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
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