> On 2018-01-14, at 17:11, Francesco Messineo <francesco.messineo@gmail.com> wrote: > >>> I've got a 1541C :) It looks like the original 1541 but in a white-ish >>> case. It does seek to track zero every time the connected C64 is switched >>> on. Is this drive supposed to do that? >> >> >> Yes. I remember when a friend got a disk drive, and it was the 1541C. > > ok, then out of curiosity, if anyone happens to know: why only 1541C > seeks to track 1 at reset? Because CBM couldn't decide what to do. It's been described in the document by WoMo: http://d81.de/R.I.P/1541C-to-1541II-diff-03.txt There was a problem with "original" 1541 that if the head was positioned beyond track 35, then under conditions it could not return to formatted area by itself. A head-bump or mechanical intervention was required but a regular LOAD"$",8 would always return error. The same with LOAD"*",8,1 etc. Rumour has it that many drives were returned as faulty, while in fact it would be enough to issue an INITIALIZE command to force the head-bump. Seems likely that in order to avoid said returns, CBM introduced head-bump upon RESET (but didn't do anything right in terms of proper utilisation of the track0 sensor). This OTOH created compatibility problem, especially with commercial, copy protected, software positions, which used drive RESET as part of their protection flow. So CBM back-pedalled and removed the head-bump from startup-sequence (but forgot to free the VIA bit reserved for the sensor) in 1541-II. -- SD! Message was sent through the cbm-hackers mailing listReceived on 2018-01-15 13:00:03
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