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Alpha Micro -  AM-500 Hard Disk Controller

This board interfaced the one to four CDC 9427H (Hawk) hard drives that came with the Alpha Micro systems.


The board contained a CPU module, a DMA controller and a 16X8 FIFO buffer, 1K of RAM and 2K of ROM.  The max transfer rate was 2.5 MHZ. The sector size was 512 bytes/sector. The S-100 Phantom line could be used with the board. It went low during a bootstrap load.  The CPU  loads the PROM at address 0F400H and moves it to 7C00H on the S-100 Bus.  Its not clear why but the manual never names the onboard CPU. It seems in every way to be a Z80 with presumably a Zilog DMA controller.
The manual for this board can be obtained here.


Other Alpha Micro  S-100 Boards
AM-100 CPU Board      AM-300 Serial I/O     AM-310 Serial I/O   AM-500  HDC   AM-600T  AM-200 FDC  Other Boards


This page was last modified on 06/26/2015