[Coco] [Color Computer] 1M simms in Cloud9 SIMM upgrade kit
deleted2006 at yahoo.com
Wed Jun 29 16:31:16 EDT 2005
--- In ColorComputer at yahoogroups.com, "Paul T. Barton"
<idezilla at y...> wrote:
> Just let it sit for a minute or so,
> doing nothing, it may crash. My experience.
Sorry to just jump into the discussion, but you are right...
Way back when I did my 512k upgrade for my brand new CC3, I too had a
It'd work okay as long as I ran it hard (doing memory tests etc.),
but it'd fail if I let it sit doing nothing.
(Long story, but the solution was to leave a long jumper hooked up.
It left enough capacitance or provided enough delay that the memory
Testing memory involves three distinct aspects, each with several
phases and their own requirements. Testing for refresh problems,
testing for path errors (shorted or opened paths, etc.) and actually
testing the memory itself (usually in such a way that certain types
of problems show up more easily.)
Most memory tests do little more than a few flavors of checkerboards
etc. The results are rarely useful beyond saying you have a
problem. And most of the checks wont even detect some sorts of
And the way they work can often hide a refresh issue because the test
itself will provide enough memory accesses to refresh the memory.
(Just like in the old days of the CC1/2 where you'd POKE it to
increase the speed. Then you had to do your own memory refreshes.)
A good memory test is very hard to write. Most get it wrong. And
will usually take advantage of the memory type / organization to
better test it wihout having to spend hours doing a single pass.
Still, a decent test can detect most errors. They just may not be
able to say exactly what the cause is.
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