TAGLANCE@UWPLATT.EDU (LANCE TAGLIAPIETRA) (09/09/90)
Hello All, Since I made my plea for help about SYSGEN on the TRS-80 Model 4, I have discovered a few more things as I attempt to install Z80CCP. I verified that DDT is loading the Z80CCP overlay correctly over the old CCP which I placed in memory with SYSGEN. I am using the correct offset. SYSGEN seems to be checking a few bytes in the image, and will lock the system up if those bytes do not agree with the cp/m ccp. I found these by using ddt to fill areas of the cp/m ccp with 00H untill SYSTEN would lock up (requiring reset) when looking at the memory image of cp/m. I used divide-and-conquer until I located 5 bytes in the ccp that cannot be changed to 0: (in the sysgen image) 0d28:10, 0d29:16, 0d2a:04, 0d2c:bf 0d2d:08. Other times sysgen will say I a bad image and abort when I try to use the modified image. Using DU-V85 (a disk utility available on simtel20) I found the sectors on my system disk where the ccp is located. I have also worked out the correct offset for DDT so that I can overlay the Z80CCP correctly over the old version as Yanked off my system disk with DU (no offset for SYSGEN). What I need is a routine that will take sectors from a file and write them to disk. DU will talk sectors Yanked into memory and put them into a file, but not the reverse. Does anyone have any suggestions? Thanks again for your reply. It is nice to know that at least someone read my posting. Lance Tagliapietra taglance@uwplatt.edu
aduncan@rhea.trl.oz.au (Allan Duncan) (09/10/90)
From article <392E37688B1F801A10@uwplatt.edu>, by TAGLANCE@UWPLATT.EDU (LANCE TAGLIAPIETRA): ... > SYSGEN seems to be checking a few bytes in the image, and will lock > the system up if those bytes do not agree with the cp/m ccp. I found It is _copy protection_! Sysgen and CCP contain the serial number of the o/s, and sysgen checks if they match before doing a copy. I think it was to cater for OEM specials that were not supplied with a sysgen, and you could only get new copies from the supplier, rather than create your own. Allan Duncan ACSnet a.duncan@trl.oz (03) 541 6708 ARPA a.duncan%trl.oz.au@uunet.uu.net UUCP {uunet,hplabs,ukc}!munnari!trl.oz!a.duncan Telecom Research Labs, PO Box 249, Clayton, Victoria, 3168, Australia.