![S100 Computers](../../../Header/S100_Banner.jpg)
Cromemco 4FDC
The 4FDC was Cromemco's first Western
Digital chip based floppy disk controller and was designed to work with both 5 &
8" drives.
![Cromemco 4FDC](4FDC.jpg)
The board also contained an
RS232
serial port (which was the default CRT terminal
port on boot up) with software-selectable
baud rates from 110 to 76,800. It had a 1K resident 2708
ROM containing Cromemco's RDOS BIOS (@C000H).
The 4FDC was really designed to drive a pair of Persci 277 8-inch single-density
floppy drives that they had in their System 3
computer. These drives used a fast
voice coil actuator and not a
stepper motor to position the drive read write
head. Fast but often went out of alignment. More important the data
separator electronics were on the drive itself - like today's hard disks!
Because of the location of the data separator, an unmodified 4FDC can
not be used with 8-inch drives that don't have single-density data
separators on the drive electronics. Later Cromemco replaced the unreliable
Persci's. They had to also change the 4FDC. This lead to the
16FDC and
64FDC boards which contained both single and double density data separators
on board.
BTW, the card soaks up some 15 IO ports
out of the S-100's possible 256s.
The manual for the board can be obtained
here.
Other Cromemco S-100
Boards
ZPU
SBC 4KRAM
16K RAM
64KZ RAM
64KZ-II
RAM
256KRAM
8KBytesaver Bytesaver-II
16KPROM
32K Bytesaver
4FDC 16FDC 64FDC
WDI WDI-II
STDC
4PIO
8PIO TU-ART
D+7A I/O
Dazzler PRI
GPIB Board
XMU
XXU
Other Boards
This page was last modified
on
01/08/2011