On 28/06/2017 15:40, silverdr@wfmh.org.pl wrote: > I don't stand firmly behind the version I mentioned. I wasn't there > where and when it happened. I only repeat the most common rumour, > source of which is supposed to be credible (as with all rumours :-) We may be arguing at odds. The 1540 prototype was created by someone on the TOI group by hacking the IEEE connector off a 2031 and when they plugged it into a vic 20 prototype, they found the bug. It's a monster drive which looks nothing like the 1540 or the 2031LP, which took another year or two to create. So that part of the hardware wasn't finished. The VIC20 motherboard had to be revised as different VIA pins needed hooking up to the IEC port. So that hardware wasn't finished either. I don't remember where I read it (maybe bagnalls book), but they supposedly floated the idea of working round the 6522 bug (which goes something like this): http://forum.6502.org/viewtopic.php?f=4&t=2175 They could also have had the 6522 in the vic 20 always generate the clock and just have the drive signal when a byte was ready to be transferred. The drive could have had expensive stuff in it to fix the issue, because it was expensive anyway plus they had way more time to ship it. The 6522 had been around since 1977, for nobody to know about the issues seems unlikely. What seems to have happened is Jack shouted & so they picked the option that they knew reliably how long it would take to change. It could easily have been quicker to go with one of the other options, but they didn't want to risk upsetting Jack. Because of the price of SRAM, nobody expected users to be loading or saving much anyway so the speed wasn't considered a major problem. Plus they would just sell them a new computer the following year. Message was sent through the cbm-hackers mailing listReceived on 2017-06-28 17:00:02
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