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118-575: Heathkit 's H8 is an Intel 8080A -based microcomputer sold in kit form starting in 1977. The H8 is similar to the S-100 bus computers of the era, and like those machines is often used with the CP/M operating system on floppy disk . The main difference between the H8 and S-100 machines is the bus ; the H8 uses a 50-pin bus design that was smaller, more robust and better engineered electrically. The machine also includes

236-633: A Z80 processor board and a floppy disk drive into the cabinet of an Heathkit H19 terminal . This model also was sold in fully assembled form as the WH89 . These were later sold by Zenith Electronics with their name on the front as the Zenith Z-89 . MITS announced the Altair 8800 in January 1975 and started selling kits soon after. Marketed to electronics hobbyists through trade magazines like Popular Electronics ,

354-435: A bootstrap ROM that makes it easier to start up, including code for running basic input/output and allowing input through a front-mounted octal keypad and front panel display, instead of the binary switches and lights used on machines like the Altair 8800 . The H8 requires a separate terminal to be truly useful; Heathkit introduced several terminals as well. A successor model, the "All-in-One" Heathkit H89 , combines

472-423: A 4 KiB ROM occupying through FFF 16 . The ROMs interfere with the operation of standard CP/M, which assumes it can write the memory near location 0, in particular the interrupt handler pointers. PAM8 and portions of HDOS use an unusual address notation called " split octal " where 16-bit numbers are split into two 8-bit numbers printed in octal: the first location was "000.000" and the location after "000.377"

590-413: 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

708-464: 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

826-528: 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

944-556: A customized "turn-key" version of their accounting , CPA, and real estate management software. Shortly after the release of the Z-90, they released a 10MB hard disk unit and double-density external floppy disk drives. While the H11 was popular with hard-core hobbyists, Heath engineers realized that DEC's low-end PDP-11 microprocessors would not be able to get Heath up the road to more powerful systems at an affordable price. Heath/Zenith then designed

1062-473: A deeper knowledge of electronics (or for those who wanted to be able to troubleshoot/repair the product in the future), the assembly manuals usually included a detailed "Theory of Operation" chapter, which explained the functioning of the kit's circuitry, section by section. Heath developed a business relationship with electronics correspondence schools (e.g., NRI and Bell & Howell ), and supplied electronic kits to be assembled as part of their courses, with

1180-773: 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

1298-460: 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

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1416-449: 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

1534-457: A dual Intel 8085 / 8088 -based system dubbed the H100 (or Z-100 , in assembled form, sold by ZDS). The machine featured advanced (for the day) bit mapped video that allowed up to 640 x 225 pixels of 8 color graphics. The H100 was interesting in that it could run either the CP/M operating system, or their OEM version of MS-DOS named Z-DOS , which were the two leading business PC operating systems at

1652-571: A few years as Heathkit Educational Systems located in Saint Joseph, Michigan , concentrating on the educational market. The Heathkit company filed for bankruptcy in 2012. In May 2013, Heathkit's corporate restructuring was announced on their website. An extensive FAQ accessible from their homepage stated clearly that Heathkit was back, and that they would resume electronic kit production and sales. On October 8, 2015, Heathkit circulated an email to its "insiders", who had indicated an interest in

1770-429: 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

1888-469: A flourishing of companies selling into the S-100 market. The introduction of floppy disk controllers and the disk-based CP/M operating system dramatically improved the system's capabilities and started the process of turning them into practical small-business tools. By the late 1970s they were beginning to displace minicomputers and other systems in a number of roles. Heathkit was a long-established player in

2006-462: A huge seller. After the success of the oscilloscope kit, Heath went on to produce dozens of Heathkit products. Heathkits were influential in shaping two generations of electronic hobbyists. The Heathkit sales premise was that by investing the time to assemble a Heathkit, the purchasers could build something comparable to a factory-built product at a significantly lower cash cost and, if it malfunctioned, could repair it themselves. During those decades,

2124-460: A keypad and seven-segment LED display (early S-100 machines like the Altair or IMSAI 8080 contain no ROM and when they are started, the user "keys in" a program via the toggle switches to read a paper tape . Once this "loader" program is ready, a paper tape containing a more complete loader can be read in, allowing the user to load programs from cassette or floppy disk). On the H8, all of this code

2242-508: A kit might still be fun, but it could no longer save much money. The switch to surface mount components and LSI ICs finally made it impossible for the home assembler to construct an electronic device for significantly less money than assembly line factory products. As sales of its kits dwindled during the decade, Heath relied on its training materials and a new venture in home automation and lighting products to stay afloat. When Zenith eventually sold ZDS to Groupe Bull in 1989, Heathkit

