IBM PCjr (model 4860)
PCjr expanded cropped.jpg
Pictured with Racore Drive II third-party add-on
Manufacturer Teledyne, Lewisburg, Tennessee
Release date March 1984 (1984-03)
Discontinued April 2, 1987
Units shipped 500,000
Operating system IBM PC-DOS 2.10
CPU Intel 8088 @ 4.77 MHz
Memory 64 KB

The IBM PCjr (read "PC junior") was IBM's first attempt to enter the home computer market. The PCjr, IBM model number 4860, retained 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$669 ($ 1,475 in today's dollars); and the 4860-067, with 128 KB of memory and a 360 KB 5.25-inch floppy disk drive, priced at US$1269 ($ 2,797 in today's dollars). It was manufactured for IBM in Lewisburg, Tennessee by Teledyne. Roughly 500,000 units were shipped. 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 were better than the standard PC speaker sound and color graphics of the standard IBM PC and compatibles of the day. The graphics were produced via a graphics chip known as the VGA—which stood for "Video Gate Array". This was an extension of CGA and should not be confused with the later Video Graphics Array standard that IBM released with the PS/2 line in 1987. The PCjr's sound was provided by a Texas Instruments SN76489 which could produce three square waves of varying amplitude and frequency along with a noise channel powered by a shift register. The PCjr was also the first PC compatible machine that supported page flipping for graphics operation. Since the PCjr used system RAM to store video content and the location of this storage area could be changed, the PCjr could perform flicker-free animation and other effects that were either difficult or impossible to produce on contemporary PC clones.

The PCjr's 4.77 MHz Intel 8088 CPU was faster than other computers aimed at the home market, though the PCjr did not run at the full rated 4.77 MHz because every 4th clock cycle of the 8088 CPU was designated to refresh the PCjr's dynamic RAM as it had no dedicated memory controller; the computer's effective clockspeed was therefore 3.58MHz. 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.[3] Two cartridge slots promised easy loading of games and other software.

Differences from the IBM PC

Two joystick ports were built into the PCjr, evidence of IBM's goal for marketing the PCjr as a home-friendly machine. Other than the Tandy 1000 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. Also, in addition to the joystick ports having a different connector than used on the "game adapter" ISA card for PC compatibles, they required joysticks that had a different electrical resistance range in their X/Y axis controllers, necessitating the use of PCjr-specific joysticks (or generic joysticks that had a dual-mode switch).

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) would be plugged in from the front, prompting the computer to automatically reboot and run the software. This was more user-friendly than other home computer systems, which had to be powered off when a cartridge was removed or inserted and came with dire warnings about damage to the computer's main board if this requirement was ignored. Loading and saving data from cartridge software was possible via the floppy drive. The cartridge BASIC for the PCjr, in particular, gave 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 would load very quickly, not needing access to the floppy disk or other storage.

The two front cartridge slots were also used with third-party cartridges to update the system BIOS and other firmware. A number of patches from various vendors were 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 were provided via add-on "sidecars" that attached to the side of the PCjr. Multiple expansions were stacked together, increasing the width of the machine.

Differences from other personal computers

The PCjr was shipped with a chiclet type keyboard powered by AA batteries to provide infrared line-of-sight wireless communication. The "Freeboard"[4] could also operate with a modular telephone-style cable if so desired, eliminating battery usage. The PCjr was also shipped with a lightpen port, which worked with a small number of applications designed for it. The light pen port was later used in combination with the serial port to supply voltage to a Mouse Systems optical mouse of the same design as Sun workstations.

Failure in the marketplace


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 announced its first personal computer in August 1981, IBM did so to defend itself against the newly popular microcomputer. Within two years the IBM PC created a large new ecosystem of PC clones and software.[5] Surprising even company executives, it became a market leader[6] with 26% of all microcomputers sold in 1983, in second place to the much less-expensive Commodore 64 and three times the Apple II's share.[7] For a year before the PCjr's announcement the computer industry discussed rumors—which IBM repeatedly denied—of a home computer, code named "Peanut", that would repeat the PC's success. Customers waited for the rumored IBM product, crippling competitors' sales, and other companies' product plans and stocks reacted to the officially nonexistent computer.[5][8][9]

