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113-457: The first actual Witkar project took place in Amsterdam between 1974 and 1986. While it provided daily service for more than 4,000 registered users over those years, the project never got beyond the limited demonstration phase due to a lack of support by government. The system was initially conceived in 1969 by Schimmelpennink in order to reduce traffic in central Amsterdam, but it failed to win

226-538: A VT100 terminal enclosure. The /150 was housed in a table-top unit which included two 8-inch floppy drives, three asynchronous serial ports, one printer port, one modem port and one synchronous serial port and required an external terminal. All three employed the same chipset as used on the LSI-11/03 and LSI-11/2 in four "microm"s. There is an option which combines two of the microms into one dual carrier, freeing one socket for an EIS/FIS chip. The /150 in combination with

339-471: A VT105 terminal was also sold as MiniMINC , a budget version of the MINC-11 . The DEC Professional series are desktop PCs intended to compete with IBM's earlier 8088 and 80286 based personal computers. The models are equipped with 5 1 ⁄ 4 inch floppy disk drives and hard disks, except the 325 which has no hard disk. The original operating system was P/OS, which was essentially RSX-11 M+ with

452-413: A ROM firmware chip) loads the operating system from the disk in drive A: . By modern standards CP/M is primitive, owing to the extreme constraints on program size. With version 1.0 there is no provision for detecting a changed disk. If a user changes disks without manually rereading the disk directory the system writes on the new disk using the old disk's directory information, ruining the data stored on

565-468: A competitor in the spreadsheet market in the MS-DOS world. AutoCAD , a CAD application from Autodesk debuted on CP/M. A host of compilers and interpreters for popular programming languages of the time (such as BASIC , Borland 's Turbo Pascal , FORTRAN and even PL/I ) were available, among them several of the earliest Microsoft products. CP/M software often came with installers that adapted it to

678-528: A corporation change-of-name filing to Digital Research, Inc. By September 1981, Digital Research had sold more than 250,000 CP/M licenses; InfoWorld stated that the actual market was likely larger because of sublicenses. Many different companies produced CP/M-based computers for many different markets; the magazine stated that "CP/M is well on its way to establishing itself as the small-computer operating system". The companies chose to support CP/M because of its large library of software. The Xerox 820 ran

791-780: A directory except those marked with the SYS attribute), DIRSYS / DIRS (list files marked with the SYS attribute in the directory), ERASE / ERA (delete a file), RENAME / REN (rename a file), TYPE / TYP (display contents of an ASCII character file), and USER / USE (change user number) as built-in commands: CP/M 3 allows the user to abbreviate the built-in commands. Transient commands in CP/M 3 include COPYSYS , DATE , DEVICE , DUMP , ED , GET , HELP , HEXCOM , INITDIR , LINK , MAC , PIP, PUT , RMAC , SET , SETDEF , SHOW , SID , SUBMIT , and XREF . The Basic Disk Operating System, or BDOS, provides access to such operations as opening

904-464: A directory or ERA to delete a file) or loads and starts an executable file of the given name (transient commands such as PIP.COM to copy files or STAT.COM to show various file and system information). Third-party applications for CP/M are also essentially transient commands. The BDOS, CCP and standard transient commands are the same in all installations of a particular revision of CP/M, but the BIOS portion

1017-449: A dozen different CP/M systems, plus two generic versions. The operating system was described as a " software bus ", allowing multiple programs to interact with different hardware in a standardized way. Programs written for CP/M were typically portable among different machines, usually requiring only the specification of the escape sequences for control of the screen and printer. This portability made CP/M popular, and much more software

1130-517: A fifth chip can be added to extend the instruction set). It uses a bus which is a close variant of the Unibus called the LSI Bus or Q-Bus ; it differs from the Unibus primarily in that addresses and data are multiplexed onto a shared set of wires rather than having separate sets of wires. It also differs slightly in how it addresses I/O devices and it eventually allowed a 22-bit physical address (whereas

1243-429: A file, output to the console, or printing. Application programs load processor registers with a function code for the operation, and addresses for parameters or memory buffers , and call a fixed address in memory. Since the address is the same independent of the amount of memory in the system, application programs run the same way for any type or configuration of hardware. The Basic Input Output System or BIOS, provides

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1356-554: A menu system on top. As the design was intended to avoid software exchange with existing PDP–11 models, the poor market response was unsurprising. The RT-11 operating system was eventually ported to the PRO series. A port of the RSTS/E operating system to the PRO series was also done internal to DEC, but it was not released. The PRO-325 and -350 units are based on the DCF-11 ("Fonz") chipset,

1469-478: A part of the Amateur Computer Club of New Jersey . ZCPR2 was released on 14 February 1983. It was released as a set of ten disks from SIG/M. ZCPR2 was upgraded to 2.3, and also was released in 8080 code, permitting the use of ZCPR2 on 8080 and 8085 systems. ZCPR3 was released on 14 July 1984, as a set of nine disks from SIG/M. The code for ZCPR3 could also be compiled (with reduced features) for

1582-516: A prevailing naming scheme of the time, as in Kildall's PL/M language, and Prime Computer's PL/P ( Programming Language for Prime ), both suggesting IBM's PL/I ; and IBM's CP/CMS operating system, which Kildall had used when working at the NPS. This renaming of CP/M was part of a larger effort by Kildall and his wife with business partner, Dorothy McEwen to convert Kildall's personal project of CP/M and

