PolyMorphic Systems - Floppy Disk Controller Board
This was the floppy disk controller board
Polymorphic Systems used in their
This disk controller was one of several models built by PolyMorphic Systems.
This, the earliest model, supported single-sided, single-density disks which
stored 90K bytes per disk. For comparison, the first IBM PCs used
double-sided, double-density disks and stored 360K per disk. The upper
right connector went to a ribbon cable which connected to one, two or three
Shugart SA-400 diskette drives. This board was was used by some in the
early Poly-88 board system but it was really made for their 8810/8813
systems. The model 8813 had three floppy disk drives, the 8810 had only 1.
Later they had a double density version of the board.
Both the single and double density boards used 10 hard sectored disks. It
seems that the double density board
was also used for the 5.25 disk with a change in firmware (the board had its
own Z80 processor). Polymorphic changed the capacitors in the PLL and the
crystal frequency in the 8 inch controller to use it for 5.25 drives.
System 88 manual
gives a good description of the early state of the art for disk operating
systems at the time as well as some general information about the board. I
have not yet located a manual for the actual board itself
Other PolyMorphic Systems S-100 Boards
8080 CPU FDC
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