The IMSAI I-8080 was borne out of necessity. IMS Associates (usually referred to as simply IMSAI) was a consulting company that found it had underbid on a contract to design and build a system for a specialized application. To avoid disaster, founder Bill Millard changed his plans from using minicomputer components to the then-new microcomputer. In fact, he might have simply bought Altair 8800s for the project, but MITS needed 90 days to deliver and wanted cash up front. IMSAI was forced to build its own system from scratch, with the hope that it could recoup some of its costs by selling the Altair-compatible units to hobbyists.
IMSAI took advantage of the Altair 8800’s popularity by using the same S-100 bus. Any expansion card that worked in the Altair would also work in the IMSAI, and the computer entered the market with a great deal of third-party vendor support. In fact, the company advertised that you could install an Altair CPU board in an IMSAI and run them in parallel, each sharing system resources such as memory.
Despite a relatively long production run (until May 1986) and several internal revisions, all IMSAI 8080s look the same. IMSAI introduced the Megabyte Micro in 1977, which was based on the 8080 and had 1MB of RAM. Around 1978, the IMSAI 8080/1 series appeared with 32K RAM, a single S-100 slot, and either two serial ports or two parallel and on serial port. The optional 50MB hard drive was absurdly large for a microcomputer of the era.
IMSAI had designed high-end computers and disk storage systems, and its know-how was obvious to hobbyists then and to collectors today. IMSAI systems, when they come on the market, command Altair-like prices.
Support, parts, and service are still available for IMSAI systems through the Fischer-Freitas Company, run by two former IMSAI employees, through the Web at http://www.imsai.net. If you can’t find a classic IMSAI to restore, Fischer-Freitas will sell you an IMSAI Series Two, an S-100-based, modernized look-alike to the 8080 based on the Zilog Z8S180 CPU.
With the optional CRT display unit, both PCS series could be housed in big blue square enclosure that made the tiny screen look even smaller than it was. IMSAI updated the motherboard shortly after introducing the PCS-80 adding three slots. The PCS-80 was sold in France under the Data Soft brand. IMDOS was IMSAI’s CP/M-compatible operating system.
VDP stood for Video Data Processor, and refers to the built-on monitors on both VDP series. The VDP-80 was sold in France under the Data Soft name.
IMSAI I-8080 Microcomputer (Dec. 1975, early micro)
Original Retail Price: $439 kit, $621 assembled
Base Configuration: 2MHz 8080A CPU, TCOS, 17 S-100 slots, 4K RAM (64K max), status LEDs, front panel switches, assembler, monitor, text editor, BASIC, aluminum enclosure, expansion board, front panel control board
Size/Weight: 19.5 x 17 x 7 inches
Important Options: 10- or 50MB hard disk drive, floppy disk drive, video adapter, keyboard, serial and parallel interfaces, line printer, printer/plotter, clock board, rack mount enclosure
IMSAI I-8080/1 Microcomputer (1978, early micro)
Base Configuration: 2MHz 8080A CPU, TCOS, 22 S-100 slots, 32K RAM (64K max), status LEDs, front panel switches, two serial ports, parallel port, cassette interface assembler, monitor, text editor, BASIC, aluminum enclosure, expansion board, front panel control board
Size/Weight: 19.5 x 17 x 7 inches
Important Options: 10- or 50MB hard disk drive, floppy disk drive, video adapter, keyboard, serial and parallel interfaces, line printer, printer/plotter, clock board, rack mount enclosure
IMSAI PCS-40, PCS-42, PCS-44 (1977, early micro)
Original Retail Price: $1,499
Base Configuration: 3MHz 8085 CPU, IMDOS, seven S-100 slots, 2.25K RAM (64K max), 3K ROM, two 5.25-inch 90K floppy disk drives (PCS-40), two 400K floppy disk drives (PCS-42), two 330K floppy disk drives (PCS-44), keyboard, two RS-232 and one parallel ports, BASIC-E, monitor in ROM
Video: 24-line x 80-column text
Size/Weight: 17 x 20 x 7 inches, 30 lbs.
Important Options: monochrome CRT unit, 10MB hard disk drive, printer
IMSAI PCS-80 (1977, early micro)
Base Configuration: 3MHz 8085 CPU, IMDOS, seven S-100 slots, 2.25K RAM (64K max), 3K ROM, two 8-inch floppy disk drives, keyboard, two RS-232 and one parallel ports, BASIC-E, monitor in ROM
Video: 24-line x 80-column text
Size/Weight: 17 x 20 x 7 inches
Important Options: monochrome CRT unit, dual 8-inch floppy disk drives, 10MB hard disk drive, printer
IMSAI VDP-40, VDP-42, VDP-44 (1977, early micro)
Base Configuration: 3MHz 8085 CPU, IMDOS, six S-100 slots, 32K RAM (196K max), 2K ROM, two 90K 5.25-inch floppy disk drives (VDP-40, two 200K 5.25-inch floppy disk drives (VDP-42), two 360K 4.25-inch floppy disk drives (VDP-44), integral 9-inch monochrome CRT, integral keyboard/keypad, RS-232 and parallel ports, BASIC-E
Video: 24-line x 80-column text
Size/Weight: 18 x 27 x 12 inches, 65 lbs.
IMSAI VDP-80 (1977, early micro)
Original Retail Price: $5,995
Base Configuration: 3MHz 8085 CPU, IMDOS, two (VDP-80) S-100 slots, 32K RAM (196K max), 2K ROM, two 8-inch floppy disk drives, integral 12-inch monochrome CRT, integral keyboard/keypad, RS-232 and parallel ports, BASIC-E
Video: 24-line x 80-column text
Size/Weight: 24.62 x 15.25 x 25 inches, 103 lbs. (VDP/80)
Literature:
1976 IMSAI new peripherals interfaces socket sets 7-76
1978 IMSAI I-8080 brochure 7-18-78
1978 IMSAI I-8080-1 Have you heard flier 7-26-78
1979- IMSAI VDP-40 series great vdp-40 flier
1978 IMSAI VDP-4x brochure 8-15-78
1978 IMSAI VDP-80 brochure 10-9-78
1979- IMSAI VDP-80 the 6995 data center flier
1979- IMSAI PCS-4x flier
1978 IMSAI PCS-4x brochure 8-15-78
1978 IMSAI PCS-80-21 PCS-80-22 brochure 9-22-78
1979 imsai product descriptions 1-79
1978 imsai vio brochure 3-1-78
1978 IMSAI RAM iii brochure 5-20-78
1978 IMSAI IMDOS brochure 8-15-78
1978- imsai fortran iv version 3-05 pr
1978 IMSAI commercial basic data specifications 3-9-78
1978- imsai announces hard disk CDC hawk 9427H
1978- imsai announces hard disk CDC hawk 9427H part 2
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