1695-508: A program was not standardized, so that there is no single option character that differentiated options from file names. Different programs can and do use different characters. The CP/M Console Command Processor includes DIR , ERA , REN , SAVE , TYPE , and USER as built-in commands. Transient commands in CP/M include ASM , DDT , DUMP , ED , LOAD , MOVCPM  [ pl ] , PIP , STAT , SUBMIT , and SYSGEN . CP/M Plus (CP/M Version 3) includes DIR (display list of files from

1808-617: A register by one (byte instructions) or two (word instructions). Use of relative addressing lets a machine-language program be position-independent . Early models of the PDP–11 had no dedicated bus for input/output , but only a system bus called the Unibus , as input and output devices were mapped to memory addresses. An input/output device determined the memory addresses to which it would respond, and specified its own interrupt vector and interrupt priority . This flexible framework provided by

1921-840: A relocating assembler and linker. CP/M 3 was available for the last generation of 8-bit computers, notably the Amstrad PCW, the Amstrad CPC , the ZX Spectrum +3 , the Commodore 128 , MSX machines and the Radio Shack TRS-80 Model 4 . There were versions of CP/M for some 16-bit CPUs as well. The first version in the 16-bit family was CP/M-86 for the Intel 8086 in November 1981. Kathryn Strutynski

2034-512: A set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, making it one of DEC's most successful product lines. The PDP-11 is considered by some experts to be the most popular minicomputer. The PDP–11 included a number of innovative features in its instruction set and additional general-purpose registers that made it easier to program than earlier models in

2147-452: A single-board large-scale integration version of the processor was developed in 1975. A two- or three-chip processor, the J-11 was developed in 1979. The last models of the PDP–11 line were the single board PDP–11/94 and PDP–11/93 introduced in 1990. The PDP–11 processor architecture has a mostly orthogonal instruction set . For example, instead of instructions such as load and store ,

2260-538: A system known as the TSD (Test System Director). As such, they were in use until their software was rendered inoperable by the Year 2000 problem . The US Navy used a PDP–11/34 to control its Multi-station Spatial Disorientation Device, a simulator used in pilot training, until 2007, when it was replaced by a PC-based emulator that could run the original PDP–11 software and interface with custom Unibus controller cards. A PDP–11/45

2373-530: A user-installed overlay containing all the code required to access a particular machine's serial port. WordStar, one of the first widely used word processors , and dBase , an early and popular database program for microcomputers, were originally written for CP/M. Two early outliners , KAMAS (Knowledge and Mind Amplification System) and its cut-down successor Out-Think (without programming facilities and retooled for 8080/V20 compatibility) were also written for CP/M, though later rewritten for MS-DOS. Turbo Pascal ,

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2486-540: A wide variety of computers. The source code for BASIC programs was easily accessible, and most forms of copy protection were ineffective on the operating system. A Kaypro II owner, for example, would obtain software on Xerox 820 format, then copy it to and run it from Kaypro-format disks. The lack of standardized graphics support limited video games , but various character and text-based games were ported , such as Telengard , Gorillas , Hamurabi , Lunar Lander , along with early interactive fiction including

2599-566: Is a mass-market operating system created in 1974 for Intel 8080 / 85 -based microcomputers by Gary Kildall of Digital Research, Inc. CP/M is a disk operating system and its purpose is to organize files on a magnetic storage medium, and to load and run programs stored on a disk. 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 became an early standard in

2712-451: Is always adapted to the particular hardware. Adding memory to a computer, for example, means that the CP/M system must be reinstalled to allow transient programs to use the additional memory space. A utility program (MOVCPM) is provided with system distribution that allows relocating the object code to different memory areas. The utility program adjusts the addresses in absolute jump and subroutine call instructions to new addresses required by

2825-534: The Zork series and Colossal Cave Adventure . Text adventure specialist Infocom was one of the few publishers to consistently release their games in CP/M format. Lifeboat Associates started collecting and distributing user-written "free" software. One of the first was XMODEM , which allowed reliable file transfers via modem and phone line. Another program native to CP/M was the outline processor KAMAS. The read/write memory between address 0100 hexadecimal and

2938-524: The C programming language took advantage of several low-level PDP–11–dependent programming features, albeit not originally by design. An effort to expand the PDP–11 from 16- to 32-bit addressing led to the VAX-11 design, which took part of its name from the PDP–11. In 1963, DEC introduced what is considered to be the first commercial minicomputer in the form of the PDP–5 . This was a 12-bit design adapted from

3051-818: The CPU , connecting semiconductor memory to the processor, with core memory and I/O devices connected via the Unibus. In the PDP–11/70, this was taken a step further, with the addition of a dedicated interface between disks and tapes and memory, via the Massbus . Although input/output devices continued to be mapped into memory addresses, some additional programming was necessary to set up the added bus interfaces. The PDP–11 supports hardware interrupts at four priority levels. Interrupts are serviced by software service routines, which could specify whether they themselves could be interrupted (achieving interrupt nesting ). The event that causes

3164-589: The PDP-11 and OS/8 for the PDP-8 . Commands take the form of a keyword followed by a list of parameters separated by spaces or special characters. Similar to a Unix shell builtin , if an internal command is recognized, it is carried out by the CCP itself. Otherwise it attempts to find an executable file on the currently logged disk drive and (in later versions) user area, loads it, and passes it any additional parameters from

