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Ibm pcjr with display.jpg
IBM PCJr with original "chiclet" keyboard, PCjr color display, and 64 KB memory expansion card
Manufacturer Teledyne, Lewisburg, Tennessee
Type Personal computer
Release date March 1984 (1984-03)
Introductory price US$1,269 with 128 KB memory and without monitor
Discontinued April 2, 1987
Units shipped 500,000
Operating system IBM PC DOS 2.10
CPU Intel 8088 @ 4.77 MHz
Memory 64 KB
Graphics Video Gate Array
Sound Texas Instruments SN76489

The IBM PCjr (read "PC junior") was IBM's first attempt to enter the home computer market. The PCjr, IBM model number 4860, retains the IBM PC's 8088 CPU and BIOS interface for compatibility, but various design and implementation decisions led the PCjr to be a commercial failure.



Announced November 1, 1983, and first shipped in late January 1984,[1] the PCjr—nicknamed "Peanut" before its debut[2]—came in two models: the 4860-004, with 64 KB of memory, priced at US$669 (equivalent to $1,589 in present-day terms); and the 4860-067, with 128 KB of memory and a 360 KB 5.25-inch floppy disk drive, priced at US$1,269 (equivalent to $3,015 in present-day terms). It was manufactured for IBM in Lewisburg, Tennessee by Teledyne. The PCjr promised a high degree of compatibility with the IBM PC, which was already a popular business computer, in addition to offering built-in color graphics and 3 voice sound that was better than the standard PC speaker sound and color graphics of the standard IBM PC and compatibles of the day. The PCjr is also the first PC compatible machine that supports page flipping for graphics operation. Since the PCjr uses system RAM to store video content and the location of this storage area can be changed, the PCjr can perform flicker-free animation and other effects that are either difficult or impossible to produce on contemporary PC clones.


The video is produced by on-board display hardware which is capable of all seven BIOS-supported modes of the Color Graphics Adapter (CGA) plus additional 160x200 16-color, 320x200 16-color, and 640x200 4-color modes. The latter two modes and the 80x25 text mode, collectively called the "high-bandwidth" modes by IBM, require the optional 64 KB internal memory upgrade card, which doubles the amount of system RAM from the base 64 KB to 128 KB (specifically by providing the second 64 KB starting at address 0x10000). (Upgrading the memory by other means, such as adding a RAM "sidecar" adapter, is not adequate to support the high-bandwidth graphics modes.) Like the CGA, the PCjr has a composite pseudo-NTSC video output that supports using a color or black-and-white television set, and the PCjr's video adapter hardware is also capable of the common undocumented composite "artifact color" mode of the CGA which is entered by enabling composite color (alias "color burst") in the 640x200 graphics mode. The PCjr is also capable of the semi-documented 160x100 16-color CGA graphics mode, although except for programming considerations, there is no advantage to using this mode instead of the 160x200 16-color PCjr graphics mode. The fully programmable 16-color palette logic in the PCjr allows any set of colors from among the 16-color RGBI color set—the same set of colors available in CGA text modes—in each mode. That is, in each graphics mode, each pixel "color" value can be independently mapped to any one of the 16 real RGBI colors. (The IBM Technical Reference is unclear as to whether the programmable palette is active in the text modes, where all 16 colors are available even without palette mapping.) When the BIOS is used to set a video mode, it always sets up the PCjr palette table (i.e. the 16 palette registers) to emulate the CGA color palette for that mode. Programs specifically written to use PCjr graphics can subsequently reprogram the palette table to use any colors desired. Palette changes must be made during horizontal or vertical blanking periods of a video frame in order to avoid corrupting the display. However, the provision of a vertical retrace interrupt (on IRQ5) simplifies this and also makes seamless page-flipping much easier. The video hardware of the PCjr is the first to offer a vertical retrace interrupt, or any raster interrupt. The PCjr video subsystem also has a little known graphics blink feature which will toggle the palette between the first and second groups of eight palette registers at the same rate used for the text blink feature, and a palette bit-masking feature that could be used to switch between palette subsets without reprogramming palette registers, by forcing one or more bits of each pixel value to zero before the value is used to look up the color in the palette table.


