Cromemco 4FDC, How do you format a disk?

From: Chuck McManis <>
Date: Tue Jul 27 16:28:39 1999

At 04:38 PM 7/27/99 -0400, Allison wrote:
>The 1771 is a single density only controller and not suitable for use with
>3.5" disks. You want a board with a 765 (compupro) or 1793 CCS and a raft
>of others.

Which defines, for the most part, the difference between a 4FDC and a
16FDC. The latter used the 1793 I believe. I've got a copy of the Western
Digital databook that has these ICs in it if someone needs a copy.

BTW, I wrote the formatter for CP/M on the 16FDC (in Turbo Pascal no less
:-)) and it simply loaded up a buffer, then did a write track and stuffed
the buffer with an OUTIR instruction. (the board did wait states so this
worked.) The process involved creating a buffer and using special 8 bit
codes for "sector gap" and "index mark" and "sync mark". I've long since
given away that code but the person I gave it to is lurking on this list...

Received on Tue Jul 27 1999 - 16:28:39 BST

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