lphillips@lpami.wimsey.bc.ca (Larry Phillips) (04/10/90)
In <890@mpirbn.UUCP>, p554mve@mpirbn.UUCP (Michael van Elst) writes: >In article <14876@s.ms.uky.edu> sam@ms.uky.edu (Michael W. Mills) writes: >>Actually, you CAN write to a write protected disk on a C64 (and 1541 >>disk drive)...you've got 1K (I think, its been a while) in which you >>can write a program that calls the write routine (which is in ROM) >>after it checks for the write protect switch. > >Must be an other 1541 than mine. >There is a small path where the signal from the phototransistor that senses >the write-protect tab to the write amplifiers that drive the read/write head. >It efficiently shuts up any writing. Yes, your 1541 was wierd then.. on the ones I played with, there was no such path to the write circuitry. In fact there was an even easier way to defeat the write protect. All you needed to do was to turn the port signal for WP into an output, and when the 1541's CPU read the signal, it allways looked like it was in the read/write state. But that doesn't answer the real question, which, of the 1541 was always... "Isn't that damn thing finished loading yet??" -larry -- Entomology bugs me. +-----------------------------------------------------------------------+ | // Larry Phillips | | \X/ lphillips@lpami.wimsey.bc.ca -or- uunet!van-bc!lpami!lphillips | | COMPUSERVE: 76703,4322 -or- 76703.4322@compuserve.com | +-----------------------------------------------------------------------+
p554mve@mpirbn.UUCP (Michael van Elst) (04/11/90)
In article <14876@s.ms.uky.edu> sam@ms.uky.edu (Michael W. Mills) writes: >Actually, you CAN write to a write protected disk on a C64 (and 1541 >disk drive)...you've got 1K (I think, its been a while) in which you >can write a program that calls the write routine (which is in ROM) >after it checks for the write protect switch. Must be an other 1541 than mine. There is a small path where the signal from the phototransistor that senses the write-protect tab to the write amplifiers that drive the read/write head. It efficiently shuts up any writing. -- Michael van Elst p554mve@mpirbn.mpifr-bonn.mpg.de