Wednesday, August 7, 2013

The Imlac's memory is alive!

This is a quick update; I'll post more details later.

After dealing with corroded pins, bad connections, and counterfeit 7400-series logic (no, really) I finally have one of the two Dataram core memory boardsets running, giving me a whopping 8KW of memory.

And now that I have some memory to play with, I can actually get it to run a program!  Since Blogger apparently refuses to let me embed the video, you can see it here.


I assembled the program manually, here it is in all its glory:

0 CAL     ; 100011
1 ISZ 37  ; 030037
2 JMP 1   ; 010001
3 IAC     ; 100004
4 JMP 1   ; 010001

Pretty fancy.  It increments the contents of memory location 37 until it overflows (becomes zero) and then increments the Accumulator and starts over again.  In this way, it slowly increments the Accumulator.

That this program executes indicates that quite a bit of the main processor is functional, which is encouraging.  Since I don't have any official diagnostics (other than a memory test routine) I'll be spending some time coding up a few diagnostics of my own, to ferret out any remaining issues in the main processor before moving onto the display processor.

That's all for now.  Until next time...

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