on beginning computer users, and they are characterized as being simple and easy to use. With the widespread adoption of programs with GUIs, the use of shells has gained greater adoption. Since graphical shells come with certain disadvantages, most GUI-enabled operating systems provide additional CLI shells. Operating systems provide services to their users, including file management, process management, batch processing. Most operating system shells are not direct interfaces to the underlying kernel, shells are actually special applications that use the kernel API in just the same way as it is used by other application programs. A shell manages the interaction by prompting users for input, interpreting their input. Since the operating system shell is actually an application, it may easily be replaced with another similar application, on Unix-like systems, Secure Shell protocol is usually used for text-based shells, while SSH tunneling can be used for X Window System–based graphical user interfaces. On Microsoft Windows, Remote Desktop Protocol can be used to provide GUI remote access, most operating system shells fall into one of two categories – command-line and graphical. Command line shells provide an interface to the operating system. Other possibilities, although not so common, include voice user interface, the relative merits of CLI- and GUI-based shells are often debated. A command-line interface is a system shell that uses alphanumeric characters typed on a keyboard to provide instructions and data to the operating system. Operating systems such as UNIX have a variety of shell programs with different commands, syntax. Application programs may also implement a command-line interface, for example, in Unix-like systems, the telnet program has a number of commands for controlling a link to a remote computer system. Since the commands to the program are made of the same keystrokes as the data being sent to a remote computer, an escape sequence can be defined, using either a special local keystroke that is never passed on but always interpreted by the local system. The program becomes modal, switching between interpreting commands from the keyboard or passing keystrokes on as data to be processed, a feature of many command-line shells is the ability to save sequences of commands for re-use
12.
COMMAND.COM
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COMMAND. COM is the default operating system shell for DOS operating systems and the default command line interpreter on Windows 95, Windows 98 and Windows ME. COMMAND. COMs successor on OS/2 and Windows NT systems is CMD. EXE, COMMAND. COM is also available on IA-32 versions of those systems to provide compatibility when running DOS applications within the NTVDM. Programs executed by COMMAND. COM are DOS programs that use the MS-DOS API to communicate with the operating system, as a shell, COMMAND. COM has two distinct modes of work. First is the mode, in which the user types commands which are then executed immediately. The second is the mode, which executes a predefined sequence of commands stored as a text file with the extension. BAT. Internal Commands are commands stored directly inside the COMMAND. COM binary, thus, they can only be executed directly from the command interpreter. All commands are run only after the Enter key is pressed at the end of the line, COMMAND. COM is not case-sensitive, meaning commands can be typed in any mixture of upper and lower case. BREAK Controls the handling of program interruption with Ctrl+C or Ctrl+Break, CHCP Displays or changes the current system code page. CHDIR, CD Changes the current working directory or displays the current directory, COPY Copies one file to another. CTTY Defines the device to use for input and output, DATE Display and set the date of the system. When used on a directory, deletes all files inside the directory only, in comparison, the external command DELTREE deletes all subdirectories and files inside a directory as well as the directory itself. DIR Lists the files in the specified directory, ECHO Toggles whether text is displayed or not. Also displays text on the screen, EXIT Exits from COMMAND. COM and returns to the program which launched it. LFNFOR Enables or disables the return of long filenames by the FOR command, LOADHIGH, LH Loads a program into upper memory. LOCK Enables external programs to perform low-level disk access to a volume, MKDIR, MD Creates a new directory. PATH Displays or changes the value of the PATH environment variable which controls the places where COMMAND. COM will search for executable files, PROMPT Displays or change the value of the PROMPT environment variable which controls the appearance of the prompt. REN, RENAME Renames a file or directory, RMDIR, RD Removes an empty directory. SET Sets the value of an environment variable, Without arguments, TIME Display and set the time of the system
13.
