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105-767: It became available two years after the similar, but CP/M -based, Osborne 1 and Kaypro II . Columbia Data Products ' MPC 1600 "Multi Personal Computer" had come out in June 1982. Other "work-alikes" included the MS-DOS and 8088-based, but not entirely IBM PC software compatible, Dynalogic Hyperion , Eagle Computer 's Eagle 1600 series, including the Eagle Spirit portable, and the Corona personal computer. The latter two companies were threatened by IBM for BIOS copyright infringement, and settled out of court, agreeing to re-implement their BIOS. There

210-541: A luggable case the size of a portable sewing machine . IBM responded to the Compaq Portable with the IBM Portable PC , developed because its sales force needed a comparable computer to sell against Compaq. Compaq sold 53,000 units in the first year with a total of US$ 111 million in revenue, an American Business record. In the second year revenue hit US$ 329 million setting an industry record. Third year revenue

315-413: A 120 or 240 Hz (current and former NTSC countries) or 100 or 200 Hz (PAL/SECAM countries) refresh rate. The rate of 120 was chosen as the least common multiple of 24 fps (cinema) and 30 fps (NTSC TV), and allows for less distortion when movies are viewed due to the elimination of telecine (3:2 pulldown). For PAL at 25 fps, 100 or 200 Hz is used as a fractional compromise of

420-414: A CRT are ideally suited to this approach, fast scenes will benefit from the 50 Hz refresh, the earlier field will have largely decayed away when the new field is written, and static images will benefit from improved resolution as both fields will be integrated by the eye. Modern CRT-based televisions may be made flicker-free in the form of 100 Hz technology. Many high-end LCD televisions now have

525-405: A CRT, the vertical scan rate is the number of times per second that the electron beam returns to the upper left corner of the screen to begin drawing a new frame. It is controlled by the vertical blanking signal generated by the video controller , and is partially limited by the monitor's maximum horizontal scan rate . The refresh rate can be calculated from the horizontal scan rate by dividing

630-413: 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

735-464: 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

840-413: A conservative rate, usually 60 Hz. Some fullscreen applications, including many games, now allow the user to reconfigure the refresh rate before entering fullscreen mode, but most default to a conservative resolution and refresh rate and let you increase the settings in the options. Old monitors could be damaged if a user set the video card to a refresh rate higher than the highest rate supported by

945-528: 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

1050-417: A datum is updated with a new external value from another source (for example; a shared public spreadsheet or hardware feed). While all raster display devices have a characteristic refresh rate, the physical implementation differs between technologies. Raster-scan CRTs by their nature must refresh the screen since their phosphors will fade and the image will disappear quickly unless refreshed regularly. In

1155-773: 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

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1260-460: 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

1365-449: 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

1470-429: 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

1575-400: A fixed 60 fps rate cannot display a 24 fps movie at an even, judder-free rate. Usually a 3:2 pulldown is used, giving a slight uneven movement. While common multisync CRT computer monitors have been capable of running at even multiples of 24 Hz since the early 1990s, recent "120 Hz" LCDs have been produced for the purpose of having smoother, more fluid motion, depending upon

1680-458: A half-height floppy drive and a tape backup drive. BYTE wrote, after testing a prototype, that the Compaq Portable "looks like a sure winner" because of its portability, cost, and high degree of compatibility with the IBM PC. Its reviewer tested IBM PC DOS , CP/M-86 , WordStar , SuperCalc , and several other software packages, and found that all worked except one game. PC Magazine also rated

1785-462: A larger external monitor, the graphics hardware is also used in the original Compaq Deskpro desktop computer. Compaq used a "foam and foil" keyboard from Keytronics, with contact mylar pads that were also featured in the Tandy TRS-80, Apple Lisa 1 and 2, Compaq Deskpro 286 AT, some mainframe terminals , SUN Type 4, and some Wang keyboards. The foam pads the keyboards used to make contact with

1890-494: A lost revenue opportunity. The Compaq Portable 286, Compaq's version of the PC AT , was offered in the original Compaq Portable chassis; it was equipped with a 6/8 MHz 286 and a high-speed 20 MB hard drive . The Compaq Portable machine was the first of a series of Compaq Portable machines . The Compaq Portable II was smaller and lighter version of Compaq Portable 286; it was less expensive but with limited upgradability and

1995-406: A minimum of 200 Hz. Different operating systems set the default refresh rate differently. Microsoft Windows 95 and Windows 98 (First and Second Editions) set the refresh rate to the highest rate that they believe the display supports. Windows NT -based operating systems, such as Windows 2000 and its descendants Windows XP , Windows Vista and Windows 7 , set the default refresh rate to

