On Fri, 23 May 2014, Martin Hoffmann-Vetter wrote: > Hello William, > >>>> What about 2.6? >>> >>> >>> This is the DOS for the single cpu version 2031/1541/1551. This is a >>> 170 kb disk format (see DOS 2.1), based on DOS 2.5. >>> >>> It's in the right chonology sequence. >> >> The chronology may be right, but the functionality isn't. Logically >> DOS >> 2.6 should have been 2.2. > > That's not true. DOS 2.6 is an extends from DOS 2.5. It use only the same > disk format as DOS 2.1 and it implements a LCC (low cost controller). Have a > look at http://mhv.bplaced.de/cbmdos/20140522.ZIP. You can make you own > diffs and compare. I have compared the ROM images of the 2031 DOS 2.6 with 4040 DOS 2, 8050 DOS 2.5, and 8050 DOS 2.7. There are only a few hundred bytes the same out of 16K, and these are distributed randomly. I then compared 8050 DOS 2.5 and 2.7. There are 2228 bytes the same, most in large blocks. I also compared 2031 DOS 2.6 with the last version of 1541 DOS. There are 10032 bytes the same. (1551 DOS is completely different). This means that dos 2.7 derives from 2.5, but not 2.6. DOS 2.6 from 2031 thru 1541 derive from 2031 DOS 2.6. These are parallel, but separate sequrences. wlevak@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org Message was sent through the cbm-hackers mailing listReceived on 2014-05-27 12:02:15
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