Hello William, >> Btw, is DOS 2.1 released after DOS 2.5? > > It's been a long time, but I think DOS 2.1 came first. There is an reference to "Commodore Drives are History Part II" from Jim Brain (Commodore World, Issue 18) where jim listed the 8050 between the 3040 with DOS 2.0 and the 4040 with DOS 2.1. So it's possible DOS 2.5 was designed before DOS 2.1 was released. > I think the 5 in DOS 2.5 refers to the 500K disk format. This is an nice idea. ;-) > 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. > The double sided format is DOS 2.7. This was designed later. It support super side blocks for large relative files. > Was there > something in between, or did they leave an extra number in case it > would be needed? They need and used this version number. It's in the right chonology sequence. The problems starts with DOS 3.0. There are two main versions known. First is based on DOS 2.7 for the 8280 and 9060/9090. The second DOS 3.0 was many years later released and based on the DOS 2.6 for 1571. The question is, was some code fragments from the DOS 2.7 or early DOS 3.0 used in the later DOS 3.0? At this time i try to analyse this. But it seems there is nothing from them in the later DOS 3.0. Only the DOS 10.0 (1581) use some things from DOS 2.7 and/or DOS 3.0 (specially super side blocks support). The other question is, what's about the 8061/8062? It was sold after DOS 2.5 was current and before DOS 2.7 is designed. But the capacity was so great, it must be use super side blocks. Martin Message was sent through the cbm-hackers mailing listReceived on 2014-05-17 17:00:03
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