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CompuPro - Disk 1A
The Disk 1A was as you might expect an
upgrade of the original Disk 1. It still used an Intel 8272 or NEC 765A
floppy disk controller instead of a at the time, then more common Western Digital
1791-7 chips. Unlike the Disk 1 it did not have on board a basic serial I/O port
to boot the system for the first time. Instead the CompuPro boot software
assumed your consol was connected to their System Support 1 board or their
Interfacer 4 board.
![CompuPro Disk1A](Disk 1A.jpg)
What was interesting about both the
Disk1 and 1A was that the boot ROM had code which via a switch selection
could be used to work with either a 8085/Z80, a 8088/8086/80286, a 68000 or a
32016 CPU based system. The board handled data transfers via 24 bit DMA with the
ability to cross 64K boundaries. There was a priority arbitration scheme
for the on-board DMA circuitry that will allow up to 16 temporary bus masters to
operate without conflict. There was an advanced digital data separator for
reliable data transfers. No cap or resistor adjustments were required. The board
had provisions for running both 5.25" and 8" floppy drives at the same time.
The manual for this board can be
obtained here.
This page was last modified
on
01/08/2011