Cmd.exe
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Command Prompt, also known as cmd. exe or cmd, is the command-line interpreter on Windows NT, Windows CE, OS/2 and eComStation operating systems. It is the counterpart of COMMAND. COM in DOS and Windows 9x systems, the initial version of Command Prompt for Windows NT was developed by Therese Stowell. Command Prompt interacts with the user through a command-line interface, in Windows, this interface is implemented through Win32 console. Command Prompt may take advantage of available to native programs of its own platform. For example, in OS/2, it can use real pipes in command pipelines, as a result, it is possible to redirect the standard error stream. In Windows, Command Prompt is compatible with COMMAND. COM but provides the following extensions over it, in the OS/2, errors are reported in the chosen language of the system, their text being taken from the system message files. The HELP command can then be issued with the error message number to obtain further information, supports using of arrow keys to scroll through command history. This function was available to COMMAND. COM via an external component called DOSKEY. Adds command-line completion for file and folder paths Treats the Caret character as the character, in other words. There special characters in Command Prompt and COMMAND. COM that are part of the syntax and, if specified without caret, supports delayed variable expansion, fixing DOS idioms that made using control structures hard and complex. The extensions can be disabled, providing a stricter compatibility mode, internal commands have also been improved, The DelTree command was merged into the RD command, as part of its /S switch. SetLocal and EndLocal commands limit the scope of changes to the environment, changes made to the command line environment after SetLocal commands are local to the batch file. EndLocal command restores the previous settings, the Call command allows subroutines within batch file. The Call command in COMMAND. COM only supports calling external batch files, File name parser extensions to the Set command are comparable with C shell. The Set command can perform expression evaluation, an expansion of the For command supports parsing files and arbitrary sets in addition to file names. The new PushD and PopD commands provide access past navigated paths similar to forward, the conditional IF command can perform case-insensitive comparisons and numeric equality and inequality comparisons in addition to case-sensitive string comparisons. This was available in DR-DOS but not in PC DOS or MS-DOS
14.
4DOS
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4DOS is a command line interpreter by JP Software, designed to replace the default command interpreter COMMAND. COM in MS-DOS and Windows 95/98/SE/ME. 4OS2 and 4NT replace CMD. EXE in OS/2 and Windows NT respectively, 4DOS was written by Rex Conn and Tom Rawson, it was first released in 1989. These programs can also be initiated from the command line and/or called by scripts, 4DOS is most often used with the MS-DOS-Windows 95 stream of operating systems and it can be also used with Windows NT type machines, IBM PC DOS and also later DR DOS versions. Since Windows NT-2000 includes both COMMAND. COM and CMD. EXE, 4DOS and 4NT and derivatives can both be installed. Earlier versions of 4OS2 can be run under Windows NT, among the many commands, statements and functions in 4DOS and lacking in MS-DOS/Windows 95/98 COMMAND. COM are reading keyboard input and a simpler method of working with colors of screen and text. The default file extension for 4DOS scripts is. btm, a graphical version of 4DOS, 4OS2, and 4NT, called Take Command, was released with a feature set corresponding to version 4DOS5.5, 4OS2, and 4NT2.5 and updated after this. Development on this line stopped with the corresponding character-mode versions, there was a graphical program Take Command/16, for Windows 3.1. 4OS2 is a replacement for IBMs OS/2 command interpreter. This was first released at the time as 4DOS version 4. Like 4DOS, this is released as open source and it appeared in the feature set of 2011s eComStation 2.10, and in the freeware os2free project. 4NT was first released as 4DOS for Windows NT, but became 4NT until the restructure after version 8, the program is a recompile of 4OS2, and continues to have features of OS/2s command processor, such as running REXX scripts, and EXTPROC support. A corresponding Take Command/32 exists for this, version 1 corresponding to 4NT2.5, 4NT and Take Command/32 were released in both ANSI and Unicode forms, with the ANSI version dropped at version 5. A new Win32 program Tabbed Command Interface, was released at the time of 4NT version 7 and this program allowed one to attach and unattach tabbed consoles to a single window. This program requires Windows XP or later, 4NT is bundled as Take Command Console. A light feature-reduced version of TCC is released as a free download, JP Software then released TC, or TCLE, or TCC, or TCC/LE. This has been released from versions 9 to 12.1, 4DOS features a number of enhancements compared to COMMAND. The last update by JP Software was version 7.50.130, during its 15-year history, 4DOS underwent numerous updates, here are a few of the most significant. Some versions of the Norton Utilities for DOS included modified copies of 4DOS called NDOS, the last version of NDOS was bundled with Norton Utilities 8, and corresponded to 4DOS4.03
15.
