4 Feb
2007
4 Feb
'07
11:39 a.m.
--- Chuck Guzis wrote:
On 4 Feb 2007 at 0:56, Tony Duell wrote:
LOL. That has a certain ring to it.
It gives character. :)
And another oddiity. The whole design of the
Apple
][ seems to have been
to save a chip if at all possible (provided the
machine still works --
just). And yet the kayboard was encoded in
hardware.
Why? It meant you
couldn't implelement a lower case keyboard in
software (there are the
well-known shift key mods where you run a wire
from
the shift keyswitch
to one of the single-bit inputs on the games
connector, which shouldn't
have been necessary).
Thank you for absolving me of being the first to use
the term
"gutless wonder". :) In a way, I suppose the disk controller was a clever
design. But it
locked the CPU into 2MHz operation. The use of a
simple arithmetic
checksum for each sector was not perhaps the most
reliable solution
either. But the biggest problem is that disk
reading
and writing
required 100% attention from the CPU. On most other
computers that
used dedicated LSI controllers, the possibility
existed for
overlapped computation/disk access.
Oh yes, that's a huge gotcha with the disk II. It
could make communications software or data logging
interesting.
There were other disk systems for the Apple though
none as ubiquitous.
I like the Disk II. I don't think it was the ultimate
disk system, just a clever/ cheap one (for Apple at
least).
Liam Busey
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