From a software perspective, the PCjr video hardware is an upward-compatible extension of the CGA, but differences in the hardware that affect mode and color selection make it incompatible from a strict hardware perspective. In general, the PCjr video hardware can do anything that a CGA can, but the design of hardware-control registers and the programming rules and techniques are different. The functions of the CGA Mode Register and Color Select Register are implemented in the VGA using different registers. The Status Register has been also moved into the VGA and has significant differences. Programs written for the CGA (using any mode or modes) will work correctly and produce equivalent displays on the PCjr if they set modes only through the BIOS and control the image either through the BIOS or by directly accessing the display buffer (based at address 0xB8000) without attempting to write to or read from any video hardware registers, except certain registers of the 6845 CRTC. Those are the cursor-related registers, the light pen registers, and the start address registers. Alteration of other CRTC registers cannot be assumed to produce the same results from the PCjr video system as from the CGA (and in the worst case might conceivably cause damage to the monitor). (Programs for the CGA that manipulate the CRTC start address and that rely on address wrap-around above address 0xBC000 may not work correctly on the PCjr, because it always has a 32 KB contiguous block of RAM in the video area from address 0xB8000 through 0xBFFFF.)


The PCjr display hardware consists primarily of two chips on the system board: a standard Motorola 6845 CRTC like the one used in the MDA and CGA adapters, and a custom IBM chip called the Video Gate Array (VGA)[3][4] The 6845 is responsible for the basic raster timing and video data address sequencing, and the Video Gate Array contains all the additional timing logic, the video data demultiplexing and color processing logic, and the programmable palette table logic, as well as the logic for multiplexing RAM access between the 8088 CPU and the video generation circuitry. The 6845 CRTC and the VGA together are completely responsible for refreshing the internal DRAM of the PCjr (64 or 128 KB), and this complicates the process of switching video modes on the PCjr. (Resetting the VGA, which must be done during certain video mode switches, must be done by code not running from the internal RAM, and if the CRTC or the VGA is disabled for too long, the contents of the internal RAM can be lost.) Additional external DRAM, in sidecar expansion modules, is refreshed separately, not by the CRTC and VGA.


The PCjr's sound is provided by a Texas Instruments SN76489 which can produce three square waves of varying amplitude and frequency along with a noise channel powered by a shift register.[5] [This device is sometimes also called a PSG (Programmable Sound Generator), and essentially equivalent devices were also used in the contemporary Sega Master System (U.S. version) and the later Sega Genesis/Sega MegaDrive.] The PCjr design also allows for an analog sound source in an expansion-bus "sidecar" module, and software-controlled internal analog switch can select the source for the sound output form among the PC speaker, the SN76489, the cassette port, or the expansion-bus sound source. Only one sound source can be selected at a time; the sources cannot be mixed.

Processor speed[edit]

The PCjr's 4.77 MHz Intel 8088 CPU is faster than that of other computers that were aimed at the home market at the time, though the stock PCjr usually does not run at the full rated 4.77 MHz because access to the internal RAM is slowed by wait states added by the Video Gate Array to synchronize shared access to RAM between the CPU and the video hardware. The exact delay added to each individual bus cycle varies according to the exact timing and phase relationship of CPU memory accesses to video display-generation accesses, but IBM claims that an average of two wait states are added. However, this does not apply to programs or data located in ROM, including software on ROM cartridges plugged into the front of the PCjr, or located in additional RAM in a sidecar attachment; it only applies to the first 64 KB or 128 KB of RAM inside the system unit. Therefore, under some circumstances the 8088 in the PCjr actually can run at the rated 4.77 MHz. The most common instances in which this maximum speed would be achieved are when running games or productivity applications from ROM cartridges; this would be a reason for PCjr users to prefer software in cartridges to software on disk media. In fact, because the PCjr video subsystem continuously refreshes the system internal DRAM transparently, without disturbing the CPU, programs running from ROM on the PCjr will actually run slightly faster on the PCjr than on an IBM PC or XT. This is because the PC and XT keep their DRAM refreshed by using a DMA channel to periodically request the bus from the CPU in order to perform a refresh cycle, whereas a program running from ROM on a PCjr will never be suspended for internal DRAM refresh cycles.

Wireless keyboard[edit]

The detached wireless infrared keyboard promised a degree of convenience none of its competitors had, eliciting visions of word processing wirelessly from one's couch with the computer connected to a TV set as a display.[6] For infrared wireless operation, it was powered by common AA cells. A keyboard cord option, which plugged into the keyboard with a modular 4-position telephone plug and into the back of the computer with a 6-pin (2x3) header connected, was also available for increased security and reliability and to eliminate dependence on batteries; the keyboard IR receiver was automatically disabled when the keyboard cord was attached to the computer.