PowerShell
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PowerShell is a task automation and configuration management framework from Microsoft, consisting of a command-line shell and associated scripting language built on the. NET Framework. Initially a Windows component only, PowerShell was made open-source and cross-platform on 18 August 2016, in PowerShell, administrative tasks are generally performed by cmdlets, which are specialized. NET classes implementing a particular operation. Sets of cmdlets may be combined into scripts, executables, or by instantiating regular. NET classes and these work by accessing data in different data stores, like the file system or registry, which are made available to the PowerShell runtime via PowerShell providers. PowerShell also provides a hosting API with which the PowerShell runtime can be embedded inside other applications and these applications can then use PowerShell functionality to implement certain operations, including those exposed via the graphical interface. Other Microsoft applications including Microsoft SQL Server 2008 also expose their management interface via PowerShell cmdlets, PowerShell includes its own extensive, console-based help, similar to man pages in Unix shells, via the Get-Help cmdlet. Local help contents can be retrieved from the Internet via Update-Help cmdlet, alternatively, help from the web can be acquired on a case-by-case basis via the -online switch to Get-Help. Every released version of Microsoft DOS and Microsoft Windows for personal computers has included a command-line interface tool, the shell is a command line interpreter that supports a few basic commands. For other purposes, a console application must be invoked from the shell. The shell also includes a language, which can be used to automate various tasks. In Windows Server 2003, the situation was improved, but scripting support was considered unsatisfactory. Microsoft attempted to address some of shortcomings by introducing the Windows Script Host in 1998 with Windows 98. It integrates with the Active Script engine and allows scripts to be written in languages, such as JScript and VBScript. Different versions of Windows provided various special-purpose command line interpreters with their own command sets, none of them were integrated with the command shell, nor were they interoperable. By 2002 Microsoft had started to develop a new approach to command line management, the shell and the ideas behind it were published in August 2002 in a white paper titled Monad Manifesto. Monad was to be a new extensible command shell with a design that would be capable of automating a full range of core administrative tasks. Microsoft first showed off Monad at the Professional Development Conference in Los Angeles in October 2003, a private beta program began a few months later which eventually led to a public beta program. Microsoft published the first Monad public beta release on June 17,2005, Beta 2 on September 11,2005, and Beta 3 on January 10,2006. Not much later, on April 25,2006 Microsoft formally announced that Monad had been renamed Windows PowerShell, Release Candidate 1 of PowerShell was released at the same time
16.
Computer file
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A computer file is a computer resource for recording data discretely in a computer storage device. Just as words can be written to paper, so can information be written to a computer file, there are different types of computer files, designed for different purposes. A file may be designed to store a picture, a message, a video. Some types of files can store different several types of information at once, by using computer programs, a person can open, read, change, and close a computer file. Computer files may be reopened, modified, and copied a number of times. Typically, computer files are organised in a system, which keeps track of where the files are. The word file derives from the Latin filum, such a file now exists in a memory tube developed at RCA Laboratories. Electronically it retains figures fed into calculating machines, holds them in storage while it memorizes new ones - speeds intelligent solutions through mazes of mathematics, in 1952, file denoted, inter alia, information stored on punched cards. In early use, the hardware, rather than the contents stored on it, was denominated a file. For example, the IBM350 disk drives were denominated disk files, although the contemporary register file demonstrates the early concept of files, its use has greatly decreased. On most modern operating systems, files are organized into one-dimensional arrays of bytes, for example, the bytes of a plain text file are associated with either ASCII or UTF-8 characters, while the bytes of image, video, and audio files are interpreted otherwise. Most file types also allocate a few bytes for metadata, which allows a file to some basic information about itself. Some file systems can store arbitrary file-specific data outside of the file format, on other file systems this can be done via sidecar files or software-specific databases. All those methods, however, are susceptible to loss of metadata than are container. At any instant in time, a file might have a size, normally expressed as number of bytes, in most modern operating systems the size can be any non-negative whole number of bytes up to a system limit. Many older operating systems kept track only of the number of blocks or tracks occupied by a file on a storage device. In such systems, software employed other methods to track the exact byte count, the general definition of a file does not require that its size have any real meaning, however, unless the data within the file happens to correspond to data within a pool of persistent storage. A special case is a zero byte file, these files can be newly created files that have not yet had any data written to them, or may serve as some kind of flag in the file system, or are accidents
17.
