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I > IBM  > PC Junior   


IBM
PC Junior

After launching the IBM PC (and its great success), IBM tried to stand out a standard for home computers, it created then the PC junior, which itself is a "light" version of the PC especially designed for home activities.

Despite its qualities, the PC jr had few success and never managed to replace the established home computers like Commodore 64, Apple II or Atari 800.

Two IBM PC junior models were available: a basic one and a enhanced one (supplied with 128k, 30 programs, a 5.25" floppy disk drive [360 KB] and its controller).

Contrary to the IBM PC, the power supply is not integrated to the case, but is external. The keyboard is linked by infra-red to the CPU, though there was a RJ11 (standard phone jack) plug that could be used instead to save batteries. It is impossible to connect a 8087 math co-processor.

The RS232 connector is not a standard one. To use a standard RS232 device, the user has to buy a special adapter ("Berg" style connector breakout -> D25 connector).

The PC Jr runs under MSDOS 2.1 (the same version as the PC) and handles a hard disk when it is not possible to connect hard disk on the PC Jr (go figure)! There was an internal modem available that ran at 300 bps sold by IBM. Third party modems were also available at 1200bps.

A cartridge containing enhanced basic (with special graphics instructions) was also available. To get a 80 column text display, the extra 64k RAM expansion is needed.

Many IBM PC programs would not originally run on the PCjr because it did not include a DMA controller. This was available through a memory side-car add-on from Tecmar Systems. Many people were able to then run the PCjr as a competent business type of system as well.



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Special thanks to Peter Prexel who donated us this computer !

 

Yan touches on some good points, but... the first point about "incompatibilities" misses a lot about the market it cam out in. Compaq would not bring out its successful Deskpro 386 until the next year, 1986. Apple II, Comodore64, Atari, TRS-80 and other computers of the time were all incompatible and idiosyncratic. Even when they had 5.5'' disks, the formats were incompatible. In truth having IBM DOS 2 and not CP/M made them weird at the time (IBM offered CP/M for an additional price on the day the 5150 came out) But yes, they did fear PCs eating into business computers, that''s why they accepted Microsoft''s OS and left them free to licence. From the beginning they thought they could make their own later (OS/2) and crush M$. Also with PS/2 line they would put out a new MCA architecture and crush the new ISA standard their clone competitors made. Also their was a lot of criticism about the awful "chiclet" keyboard. It was so bad, PC makers avoided the style for years afterwards. Basically until Apple came out with the Magic keyboard, in the 2000s which won acclaim and is still sold at premium prices. It''s an irony many seemed not to realize. Above all, was IBM''s arrogance. Picking out the smaller faults sometimes misses this larger point.

          
Sunday 25th October 2020
Cuvtixo (Colorado/USA)

Email is jaya.buckwheat@gmail.com

          
Tuesday 22nd September 2020
Jay (Washington State USA)

I am looking for one of these at a cheap price, I will pay up to 100$ including shipping if I have to pay for it

          
Tuesday 22nd September 2020
Jay (Washington State USA)

 

NAME  PC Junior
MANUFACTURER  IBM
TYPE  Home Computer
ORIGIN  U.S.A.
YEAR  November 1983
END OF PRODUCTION  March 1985
KEYBOARD  Chicklet keyboard (full stroke keyboard was available later)
CPU  Intel 8088
SPEED  4.77 MHz
CO-PROCESSOR  Texas Instrument sn76496 n (sound)
RAM  64k (up to 640 KB)
Extended model : 128k
VRAM  from 2k to 128k (use the conventional RAM)
ROM  24 KB
TEXT MODES  40 x 25 / 80 x 25
GRAPHIC MODES  160 x 200 (16 colors), 320 x 200, 640 x 200
COLORS  16
SOUND  three channels
SIZE / WEIGHT  Unknown
I/O PORTS  2 cartridges ports (64 KB each), Centronics (optional), RS232, Joystick, Light Pen, video out (RCA plug)
BUILT IN MEDIA  one 5.25'' disk drive
OS  MS DOS
POWER SUPPLY  External PSU
PRICE  Unknown




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