Differences from the IBM PC[edit]

With a built-in RF modulator, the PCjr can send video and audio to a TV; it also has an audio output jack to connect to a stereo or amplifier. The PCjr Color Display sold by IBM included an internal amplified speaker, being the only IBM monitor in the PC line to do so. Cartridge BASIC enhances the standard IBM BASIC with commands to support the new video and audio functionality.[4][5] Two joystick ports are also evidence of IBM's goal for marketing the PCjr as a home-friendly machine to compete with popular home machines like the Commodore 64, the Atari home computers, and the Apple II line. Other than the Tandy 1000, which was designed as an enhanced PCjr clone to directly compete with the PCjr, and Amstrad IBM PC compatible lines a few years later, the dual built-in joystick ports introduced by the PCjr never became standard on IBM PC compatibles, and have not been seen since. (However, the single 15-pin D-subminiature joystick port common on later PCs supports two two-axis, two-button joysticks like those supported by the PCjr, and the 15-pin port can be split out to two separate joystick ports with a passive Y-adapter cable.) Also, in addition to the joystick ports having a different connector from PC game ports, they require joysticks that had a different electrical resistance range in their X/Y axis controllers, necessitating the use of PCjr-compatible joysticks (or special electrical converter-adapters that were never mass-marketed).

Further reinforcing the "home-friendly" goal, the PCjr also introduced two ROM cartridge slots on the front of the unit, meant to load software quickly and easily. The cartridge(s) are plugged in from the front, prompting the computer to automatically reboot and run the software. This is more user-friendly than other home computer systems, which must be powered off when a cartridge was removed or inserted and come with warnings about damage to the computer if this requirement is ignored. Loading and saving data from cartridge software is possible via the floppy drive. The cartridge BASIC for the PCjr, in particular, gives programmers the advantage of a real programming language always ready without taking up system memory, as it was firmware, with its own address space. Being stored in ROM the BASIC loads very quickly, not needing access to the floppy disk or other storage.

Cartridges can also replace the system BIOS and other firmware.[7] A number of patches from various vendors are included on a single "combo-cartridge", licensed and sold by PC Enterprises, to support add-on hardware, bypass certain limitations of design, and keep up with changing OS requirements.

Expansions (such as additional parallel ports, serial ports, memory, etc.) to the PCjr are provided via add-on "sidecars" that attach to the side of the PCjr. Multiple expansions are stacked together, increasing the width of the machine.

The PCjr's video uses 32 KB of RAM as shared graphics memory, which prevents using additional memory with the built-in 128 KB under DOS.[7] The specific issue is that while additional external RAM can be added directly above the internal RAM, making a flat model, if the display is used, its buffer must reside somewhere within the first 128 KB of RAM (from where it is mirrored at address 0xB8000). Stock MS-DOS is not prepared to work around the video buffer in low RAM, using RAM both below and above it. Two obvious solutions exist: Use the additional memory as a RAM drive, or not use the built-in 128 KB.[8] Another option would be to load a special DOS device driver or TSR which would claim the RAM selected for use as the video buffer, causing DOS to load other drivers and programs above it. A fourth option would be not to use MS-DOS, or to use a specially modified version of it. For programs running from ROM cartridges, not using DOS was a very viable option, even in the mid-1980s when the PCjr was being marketed.

Differences from other personal computers[edit]

The PCjr initially shipped with a wireless chiclet keyboard called the "Freeboard",[9] powered by four AA batteries to provide infrared line-of-sight wireless communication. The keycaps are blank; labels appear between keys to permit overlays.[10] The chiclet keyboard was unpopular, and IBM replaced it with a typewriter-styled model that is otherwise identical.[9] With 62 keys compared to the PC's 83, function keys and others need multiple keystrokes.[11][10] Certain room lights cause interference with the infrared keyboard sensor,[12] as do multiple nearby keyboards.[13] As mentioned previously, the keyboard can also operate with an optional modular telephone-style cable, eliminating battery usage and IR interference.

The PCjr also has a light pen port. Besides being used for a light pen (a rarely purchased option), this port was used in combination with the serial port to supply voltage to a Mouse Systems optical mouse of the same design as those for Sun workstations.