2100-469: 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

2205-508: 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

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2310-508: 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

2415-798: 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

2520-478: A result, some systems had more TPA memory available than others. Bank switching was a common technique that allowed systems to have a large TPA while switching out ROM or video memory space as needed. CP/M 3.0 allowed parts of the BDOS to be in bank-switched memory as well. Refresh rate The refresh rate , also known as vertical refresh rate or vertical scan rate in reference to terminology originating with

2625-472: A separate picture. For this reason, it is usually recommended to use a display capable of at least 120 Hz, because divided in half this rate is again 60 Hz. Higher refresh rates result in greater image stability, for example 72 Hz non-stereo is 144 Hz stereo, and 90 Hz non-stereo is 180 Hz stereo. Most low-end computer graphics cards and monitors cannot handle these high refresh rates, especially at higher resolutions. For LCD monitors

2730-424: A slower hard drive , The Compaq Portable III , Compaq Portable 386 , Compaq Portable 486 and Compaq Portable 486c were later in the series. CP/M CP/M , originally standing for Control Program/Monitor and later Control Program for Microcomputers , is a mass-market operating system created in 1974 for Intel 8080 / 85 -based microcomputers by Gary Kildall of Digital Research, Inc. CP/M

2835-530: 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 ,

2940-540: 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

3045-418: 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

3150-451: 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

3255-403: Is drawn. The development of televisions in the 1930s was determined by a number of technical limitations. The AC power line frequency was used for the vertical refresh rate for two reasons. The first reason was that the television's vacuum tube was susceptible to interference from the unit's power supply, including residual ripple. This could cause drifting horizontal bars (hum bars). Using

Compaq Portable - Misplaced Pages Continue

3360-424: Is not being updated, during which the image data in the host system's frame buffer can be updated. Vsync options can eliminate screen tearing by rendering the whole image at the same time. On smaller CRT monitors (up to about 15 in or 38 cm), few people notice any discomfort between 60–72 Hz. On larger CRT monitors (17 in or 43 cm or larger), most people experience mild discomfort unless

3465-530: 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

3570-578: 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

3675-518: 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

3780-420: The cathode-ray tubes (CRTs), is the number of times per second that a raster-based display device displays a new image. This is independent from frame rate , which describes how many images are stored or generated every second by the device driving the display. On CRT displays, higher refresh rates produce less flickering , thereby reducing eye strain. In other technologies such as liquid-crystal displays ,

3885-483: 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

3990-432: The 120 Hz rate is produced by frame-doubling a 60 fps 3:2 pulldown signal, the uneven motion could still be visible (i.e., so-called 6-4 pulldown). Additionally, material may be displayed with synthetically created smoothness with the addition of motion interpolation abilities to the display, which has an even larger effect on filmed material. "50 Hz" TV sets (when fed with "50 Hz" content) usually get

4095-441: 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

4200-429: 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

4305-421: 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

Compaq Portable - Misplaced Pages Continue

4410-429: 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

4515-593: The Compaq Portable runs on power from an AC outlet only; it has no battery. The machine has a hybrid of the IBM MDA and CGA which supports the latter's graphics modes, but uses the former's character set in 80x25 text mode. When using the internal monochrome monitor the 9×14 font is used, and the 8×8 one when an external monitor is used (the user switches between internal and external monitors by pressing Ctrl + Alt + > ). The user can use both IBM video standards, for graphics capabilities and high-resolution text. With

4620-556: The Compaq Portable very highly for compatibility, reporting that all tested applications ran. It praised the "rugged" hardware design and sharp display, and concluded that it was "certainly worth consideration by anyone seeking to run IBM PC software without an IBM PC". Released in 1983 upgraded version; The Compaq Portable Plus simply had a hard drive to replace one floppy disk drive, and logos and badges with gold backgrounds instead of silver. Independent computer stores were previously doing this upon request of users, and Compaq saw this as

4725-631: 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

4830-531: 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

4935-511: The IBM PC in that the BIOS was limited to 544 KB of RAM and did not support expansion ROMs, thus making them unable to use EGA / VGA cards, hard disks, or similar hardware. After DOS 2.x and the IBM XT came out, Compaq upgraded the BIOS. Although the Portable was not offered with a factory hard disk, users commonly installed them. Starting in 1984, Compaq began offering a hard disk-equipped version,

