Defective via seven off-by-one errors, but otherwise identical? On Wed, Jul 8, 2015 at 10:36 PM, William Levak <wlevak@sdf.org> wrote: > > There are two sets of DOS ROMs for the 8280 on zimmers.net, 30054x-001 > and 30054x-revA. Comparing these two sets, there are a total of seven > differences between them. Where they are different, the -001 ROMs are one > higher than the -revA ROMs. This includes two locations where there are > $AA fill bytes and the -001 ROMs have two $AB amongst all the $AA. > It appears that the -001 ROMs are defective. > > On Tue, 7 Jul 2015, William Levak wrote: > > >> On zimmers.net there are two 8280 300541 files: 300541-001.bin and >> 300541-revB.bin. If you compare the two files, everywhere they are >> different, 300541-001.bin is 2 higher than 300541-revB.bin. If you >> disassemble them, 300541-revB.bin makes sense; 300541-001.bin does not. >> >> Therefore: 300541-001.bin is a version of 300541-revB.bin with a bad d1 >> line. >> >> The schematics do not show a GCR ROM. >> >> The schematics are available at: >> >> www.cbmhardware.de/floppy/cbm8280.php >> >> They are very fuzzy and hard to read. I am working on cleaning up a >> copy. When it is ready, I will send it to zimmers.net. Don't expect >> much. It was scanned at a very low resolution. >> >> wlevak@sdf.lonestar.org >> SDF Public Access UNIX System - http://sdf.lonestar.org >> >> Message was sent through the cbm-hackers mailing list >> >> > wlevak@sdf.lonestar.org > SDF Public Access UNIX System - http://sdf.lonestar.org > > Message was sent through the cbm-hackers mailing list > Message was sent through the cbm-hackers mailing listReceived on 2015-07-09 16:00:07
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