"Peanut Panic"[edit]

IBM in the early 1980s was the world's largest computer company. With 70% of the mainframe market, it had larger revenues than Apple, Compaq, DEC, HP, and TI combined. When it introduced its first personal computer in August 1981, IBM did so to defend itself against Apple and other companies' newly popular microcomputers. Within two years the IBM PC created a large new ecosystem of business computers and software. Surprising even company executives, it became a market leader[15][16] with 26% of all microcomputers sold in 1983, in second place to the much less expensive Commodore 64 (C64) and three times the Apple II's share.[17]

For a year before the PCjr's announcement the computer industry discussed rumors of a new IBM product, code named "Peanut", that would repeat the PC's success. The rumors described Peanut as a home computer with 64 KB of memory that would be compatible with the large IBM PC software library, benefit from IBM's service network and, at US$600 to $1,000, be less expensive than the Apple IIe. Customers visited stores attempting to buy the product, and rivals' revenue, product plans, and share prices reacted to the officially nonexistent computer in what the press called "Peanut Panic" or "The Great Peanut Roast".[16][18][19][20][21][10][22][23]

Many expected, or feared, that an IBM home computer would destroy Apple, Commodore, and others, leaving no competitors. While the company repeatedly denied Peanut rumors[16][24][25] it estimated that 50 to 70% of PCs sold in retail stores went to the home, a market which CEO John Opel described as "inevitable as the sunrise tomorrow" for IBM.[22] PC Magazine reported that observers believed the company did not "face substantial competition on the home front" from computers that many considered "mere gadgets or expensive toys";[22] the success "of the Peanut is as good as established", Ahoy! predicted.[20]


On what Time called "D-Day for the Home Computer",[16] IBM announced the PCjr at its New York City headquarters with an enormous amount of advance publicity, including live news-broadcast coverage of the event.[18] Compute! wrote "Never before in the history of personal computing (admittedly a brief history) has a product been so eagerly awaited by so many".[10]

Experts predicted, according to The Washington Post, that the PCjr "will quickly become the standard by which all other home computers are measured".[26] No longer facing a long-running antitrust suit by the United States government, IBM and dealers boasted that "we are going to sell as many of these things as we can possibly make".[15][2] Observers predicted sales of one million or more in 1984,[11] and expected the PCjr to change the home-computer market in a similar way to how the IBM PC had changed the business-microcomputer market.[18][27][10] They predicted that the PCjr would extend IBM's dominance, with customers able to use the company's computers in the home and in the office.[22][15][26]

Even rival companies like Coleco,[29] Commodore,[30] and Tandy[31] hoped that a home computer from IBM with, as Popular Science wrote, "the three initials on its nameplate, letters that, in the minds of many, represent quality, reliability, and an assurance that the company will be around for as long as the computer is"[18] would stabilize and bring credibility to the chaotic market, which had seen "cutthroat" price wars between Commodore, Atari, and others.[22][26][30][19][18] TI left the market four days before IBM's announcement, after losing US$223 million in nine months against Commodore[29][16][32] by selling its 99/4A for as low as $99;[21] such low prices likely damaged the reputation of the industry by making home computers appear to be inferior game machines.[30] PaineWebber predicted that the PCjr would open a "price umbrella" under which home-computer companies could safely compete.[26]

Observers did not see low-end computers as the PCjr's main competition, however, expecting it to most affect sales of the IIe, another home-business crossover product.[11][29] PC expert Peter Norton wrote that the new computer "has all, or nearly all, the capacity and flexibility that most of us who are already using PC's need ... All in all, the PCjr looks like a remarkable machine for its capabilities and an astounding one for its price", and predicted that "the PCjr will make an even bigger splash" than the PC.[33] Financial writer John Gantz wrote "Conventional wisdom says that with the PCjr, IBM has the personal-computer market sewed up [and that] IBM will kick hind end in any market remotely related to the PC, maybe in any market whatsoever".[34]

Developers began developing PCjr software in 1982,[35] for which a rumor stated that IBM paid US$10 million.[36] Sierra On-Line, SPC, and The Learning Company were among those that produced two dozen games, productivity, and educational software as launch titles.[11][37] The PCjr's graphics and sound features were superior to the PC's,[5][38][11] and PC Magazine speculated that "the PCjr might be the best game machine ever designed".[37] IBM did not plan to sell through discount stores,[30] however, and observers believed that software companies would also publish many non-game applications for the new computer[30] without fearing that it would become orphaned quickly.[11][39] Major peripheral manufacturer Tecmar stated in full-page magazine advertisements "We're glad you're here, PCjr. Tecmar will have a boat-load of products for you."[40]