Computer terminal
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A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system. The function of a terminal is confined to display and input of data, a terminal that depends on the host computer for its processing power is called a dumb terminal or thin client. A personal computer can run terminal emulator software that replicates the function of a terminal, sometimes allowing concurrent use of local programs and access to a distant terminal host system. The terminal of the first working programmable, fully automatic digital Turing-complete computer, the Z3, had a keyboard, early user terminals connected to computers were electromechanical teleprinters/teletypewriters, such as the Teletype Model 33 ASR, originally used for telegraphy or the Friden Flexowriter. Later printing terminals such as the DECwriter LA30 were developed, however printing terminals were limited by the speed at which paper could be printed, and for interactive use the paper record was unnecessary. The problem was that the amount of memory needed to store the information on a page of text was comparable to the memory in low end minicomputers then in use. Displaying the information at video speeds was also a challenge and the control logic took up a rack worth of pre-integrated circuit electronics. Another approach involved the use of the tube, a specialized CRT developed by Tektronix that retained information written on it without the need to refresh. The Datapoint 3300 from Computer Terminal Corporation was announced in 1967 and shipped in 1969 and it solved the memory space issue mentioned above by using a digital shift-register design, and using only 72 columns rather than the later more common choice of 80. Some type of blinking cursor that can be positioned, the term intelligent in this context dates from 1969. Notable examples include the IBM2250 and IBM2260, predecessors to the IBM3270, providing even more processing possibilities, workstations like the Televideo TS-800 could run CP/M-86, blurring the distinction between terminal and Personal Computer. Most terminals were connected to minicomputers or mainframe computers and often had a green or amber screen, typically terminals communicate with the computer via a serial port via a null modem cable, often using an EIA RS-232 or RS-422 or RS-423 or a current loop serial interface. In fact, the design for the Intel 8008 was originally conceived at Computer Terminal Corporation as the processor for the Datapoint 2200. While early IBM PCs had single color green screens, these screens were not terminals. The screen of a PC did not contain any character generation hardware, all signals and video formatting were generated by the video display card in the PC, or by the CPU. An IBM PC monitor, whether it was the monochrome display or the 16-color display, was technically much more similar to an analog TV set than to a terminal. With suitable software a PC could, however, emulate a terminal, the Data General One could be booted into terminal emulator mode from its ROM. Since the advent and subsequent popularization of the computer, few genuine hardware terminals are used to interface with computers today
18.
Unix
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Among these is Apples macOS, which is the Unix version with the largest installed base as of 2014. Many Unix-like operating systems have arisen over the years, of which Linux is the most popular, 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-programmer users. The system grew larger as the system started spreading in academic circles, as users added their own tools to the system. Unix was designed to be portable, multi-tasking and multi-user in a time-sharing configuration and these concepts are collectively known as the Unix philosophy. By the early 1980s users began seeing Unix as a universal operating system. Under Unix, the system consists of many utilities along with the master control program. To mediate such access, the kernel has special rights, reflected in the division between user space and kernel space, the microkernel concept was introduced in an effort to reverse the trend towards larger kernels and return to a system in which most tasks were completed by smaller utilities. In an era when a standard computer consisted of a disk for storage and a data terminal for input and output. However, modern systems include networking and other new devices, as graphical user interfaces developed, the file model proved inadequate to the task of handling asynchronous events such as those generated by a mouse. 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. In microkernel implementations, functions such as network protocols could be moved out of the kernel, Multics introduced many innovations, but had many problems. Frustrated by the size and complexity of Multics but not by the aims and their last researchers to leave Multics, Ken Thompson, Dennis Ritchie, M. D. McIlroy, and J. F. Ossanna, decided to redo the work on a much smaller scale. The name Unics, a pun on Multics, was suggested for the project in 1970. Peter H. Salus credits Peter Neumann with the pun, while Brian Kernighan claims the coining for himself, in 1972, Unix was rewritten in the C programming language. Bell Labs produced several versions of Unix that are referred to as Research Unix. In 1975, the first source license for UNIX was sold to faculty at the University of Illinois Department of Computer Science, UIUC graduate student Greg Chesson was instrumental in negotiating the terms of this license. During the late 1970s and early 1980s, the influence of Unix in academic circles led to adoption of Unix by commercial startups, including Sequent, HP-UX, Solaris, AIX. In the late 1980s, AT&T Unix System Laboratories and Sun Microsystems developed System V Release 4, in the 1990s, Unix-like systems grew in popularity as Linux and BSD distributions were developed through collaboration by a worldwide network of programmers
19.
