14.003 3 How did Woz invent the Apple computer? C.T.: Even Commodore's Vic20, which appeared years later, uses easy-to-design-for static memory IC's. What was behind the decision to use dynamic RAM?
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This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
14.003 3 How did Woz invent the Apple computer? C.T.: Even Commodore's Vic20, which appeared years later, uses easy-to-design-for static memory IC's. What was behind the decision to use dynamic RAM?
Woz: I switched to dynamic RAMs when someone at our club sold some for a couple
of bucks each. After all, in 1975 these were the first RAMS cheaper than core
memory, the 4K dynamics. I bought some 22 pin AMI ones, there were three
vendors.
Virtually none of the other hobby computers around that time used dynamic
RAMs, I decided it was because of the hobbyist technician sense of most fans I
met, they weren't true engineers. Also, they were familiar with low-cost routes
like surplus stores where the favorite RAM was the 2102 static. But for me,
designing for the dynamic RAM was a piece of cake and I had fun at that which I
excelled, combining MSI chips in clever ways.
Steve Jobs asked what did I think of the Intel dynamic RAMs. I told him I
felt they were the best. Although they required more driving circuitry for Row
and Column addressing (not just a wire from the CPU for each address line) they
were in a smaller package. I had for some time measured the worth of my IC
designs in terms of how little board space they took, not how few chips. So
these 16-pin Intel chips, plus some row/column multiplexers and timing signals,
actually took less board space than the 22
-pin AMI RAMS. And saved some transistor clock drivers as well.
I felt we could never afford any Intel chip, having heard how the 8080 was
$370. But Steve got a rep to give us 16 samples. So the Apple I started with
the best possible RAM choice, even before it was certain how things would go
with RAMs. When the 16K dynamics appeared in the Intel compatible format we
were luckily on the right track.
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