IBM launched the PCjr at its New York City headquarters with an enormous amount of advance publicity, including live news-broadcast coverage of the product announcement.[8] Ziff-Davis, publisher of the successful PC Magazine, printed the first issue of PCjr Magazine even before the first units shipped; competitors included PCjr World,[10] jr, and Compute! for the PC and PCjr.[11] Time called its debut "D-Day for the Home Computer";[5] observers predicted sales of one million or more in 1984,[12] and expected the PCjr to change the home-computer market in a similar way to how the IBM PC had single-handedly changed the business-microcomputer market.[13][8] They predicted that the PCjr would be "the last link in [IBM's] chain", with customers able to use the company's computers in the home and in the office.[6]

Because of IBM's size, reputation, and history, many expected that the PCjr would stabilize the chaotic home-computer market,[9][8] which had seen "cutthroat" competition between Commodore, Atari, and others; TI exited the market the same week as IBM's announcement, after losing $223 million in nine months by trying to compete with Commodore with its 99/4A computer.[5][14] Observers expected that, by contrast, many software companies would write applications for the new computer without fear of it becoming orphaned quickly[15] like the 99/4A. George Morrow was one of the few to be pessimistic, predicting that Commodore would "make mincemeat" of the "toylike" PCjr.[9]

IBM—which likely timed its announcement to hurt competitors' sales during Christmas[6]—reportedly spent $40 million on PCjr advertising,[13] which used Charlie Chaplin's iconic character "The Tramp", already used in a successful campaign for the IBM PC, to link the two products together.[16]

"One of the biggest flops in the history of computing"

The original, problematic "chiclet" keyboard.

At the PCjr's announcement, reporters "gasp[ed in] dismay" when they saw its chiclet keyboard, which had 62 keys versus the IBM PC's 83 and was "not suitable for serious long-term typing".[8][2][3][12] IBM's choice of keyboard design shocked industry executives,[17][9] and even IBM salespeople advised customers to buy a replacement keyboard. After missing the Christmas 1983 shopping period, sales were below expectations from the beginning, even with discounts;[1][18] "Inventory is beginning to pile up",[2] Time wrote in April 1984, in part due to the early 1984 launch of the "exciting" Apple Macintosh. By December it 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".[13]


The PCjr's cost was its biggest disadvantage, even more so than the keyboard.[2] IBM did not say whether the target market was the home, schools, or executives working at home, confusing software developers,[15] but likely made a mistake by targeting the $800-$1,600 price range, where demand was weaker than for computers that cost less—especially the Commodore 64—or more.[1] The company was unfamiliar with the consumer market but hoped that customers would be willing to pay more for an IBM product.[6] At $669 and up, however, the PCjr cost more than twice as much as the Commodore 64 and the Atari 8-bit family, while inferior to both and the Apple IIe for games;[12][19] its price was close to that of the Coleco Adam, but the Adam also included a tape drive, a printer, and software.[5] A basic 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.[8] The Apple IIe was the PCjr's most direct competition.[18] Although the $669 PCjr model compared favorably to a $1,400 Apple IIe also with 64 KB and no floppy drive,[12] Apple cut the IIe's price,[2] offered a 30% discount to the important education market,[9] and in April 1984 responded[20] with the IIc, with 128 KB and a floppy drive.[21]

Not fully PC compatible

Despite its price, many compared the PCjr unfavorably to the IBM PC rather than to other home computers, as IBM gave it "far less overall keep it from biting deeply into the costlier product's sales".[8][5] The company expected most PCjr customers would be new to computers, but 75% were familiar with computers and wanted to run business software on it.[22] While many potential customers believed that the smaller computer could run most IBM PC software and an important market for the PCjr was executives who took data home to work on,[1][6] in practice it proved incompatible with about 60% of PC applications including WordStar and two programs often used to test PC clones' compatibility, Lotus 1-2-3 and Microsoft Flight Simulator. Reasons included insufficient memory, IBM PC-specific copy-protection, and the PCjr's smaller keyboard.[23][2][13][24]