5040-464: 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

5145-562: 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

5250-480: 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

5355-513: 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

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5460-665: 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

5565-521: The Portable Plus, which also featured a single half-height floppy drive. The hard disk offered would be 10 to 21 megabytes, although bad sectors often reduced the space available for use. In 1985, Compaq introduced the Portable 286, but it was replaced by the more compact Portable II in a redesigned case within a few months. The Portable 286 featured a full-height hard disk, and the options of one half-height floppy drive, two half-height floppy drives, or

5670-553: 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

5775-496: 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

5880-537: 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

5985-402: 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

6090-408: The apparent flicker by painting first the odd lines and then the even lines (these are known as fields). This doubles the refresh rate, compared to a progressive scan image at the same frame rate. This works perfectly for video cameras, where each field results from a separate exposure – the effective frame rate doubles, there are now 50 rather than 25 exposures per second. The dynamics of

6195-420: 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

6300-531: 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

6405-491: The circuit board when pressed disintegrate over time, due to both the wear of normal use and natural wear. The CRT display also suffered from a low refresh rate and heavy ghosting . Compaq's efforts were possible because IBM had used mostly off-the-shelf parts for the PC and published full technical documentation for it, and because Microsoft had kept the right to license MS-DOS to other computer manufacturers. The only difficulty

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6510-452: 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

6615-403: 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

6720-444: The film by 4%. The resulting picture is therefore smooth, however, there is a small shift in the pitch of the audio. NTSC sets display both 24 fps and 25 fps material without any speed shifting by using a technique called 3:2 pulldown , but at the expense of introducing unsmooth playback in the form of telecine judder . Similar to some computer monitors and some DVDs, analog television systems use interlace , which decreases

6825-640: The first full-color portable computer. Like the Z80 and "work-alike" portables, its sales fell into insignificance in the face of the Compaq Portable series . The Compaq Portable was announced in November 1982 and first shipped in March 1983, priced at US$ 2,995 (equivalent to $ 9,200 in 2023) with a single half-height 5 + 1 ⁄ 4 " 360 KB diskette drive or US$ 3,590 for dual, full-height diskette drives. The 28 lb (13 kg) Compaq Portable folded up into

6930-478: 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

7035-409: 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

7140-456: 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

7245-562: The least common multiple of 600 (24 × 25). These higher refresh rates are most effective from a 24p -source video output (e.g. Blu-ray Disc ), and/or scenes of fast motion. As movies are usually filmed at a rate of 24 frames per second, while television sets operate at different rates, some conversion is necessary. Different techniques exist to give the viewer an optimal experience. The combination of content production, playback device, and display device processing may also give artifacts that are unnecessary. A display device producing

7350-546: 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

7455-522: The lower refresh rate of 50 Hz introduces more flicker, so sets that use digital technology to double the refresh rate to 100 Hz are now very popular. (see Broadcast television systems ) Another difference between 50 Hz and 60 Hz standards is the way motion pictures (film sources as opposed to video camera sources) are transferred or presented. 35 mm film is typically shot at 24 frames per second (fps). For PAL 50 Hz this allows film sources to be easily transferred by accelerating

7560-470: 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

7665-434: 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,

7770-500: 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

7875-523: 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

7980-402: The monitor. Some models of monitors display a notice that the video signal uses an unsupported refresh rate. Some LCDs support adapting their refresh rate to the current frame rate delivered by the graphics card. Two technologies that allow this are FreeSync and G-Sync . When LCD shutter glasses are used for stereo 3D displays , the effective refresh rate is halved, because each eye needs

8085-434: 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

8190-427: The only time available for computation was during the vertical blanking interval , during which the beam is returning to the top right corner of the screen and no image is being drawn. Even in modern games, however, it is important to avoid altering the computer's video buffer except during the vertical retrace, to prevent flickering graphics or screen tearing . Unlike CRTs, where the image will fade unless refreshed,

8295-406: The open market. The first Portables used Compaq DOS 1.10, essentially identical to PC DOS 1.10 except for having a standalone BASIC that did not require the IBM PC's ROM Cassette BASIC, but this was superseded in a few months by DOS 2.00 which added hard disk support and other advanced features. Aside from using DOS 1.x, the initial Portables are similar to the 16 KB – 64 KB models of

8400-451: 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

8505-411: The pixel brightness changes are much slower than CRT or plasma phosphors. Typically LCD pixel brightness changes are faster when voltage is applied than when voltage is removed, resulting in an asymmetric pixel response time. With 3D shutter glasses this can result in a blurry smearing of the display and poor depth perception, due to the previous image frame not fading to black fast enough as the next frame