3277-529: The TOPS-10 operating system of the DECsystem-10 mainframe computer , which Kildall had used as a development environment. An early outside licensee of CP/M was Gnat Computers , an early microcomputer developer out of San Diego, California . In 1977, the company was granted the license to use CP/M 1.0 for any micro they desired for $ 90. Within the year, demand for CP/M was so high that Digital Research

3390-486: The extension .COM on disk. The BIOS directly controls hardware components other than the CPU and main memory. It contains functions such as character input and output and the reading and writing of disk sectors. The BDOS implements the CP/M file system and some input/output abstractions (such as redirection) on top of the BIOS. The CCP takes user commands and either executes them directly (internal commands such as DIR to show

3503-493: The "Desk Calculator" project. Not long after, Datamation published a note about a desk calculator being developed at DEC, which caused concern at Wang Laboratories , who were heavily invested in that market. Before long, it became clear that the entire market was moving to 16-bit, and the Desk Calculator began a 16-bit design as well. The team decided that the best approach to a new architecture would be to minimize

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3616-557: The 1962 LINC machine that was intended to be used in a lab setting. DEC slightly simplified the LINC system and instruction set, aiming the PDP-5 at smaller settings that did not need the power of their larger 18-bit PDP-4 . The PDP-5 was a success, ultimately selling about 1,000 machines. This led to the PDP–8 , a further cost-reduced 12-bit model that sold about 50,000 units. During this period,

3729-441: The 7-bit boundary. In the 8-bit versions, while running, the CP/M operating system loaded into memory has three components: The BIOS and BDOS are memory-resident, while the CCP is memory-resident unless overwritten by an application, in which case it is automatically reloaded after the application finished running. A number of transient commands for standard utilities are also provided. The transient commands reside in files with

3842-429: The 8080 I/O address space. All of these variations in the hardware are concealed from other modules of the system by use of the BIOS, which uses standard entry points for the services required to run CP/M such as character I/O or accessing a disk block. Since support for serial communication to a modem is very rudimentary in the BIOS or may be absent altogether, it is common practice for CP/M programs that use modems to have

3955-421: The 8080 and would run on systems that did not have the requisite Z80 microprocessor. Features of ZCPR as of version 3 included shells, aliases, I/O redirection, flow control, named directories, search paths, custom menus, passwords, and online help. In January 1987, Richard Conn stopped developing ZCPR, and Echelon asked Jay Sage (who already had a privately enhanced ZCPR 3.1) to continue work on it. Thus, ZCPR 3.3

4068-609: The Amsterdam Savings Bank. The idea was that any person could take a Witkar, and leave it at the Witkar station closest to their destination. The initiators thought that the flow of traffic to and from these stations would allow for an even spread of Witkarren (the Dutch plural of Witkar). The system actually operated. The problems were several: the vehicles needed long recharging times, so many were needed to have some on

4181-429: The CP/M base included Robert "Bob" Silberstein and David "Dave" K. Brown. CP/M originally stood for "Control Program/Monitor", a name which implies a resident monitor —a primitive precursor to the operating system. However, during the conversion of CP/M to a commercial product, trademark registration documents filed in November 1977 gave the product's name as "Control Program for Microcomputers". The CP/M name follows

4294-656: The DEQNA Q-Bus card, were also available. Many of the earliest systems on the ARPANET were PDP–11's A wide range of peripherals were available; some of them were also used in other DEC systems like the PDP–8 or PDP–10 . The following are some of the more common PDP–11 peripherals. The PDP–11 family of computers was used for many purposes. It was used as a standard minicomputer for general-purpose computing, such as timesharing , scientific, educational, medical, government or business computing. Another common application

4407-764: The DN100 in 1981 running Domain/OS , which was proprietary but offered a degree of Unix compatibility; and the Silicon Graphics IRIS range, which developed into Unix-based workstations by 1985 (IRIS 2000). Personal computers based on the 68000 such as the Apple Lisa and Macintosh , the Atari ST , and the Commodore Amiga arguably constituted less of a threat to DEC's business, although technically these systems could also run Unix derivatives. In

4520-645: The Digital Research distributed core of CP/M (BDOS, CCP, core transient commands) did not use any of the Z80-specific instructions, many Z80-based systems used Z80 code in the system-specific BIOS, and many applications were dedicated to Z80-based CP/M machines. Digital Research subsequently partnered with Zilog and American Microsystems to produce Personal CP/M, a ROM-based version of the operating system aimed at lower-cost systems that could potentially be equipped without disk drives. First featured in

4633-589: The IBM PC after DRI threatened legal action, it never overtook Microsoft's system. Most customers were repelled by the significantly greater price IBM charged for CP/M-86 over PC DOS ( US$ 240 and US$ 40, respectively). When Digital Equipment Corporation (DEC) put out the Rainbow 100 to compete with IBM, it came with CP/M-80 using a Z80 chip, CP/M-86 or MS-DOS using an 8088 microprocessor, or CP/M-86/80 using both. The Z80 and 8088 CPUs ran concurrently. A benefit of