Limited hardware expansion

Along with the lack of software, computer dealers quickly identified the PCjr's limited hardware expansion capability as a major disadvantage.[18] It only had an internal slot for a modem and an external slot on the right side for "sidecar" peripherals. IBM published technical details publicly 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,[8] or memory beyond 128 KB.[3] Multiple sidecars proved very clumsy, and the computer required additional power supplies with a second floppy drive or several sidecars.[13][8] The PCjr also lacked a DMA controller, so the 8088 CPU had to service standard system interrupts such as the serial port or the keyboard directly. The PCjr thus could not use modems faster than 2400 baud, and it would refuse to process keyboard input if its buffer was full.[3]


In July 1984—by which time PCjr sales had declined to only a few thousand a month—IBM replaced the chiclet keyboard for free with a different wireless model,[13] an unusually generous act for the company and the industry.[19] The company had to replace only about 60,000 keyboards, compared to the 250,000 to 480,000 computers that experts had estimated IBM would sell during the first six months. IBM also reduced the PCjr's list price, offering a $999 package that was arguably superior to the comparably priced Apple IIe and IIc, while deemphasizing the PCjr's marketing as a home computer and emphasizing its ability to run IBM PC programs.[4] Advertisements listed the new price, "new typewriter-style keyboard", standard 128 KB of memory with new IBM-made expansion options to 512 KB, a new cartridge-based version of Lotus 1-2-3, and the ability to "run over a thousand of the most popular programs written for the IBM PC."[25]

Although sales improved due to the better keyboard and significant discounts to the new list price,[13] they declined again when the discounts ended after Christmas, with sales decreasing from an estimated 50 per store in December to 2.4 in February.[26] By this time three PCjr-specific magazines had ended publication.[11] With the overall home-computer market in decline—even while IBM could not meet the demand for its new PC AT business microcomputer[22]—and likely unable to make a sufficient profit when the PCjr was sufficiently discounted to increase sales, the company discontinued it in March 1985[26][27] and, reportedly with more than 100,000 leftover PCjrs, sold them at a large discount to its employees.[28]


Tandy Corporation produced a clone of the PCjr, the Tandy 1000. Since the PCjr was discontinued soon after the new computer was released in November 1984,[29] Tandy had to hastily change its marketing strategy. However, the machine and its many successors ultimately proved much more enduring than the PCjr itself, 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. Ironically, the enhanced graphics and sound standards the PCjr pioneered ultimately became known as "Tandy-compatible", with the extended graphics modes eventually coined "TGA" (Tandy Graphics Adapter) graphics.

King's Quest, a popular adventure game series, was originally developed for the PCjr, as IBM had commissioned Sierra On-Line for a game that would take advantage of the PCjr's expanded graphics and sound capabilities for the product's launch.

IBM returned to the home market in 1990 with its much more successful IBM PS/1 line. Unlike the PCjr's radical departure from the IBM PC, the PS/1 line concentrated on IBM brand-name compatibility and affordability.

"PCjr magazine" ran articles written by many of the legends of the computer industry from back in their early days. This comprises a collection of entry level PC articles, from such people as Peter Norton, that could be considered mentionable.

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.

IBM's later attempt to build a computer targeted at home users, the PS/2 Model 30 was also unsuccessful due to its similar use of nonstandard technologies that were less capable than alternatives already available from IBM's competitors.

Technical specifications

  • CPU: Intel 8088, 4.77 MHz
  • Memory: 64K on the motherboard expandable to 128K via a card in a dedicated slot. Further expansion via IBM sidecar adapters. Later third-party add-ons and modifications raised the limit to 736K.
  • 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: 3 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).
    • 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
    • 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


