On 4 Feb 2007 at 0:56, Tony Duell wrote:
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.
Cheers,
Chuck