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4746-471: The IBM-compatible platform, and it never regained its former popularity. Byte magazine, at the time one of the leading industry magazines for microcomputers, essentially ceased covering CP/M products within a few years of the introduction of the IBM PC. For example, in 1983 there were still a few advertisements for S-100 boards and articles on CP/M software, but by 1987 these were no longer found in

4859-576: The Intel 8080 processor into .A86 source code for the Intel 8086. The translator would also optimize the output for code size and take care of calling conventions, so that CP/M-80 and MP/M-80 programs could be ported to the CP/M-86 and MP/M-86 platforms automatically. XLT86 itself was written in PL/I-80 and was available for CP/M-80 platforms as well as for VAX/VMS . Many expected that CP/M would be

4972-489: The Intel-contracted PL/M compiler into a commercial enterprise. The Kildalls intended to establish the Digital Research brand and its product lines as synonymous with "microcomputer" in the consumer's mind, similar to what IBM and Microsoft together later successfully accomplished in making " personal computer " synonymous with their product offerings. Intergalactic Digital Research, Inc. was later renamed via

5085-538: The LSI-11. This option allowed programming of the internal 8-bit micromachine to create application-specific extensions to the PDP–11 instruction set. The WCS is a quad Q-Bus board with a ribbon cable connecting to the third microcode ROM socket. The source code for EIS/FIS microcode was included so these instructions, normally located in the third MICROM, could be loaded in the WCS, if desired. Later Q-Bus based systems such as

5198-506: The LSI–11/23, /73, and /83 are based upon chip sets designed in house by Digital Equipment Corporation. Later PDP–11 Unibus systems were designed to use similar Q-Bus processor cards, using a Unibus adapter to support existing Unibus peripherals , sometimes with a special memory bus for improved speed. There were other significant innovations in the Q-Bus lineup. For example, a system variant of

5311-475: The Municipal Council. On April 3, 2017, the 82-years old Luud Schimmelpennink received the ‘Frans Banninck Cocq’ medal from the alderman of transportation in Amsterdam, Pieter Litjens. [REDACTED] Media related to Witkar at Wikimedia Commons PDP-11 The PDP–11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the late 1990s, one of

5424-517: The NIAT, a custom handheld computer designed for A. C. Nielsen 's internal use with 1  MB of SSD memory. In 1979, a multi-user compatible derivative of CP/M was released. MP/M allowed multiple users to connect to a single computer, using multiple terminals to provide each user with a screen and keyboard. Later versions ran on 16-bit processors. The last 8-bit version of CP/M was version 3, often called CP/M Plus, released in 1983. Its BDOS

5537-686: The OS and BIOS (this was also a common problem in early DOS machines). Bill Gates claimed that the Apple II with a Z-80 SoftCard was the single most-popular CP/M hardware platform. Many different brands of machines ran the operating system, some notable examples being the Altair 8800 , the IMSAI 8080 , the Osborne 1 and Kaypro luggables , and MSX computers. The best-selling CP/M-capable system of all time

5650-670: The PC based on BSD or Linux became available. By the late 1990s, not only DEC but most of the New England computer industry which had been built around minicomputers similar to the PDP–11 collapsed in the face of microcomputer-based workstations and servers. The PDP–11 processors tend to fall into several natural groups depending on the original design upon which they are based and which I/O bus they use. Within each group, most models were offered in two versions, one intended for OEMs and one intended for end-users. Although all models share

5763-504: The PDP series. Further, the innovative Unibus system allowed external devices to be more easily interfaced to the system using direct memory access , opening the system to a wide variety of peripherals . The PDP–11 replaced the PDP–8 in many real-time computing applications, although both product lines lived in parallel for more than 10 years. The ease of programming of the PDP–11 made it popular for general-purpose computing. The design of

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5876-557: The PDP–11 and could use its peripherals and system software. These include: Several operating systems were available for the PDP–11. The DECSA communications server was a communications platform developed by DEC based on a PDP–11/24, with the provision for user installable I/O cards including asynchronous and synchronous modules. This product was used as one of the earliest commercial platforms upon which networking products could be built, including X.25 gateways, SNA gateways, routers , and terminal servers . Ethernet adaptors, such as

5989-709: The PDP–11 has a move instruction for which either operand (source and destination) can be memory or register. There are no specific input or output instructions; the PDP–11 uses memory-mapped I/O and so the same move instruction is used; orthogonality even enables moving data directly from an input device to an output device. More complex instructions such as add likewise can have memory, register, input, or output as source or destination. Most operands can apply any of eight addressing modes to eight registers. The addressing modes provide register, immediate, absolute, relative, deferred (indirect), and indexed addressing, and can specify autoincrementation and autodecrementation of

6102-510: The PDP–11 inspired the design of late-1970s microprocessors including the Intel x86 and the Motorola 68000 . The design features of PDP–11 operating systems, and other operating systems from Digital Equipment, influenced the design of operating systems such as CP/M and hence also MS-DOS . The first officially named version of Unix ran on the PDP–11/20 in 1970. It is commonly stated that

6215-402: The PDP–11 system-software rights to Mentec Inc., an Irish producer of LSI-11 based boards for Q-Bus and ISA architecture personal computers, and in 1997 discontinued PDP–11 production. For several years, Mentec produced new PDP–11 processors. Other companies found a niche market for replacements for legacy PDP–11 processors, disk subsystems, etc. At the same time, free implementations of Unix for