  1. ^ a b c d Sanger, David E. (1984-05-17). "I.B.M.'S PROBLEMS WITH JUNIOR". The New York Times. Retrieved 2011-02-25. 
  2. ^ a b c d e f McCarroll, Thomas; Michael Moritz; Philip Elmer-DeWitt (1984-04-02). "The Peanut Meets the Mac". Time.,8816,954205,00.html. Retrieved 2011-02-23. 
  3. ^ a b c d Hoffmann, Thomas V. (1984-03). "IBM PCjr". Creative Computing. pp. 74. Retrieved 2011-02-25. 
  4. ^ a b Halfhill, Tom R. (1984-10). "IBM's New & Improved PCjr". Compute!: pp. 50. Retrieved 2011-02-24. 
  5. ^ a b c d e f Moritz, Michael; John Greenwald; Frederick Ungeheuer (1983-11-07). "D-Day for the Home Computer". Time.,8816,949869,00.html. Retrieved 2011-02-23. 
  6. ^ a b c d e "I.B.M.'S SPEEDY REDIRECTION". The New York Times. 1983-11-02. Retrieved 2011-02-25. 
  7. ^ Reimer, Jeremy (2009-11-02). "Total Share: Personal Computer Market Share 1975-2005". Jeremy Reimer's Blog. Retrieved March 15, 2011. 
  8. ^ a b c d e f g h i Ruby, Daniel (1984-02). "IBM's PCjr—was it worth the wait?". Popular Science: pp. 68–71. Retrieved 2011-02-24. 
  9. ^ a b c d e Mace, Scott; Paul Freiberger (1983-11-21). "Industry reacts to PCjr". InfoWorld: pp. 21–22. Retrieved 2011-02-25. 
  10. ^ "BOOM IN COMPUTER MAGAZINES". The New York Times. 1983-11-09. Retrieved 2011-02-25. 
  11. ^ a b Bartimo, Jim (1984-12-10). "MAGAZINES WOO USERS". InfoWorld: pp. 35–36. Retrieved March 14, 2011. 
  12. ^ a b c d Pollack, Andrew (1983-11-02). "THE DEBUT OF I.B.M.'S JUNIOR". The New York Times. Retrieved 2011-02-25. 
  13. ^ a b c d e f g McCarroll, Thomas and Philip Elmer-DeWitt (1984-12-24). "A Flop Becomes a Hit". Time.,8816,951424,00.html. Retrieved 2011-02-23. 
  14. ^ Mace, Scott (1983-11-21). "TI retires from home-computer market". InfoWorld: pp. 22, 27. Retrieved 2011-02-25. 
  15. ^ a b Wierzbicki, Barbara (1983-12-19). "Developers embrace PCjr despite drawbacks". InfoWorld. Retrieved 2011-02-25. 
  16. ^ "IBM PCjr Classic Ad". 1984. 
  17. ^ "FROM HOME TO BUSINESS: THE ECLECTIC RADIO SHACK COMPUTER LINE". InfoWorld: pp. 47–52. 1984-08-20. Retrieved May 26, 2011. 
  18. ^ a b c Zientara, Marguerite (1984-04-09). "PCjr sales below expectations, dealers say". InfoWorld (IDG). Retrieved April 03, 2011. 
  19. ^ a b Lima, Tony (1984-12-03). "NEW PC JR". InfoWorld: pp. 60–61. Retrieved 2011-02-25. 
  20. ^ Miller, George A. (1984-07). "Apple announces the IIc". Creative Computing: pp. 116. Retrieved 2011-03-17. 
  21. ^ "The Apple IIc". Apple II History. Retrieved 2011-02-25. 
  22. ^ a b Sanger, David E. (1985-01-18). "COMPUTER GIANT FINDS PROBLEMS IN SUCCESS". The New York Times. Retrieved 2011-02-25. 
  23. ^ Alsop, Stewart (1994-01-31). "A public Windows pane to make compatibility clearer". InfoWorld: pp. 102. Retrieved February 28, 2011. 
  24. ^ Shea, Tom (1984-03-12). "PCjr users wait for packages". InfoWorld: pp. 37–39. Retrieved 2011-02-24. 
  25. ^ "Now picture this.". IBM advertisement, Black Enterprise. 1984-12. pp. 47. Retrieved 2011-02-25. 
  26. ^ a b Pollack, Andrew (1985-03-20). "I.B.M. DROPS PCJR PRODUCTION". The New York Times. Retrieved 2011-02-25. 
  27. ^ Castro, Janice; Bob Buderi; Thomas McCarroll (1985-04-01). "Kicking Junior Out of the Family". Time.,8816,964850,00.html. Retrieved 2011-02-23. 
  28. ^ "I.B.M. Offers a PCjr Deal". The New York Times. 1985-09-19. Retrieved 2011-02-25. 
  29. ^ "BRIEFS". InfoWorld. 1985-02-12. pp. 23. Retrieved February 27, 2011. 

External links

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