2360-400: 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 the microcomputer industry. This computer platform

2478-507: A major product line of its own. The H17 floppy disk system became available in 1978, normally sold with one drive but expandable with a second (and later to three). Use of the H17 requires at least 16 KiB of RAM. The H8 can run CP/M , and often did, but early machines require either a special version of CP/M that was "org'd" at 8 KiB instead of zero, or a small hardware modification and an updated ROM to do so. Heath also offered HDOS , which

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2596-469: 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

2714-508: 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

2832-508: 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

2950-798: 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

3068-408: A selection of ham equipment as any company in the field. 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 is a disk operating system and its purpose is to organize files on

3186-679: A small trainer kit, it was powerful and flexible enough to be used in rudimentary control systems. In 1977, Heathkit introduced the Heathkit H8 home computer. The H8 was very successful, as were the H19 and H29 terminals, and the H89 "All in One" computer. The H8 and H89 ran the Heathkit custom operating system HDOS as well as the popular CP/M operating system. The H89 contained two Zilog Z80 8-bit processors, one for

3304-596: A strong resemblance to the TRS-80 Model III and similar all-in-one computers. The H89 was sold both in kit form for $ 1595, and fully assembled form as the WH89 for $ 2295. Soon after the introduction of the H89, Heathkit was purchased by Zenith, who were looking to enter the microcomputer market. They continued sales of the H89 with their own labeling on the front as the Zenith Z89 . Eventually, Zenith Data Systems (Heathkit plus

3422-530: 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 ,

3540-540: 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

3658-564: Is already pre-installed in a 1 KiB ROM in a monitor program known as "PAM8", occupying locations 0 through 3FF 16 and the H17 disk I/O drivers used for booting, occupying a 2 KiB ROM occupying locations 1800 16 through 1FFF 16 The ROM contains code to control the keypad and display, booting it directly into an operable state. Several versions of the PAM-8 ROM were sold as upgrades; at one point Heathkit switched to using 2 KiB ROMs, occupying through 7FF 16 and subsequently to

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3776-451: 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

3894-530: 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

4012-570: The David Hafler Company . Before entering the burgeoning home computer market, Heathkit marketed and sold microprocessor-based systems aimed at learning about this technology. The ET-3400, for example, was released in 1976 and was based on the Motorola 6800 microprocessor. This system included 256 bytes of RAM, a 1k monitor in ROM, and a keypad for easy entry and modification of programs. Despite being

4130-624: The Kansas City standard format. Another common accessory is the H9 video terminal, which is also driven by the H8-5 card; although any serial terminal will suffice. The H9 is limited to upper case characters and 12 display lines, and uses a cheap array of switches for its keyboard. It was eventually superseded by the H19 terminal, a more ergonomic design, and capable of lower-case and graphic-like characters. The H19 became

4248-578: 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

4366-518: 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

4484-607: The WH17 . For the CP/M operating system, Heathkit provided the WH67, a 10 MB eight-inch hard drive and the H47 eight-inch floppy disk system. In 1978 Heath introduced the Heathkit H88 which integrated the H19 terminal and a new Zilog Z80 -based single-board processor into the case of the H19. A version with a disk drive incorporated to the right of the terminal screen became the H89 . The machines bear

4602-483: 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

4720-441: 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

4838-429: 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

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4956-421: 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

5074-571: The Altair but addressing its more obvious shortcomings. The H8 was announced in July 1977 and started selling that fall at a price of $ 379. For full functionality, the system also requires a 4 KiB SRAM card ($ 139) and some form of storage controller; at a minimum this would be the H10 paper tape punch/reader or the H8-5 Serial I/O card ($ 110) which controls a cassette tape , using a 1200-baud variant of

5192-429: 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

5310-631: 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

5428-612: The GR-2000 color television set. In 1974, Heathkit started "Heathkit Educational Systems", which expanded their manuals into general electronics and computer training materials. Heathkit also expanded their expertise into digital and, eventually, computerized equipment, producing among other things digital clocks and weather stations with the new technology. Kits were compiled in small batches mostly by hand, using roller conveyor lines. These lines were put up and taken down as needed. Some kits were sold completely "assembled and tested" in

