The RAIR Business Computer is an obscure system since nearly nothing can be found on the net about it (apart from here :-))
The Business Computer is a multipost system. It can control/serve up to 4 attached terminal stations via RS422 connectors.
Its main particularity is to mix two technologies: 8-bit with its Intel 8085 CPU and 16-bit with its Intel 8088 CPU. Thus it can run CP/M, MP/M and PC-DOS software with no problem (according to the advert).
For mass storage, the system is equiped with a 19 MB Winchester hard-disk (up to 4 can be mounted) and a 5.25'' 1 MB floppy drive.
Lots of interesting information from Tim Hill
I managed the design of this system and was responsible for most of the OS software. Hardware design was by Dick Akers and Bob Marsh (of Processor Technology fame). Industrial design was by Mike Nutall (now in ID3) and for the time was pretty "wow" (most of the competition was sheet metal). The main unit was based on a RAIR Black Box but included two new features: a dual-CPU processor card (8085 and 8088) and a console card capable of driving four "consoles".
The dual-cpu card could only run one processor at a time; they switched back-and-forth under a software controlled dance. The 8088 was the main CPU, with the 8085 kicked in to run legacy 8-bit software (of which there was a lot at that time). Later units replaced this board with an early 80286 cpu card and running 8-bit software was handled by an emulator (written by me) -- not as crazy as it sounds as in fact it was *faster* than the hardware 8085!
The display card was probably the most interesting part. The single card contained a dedicated 8085 cpu with enough muscle (for then!) to drive 4 color displays and handle keyboard input. This allowed the system to run 4 console sessions at once, even though each "console" was actually just a CRT and dumb keyboard.
The OS was MP/M-86, which could run the 4 consoles simultaneously. Native 16-bit CP/M programs ran directly. To run an 8-bit program, a tool called RUN85 was used which created a virtual 8-bit CP/M environment (easy since the two OSes were very similar) and then handed off to the 8-bit CPU for a time-slice. In addition, a purely software based MSDOS emulation facility allowed the "new" programs written for MSDOS to run as well; all of these at the same time just by running an application. Quite advanced for its time.
The achilles heel of the system was the slow performance of the display card (the 8085 really had trouble keeping up with the main system) and the lack of software that could support the (for the time) spiffy color display output. Overall, though, the system was well engineered and in some ways way ahead of its time.
We need more info about this computer ! If you designed, used, or have more info about this system,
please send us pictures or anything you might find useful.
END OF PRODUCTION
Full stroke keyboard, 83 keys, 10 programmable function keys, numeric keypad
16-bit Intel 8088 & 8-bit Intel 8085
256 KB (1 MB max.)
80 x 25 characters
high resolution ?
SIZE / WEIGHT
4 x terminal connectors (RS 422 compatible), 2 x RS232 ports