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A PCjr with the revised keyboard and a third-party floppy drive (attached to the top of the computer).
A PCjr with the revised keyboard and a third-party floppy drive (attached to the top of the computer). The IBM PC Series personal computer was the follow-on to the IBM PS/ValuePoint and IBM Personal System/2.

The IBM PCjr (read "PC junior") was IBM's first attempt to enter the market for relatively inexpensive educational and home-use personal computers. International Business Machines Corporation abbreviated IBM and nicknamed "Big Blue", is a multinational Computer Technology Sao Paulo Stock Exchangejpg|thumb| Virtual market arena where buyer and seller are not present and trade via intemediates and electronical information Education encompasses both the Teaching and Learning of Knowledge, proper conduct, and technical competency A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s The PCjr, IBM model number 4860, retained the IBM PC's 8088 CPU and BIOS interface for compatibility, but differences in the PCjr's architecture, as well as other design and implementation decisions, eventually led the PCjr to be a commercial failure in the marketplace. The Intel 8088 is an Intel X86 Microprocessor based on the 8086, with 16- Bit registers and an 8-bit external Data bus In Computing, the BIOS (ˈbaɪoʊs

Contents

Features

Announced November 1, 1983, and first shipped in March 1984, the PCjr (referred to internally by IBM as "Green Dragon", and later called "Peanut" by several trade publications until a short while after its debut) came in two models: the 4860-004, with 64 KB of memory, priced at US$669; and the 4860-067, with 128 KB of memory and a 360 KB 5. Events 996 - Emperor Otto III issues a deed to Gottschalk Bishop of Freising which is the oldest known document using the name Ostarrîchi Year 1983 ( MCMLXXXIII) was a Common year starting on Saturday (link displays the 1983 Gregorian calendar) Year 1984 ( MCMLXXXIV) was a Leap year starting on Sunday (link displays the 1984 Gregorian calendar) A kilobyte (derived from the SI prefix Kilo -, meaning 1000 is a unit of Information or Computer storage equal to either 1024 25-inch floppy disk drive, priced at US$1269. The PCjr promised a high degree of compatibility with the IBM PC, already a popular business computer, and offered built-in color graphics (via a graphics chip known as the "VGA", which stood for "Video Gate Array" - not to be confused with the later VGA (Video Graphics Adapter or Array) chip and standard that IBM released with its PS/2 line in 1987) and sound that was better than the standard PC speaker sound and color graphics of the standard IBM PC and compatible machines of the day. The term Video Graphics Array ( VGA) refers specifically to the display hardware first introduced with the IBM PS/2 line of computers in 1987, but through its widespread The PC speaker is the most primitive sound system used in IBM compatible PCs It was the only source of sound available to PC games before more technologically advanced The Color Graphics Adapter ( CGA) originally also called the Color/Graphics Adapter or IBM Color/Graphics Monitor Adapter The PCjr was also the first PC compatible machine that supported page flipping for graphics operation. In Computer science, double buffering (or ping-pong buffering is a widely used technique for minimizing the delay (flicker in Input/output operations which 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.

Additionally, its 4. 77 MHz Intel 8088 CPU was faster than other computers aimed at the home market (though the PCjr actually ran slower than the stated 4. The Intel 8088 is an Intel X86 Microprocessor based on the 8086, with 16- Bit registers and an 8-bit external Data bus 77Mhz, because every 4th clock cycle of the 8088 CPU was designated to refresh the PCjr's RAM as it had no dedicated memory controller), and its detached wireless infrared keyboard promised a degree of convenience none of its competitors had. The memory controller is a chip on a computer's Motherboard or CPU die which manages the flow of data going to and from the memory. 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 haven't 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 access controllers, necessitating the use of PCjr-specific joysticks (or generic joystics 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. A ROM cartridge is a removable cartridge that contains ROM devices and commonly Flash memory devices to allow some read-write capability The cartridge(s) would be plugged in from the front, prompting the computer to automatically reboot and run the software. 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 shipped with a chiclet type keyboard powered by AA batteries to provide infrared line-of-sight wireless communication. A chiclet keyboard is slang for a Computer keyboard built with an array of small flat rectangular or lozenge-shaped rubber or plastic keys that look like Erasers or The keyboard could also operate with a modular telephone-style cable if so desired, eliminating battery usage. Modular connector is the name given to a family of Electrical connectors examples of which are pictured The PCjr also shipped with a lightpen port, which worked with a small number of applications designed for it. A light pen is a Computer Input device in the form of a light-sensitive wand used in conjunction with a the computer's CRT TV set or monitor The lightpen port was later used in combination with the serial port to supply voltage to a Mouse Systems optic mouse of the same design as Sun workstations.