5546-601: The Heath/Zenith name and products to DESA International , a maker of specialty tools and heaters . In late 2008, Heathkit Educational Systems sold a large portion of its physical collection of legacy kit schematics and manuals along with permission to make reproductions to Don Peterson, though it still retained the copyrights and trademarks, and had pointers to people that could help with the older equipment. DESA filed bankruptcy in December 2008. The Heathkit company existed for

5664-580: 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

5782-464: 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

5900-562: 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

6018-480: 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

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6136-513: 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

6254-617: 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

6372-553: 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

6490-496: 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

6608-537: 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

6726-402: 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

6844-513: The arm purchased for $ 999. This was the first in a popular series of Heathkit robot kits sold to educational and hobbyist users. While Heath/Zenith's computer business was successful, the growing popularity of home computers as a hobby hurt the company because many customers began writing computer programs instead of assembling Heathkits. Also, while their assembly was still an interesting and educational hobby, kits were no longer less expensive than preassembled products; BYTE reported in 1984 that

6962-420: 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

7080-416: The beginning. In addition to their low prices compared with commercially manufactured equipment, Heathkits appealed to amateurs who had an interest in building their own equipment, but did not necessarily have the expertise or desire to design it and obtain all the parts themselves. They expanded and enhanced their line of amateur radio gear through nearly four decades. By the late 1960s, Heathkit had as large

7198-531: 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

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7316-448: The case of electronic test equipment, Heathkits often filled a low-end entry-level niche, giving hobbyists access at an affordable price. The instruction books were regarded as among the best in the kit industry, being models of clarity, beginning with basic lessons on soldering technique, and proceeding with explicit step-by-step directions, illustrated with numerous line drawings; the drawings could be folded out to be visible next to

7434-462: The case to be reduced in height. Each card contains its own voltage regulators, using the Z-shaped mounting bracket as a heat-sink. (Power distribution on the backplane is unregulated +8V and +/-18V; the cards regulate these to their requirements, typically +5V and +/-12V.) Another notable change is the replacement of the front-panel toggle switches and lights of a standard early-model S-100 system with

7552-452: 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

7670-415: The company founders felt there would be limited appeal and expected to sell only a few hundred systems. Instead, they received orders for thousands in the first month. Sales were so much greater than expected that MITS was unable to clear the order backlog for the better part of the year. The Altair sparked off such intense interest in the microcomputer world that a number of other companies jumped in to fill

7788-503: The company has a live website with newly designed products, services, vintage kits, and replacement parts for sale. In August 2023 Heath Company announced its acquisition by Kirkwall (company) as part of a planned expansion in North Dakota , and named former CIA officer and entrepreneur Will Cromarty as President and Chief Executive Officer. The Heath Company was founded as an aircraft company in 1911 by Edward Bayard Heath with

7906-704: The company's progress by completing its online marketing survey. It had now secured the rights to all Heathkit designs and trademarks; secured several new patents; established new offices, warehouse space, and a factory in Santa Cruz, California ; and had introduced the renewed company's first new electronic kit in decades. Since then, Heathkit has announced and sold further kits in its new lineup of products. In addition, limited repair service on vintage products, reprints of manuals and schematics, remaining inventories of original parts, and upgrades of some vintage models are available. Heathkit made amateur radio kits almost from

8024-481: The computer and one for the built-in H-19 terminal. The H11 , a low-end DEC LSI-11 16-bit computer, was less successful, probably because it was substantially more expensive than the 8-bit computer line. Seeing the potential in personal computers, Zenith Radio Company bought Heath Company from Schlumberger in 1979 for $ 63 million, renaming the computer division Zenith Data Systems (ZDS). Zenith purchased Heath for

8142-434: The computer division of Zenith) was purchased by Bull HN (CII Bull, Honeywell and Nippon Electric) because they needed a US maker of microcomputers to comply with government purchase requirements. Kit sales were ended soon after that purchase. Heath chose not to implement the S-100 bus and instead created their own, known as "Benton Harbor Bus" after their home town. The bus is based on a 50-pin connector and laid out to avoid

8260-450: 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

8378-440: The electrical problems of the S-100 system (like +5V and ground being placed beside each other). The H8 is packaged in a box-like chassis with pressboard sides and metal sheeting for the rest of the case. The top sheet is heavily perforated to form cooling vents. The machine is built up from the backplane mounted on the right-hand side panel of the case, with ten 50-pin card slots. The first and last slots are spaced differently from