86-DOS
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86-DOS is a discontinued operating system developed and marketed by Seattle Computer Products for its Intel 8086-based computer kit. Initially known as QDOS the name was changed to 86-DOS once SCP started licensing the operating system in 1980, 86-DOS had a command structure and application programming interface that imitated that of Digital Researchs CP/M operating system, which made it easy to port programs from the latter. The system was purchased by Microsoft and developed further as MS-DOS, 86-DOS was created because sales of the Seattle Computer Products 8086 computer kit, demonstrated in June 1979 and shipped in November, were languishing due to the absence of an operating system. The only software which SCP could sell with the board was Microsofts Standalone Disk BASIC-86, SCP wanted to offer the 8086-version of CP/M that Digital Research had announced, but its release date was uncertain. This was not the first time Digital Research had lagged behind hardware developments, in April 1980 SCP assigned 24-year-old Tim Paterson to develop a substitute for CP/M-86. At the same time he made a number of changes and enhancements to address what he saw as CP/Ms shortcomings. CP/M cached file system information in memory for speed, but this required a user to force an update to a disk before removing it, if the user forgot, Paterson took the safer but slower approach of updating the disk with each operation. CP/Ms PIP command, which copied files, supported several special file names that referred to hardware such as printers. Paterson built these names into the system as device files so that any program could use them. He gave his copying program the more intuitive name COPY, rather than implementing CP/Ms file system, he drew on Microsoft Standalone Disk BASIC-86s FAT filesystem. By mid-1980 SCP advertised 86-DOS, priced at $95 for owners of its $12908086 board, in October 1980, IBM was developing what would become the original IBM Personal Computer. CP/M was by far the most popular operating system in use at the time, IBMs representatives visited Digital Research and discussed licensing with Digital Researchs licensing representative, Dorothy Kildall, who hesitated to sign IBMs non-disclosure agreement. Although the NDA was later accepted, Digital Research would not accept IBMs proposal of $250,000 in exchange for as many copies as IBM could sell, insisting on the usual royalty-based plan. In later discussions between IBM and Bill Gates, Gates mentioned the existence of 86-DOS and IBM representative Jack Sams told him to get a license for it, Microsoft purchased a non-exclusive license for 86-DOS from Seattle Computer Products in December 1980 for $25,000. In May 1981, it hired Tim Paterson to port the system to the IBM PC, IBM watched the developments daily, submitted over 300 change requests before it accepted the product and wrote the user manual for it. In July 1981, a month before the PCs release, Microsoft purchased all rights to 86-DOS from SCP for $50,000, Microsoft licensed 86-DOS to IBM, and it became PC DOS1.0. This license also permitted Microsoft to sell DOS to other companies, the deal was spectacularly successful, and SCP later claimed in court that Microsoft had concealed its relationship with IBM in order to purchase the operating system cheaply. SCP ultimately received a 1 million dollar settlement payment, when Digital Research founder Gary Kildall examined PC DOS and found that it duplicated CP/Ms programming interface, he wanted to sue IBM, which at the time claimed that PC DOS was its own product
20.