6328-479: The PDP–11/03 introduced full system power-on self-test (POST). The basic design of the PDP–11 was flexible, and was continually updated to use newer technologies. However, the limited throughput of the Unibus and Q-Bus started to become a system-performance bottleneck , and the 16-bit logical address limitation hampered the development of larger software applications. The article on PDP–11 architecture describes

6441-607: The PSW (priority level) on entry to the service routine. The PDP–11 was designed for ease of manufacture by semiskilled labor. The dimensions of its pieces were relatively non-critical. It used a wire-wrapped backplane . The LSI–11 (PDP–11/03), introduced in February 1975 is the first PDP–11 model produced using large-scale integration ; the entire CPU is contained on four LSI chips made by Western Digital (the MCP-1600 chip set;

6554-565: The Rainbow was that it could continue to run 8-bit CP/M software, preserving a user's possibly sizable investment as they moved into the 16-bit world of MS-DOS. A similar dual-processor adaption for the CompuPro System 816  [ sr ] was named CP/M 8-16 . The CP/M-86 adaptation for the 8085/8088-based Zenith Z-100 also supported running programs for both of its CPUs. Soon following CP/M-86, another 16-bit version of CP/M

6667-502: The S83 was quoted as $ 32 in 1,000 unit quantities. On most machines the bootstrap was a minimal bootloader in ROM combined with some means of minimal bank switching or a means of injecting code on the bus (since the 8080 needs to see boot code at Address 0 for start-up, while CP/M needs RAM there); for others, this bootstrap had to be entered into memory using front-panel controls each time

6780-543: The Sharp MZ-800, a cassette-based system with optional disk drives, Personal CP/M was described as having been "rewritten to take advantage of the enhanced Z-80 instruction set" as opposed to preserving portability with the 8080. American Microsystems announced a Z80-compatible microprocessor, the S83, featuring 8 KB of in-package ROM for the operating system and BIOS, together with comprehensive logic for interfacing with 64-kilobit dynamic RAM devices. Unit pricing of

6893-418: The Unibus only allows an 18-bit physical address) and block-mode operations for significantly improved bandwidth (which the Unibus does not support). The CPU microcode includes a debugger : firmware with a direct serial interface ( RS-232 or current loop ) to a terminal . This lets the operator do debugging by typing commands and reading octal numbers, rather than operating switches and reading lights,

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7006-402: The ancestor of Borland Delphi , and Multiplan , the ancestor of Microsoft Excel , also debuted on CP/M before MS-DOS versions became available. VisiCalc , the first-ever spreadsheet program, was made available for CP/M. Another company, Sorcim , created its SuperCalc spreadsheet for CP/M, which would go on to become the market leader and de facto standard on CP/M. Supercalc would go on to be

7119-420: The basic concepts and mechanisms of early versions of MS-DOS resembled those of CP/M. Internals like file-handling data structures were identical, and both referred to disk drives with a letter ( A: , B: , etc.). MS-DOS's main innovation was its FAT file system. This similarity made it easier to port popular CP/M software like WordStar and dBase . However, CP/M's concept of separate user areas for files on

7232-408: The basis for the PDP–11. When they first presented the new architecture, the managers were dismayed. It lacked single instruction-word immediate data and short addresses, both of which were considered essential to improving memory performance. McGowan and McFarland were eventually able to convince them that the system would work as expected, and suddenly "the Desk Calculator project got hot". Much of

7345-531: The blocking and deblocking and the management of a disk buffer area is handled by model-specific code in the BIOS. Customization is required because hardware choices are not constrained by compatibility with any one popular standard. For example, some manufacturers designed built-in integrated video display systems, while others relied on separate computer terminals. Serial ports for printers and modems can use different types of UART chips, and port addresses are not fixed. Some machines use memory-mapped I/O instead of

7458-452: The command line. These are referred to as "transient" programs. On completion, BDOS will reload the CCP if it has been overwritten by application programs — this allows transient programs a larger memory space. The commands themselves can sometimes be obscure. For instance, the command to duplicate files is named PIP (Peripheral-Interchange-Program), the name of the old DEC utility used for that purpose. The format of parameters given to

7571-451: The computer market was moving from computer word lengths based on units of 6 bits to units of 8 bits, following the introduction of the 7-bit ASCII standard. In 1967–1968, DEC engineers designed a 16-bit machine, the PDP–X, but management ultimately canceled the project as it did not appear to offer a significant advantage over their existing 12- and 18-bit platforms. This prompted several of

7684-454: The disk. From version 1.1 or 1.2 onwards, changing a disk then trying to write to it before its directory is read will cause a fatal error to be signalled. This avoids overwriting the disk but requires a reboot and loss of the data to be stored on disk. The majority of the complexity in CP/M is isolated in the BDOS, and to a lesser extent, the CCP and transient commands. This meant that by porting

7797-652: The early years, in particular, Microsoft 's Xenix was ported to systems like the TRS-80 Model 16 (with up to 1 MB of memory) in 1983, and to the Apple Lisa, with up to 2 MB of installed RAM, in 1984. The mass-production of those chips eliminated any cost advantage for the 16-bit PDP–11. A line of personal computers based on the PDP–11, the DEC Professional series, failed commercially, along with other non-PDP–11 PC offerings from DEC. In 1994, DEC sold

