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Heath/Zenith     Z-207 Floppy Disk Controller (FDC) Board
This was one of the two S-100 boards Heathkit supplied with their Z/H-100 computer system.

Heathkit FDC

The Z-207 was the floppy disk controller board used for all floppy disk IO with the Z-100 Computer. It functioned as an intelligent interface between the CPU and the disk drives. The Z-207 selected the correct drive in a multi-drive system and properly handled the data flow to and from the drives. The Z-207 operated as a slave processor. This means the disk controller board contains its own processor which was controlled by the master CPU. Thus, the disk controller board took commands from the master CPU and converted them into the necessary signals required to control the drives. This type of system allowed the master CPU to do other tasks while the disk controller board processor actually does the   work of controlling   the  disk drives. The Z-207 was versatile. It could support up to four 5-1/2" and four 8" disk drives. User software will selected the type of drive used and the density of the media. However, the Heath Company software limited the number of drives to  three.
The Z-207 could be operate in three different modes; Wait State, Polled I/O, or Interrupt. This allowed the disk controller board to support almost all available soft-sectored disk formats. When placed in the H/Z-100, the disk controller board used the Wait State mode of operation. By using the Wait State mode, the board could be jumpered  to operate  at speeds up to 6 MHz.

Because the Z-207 was a S-100 compatible card, it could be installed in other makes of computers using the S-100 bus. Additional features that make the controller board acceptable to other computers are: user selectable addressing, software controllable formatting, Shugart compatible 8"   interface,   and   adjustable   pre-compensation.  The board utilized the Western Digital 1797 FDC chip

The relevant sections of the Z-100 user manual for this FDC board and drive can be obtained here.


Other Heathkit S-100 Boards
Motherboard    FDC      Winchester Disk Controller   256K RAM    ARCNET


This page was last modified on 10/25/2013