IBM JX: Difference between revisions

The IBM JX (or JXPC) was an personal computer released in 1984 into the Japanese, Australian and New Zealand markets. Designed in Japan, it was based on the technology of the IBM PCjr and was designated the IBM 5511.

With a professional keyboard (rather than IBM PCjr's disparaged chiclet), a hard drive option, and targeted at the small business and education market, the IBM JX was much more successful in Australia and New Zealand than the PCjr had been in the United States.

It had several innovative features:

• Twin 720kB 3.5" diskette drives
• Wireless infra-red keyboard
• 16-colour monitor
• Stackable expansion

In Japan both white and black units were available, but elsewhere all JX's were black—very unusual in the days the "beige box".

However, it shared many of the disadvantages of the IBM PCjr:

• Could not the use the standard ISA bus cards of the PC XT
• Would not run software written to directly address hardware (such as Microsoft Flight Simulator)

The system operated PC-DOS 2.11 and Advanced BASIC. Like the IBM PC, if the system was left to boot without inserting a diskette into one of the drives the BASIC interpreter would be loaded, which was compatible with IBM PCjr BASIC, including Cartridge BASIC. PC-DOS 2.11 could only use half of the tracks of a 3.5" drive, however, since it didn't really understand what a 3.5" drive even was. The PCjx's BIOS pretended that it was a 5.25" drive.

The PCjx later had a BIOS upgrade chip, sold together with DOS 3.21, which permitted the full 720kB capacity of the diskette drives to be used. Some popular options for the PCjx were a 10MB external hard disk (as a stackable unit the same size as the JX itself) and a joystick. IBM never released any kind of 3270 emulation adapter for the PCjx in order to steer enterprise customers to more expensive PCs and PC XTs.

External links

• http://www.thepcmuseum.com/ibm/IBMJX/default.htm
• http://www.old-computers.com/museum/computer.asp?st=1&c=187
• http://www.islandnet.com/~KPOLSSON/ibmpc/ibm1983.htm
• http://www.pbase.com/sinisterdragon/image/61176640
• http://www.youtube.com/watch?v=xUd14Rpihds
• http://www.youtube.com/watch?v=HGa-l8P_ep0