7910-599: The emergence of a market of increasingly powerful scientific and technical workstations that would often run Unix variants. These included the HP 9000 series 200 (starting with the HP 9826A in 1981) and 300/400, with the HP-UX system being ported to the 68000 in 1984; Sun Microsystems workstations running SunOS , starting with the Sun-1 in 1982; Apollo/Domain workstations starting with

8023-459: The end of 1976, by which time the fleet was to have been extended to 100 vehicles. The ultimate target was 150 stations and 1,000 vehicles, but as a result of lack of government support this never happened. The core of the Witkar concept is that of people sharing small environmentally-acceptable vehicles specially designed for urban use. It was seen by Schimmelpennink and his team as a way to wean people away from conventional car ownership and use, on

8136-454: The engineers from the PDP-X program to leave DEC and form Data General . The next year they introduced the 16-bit Data General Nova . The Nova sold tens of thousands of units and launched what would become one of DEC's major competitors through the 1970s and 1980s. Ken Olsen , president and founder of DEC, was more interested in a small 8-bit machine than the larger 16-bit system. This became

8249-532: The following components: The only hardware system that CP/M, as sold by Digital Research, would support was the Intel 8080 Development System. 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 systems based on the Zilog Z80 processor since the Z80 was compatible with 8080 code. While

8362-514: The forward slash character for comments in the assembler code, as was the case in the PDP–8 assembler. McGowan stated that he would then have to use semicolon to indicate division, and the idea was dropped. The PDP–11 family was announced in January 1970 and shipments began early that year. DEC sold over 170,000 PDP–11s in the 1970s. Initially manufactured of small-scale transistor–transistor logic ,

8475-454: The grounds that such vehicles have no place in densely settled cities. These were specially designed electric vehicles. They had two seats, and offered little luxury. They were very easy to recognize. The vehicles were located around the city in pods. In Amsterdam 35 of these cars were available to hire from five stations in the city centre. The original system was designed for fully automatic control, including direct debit of hirers' accounts at

8588-515: The hardware and software techniques used to work around address-space limitations. DEC's 32-bit successor to the PDP–11, the VAX–11 (for "Virtual Address eXtension") overcame the 16-bit limitation, but was initially a superminicomputer aimed at the high-end time-sharing market. The early VAX CPUs provided a PDP–11 compatibility mode under which much existing software could be immediately used, in parallel with newer 32-bit software, but this capability

8701-409: The home market had been largely unsuccessful and most CP/M software was too expensive for home users. In 1986 the magazine stated that Kaypro had stopped production of 8-bit CP/M-based models to concentrate on sales of MS-DOS compatible systems, long after most other vendors had ceased production of new equipment and software for CP/M. CP/M rapidly lost market share as the microcomputing market moved to

8814-412: The interrupt is indicated by the device itself, as it informs the processor of the address of its own interrupt vector. Interrupt vectors are blocks of two 16-bit words in low kernel address space (which normally corresponded to low physical memory) between 0 and 776. The first word of the interrupt vector contains the address of the interrupt service routine and the second word the value to be loaded into

8927-460: The keyboard and conveys results to the terminal. CP/M itself works with either a printing terminal or a video terminal. All CP/M commands have to be typed in on the command line . The console most often displays the A>; prompt, to indicate the current default disk drive. When used with a video terminal, this is usually followed by a blinking cursor supplied by the terminal. The CCP awaits input from

9040-546: The limited number of simple routines in the BIOS to a particular hardware platform, the entire OS would work. This significantly reduced the development time needed to support new machines, and was one of the main reasons for CP/M's widespread use. Today this sort of abstraction is common to most OSs (a hardware abstraction layer ), but at the time of CP/M's birth, OSs were typically intended to run on only one machine platform, and multilayer designs were considered unnecessary. The Console Command Processor, or CCP, accepts input from

9153-480: The lowest address of the BDOS was the Transient Program Area (TPA) available for CP/M application programs. Although all Z80 and 8080 processors could address 64 kilobytes of memory, the amount available for application programs could vary, depending on the design of the particular computer. Some computers used large parts of the address space for such things as BIOS ROMs, or video display memory. As

9266-434: The lowest level functions required by the operating system. These include reading or writing single characters to the system console and reading or writing a sector of data from the disk. The BDOS handles some of the buffering of data from the diskette, but before CP/M 3.0 it assumes a disk sector size fixed at 128 bytes, as used on single-density 8-inch floppy disks. Since most 5.25-inch disk formats use larger sectors,

9379-513: The magazine. Later versions of CP/M-86 made significant strides in performance and usability and were made compatible with MS-DOS. To reflect this compatibility the name was changed, and CP/M-86 became DOS Plus , which in turn became DR-DOS . ZCPR (the Z80 Command Processor Replacement) was introduced on 2 February 1982 as a drop-in replacement for the standard Digital Research console command processor (CCP) and

9492-408: The memory bandwidth needed to execute the instructions. Larry McGowan coded a series of assembly language programs using the instruction sets of various existing platforms and examined how much memory would be exchanged to execute them. Harold McFarland joined the effort and had already written a very complex instruction set that the team rejected, but a second one was simpler and would ultimately form