Failure in the marketplace

The PCjr launched with an enormous amount of advance publicity, including live news-broadcast coverage of the product announcement. Ziff-Davis, publisher of the successful PC Magazine, printed the first issue of PCjr Magazine even before the first PCjr units shipped. Ziff Davis Inc (ZD is an American publisher and Internet company PC Magazine (sometimes referred to as PC Mag) is a Computer magazine that is published monthly in the United States (until 2008 it was published Observers expected the PCjr to change the home-computer market in a similar way to how the IBM PC had singlehandedly changed the business market in the two years since its debut. PCjr advertising featured a Charlie Chaplin character from The Tramp connecting it to the successful campaign for the business model. The Tramp, also known as The Little Tramp ( Charlot internationally Carlitos in Brazilian Portuguese) was Charlie Chaplin 's most memorable [1]

However, the PCjr was never well received. A prime target of criticism was its keyboard; IBM chose to use an infrared wireless chiclet keyboard, similar to that of a pocket calculator, with wide spaces between keys to leave room for instructional overlays bundled with software packages. A chiclet keyboard is slang for a Computer keyboard built with an array of small flat rectangular or lozenge-shaped rubber or plastic keys that look like Erasers or It was widely criticized as feeling cheap and being difficult to type on. IBM eventually replaced it for free with a different wireless keyboard with more conventional keys. Regardless of the keys' design, with only 62 keys, it lacked the numeric keypad and separate function keys of the IBM PC, and the layout was more awkward than that of most of its competitors.

At $669, the PCjr's price was not competitive. It cost more than twice as much as the Commodore 64 and the Atari 8-bit family; its price was close to that of the Coleco Adam, but the Adam also included two tape drives, a printer, and software. The Atari 8-bit family is a series of 8-bit Home computers manufactured from 1979 to 1992 The Coleco Adam was a Home computer, an attempt in the early 1980s by American toy manufacturer Coleco to follow on the success of its ColecoVision With the exception of the Apple II, it was possible to purchase a complete system (computer, disk drive, printer, and monitor) from almost any of IBM's competitors for less than the PCjr's entry price.

Many people compared the PCjr unfavorably to the IBM PC rather than to the machines against which it was directly competing. While compatibility with the IBM PC's large software library was a key selling point, in practice the PCjr proved incompatible with many popular PC applications, in part due to memory limitations and in part due to architectural differences.

The PCjr was often purchased by business people as a lower-cost alternative to the PC, but then was quickly abandoned for business use. The BIOS was produced by the same company that wrote the BIOS for the PC, IBM, with published differences. At the time, it was popular for many programmers to use direct hardware BIOS "pokes" and "peeks" and process with assembly language as this offered performance advantages and compilers for PCs were limited. Programmers had to keep the PCjr in mind when developing code, which most didn't. So, while most PC software would work, including the "acid test" for PC-compatibles at the time, Microsoft Flight Simulator, business packages competing for features and performance would often have odd hardware related crashes. Microsoft Flight Simulator (sometimes abbreviated to MSFS or FS) is a Flight simulator program for Microsoft

The keyboard issue alone was enough to sink the PCjr, but not having the same expansion slot type was really the death of the PCjr. When an expansion came out to add a hard drive, it would only work on the PC. The PC with a built-in hard drive came out next, known as the XT. No further development was done with the PCjr. The PCjr was not a PC clone as the first Compaq would be. It was a separate computer, technically linked by being from the same vendor, that, like an unusual mutation of early species, would just die out.

Arguably, the PCjr's technical capabilities may have justified its higher price tag: it was a 16-bit machine competing in an 8-bit world. It offered better memory expansion, had a built-in 80 column display, and was faster than any of its competition. However, reviewers of home computers at the time cared much less about raw power and more about price, available software, and the quality of the keyboard. Moreover, while the PCjr may have been superior to its competitors in running office suite software, it was clearly inferior to the Commodore 64 and the Atari 8-bit family as a gaming platform; unlike them, it had very limited color capabilities (due to its CGA-derived graphics chip) and no support for hardware sprites. In Computing, an office suite, sometimes called an office software suite or productivity suite is a Software suite intended to be used by typical The Atari 8-bit family is a series of 8-bit Home computers manufactured from 1979 to 1992 The Color Graphics Adapter ( CGA) originally also called the Color/Graphics Adapter or IBM Color/Graphics Monitor Adapter In Computer graphics, a sprite (also known by other names see Synonyms below is a two-dimensional/three-dimensional Image or Animation that Also, the sound chip was nowhere near as advanced as the MOS Technology SID found in the C64 (although it rivaled Atari's POKEY). The MOS Technology 6581/8580 SID (Sound Interface Device was the built-in Programmable Sound Generator chip of Commodore 's CBM-II, Since gaming capabilities were important to many home computer buyers of the time (who often purchased the machines as replacements for older game consoles), this was another strike against the PCjr. A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s

