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Digital Research Computers -- 128K RAM/EPROM Board  III
This was a useful ROM board in that it could take RAM or ROM together on the same board.  It may be the last S-100 board DRC made.


I used this board to hold my version of the IBM PC BIOS. It used the popular 28 pin 2764 style 8K x 8  RAM/ROM chips. Each chip location could be disabled. It  met all the IEEE-696 specifications and so had 24 bit addressing as well as 8 or 16 bit data paths.  You could add up to 7 wait states. You could set it to byte low or byte high mode for even/odd  addresses.   It did support the S-100 bus Phantom line for input but unfortunately not output (to inactivate othere overlapping RAM on the bus). 

The (short but adequate) manual for this board can be obtained here.


Digital Research Computers S-100 Boards
16K RAM     8K RAM    16K ROM    32K EPROM    Sound Effects Board    Z80 CPU Board   128K RAM/EPROM   LS-100 RAM Disk
64K Static RAM


This page was last modified on 12/01/2013