8610-401: The pixels of liquid-crystal displays retain their state for as long as power is provided, and consequently there is no intrinsic flicker regardless of refresh rate. However, the refresh rate still determines the highest frame rate that can be displayed, and despite there being no actual blanking of the screen, the vertical blanking interval is still a period in each refresh cycle when the screen

8715-413: The refresh is set to 72 Hz or higher. A rate of 100 Hz is comfortable at almost any size. However, this does not apply to LCD monitors. The closest equivalent to a refresh rate on an LCD monitor is its frame rate , which is often locked at 60 fps. But this is rarely a problem, because the only part of an LCD monitor that could produce CRT-like flicker—its backlight—typically operates at around

8820-424: The refresh rate affects only how often the image can potentially be updated. Non-raster displays may not have a characteristic refresh rate. Vector displays , for instance, do not trace the entire screen, only the actual lines comprising the displayed image, so refresh speed may differ by the size and complexity of the image data. For computer programs or telemetry , the term is sometimes applied to how frequently

8925-513: 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

9030-831: The same frequency reduced this, and made interference static on the screen and therefore less obtrusive. The second reason was that television studios would use AC lamps, filming at a different frequency would cause strobing . Thus producers had little choice but to run sets at 60 Hz in America, and 50 Hz in Europe. These rates formed the basis for the sets used today: 60 Hz System M (almost always used with NTSC color coding) and 50 Hz System B/G (almost always used with PAL or SECAM color coding). This accident of chance gave European sets higher resolution, in exchange for lower frame-rates. Compare System M (704 × 480 at 30i) and System B/G (704 × 576 at 25i). However,

9135-480: The scanning frequency by the number of horizontal lines, plus some amount of time to allow for the beam to return to the top. By convention, this is a 1.05x multiplier. For instance, a monitor with a horizontal scanning frequency of 96 kHz at a resolution of 1280 × 1024 results in a refresh rate of 96,000 ÷ (1024 × 1.05) ≈ 89 Hz (rounded down). CRT refresh rates have historically been an important factor in video game programming. In early videogame systems,

9240-408: The source material, and any subsequent processing done to the signal. In the case of material shot on video, improvements in smoothness just from having a higher refresh rate may be barely noticeable. In the case of filmed material, as 120 is an even multiple of 24, it is possible to present a 24 fps sequence without judder on a well-designed 120 Hz display (i.e., so-called 5-5 pulldown). If

9345-504: 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

9450-609: 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

9555-411: 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

9660-681: 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

9765-514: Was able to fully capitalize on this, by aiming for complete IBM PC and PC DOS software compatibility, while reverse-engineering the BIOS to head off copyright legal claims. Other contemporary systems include the portable Commodore SX-64 , also known as the Executive 64, or VIP-64 in Europe, a briefcase/suitcase-size "luggable" version of the popular Commodore 64 home computer built with an 8-bit MOS 6510 ( 6502 -based) CPU microprocessor , and

9870-454: 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

9975-460: 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

10080-484: Was also the Seequa Chameleon , which had both 8088 and Z80 CPUs to alternately run MS-DOS or CP/M. Unlike Compaq, many of these companies had previously released computers based on Zilog 's Z80 and Digital Research 's CP/M operating system. Like Compaq, they recognized the replicability of the IBM PC's off-the-shelf parts, and saw that Microsoft retained the right to license MS-DOS to other companies. Only Compaq

10185-401: Was at US$ 503.9 million , another US business record. The Compaq Portable has basically the same hardware as an IBM PC , transplanted into a luggable case (specifically designed to fit as carry-on luggage on an airplane), with Compaq's BIOS instead of IBM's. All Portables shipped with 128 KB of RAM and 1-2 double-sided double-density 360 KB disk drives. Like the non-portable IBM PC,

10290-399: 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

10395-463: 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

10500-508: 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

10605-426: 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),

10710-548: 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

10815-595: Was the BIOS, because it contained IBM's copyrighted code. Compaq solved this problem by producing a clean room workalike that performed all documented functions of the IBM PC BIOS, but was completely written from scratch. Although numerous other companies soon also began selling PC compatibles, few matched Compaq's achievement of essentially-complete software compatibility with the IBM PC (typically reaching " 95% compatibility " at best) until Phoenix Technologies and others began selling similarly reverse-engineered BIOSs on

10920-465: 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

11025-422: 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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