Digital Research
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Digital Research, Inc. was the company created by Dr. Gary Kildall to market and develop his CP/M operating system and related products. It was the first large company in the microcomputer world. Digital Research was based in Pacific Grove, California, the companys operating systems, starting with CP/M for 8080/Z80-based microcomputers, were the de facto standard of their era, as MS-DOS and Microsoft Windows came later. DRs product suite included the original CP/M and its various offshoots, DR-DOS which was a MS-DOS compatible version of CP/M, and MP/M, the first 16-bit system was CP/M-86, which was to be unsuccessful in competition with MS-DOS. There followed Concurrent CP/M, a version of the multi-tasking MP/M-86 featuring virtual consoles from which applications could be launched to run concurrently. Successive revisions of this system, which gradually supported MS-DOS applications, in May 1983 Digital Research announced that it would offer PC DOS versions of all of its languages and utilities. It remained influential, with $45 million in 1983 sales making Digital Research the fourth-largest microcomputer software company, jerry Pournelle warned later that year, however, that Many people of stature seem to have left or are leaving Digital Research. DR had better get its act together, in 1985, soon after the introduction of the Intel 80286, Digital Research introduced a real-time system, initially called Concurrent DOS286 and subsequently FlexOS. This exploited the greater memory addressing capability of the new CPU to provide a more flexible multi-tasking environment, there was a small but powerful set of system APIs, each with a synchronous and an asynchronous variant. Pipes were supported, and all named resources could be aliased by setting Environment variables and this system was to enjoy enduring favour in point-of-sale systems and was adopted as the basis for IBM4680 OS and IBM4690 OS. Digital Research was purchased by Novell in 1991, primarily for Novell to gain access to the operating system line. Digital Research produced a selection of programming language compilers and interpreters for their OS-supported platforms, including C, Pascal, COBOL, Forth, PL/I, PL/M, CBASIC, BASIC, and Logo. They also produced a version of the GKS graphics standard called GSX. Less known are their application programs, limited largely to the GSX-based DR DRAW, Dr. Halo for DOS, at the time IBM Personal Computer was being developed, Digital Researchs CP/M was the dominant operating system of the day. IBM asked DR to supply a version of CP/M written for the Intel 8086 microprocessor as the operating system for the PC. Digital Research, uneasy about making such an agreement with IBM, Microsoft seized this opportunity to supply an OS, in addition to other software for the new IBM PC. When the IBM PC arrived in late 1981, it came with PC DOS, which was developed from 86-DOS, by mid-1982, it was marketed as MS-DOS for use in hardware-compatible non-IBM computers. This one decision resulted in Microsoft becoming the name in computer software
21.
Recovery Console
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The Recovery Console is a feature of the Windows 2000, Windows XP and Windows Server 2003 operating systems. It provides the means for administrators to perform a range of tasks using a command line interface. Its primary function is to enable administrators to recover from situations where Windows does not boot as far as presenting its graphical user interface, the recovery console is used to provide a way to access the hard drive in an emergency through the command prompt. The Recovery Console has a simple command-line interpreter, many of the available commands closely resemble the commands that are normally available in CMD. EXE, namely attrib, copy, del, and so forth. This can be changed by changing Security Policies to enable access to the complete file system including copying files from removable media. Although it appears in the list of commands available by using the command, and in many articles about the Recovery Console. No protocol stacks are loaded, so there is no way to connect to a folder on a remote computer as implied. Description of the Windows XP Recovery Console, description of the Windows 2000 Recovery Console. Primer, Creating A Windows XP Recovery Console CD Image
22.
