On Wed, 2 Dec 2009, Richard wrote: > > In article <008501ca6f37$b5b590a0$1e04a8c0@ad.mediawebbsupport.se>, > "Anders Carlsson" <anders.carlsson@sfks.se> writes: > >> [...] Interestingly enough almost all of them origin from >> earlier PET 3000 and 8000 versions, on which there was no cost effective way >> to create dongles, thus the business software on the PET side seemed >> completely unprotected? > > VisiCalc for the CBM 8032 was protected by a custom PROM you placed > into one of the empty sockets on the motherboard. The VisiCalc ROM contains no actual program code, just some numbers that the loader routine looks for. All the copy protection is in the loader. If you disassemble the loader, you can follow the sequence and remove all the copy protection. Be careful though. At one point, if it finds the routine has been altered, it erases all the files on the disk. wlevak@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org Message was sent through the cbm-hackers mailing listReceived on 2009-12-02 15:00:05
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