Although IBM missed the important Christmas sales season because of production delays, by announcing early the company succeeded in its likely goal of hurting competitors;[15][28][2][25] ComputerLand sold gift certificates with a large model of the computer "'beautifully wrapped to go under your Christmas tree'".[41] IBM planned to spend US$40 million on advertising,[27] which used Charlie Chaplin's iconic character "The Little Tramp"—already used in a successful campaign for the PC—to link the two products together.[42][43] Ziff Davis, publisher of the successful PC Magazine, printed the first issue of PCjr Magazine even before the first units shipped; competing computer magazines included Peanut, PCjr World,[44] jr, and Compute! for the PC and PCjr.[45]

"One of the biggest flops in the history of computing"[edit]

George Morrow was one of the few to be pessimistic about the PCjr after its announcement, predicting that Commodore's Jack Tramiel would "make mincemeat" of the "toylike" computer.[19] Also offering a "contrarian view: the PCjr could actually turn out to be a dog", Gantz wrote that "it's consumer and buyer demand that will spell success, not how awesome IBM is. It's still a free country, we don't have to buy the PCjr."[34] Fellow InfoWorld writer John Clapp called PCjr "a pathetic, crippled computer", but glumly expected that "the magic letters IBM" and the company's enormous financial and marketing resources would let it "get away with this stuff".[36]

Despite Clapp's fear, when the PCjr became widely available in early 1984[41] sales were below expectations. Despite The Wall Street Journal‍ '​s observation that "The PCjr ... has at least three invaluable assets: the letters I, B, and M", one store owner reported that "Interest was at a fever pitch" after the announcement, but "Once we had a demonstration model (in January), the only thing I can say is that the response was underwhelming".[28] Stores began discounts almost immediately,[46][1] and IBM—admitting that demand was "variable and not growing as expected"[47]—began unusually early discounts of up to US$370 in June,[48] but many of its 1,400 dealers could not sell their initial allotments of 25 computers.[28] "Inventory is beginning to pile up", Time wrote in April;[2] by August InfoWorld described it as "the colossal flop that the experts said couldn't happen";[49] and in December Time stated that the PCjr "looked like one of the biggest flops in the history of computing...[it] sold as sluggishly as Edsels in the late 1950s".[27]


One observer compared using the original chiclet keyboard to "massaging fruit cake".[50]

Journalists at the PCjr announcement who hoped for, Compute! reported, "a revolutionary machine that would reinvent the home computer"[10] "gasp[ed in] dismay" when they saw its chiclet keyboard. The New York Times described it as "not suitable for serious long-term typing"[11] and "nearly useless".[51] PC Magazine reported hearing another comparing the keys' feel to "massaging fruit cake",[50] and stated that using IBM's function keys-dependent DisplayWrite word processor on the PCjr "requires a level of digital dexterity more normally associated with concert piano playing".[52]

Clapp wrote that "to say that jr even has a keyboard is far too charitable".[36] Compute! agreed, stating that the computer "leaves something to be desired. A keyboard for one". The magazine observed that "Atari and Coleco must have breathed collective sighs of relief, because both promptly raised January 1 pricing of their personal computer systems".[53] BYTE called the keyboard "a new standard for intentional product handicapping",[54] and other publications agreed that the keyboard was evidence IBM gave the PCjr less capability to avoid cannibalizing IBM PC sales.[18][16][55][27]

"How could IBM have made that mistake with the PCjr?", an astounded Tandy executive asked.[56] The keyboard design stunned many in the industry, including Ken Williams and others at Sierra—which had only had prototypes—and Doug Carlston of Brøderbund Software.[19][35] IBM factory workers manufacturing the keyboard mocked its poor quality,[57] and even IBM salesmen advised customers to buy a replacement.[1]


The Wall Street Journal reported that customers "find that the PCjr is expensive for a home computer but isn't very powerful for an expensive computer."[28] The PCjr's cost was its biggest disadvantage, even more so than the keyboard;[2] Ahoy! wrote that "a machine with relatively limited technology at a relatively high price, not only presented much less of a threat than the industry had feared", but benefited the C64 by encouraging Atari and Coleco to raise prices.[59] IBM did not say whether the target market was the home, schools, or executives working at home, confusing software developers,[39] but likely made a mistake by setting the PCjr's price in the US$800–$1,600 range, where demand was weaker than for computers that cost less—especially the C64—or more. Norton warned that the PCjr "may well be targeted at a gray area in the market that just does not exist",[1] and an observer estimated that "perhaps only 10 to 15% of the home market will be interested".[60]