8496-457: The electronics industry was a good idea, and bought a large stock of surplus wartime electronic parts with the intention of building kits with them. In 1947, Heath introduced its first electronic kit , the O1 oscilloscope with 5-inch diameter cathode-ray tube (CRT) display that sold for US$ 39.50 (equivalent to $ 539 in 2023) – the price was unbeatable at the time, and the oscilloscope went on to be

8614-405: The electronics market, making kits for products that had proven themselves in the market. Some of these were quite complex, including a color television . The company had considered designing a kit computer as early as 1974, but concluded that it was not a good fit for their traditional market. The successful launch of the Altair changed things, and in 1977 Heathkit decided to design a kit similar to

8732-576: The electronics. No knowledge of electronics was needed to assemble a Heathkit. The assembly process itself did not teach much about electronics, but provided a great deal of what could have been called basic "electronics literacy", such as the ability to identify tube pin numbers or to read a resistor color code . Many hobbyists began by assembling Heathkits, became familiar with the appearance of components like capacitors , transformers , resistors, and tubes, and were motivated to understand just what these components actually did. For those builders who had

8850-567: The factory. These models were differentiated with a "W" suffix after the model number, indicating that they were factory-wired. For much of Heathkit's history, there were competitors. In electronic kits: Allied Radio , an electronic parts supply house, had its KnightKits, Lafayette Radio offered some kits, Radio Shack made a few forays into this market with its Archerkit line, Dynaco made its audio products available in kit form (Dynakits), as did H. H. Scott, Inc. , Fisher , and Eico ; and later such companies as Southwest Technical Products and

8968-523: The flexible assembly line infrastructure at the nearby St. Joseph facility as well as the R&;D assets. Heath/Zenith was in the vanguard of companies to start selling personal computers to small businesses. The WH-89 assembled version of the H-89 kit was re-branded as the Zenith Z-89 / Z-90 , an assembled all in one system with a monitor and a floppy disk drive . They had agreements with Peachtree Software to sell

9086-524: 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

9204-409: 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

9322-456: 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

9440-482: The kit version of the Z-150 IBM PC compatible cost $ 100 more than the preassembled computer from some dealers, but needed about 20 hours and soldering skills to assemble. The continuation of the integration trend ( printed circuit boards , integrated circuits , etc.), and mass production of electronics (especially computer manufacturing overseas and plug-in modules) eroded the basic Heathkit business model. Assembling

9558-562: The language had a number of idiosyncrasies. Heathkit Heathkit manufactured electronic kits from 1947 until 1992. After closing that business, the Heath Company continued with its products for education, and motion-sensor lighting controls. The lighting control business was sold around 2000. The company announced in 2011 that they were reentering the kit business after a 20-year hiatus but then filed for bankruptcy in 2012, and under new ownership began restructuring in 2013. As of 2022 ,

9676-546: 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

9794-470: 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

9912-434: 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,

10030-500: 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

10148-401: The most basic commands and lacked string variables, and Extended Benton Harbor BASIC which required at least 24 kB of memory and added string variables, integer types, and commands for working directly with the floppy disk without having to exit to CP/M or the monitor. Modelled on Dartmouth BASIC , as opposed to popular later variations like HP Time-Shared BASIC or Microsoft BASIC ,

10266-434: 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

10384-451: 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

10502-461: The parts separately and relying on often-experimental designs. Kits brought the convenience of all parts being supplied together, with the assurance of a predictable finished product; many Heathkit model numbers became well known in the ham radio community. The HW-101 HF transceiver became so ubiquitous that even today the "Hot Water One-Oh-One" can be found in use, or purchased as used equipment at hamfests , decades after it went out of production. In

10620-403: The premise was basically valid. Commercial factory-built electronic products were constructed from generic, discrete components such as vacuum tubes , tube sockets, capacitors, inductors, and resistors , mostly hand-wired and assembled using point-to-point construction technology. The home kit-builder could perform these labor-intensive assembly tasks himself, and if careful, attain at least

10738-501: The purchase of Bates Aeroplane Co, soon renamed to E.B. Heath Aerial Vehicle Co. Starting in 1926 it sold a light aircraft, the Heath Parasol , in kit form. Heath died during a 1931 test flight . The company reorganized and moved from Chicago to Niles, Michigan . In 1935, Howard Anthony purchased the then-bankrupt Heath Company, and focused on selling accessories for small aircraft. After World War II, Anthony decided that entering

10856-424: The relevant text (which might be bound several pages away) and were aligned with the assembler's viewpoint. Also in view was a checkbox to mark with a pencil as each task was accomplished. The instructions usually included complete schematic diagrams , block diagrams depicting different subsystems and their interconnections, and a "Theory of Operation" section that explained the basic function of each section of