9605-523: The microcomputer industry. This computer platform was widely used in business through the late 1970s and into the mid-1980s. CP/M increased the market size for both hardware and software by greatly reducing the amount of programming required to port an application to a new manufacturer's computer. An important driver of software innovation was the advent of (comparatively) low-cost microcomputers running CP/M, as independent programmers and hackers bought them and shared their creations in user groups . CP/M

9718-434: The new location of the operating system in processor memory. This newly patched version can then be saved on a new disk, allowing application programs to access the additional memory made available by moving the system components. Once installed, the operating system (BIOS, BDOS and CCP) is stored in reserved areas at the beginning of any disk which can be used to boot the system. On start-up, the bootloader (usually contained in

9831-451: The operating system because "where there are literally thousands of programs written for it, it would be unwise not to take advantage of it", Xerox said. (Xerox included a Howard W. Sams CP/M manual as compensation for Digital Research's documentation, which InfoWorld described as atrocious, incomplete, incomprehensible, and poorly indexed. ) By 1984, Columbia University used the same source code to build Kermit binaries for more than

9944-624: The predecessors of Alcatel-Lucent , the Bell Telephone Manufacturing Company , developed the BTMC DPS-1500 packet-switching ( X.25 ) network and used PDP–11s in the regional and national network management system, with the Unibus directly connected to the DPS-1500 hardware. Higher-performance members of the PDP–11 family departed from the single-bus approach. The PDP–11/45 had a dedicated data path within

10057-443: The processor architecture made it unusually easy to invent new bus devices, including devices to control hardware that had not been contemplated when the processor was originally designed. DEC openly published the basic Unibus specifications, even offering prototyping bus interface circuit boards, and encouraging customers to develop their own Unibus-compatible hardware. The Unibus made the PDP–11 suitable for custom peripherals. One of

10170-411: The road all the time. The biggest problem was that the flow of traffic was generally in one direction. As a result of this, some stations were always full, and others always empty. To correct this by moving Witkarren would have caused a lot of extra traffic. In January 2007, Schimmelpennink and his associates planned a new Witkar program for Amsterdam, where he had recently (March 2006) been re-elected to

10283-532: The same as found in the 11/23, 11/23+ and 11/24. The PRO-380 is based on the DCJ-11 ("Jaws") chipset, the same as found in the 11/53,73,83 and others, though running only at 10 MHz because of limitations in the support chipset. The PDP–11 was sufficiently popular that many unlicensed PDP–11-compatible minicomputers and microcomputers were produced in Eastern Bloc countries. Some were pin-compatible with

10396-513: The same disk was never ported to MS-DOS. Since MS-DOS had access to more memory (as few IBM PCs were sold with less than 64 KB of memory, while CP/M could run in 16 KB if necessary), more commands were built into the command-line shell , making MS-DOS somewhat faster and easier to use on floppy-based computers. Although one of the first peripherals for the IBM PC was a SoftCard-like expansion card that let it run 8-bit CP/M software, InfoWorld stated in 1984 that efforts to introduce CP/M to

10509-516: The same instruction set, later models added new instructions and interpreted certain instructions slightly differently. As the architecture evolved, there were also variations in handling of some processor status and control registers. The following models use the Unibus as their principal bus: The following models use the Q-Bus as their principal bus: The PDT series were desktop systems marketed as "smart terminals". The /110 and /130 were housed in

10622-513: The standard operating system for 16-bit computers. In 1980 IBM approached Digital Research, at Bill Gates ' suggestion, to license a forthcoming version of CP/M for its new product, the IBM Personal Computer. Upon the failure to obtain a signed non-disclosure agreement , the talks failed, and IBM instead contracted with Microsoft to provide an operating system. The resulting product, MS-DOS , soon began outselling CP/M. Many of

10735-538: The support of the City Council and was spun off to be developed by a specially formed co-operative society. The co-operative managed to raise loans of US$ 250,000 for the first phase through 1974. This included the design and construction of the vehicles, the purchase of a PDP-11 minicomputer for the central control system, development of the control software, and construction of the first 35 cars and five stations. A further 10 stations were scheduled for operation by

10848-457: The system was developed using a PDP-10 where the SIM-11 simulated what would become the PDP–11/20 and Bob Bowers wrote an assembler for it. At a late stage, the marketing team wanted to ship the system with 2K of memory as the minimal configuration. When McGowan stated this would mean an assembler could not run on the system, the minimum was expanded to 4K. The marketing team also wanted to use

10961-616: The system was started. 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, and Osborne machines used the 8th bit set to indicate an underlined character. WordStar used the 8th bit as an end-of-word marker. International CP/M systems most commonly used the ISO 646 norm for localized character sets, replacing certain ASCII characters with localized characters rather than adding them beyond

11074-472: The typical debugging method at the time. The operator can thus examine and modify the computer's registers, memory, and input/output devices, diagnosing and perhaps correcting failures in software and peripherals (unless a failure disables the microcode itself). The operator can also specify which disk to boot from. Both innovations increased the reliability and decreased the cost of the LSI-11. A Writable Control Store (WCS) option (KUV11-AA) could be added to

11187-411: The user. A CCP internal command, of the form drive letter followed by a colon, can be used to select the default drive. For example, typing B: and pressing enter at the command prompt changes the default drive to B, and the command prompt then becomes B> to indicate this change. CP/M's command-line interface was patterned after the operating systems from Digital Equipment , such as RT-11 for