IBM was unfamiliar with the consumer market but hoped that customers would be willing to pay more for a product with, as an industry expert said, "those three letters".[15][26] Gantz warned that "inasmuch as it goes after the home market, goes to a very price-sensitive crowd." Unlike IBM's traditional corporate customers, he wrote, "the home computer crowd has no notion of concepts like upward compatibility, software availability, or the importance of vendor stability";[34] such customers usually bought the C64, which gained in popularity.[1] At US$669 and up, the PCjr cost more than twice as much as the C64 and the Atari 8-bit family, while inferior to both and the IIe for games.[11][61] Imagic stated that the C64 was "a lot faster and it sells for one third the price",[30] Sierra's Williams predicted that "There's no way our game Frogger will ever look as good on the PCjr as it does on the Commodore 64 or the Atari",[11] and Spinnaker Software said that "for its level of performance it is simply the most expensive machine on the market".[2]

Consumers were reportedly much more excited about the also-new Apple Macintosh, more sophisticated than the PCjr but only US$300 more expensive with accessories and software.[2][28] Its price was close to that of the Coleco Adam, but the Adam also included a tape drive, a printer, and software.[16] A basic PCjr package for playing games on a TV cost about $900, one for word processing with a thermal printer cost twice that much, and other packages cost $3,000 or more,[18] even while IBM did not include batteries for the wireless keyboard.[58]

The IIe was the PCjr's most direct competition.[46] Apple estimated that 80% of its dealers sold both computers, and many visitors interested in the latter or the Macintosh reportedly left with the former.[24] Although the US$669 PCjr model compared favorably to a $1,400 IIe also with 64 KB and no floppy drive,[11][39] Apple lowered the computer's price,[2] offered a 30% discount to the important education market,[19] and in April 1984 introduced the Apple IIc with 128 KB and floppy drive. Although the PCjr's CPU was superior, the IIc—which Apple did not describe as a home computer, to avoid the "game machine" connotation—had a much better keyboard,[47][1][62][63] and was compatible with almost all of the Apple II's 16,000 programs.[64] A dealer stated that Apple "has very neatly bracketed the PCjr", and the IIc and IIe's good sales compared to the PCjr implied that cost was not the latter's only problem.[1]

Not fully PC compatible[edit]

By early 1984, PC compatibility had become vital for any new non-Apple computer's success. Clapp wrote that were Cray to introduce an incredibly sophisticated, shirt pocket-sized computer, "what's the first question that the computer community asks? 'Is it PC compatible?'"[65] An important market was executives who took data home to work on applications such as the spreadsheet Lotus 1-2-3, and many customers visited stores believing that the PCjr could run most PC software;[28][2][1][15][34] they compared it—which The New York Times warned "cannot be used for serious business computing"[11]—unfavorably to the PC instead of other home computers. IBM expected that most would be new to computers, but 75% were familiar with them and wanted to run business software on the PCjr.[66]

Norton estimated that the PCjr had about 85% of the IBM PC's capability for a smaller fraction of its price.[33] IBM technical documentation stated that the "PCjr is a different computer than the" PC, but "has a high level of programming compatibility"; it promised software developers that "if your application maintains an interface ... at the BIOS and DOS interrupt interfaces, then all hardware differences are handled transparently to your application".[67] Norton expected that "any program that followed a design guideline of 64 KB and one disk drive is likely to run beautifully on the PCjr. That means that the PCjr will run most of the PC's programs nicely".[33] He warned, however, that developers "must understand the PCjr's basic limitations and promise not to cheat", and predicted that applications that required more than 128 KB of memory, did not support using only one disk drive, or used IBM PC-specific copy protection, would have problems.[68]

IBM's own stores had a list of software they distributed that was compatible with the PCjr, but customers had to—as the Chicago Tribune reported—learn from "trial and error" whether other programs worked with the computer.[47] In practice the PCjr proved incompatible with about 60% of PC applications including WordStar and two programs often used to test PC compatibles' compatibility, 1-2-3 and Microsoft Flight Simulator;[2][27][69][38][70] even IBM DisplayWrite required a separate PCjr version.[52] Although 1-2-3 was so important that InfoWorld joked that "PC compatible" really meant "1-2-3 compatible",[65] a PCjr version did not become available until a year after the computer's announcement.[70] An analyst stated that its incompatibility with PC software made the PCjr akin to a game machine, benefiting Apple,[64] but InfoWorld stated that compared to Apples it "is a failure as a game machine" because of poor performance with arcade games.[61] Apple satirized IBM's Tramp mascot in a commercial that emphasized the IIc's larger software library.[43][71]

