tonyrich@titanic.cs.wisc.edu (Anthony Rich) (02/14/90)
Good news/Bad news: Thank you to David Goodenough for showing me how to work around the "synchronization error" message. The good news is that his tip allowed me to run MOVCPM; the bad news is that it didn't do any good, since the resulting CP/M image hangs. A previous posting to this newsgroup said that the serial-number comparison isn't really copy protection, it's to make sure you get a valid resulting image. Apparently that's correct. The upshot is that I have to have my copy of MICAH CP/M running in order to reconfigure it so I can get it running. (That's a tough one!) FYI, I WAS using a program called DEBUG...it's Cromemco's version of DDT. (Since I didn't have a reliable CP/M to boot with, I had to boot with Cromemco CDOS to do my fiddling with my CP/M boot disk, see. CDOS isn't completely CP/M compatible; it can read CP/M 8" disks, but lots of CP/M programs crash under CDOS, which is why I bought MICAH CP/M in the first place.) If anyone still cares, here's the workaround that David sent me: > There are two copies of the serial # in the BDOS/CCP image: mine were at > 1200H and (about) 0D20H in the MOVCPM.COM program (when loaded). Here's > how to find them: > > The CCP copy comes right after the command table, so hunt for the > 'DIR ERA USER' strings, they're all glued together, part way up the > CCP, and the serial # comes right after them (the next 6 bytes). > > The BDOS copy is just at the start of BDOS, so look for the '$$$ SUB' > fcb towards the top - it's followed by a bunch of zeroes and then on the > next page boundary, you'll find the serial # again. > > At about 02CBH in the MOVCPM.COM program is the code that tests it: I found > > LD HL,(????) > LD DE,1200 ; address of the BDOS serial # in the core image > ... > LD C,6 > > then some ld, cp etc. stuff, and a > > JP NZ,SOMEWHERE > > If you nuke the JP NZ, it ought to work. [It does. -T.R.] > > dg@lakart.UUCP - David Goodenough -- ------------------------------------------------------------------------ Email: tonyrich@titanic.cs.wisc.edu Phone: 608-271-8450 Disclaimer: The opinions above are mine. Others may agree or disagree. ------------------------------------------------------------------------