Cd (command)
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The cd command, also known as chdir, is a command-line OS shell command used to change the current working directory in operating systems such as Unix, DOS, OS/2, AmigaOS, Windows, and Linux. It is also available for use in shell scripts and batch files, the system call that affects the command in most operating systems is chdir that is defined by POSIX. A directory is a section of a file system used to hold files. Directories may also contain other directories, the cd command can be used to change into a subdirectory, move back into the parent directory, move all the way back to the root directory or move to any given directory. Consider the following subsection of a Unix filesystem, which shows a home directory with a file. If the users current working directory is the directory, then entering the command ls followed by cd games might produce the following transcript. The cd command can be used to change the working directory of the drive or another lettered drive. Modern versions of Windows simulate this behaviour for backwards compatibility under CMD. EXE, note that executing cd from the command line with no arguments has different effects in different operating systems. For example, if cd is executed without arguments in DOS, OS/2, or Windows, if cd is executed without arguments in Unix, the user is returned to the home directory. Executing the cd command within a script or batch file also has different effects in different operating systems, in DOS, the callers current directory can be directly altered by the batch files use of this command. In Unix, the current directory is not altered by the scripts invocation of the cd command. This is because in Unix, the script is executed within a subshell. Cd is frequently included built directly into a command-line interpreter and this is the case in most of the Unix shells, cmd. exe and Windows PowerShell on Windows and COMMAND. COM on DOS. Command line shells on Windows usually use the Windows API to change the current working directory and this means that when the command is executed, no new process is created to migrate to the other directory as is the case with other commands such as ls. Instead, the shell itself executes this command and this is because, when a new process is created, child process inherits the directory in which the parent process was created. If the cd command inherits the parent process directory, then the objective of the command cd will never be achieved, Windows PowerShell, Microsofts object-oriented command line shell and scripting language, executes the cd command within the shells process. However, since PowerShell is based on the. NET Framework and has a different architecture than previous shells, all of PowerShells cmdlets like ls, of course, this is not true for legacy commands which still run in a separate process. Cd by itself or cd ~ will always put you in your home directory, cd. will leave you in the same directory you are currently in
23.
Encrypting File System
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The Encrypting File System on Microsoft Windows is a feature introduced in version 3.0 of NTFS that provides filesystem-level encryption. The technology enables files to be encrypted to protect confidential data from attackers with physical access to the computer. EFS is available in all versions of Windows developed for environments from Windows 2000 onwards. By default, no files are encrypted, but encryption can be enabled by users on a per-file, per-directory, some EFS settings can also be mandated via Group Policy in Windows domain environments. Cryptographic file system implementations for other operating systems are available, see also the list of cryptographic file systems. When an operating system is running on a system without file encryption, access to files normally goes through OS-controlled user authentication, however, if an attacker gains physical access to the computer, this barrier can be easily circumvented. The most widely accepted solution to this is to store the files encrypted on the physical media, however, the cryptography keys for EFS are in practice protected by the user account password, and are therefore susceptible to most password attacks. In other words, the encryption of a file is only as strong as the password to unlock the decryption key, EFS works by encrypting a file with a bulk symmetric key, also known as the File Encryption Key, or FEK. It uses an encryption algorithm because it takes less time to encrypt and decrypt large amounts of data than if an asymmetric key cipher is used. The symmetric encryption algorithm used will vary depending on the version and configuration of the operating system, see Algorithms used by Windows version below. The FEK is then encrypted with a key that is associated with the user who encrypted the file. To decrypt the file, the EFS component driver uses the key that matches the EFS digital certificate to decrypt the symmetric key that is stored in the $EFS stream. The EFS component driver uses the symmetric key to decrypt the file. Because the encryption & decryption operations are performed at a layer below NTFS, it is transparent to the user, folders whose contents are to be encrypted by the file system are marked with an encryption attribute. When encrypted files are moved within an NTFS volume, the files remain encrypted, however, there are a number of occasions in which the file could be decrypted without the user explicitly asking Windows to do so. Files and folders are decrypted before being copied to a formatted with another file system. Finally, when encrypted files are copied over the network using the SMB/CIFS protocol, the most significant way of preventing the decryption-on-copy is using backup applications that are aware of the Raw APIs. Backup applications that have implemented these Raw APIs will simply copy the encrypted file stream, in other words, the files are copied in encrypted form, and are not decrypted during backup
24.