The PCjr was more difficult to expand than many of its intended competitors. It was not designed to add a second floppy drive, a hard drive, or easily expand memory beyond 256K, which made it difficult to deliver on the promise of running business software for the IBM PC. A hard disk drive ( HDD) commonly referred to as a hard drive, hard disk, or fixed disk drive, is a Non-volatile storage device Third parties created PCjr add-ons, including a second floppy drive or a 20-megabyte hard drive, but were not available right away. One particular company, PC Enterprises, produced several useful expansion kits, including a CPU speedup board, SCSI controller for hard drives, VGA video card, 3. 5" floppy drive, SoundBlaster sound card, and also many software products that shipped on floppy and on plug-in cartridge that enhanced the PCjr's compatibility with the IBM PC. Many of these products ended up being fairly costly due to the limited PCjr expansion market; for example, the Combo Cartridge, a cartridge which simply improved BIOS compatibility and sped up certain BIOS calls, was $89 when it was last sold. PC Enterprises no longer provides PCjr products so these items are increasingly harder to find today. PC Enterprises' online catalog of PCjr products is still available for viewing.

Many IBM and third-party add-ons attached to an expansion slot on the computer's right side (dubbed "Sidecars"), similar to the design of the discontinued TI 99/4A; thus, as with the TI, multiple add-ons proved very clumsy. The Texas Instruments TI-99/4A was an early Home computer, released in June 1981 originally at a price of USD $525 In addition, it was necessary to purchase additional power supplies for every few expansion modules attached to the computer; it was not unheard of for the computer to require three separate power bricks just to run with its expansions.

The PCjr also lacked a DMA controller. Thus, the 8088 CPU had to service standard system interrupts such as the serial port or the keyboard directly. Hence, the PCjr couldn't be used with modems faster than 2400 baud, and it would refuse to process keyboard input if its buffer was full.

Unable to compete with the C64 and Apple Computer's IIe and IIc, let alone the forthcoming Atari ST and Commodore Amiga, IBM withdrew the PCjr from the marketplace in mid-1985. Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics The Apple IIe is the third model in the Apple II series of personal computers produced by Apple Computer. The Apple IIc, the fourth model in the Apple II series of personal computers was Apple Computer ’s first endeavor to produce a Portable computer. The Atari ST is a home / Personal computer that was commercially available from 1985 to the early 1990s The Amiga is a family of Personal computers originally developed by Amiga Corporation. Year 1985 ( MCMLXXXV) was a Common year starting on Tuesday (link displays 1985 Gregorian calendar)

The PCjr legacy

Tandy produced a clone of the PCjr, the Tandy 1000. Tandy Corporation was a family-owned Leather goods company based in Fort Worth Texas, which is best known for purchasing and giving its name to the Fort Worth The Tandy 1000 was the first in a line of more or less IBM PC compatible Home computer systems produced by the Tandy Corporation for sale in its Radio Since the PCjr was discontinued two weeks before the new computer was to be released, 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. RadioShack Corporation (formerly Tandy Corporation) (  is a chain of electronics retail stores in the United States, as well as parts of North America 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. King's Quest is an Adventure game series made by the American Computer game company Sierra Entertainment

IBM returned to the home market in 1990 with its much more successful IBM PS/1 line. Year 1990 ( MCMXC) was a Common year starting on Monday (link displays the 1990 Gregorian calendar) The IBM PS/1 Personal computer was IBM 's return to the home market in 1990, five years after the IBM PCjr. 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. Peter Norton (born November 14 1943) is an American Software Publisher, Author, and Philanthropist.

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

See also

References

  1. ^ IBM PCjr Classic Ad (1984). The IBM JX (or JXPC) was an Personal computer released in 1984 into the Japanese Australian and New Zealand markets

External links

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