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Static Memory Systems
- 64K RAM/EPROM Board

SMS called this board "The last Memory" board.


THE LAST MEMORY was a high  performance 64K memory board for 8 bit (only) S-100 systems. This board uses TMM 2016, MB8128, or equivalent static RAM's. The use of static RAM eliminated the timing and reliability problems associated with some dynamic RAM boards (using DMA etc). The 2K by 8 architecture of these RAM's allowed high density and low power consumption, a characteristic not found  in most  static memories up until that time.   THE LAST MEMORY™ also accommodated 2716 type EPROM's in place of the RAM IC's with no modifications.  Mixing  RAM and   EPROM the 2K by 8 static RAM and 2716 EPROM's are pin-for-pin compatible and could be located at any position on this board. However, caution had to be exercised when mixing RAMs and 2716a. The RAM's supplied have an access time of 150 nsec, allowing full speed operation with many 6 MHz processors. High speed versions of the 2716 were not available and  since wait states are  not  generated by the board, system speed was limited by the speed of the 2716's used. If high speed operation was required, the Harris semiconductor HM7617 bipolar PROM could be used in place of the 2716 EPROM. This was a 60 nsec part, but it was not reprogrammable.

The board could be addressed on 64K boundary in the 24-bit address space.  The board responded to the Phantom line.  However the board did not have circuitry for 16-bit data transfers and so was limited in use (and demand) for 16 bit CPU's appearing at the time.

The manual for this board can be obtained here.


Static Memory Systems  S-100 Boards


This page was last modified on 10/25/2013