Fulcrum - Omnidisk FDC Board
This was not an IMSAI board but a board designed and produced by Fulcrum
The board could support 5" and 8" floppy disks. It had 24-bit DMA
addressing capability. it had an onboard PROM for power on boot. There
was onboard RAM for sector de-blocking to conserve valuable RAM space above
the BIOS. There was an interface for a Western Digital 1001 hard disk
controller as well. The board had full 16-bit port addressing. The board had
its own onboard 4MHz 8085 CPU.
Full track buffers allowed the controller to recall entire tracks, not just
sectors. This gave great speed increases (typically 3-7X other systems).
The manual for this interesting looking board can be obtained
A Z80 BIOS and related software can be obtained
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