Limited hardware expansion[edit]

Computer dealers quickly identified the PCjr's limited hardware expansion capability as another major disadvantage.[46][2] Spinnaker expected to sell most PCjr programs on disk because of cartridges' small storage capacity;[30] the PCjr version of Lotus 1-2-3 requires two cartridges and a floppy disk, and a 128 KB model running it does not have enough memory for many business spreadsheets.[70] The computer only has an internal slot for a modem and an external slot on the right side for "sidecar" peripherals. IBM published technical details for the PCjr as it had done for the IBM PC to encourage third parties to develop accessories, but did not offer a second floppy drive, hard drive,[26][18] or memory beyond 128 KB[6] although many customers preferred to use IBM peripherals.[9] Multiple sidecars are very clumsy, and the computer requires additional power supplies with a second floppy drive or several sidecars.[18][27] The PCjr also lacks a DMA controller, so the 8088 CPU has to service standard system interrupts such as the serial port or the keyboard directly. The PCjr thus cannot not use modems faster than 2400 baud, and it refuses to process keyboard input if its buffer is full or while the disk drive is in use.[6][58]

The "Save-the-Junior campaign"[edit]

By mid-1984, the PCjr had experienced months of bad publicity. Despite the discounts, sales were poor, and dealers were panicking; Steven Levy wrote "The machine has the smell of death about it."[27]

IBM allowed dealers to postpone paying for inventory, and in July replaced customers' chiclet keyboards for free with a new model with conventional typewriter keys. Although it attempted to reduce attention on the decision with other, simultaneous announcements, the press focused on the new keyboard. The act surprised observers by being unusually generous even for IBM—with a reputation for excellent customer service—and the industry;[9][27][61] Creative Computing compared it to an auto maker sending four new free tires to customers.[73] By replacing the keyboards IBM also acknowledged its initial mistake;[9] other than the keycaps the two designs are identical, so the company could have used the conventional one from the PCjr's debut.[12] The new keyboards cost US$50 each but IBM had to replace only about 60,000, compared to the 250,000 to 480,000 computers that experts had estimated the company would sell during the first six months.[72][9]

IBM reduced the PCjr's list price, offering a US$999 package that was arguably superior to the comparably priced IIe and IIc, and introduced new IBM-made memory expansion options to 512 KB.[9] It began what the company described as the most extensive advertising campaign in IBM history, in which 98% of Americans would see at least 30 PCjr advertisements in the last four months of the year. Three simultaneous bundled software promotions, a sweepstakes with Procter & Gamble, and direct mail to more than 10 million people marketed the redesigned computer,[73][74] while deemphasizing the PCjr's role as a home computer and emphasizing PC compatibility.[9] Advertisements listed the new price, "new typewriter-style keyboard", standard 128 KB of memory and expansion options, the PCjr version of 1-2-3, and the ability to "run over a thousand of the most popular programs written for the IBM PC."[75] A $500 rebate to dealers let them include a free color monitor with the discounted PCjr.[48]

Despite widespread skepticism,[76] what observers called the "Save-the-Junior campaign"[74] succeeded, amazing the industry. One large dealer stated in November 1984 that "it could be a PCjr Christmas".[27] With the new hardware options and lower prices consumers could buy a PCjr for $1000 less than a comparable PC,[72][9] and many reported selling more in the weeks following the changes than in the previous seven months.[27][77][74] The PCjr reportedly became the best-selling computer,[78] outselling the IIe and IIc by four to one in some stores[79] and even the C64.[27] Tecmar resumed production of PCjr periperals after dealers suddenly ordered its millions of dollars of unwanted inventory.[74]


By January 1985, experts estimated that IBM had sold 250,000 PCjrs, including 200,000 in the fourth quarter of 1984. When the discounts ended, however, sales decreased from an estimated 50 computers sold per store in December to 2.4 in February.[78][80][25] By this time three PCjr-specific magazines had ended publication.[45] IBM was unable to meet the demand for its new PC AT business microcomputer, but the home-computer market was in decline[66][25] and the company was likely unable to make a sufficient profit when selling the PCjr at a discount. IBM discontinued it in March,[80][25] astounding Sierra and other vendors of PCjr products.[78]

Rumored to have 100,000 to 400,000 unsold PCjrs[78][81][82] despite not having ordered new microprocessors from Intel since summer 1984,[83] the company offered large discounts to its employees[84] and consumers. Inventory remained through Christmas 1985, however, and IBM used discounts and radio and full-page print ads for the computer;[82] one industry executive stated that "only the unaware purchaser would be liable to pick that thing up".[85]


Sell-side analyst Barbara Isgur stated in 1984 that the PCjr:[60]

will probably establish the standard operating system for the home market as it has in business. So even if the PCjrs have gone into the closet, I think that as the software continues to evolve and increase, they will be brought out.