11300-601: Was CP/M-68K for the Motorola 68000 . The original version of CP/M-68K in 1982 was written in Pascal/MT+68k , but it was ported to C later on. CP/M-68K, already running on the Motorola EXORmacs systems, was initially to be used in the Atari ST computer, but Atari decided to go with a newer disk operating system called GEMDOS . CP/M-68K was also used on the SORD M68 and M68MX computers. In 1982, there

11413-469: Was real-time process control and factory automation . Some OEM models were also frequently used as embedded systems to control complex systems like traffic-light systems, medical systems, numerical controlled machining , or for network management. An example of such use of PDP–11s was the management of the packet switched network Datanet 1. In the 1980s, the UK's air traffic control radar processing

11526-454: Was able to increase the license to tens of thousands of dollars. Under Kildall's direction, the development of CP/M 2.0 was mostly carried out by John Pierce in 1978. Kathryn Strutynski , a friend of Kildall from Naval Postgraduate School (NPS), became the fourth employee of Digital Research Inc. in early 1979. She started by debugging CP/M 2.0, and later became influential as key developer for CP/M 2.2 and CP/M Plus. Other early developers of

11639-466: Was also a port from CP/M-68K to the 16-bit Zilog Z8000 for the Olivetti M20 , written in C , named CP/M-8000 . These 16-bit versions of CP/M required application programs to be re-compiled for the new CPUs. Some programs written in assembly language could be automatically translated for a new processor. One tool for this was Digital Research's XLT86 , which translated .ASM source code for

11752-455: Was conducted on a PDP 11/34 system known as PRDS – Processed Radar Display System at RAF West Drayton. The software for the Therac-25 medical linear particle accelerator also ran on a 32K PDP 11/23. In 2013, it was reported that PDP–11 programmers would be needed to control nuclear power plants through 2050. Another use was for storage of test programs for Teradyne ATE equipment, in

11865-399: Was designed by David K. Brown. It incorporated the bank switching memory management of MP/M in a single-user single-task operating system compatible with CP/M 2.2 applications. CP/M 3 could therefore use more than 64 KB of memory on an 8080 or Z80 processor. The system could be configured to support date stamping of files. The operating system distribution software also included

11978-467: Was developed and released. ZCPR 3.3 no longer supported the 8080 series of microprocessors, and added the most features of any upgrade in the ZCPR line. ZCPR 3.3 also included a full complement of utilities with considerably extended capabilities. While enthusiastically supported by the CP/M user base of the time, ZCPR alone was insufficient to slow the demise of CP/M. A minimal 8-bit CP/M system would contain

12091-587: Was dropped with the first MicroVAX . For a decade, the PDP–11 was the smallest system that could run Unix , but in the 1980s, the IBM PC and its clones largely took over the small computer market; BYTE in 1984 reported that the PC's Intel 8088 microprocessor could outperform the PDP–11/23 when running Unix. Newer microprocessors such as the Motorola 68000 (1979) and Intel 80386 (1985) also included 32-bit logical addressing. The 68000 in particular facilitated

12204-460: Was eventually displaced by DOS following the 1981 introduction of the IBM PC . Gary Kildall originally developed CP/M during 1974, as an operating system to run on an Intel Intellec-8 development system, equipped with a Shugart Associates 8-inch floppy-disk drive interfaced via a custom floppy-disk controller . It was written in Kildall's own PL/M ( Programming Language for Microcomputers ). Various aspects of CP/M were influenced by

12317-426: Was initially written by a group of computer hobbyists who called themselves "The CCP Group". They were Frank Wancho, Keith Petersen (the archivist behind Simtel at the time), Ron Fowler, Charlie Strom, Bob Mathias, and Richard Conn. Richard was, in fact, the driving force in this group (all of whom maintained contact through email). ZCPR1 was released on a disk put out by SIG/M (Special Interest Group/Microcomputers),

12430-514: Was probably the Amstrad PCW . In the UK, CP/M was also available on Research Machines educational computers (with the CP/M source code published as an educational resource), and for the BBC Micro when equipped with a Z80 co-processor. Furthermore, it was available for the Amstrad CPC series, the Commodore 128 , TRS-80 , and later models of the ZX Spectrum . CP/M 3 was also used on

12543-465: Was the project manager for the evolving CP/M-86 line of operating systems. At this point, the original 8-bit CP/M became known by the retronym CP/M-80 to avoid confusion. CP/M-86 was expected to be the standard operating system of the new IBM PCs , but DRI and IBM were unable to negotiate development and licensing terms. IBM turned to Microsoft instead, and Microsoft delivered PC DOS based on 86-DOS . Although CP/M-86 became an option for

12656-713: Was used for the experiment that discovered the J/ψ meson at the Brookhaven National Laboratory . In 1976, Samuel C. C. Ting received the Nobel Prize for this discovery. Another PDP–11/45 was used to create the Death Star plans during the briefing sequence in Star Wars . CP/M CP/M , originally standing for Control Program/Monitor and later Control Program for Microcomputers ,

12769-422: Was written for CP/M than for operating systems that ran on only one brand of hardware. One restriction on portability was that certain programs used the extended instruction set of the Z80 processor and would not operate on an 8080 or 8085 processor. Another was graphics routines, especially in games and graphics programs, which were generally machine-specific as they used direct hardware access for speed, bypassing

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