10974-424: The rest, and the power supplies occupy some of the space needed for the last card. This means that the last card not only has to accommodate the narrow spacing but also cannot be full-length, leaving eight "standard" slots available for full-length cards. The front panel plugs into the first slot and the CPU plugs into the second, leaving seven for further expansion. The card slots are arranged on an angle, which allows

11092-414: The sales backlog, building machines that were clones of the Altair. The primary component of this design is the S-100 bus, so named because it uses a 100-pin edge connector that MITS found at bargain prices when they were designing the machine. Unfortunately, the pins are connected from the backplane with a disorganized layout, and it has a number of problems that make it unreliable. Standardization led to

11210-513: 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

11328-460: The same standard of quality. In the case of Heathkit's most expensive product at the time, the Thomas electronic organ , building the kit version represented substantial savings. One category in which Heathkit enjoyed great popularity was amateur radio . Ham radio operators had frequently been forced to build their equipment from scratch before the advent of kits, with the difficulty of procuring all

11446-449: The schools basing their texts and lessons around the kits. In the 1960s, Heathkit marketed a line of its electronic instruments which had been modified for use in teaching physics at the high school ( Physical Science Study Committee , PSSC) and college levels ( Berkeley Physics Course ). Heathkits could teach deeper lessons. "The kits taught Steve Jobs that products were manifestations of human ingenuity, not magical objects dropped from

11564-438: The sky", writes a business author, who goes on to quote Jobs as saying "It gave a tremendous level of self-confidence, that through exploration and learning one could understand seemingly very complex things in one's environment." After the death of Howard Anthony in a 1954 airplane crash, his widow sold the company to Daystrom Company, a management holding company that also owned several other electronics companies. Daystrom

11682-504: 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

11800-609: 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

11918-458: The time. Although the machine had to be rebooted to change modes, the competing operating systems could read each other's disks. In 1982 Heath introduced the Hero-1 robot kit to teach principles of industrial robotics. The robot included a Motorola 6808 processor, ultrasonic sensor, and optionally a manipulator arm; the complete robot could be purchased assembled for $ 2495 or a basic kit without

12036-411: 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

12154-631: 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

12272-473: Was "001.000". In order to distinguish numbers in split-octal notation from 16-bit octal numbers, the two digit groups are often separated by a special symbol. Most mini- and micro-computers use either straight octal (377 was followed by 400) or hexadecimal.) With the introduction of the optional HA8-6 Z-80 processor replacement for the 8080 board, the front-panel keyboard got a new set of labels and hexadecimal notation replaced octal. The 50-pin "Benton Harbor Bus"

12390-454: 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

12508-624: Was absorbed by oilfield service company Schlumberger Limited in 1962, and the Daystrom/Schlumberger days were to be among Heathkit's most successful. Those years saw some "firsts" in the general consumer market. The early 1960s saw the introduction of the AA-100 integrated amplifier. The early 1970s saw Heath introduce the AJ-1510 , an FM tuner using digital synthesis, the GC-1005 digital clock, and

12626-460: 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

12744-536: Was considered an improvement on the S-100 bus . The 50-pin bus of the H8 contains sixteen address lines, eight data lines, five interrupt lines, and the system control lines. Like the S-100 bus, it does not supply +5 V; each card is expected to have its own local +5 V regulator powered from "unregulated" +8 V on the bus. Heathkit also introduced their own dialect of the BASIC programming language . Two versions were available, Benton Harbor BASIC that supported

12862-399: 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

12980-463: 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

13098-508: 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

13216-408: Was included in the deal. In March 1992, Heath announced that it was discontinuing electronic kits after 45 years. The company had been the last sizable survivor of a dozen kit manufacturers from the 1960s. In 1995, Bull sold Heathkit to a private investor group called HIG, which then sold it to another investment group in 1998. Wanting to only concentrate on the educational products, this group sold

13334-426: 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),

13452-548: 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

13570-465: 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

13688-470: 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

13806-573: Was written by Gordon Letwin . Letwin later went to Microsoft and was chief architect of OS/2 . At the time the H8 was introduced, the computer market was in the midst of a shift from the hobby market that had spawned it to a "user" market that purchased pre-assembled machines. Heath followed this trend and introduced the WH8 in fully assembled form for $ 475. Like the H8, the WH8 requires several other cards for functionality. The disk drive system came fully assembled as

13924-422: 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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