Although the Chicago Tribune later compared the PCjr's failure to that of the Edsel and New Coke,[87] Isgur was correct about the computer's influence on software.[88] Tandy Corporation released a clone, the Tandy 1000, in November 1984,[89] describing it as "what the PCjr should have been".[90] After its discontinuation Tandy quickly removed any mention of the PCjr in advertising while emphasizing the 1000's PC compatibility. The machine and its many successors sold well, unlike the PCjr, partly because the Tandy 1000 was sold in ubiquitous Radio Shack stores and partly because it was less costly, easier to expand, and almost-entirely compatible with the IBM PC. The PCjr's enhanced graphics and sound standards became known as "Tandy-compatible", and many PC games advertised their Tandy support. A company developed a PCjr modification that made it compatible with Tandy software.[88]

From mid-1985, what Compute! described as a "wave" of inexpensive clones from American and Asian companies caused prices to decline; by the end of 1986, the equivalent to a US$1600 real IBM PC with 256 KB RAM and two disk drives cost as little as $600, lower than the price of the Apple IIc. Consumers began purchasing DOS computers for the home in large numbers; Radio Shack estimated that half of Tandy 1000 sales went to homes, not offices. The inexpensive clones succeeded with consumers where the PCjr had failed; unlike the IBM product, they were as fast as or faster than the IBM PC and highly compatible.[91]

Among the games IBM asked Sierra to develop was the revolutionary graphical adventure King's Quest I, which became the first of a very successful series of adventure games for the company.[35]

IBM returned to the home market in 1990, with the IBM PS/1 line. Unlike the PCjr, the PS/1 line offered full PC compatibility, a low price, and a conventional keyboard.[87]

Several upgrades for the PCjr were designed by IBM/Teledyne but never reached the store shelves before the IBM PCjr was canceled. These included a wireless joystick and various memory/drive upgrades. PC Enterprises became the last of the major third party vendors to supply full service, parts, and add-ons, extending the functional life of the PCjr to about 10 years, often buying out inventory and rights for PCjr support.

Technical specifications[edit]

  • CPU: Intel 8088, 4.77 MHz
  • Memory: 64 KB on the motherboard expandable to 128 KB via a card in a dedicated slot. Further expansion via IBM sidecar adapters. Later third-party add-ons and modifications raised the limit to 736 KB.
  • Operating system: IBM PC DOS 2.10, (Boots to Cassette BASIC without cartridge or DOS)
  • Input/Output: cassette port, light-pen port, two joystick ports, RGB monitor port, composite video port, television adapter output port, audio port, wired keyboard port, infrared keyboard sensor, serial port, two cartridge slots
  • Expandability: three internal slots, dedicated to PCjr specific memory, modem (300 bits per second non-Hayes-compatible modem available from IBM, although 2400 bit/s Hayes-compatible modems were available from third parties), and floppy controller cards. External sidecar connector capable of daisy-chaining multiple sidecars.
  • Video: Motorola 6845, "CGA Plus" This chip was officially called the VGA (Video Gate Array[3]).
    • Text modes: 40×25, 80×25, 16 colors
    • Graphics modes: 320×200×4, 640×200×2, 160×100×16, 160×200×16, 320×200×16, 640×200×4[10]
    • Video memory is shared with the first 128 KB of system memory, and can be as small as 2 KB and as large as 96 KB.
  • Sound: Texas Instruments SN76496; three voices, 16 independent volume levels per channel, white noise
  • Storage: Optional 5.25-inch diskette drive or cassette. Other storage options were provided by third parties.
  • Keyboard: 62 key detached. Corded or infra-red operation. IBM supplied two different keyboards, the first being the maligned 'Chiclet' keyboard, so named for its square rubber keys that resembled Chiclets. Many third-party keyboards were also available.

See also[edit]


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External links[edit]

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IBM Personal Computer
IBM Personal Computers Succeeded by