NTFS
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NTFS is a proprietary file system developed by Microsoft. Starting with Windows NT3.1, it is the file system of Windows NT family. Additional extensions are an elaborate security system based on Access control lists. MacOS kernels also have a limited ability to read NTFS. Linux and BSD kernels have a free and open-source driver for the NTFS filesystem with both read and write functionality, in the mid-1980s, Microsoft and IBM formed a joint project to create the next generation of graphical operating system, the result was OS/2 and HPFS. Because Microsoft disagreed with IBM on many important issues they eventually separated, OS/2 remained an IBM project and Microsoft worked to develop Windows NT, the HPFS file system for OS/2 contained several important new features. When Microsoft created their new operating system, they borrowed many of these concepts for NTFS, NTFS developers include, Tom Miller, Gary Kimura, Brian Andrew and David Goebel. Probably as a result of common ancestry, HPFS and NTFS use the same disk partition identification type code. Using the same Partition ID Record Number is highly unusual, since there were dozens of unused code numbers available, for example, FAT has more than nine. Algorithms identifying the system in a partition type 07 must perform additional checks to distinguish between HPFS and NTFS. Microsoft has released five versions of NTFS, v1.0, v1.0 is incompatible with v1.1 and newer, Volumes written by Windows NT3. 5x cannot be read by Windows NT3.1 until an update is installed. V1.1, Released with Windows NT3.51 in 1995, supports compressed files, named streams and access control lists v1.2, Released with Windows NT4.0 in 1996. Commonly called NTFS4.0 after the OS release, supports disk quotas, Encrypting File System, sparse files, reparse points, update sequence number journaling, the $Extend folder and its files. Reorganized security descriptors so that multiple files using the same security setting can share the same descriptor, commonly called NTFS5.0 after the OS release. V3.1, Released with Windows XP in Autumn,2001, expanded the Master File Table entries with redundant MFT record number. Commonly called NTFS5.1 after the OS release The NTFS. sys version number is based on the system version. Although subsequent versions of Windows added new file system-related features, they did not change NTFS itself, for example, Windows Vista implemented NTFS symbolic links, Transactional NTFS, partition shrinking, and self-healing. NTFS symbolic links are a new feature in the file system, NTFS is optimized for 4 kB clusters, but supports a maximum cluster size of 64 kB
25.
Deltree
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DELTREE is a command line command in some Microsoft operating systems that recursively deletes an entire subdirectory of files. When IBM and Microsoft introduced PC-DOS1.0 / MS-DOS1.0, by 1991 at least one competing product, DR-DOS, had introduced a well-received utility that enabled recursive file deletion. With the introduction of MS-DOS6.0, Microsoft regained parity by adding the DELTREE command, DELTREE was implemented as an external command, with its functionality kept in a separate file outside of COMMAND. COM. Normal operation prompted the user for verification that the specified directories were indeed intended to be removed, unlike most other commands that operated on the file system, multiple directories could be passed to the command at one time. An undocumented feature allowed the user to append a trailing / character to a name in order to preserve the directory. In theory, deleted material could be recovered, DELTREE was designed to ignore all file and directory attributes, such as hidden, read-only and system. The command was described as dangerous and capable of wiping out hundreds of files at a time. Combined with the PURGE command, it became an example of a payload for malware as well as figuring in one of the early computer sabotage trials. DELTREE was retained throughout all Windows versions based upon MS-DOS, including Windows 95, Windows 98, Windows 98 SE and Windows ME. DELTREE was not shipped in Windows NT-based operating systems, including Windows NT, Windows 2000, Windows XP, Windows Server, Windows Vista, Windows 7, and Windows 8. Instead, the RD or RMDIR command removes a subdirectory along with all its files if the /S command-line switch is given, list of DOS commands del rmdir
26.
Ren (command)
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In computing, ren is a command in various DOS, OS/2 and Microsoft Windows command line interpreters such as COMMAND. COM, cmd. exe, 4DOS, 4NT and Windows PowerShell. It is used to rename files and in some implementations also directories and it can also move a file to a new path, if it is on the same device. It is analogous to the Unix mv command, rT-11, RSX-11 and OpenVMS also provide the rename command which can be contracted to ren. In Windows PowerShell, ren is a predefined command alias for the Rename-Item Cmdlet which basically serves the same purpose and this will rename a default video found in Windows 7 with a new name, List of DOS commands List of PowerShell commands
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