Thread: 88-4mcs
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Old 06-24-2007, 11:06 PM
Geoff Harrison Geoff Harrison is offline
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Quote:
Originally Posted by sje View Post
Very nice.

How does the 88-4MCS 4 KB RAM board compare with the IMSAI 4 KB board? I assembled one of the latter and I recall that it had a cycle time of less than 450 ns (hence no wait states needed for a 2 MHz clock) along with a static (non dynamic) implementation. Oh, and the IMSAI card had those nifty red and green LEDs for the 1 KB protect feature.
Both boards use the same 2102 static RAM chips. Protection on the MITS board is at the board level instead of at the 1k bank level. And, you're right, those indicator LEDs on the IMSAI board are nice; there are no LEDs on the MITS board.

I populated the board with my own 2102s of unknown heritage and had a couple of memory errors when the board was up on an extender card. When it's plugged directly into the backplane, though, it's 100% reliable. I ran a memory test all day yesterday with no failures. One day when I have nothing better to do, I'll track down what's going on with the extender card, but I'm in no hurry.

Geoff.
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