>Hi, > > I have a need to duplicate a BBC style ADFS single density disk, but >have discovered that every IBM PC I can find has broken single density >floppy disk compatibility, such that none of the physical sector copiers >will work.
Do you really mean single density? (as opposed to double which the Sam normally uses, or High which the PC normally uses) The tech docs for the VL1772-02 floppy controller chip do indeed claim that it can handle single density, although they think you're using 5.25 inch disks.... HOWEVER the disk state (single or double density) is determined by the signal on an input pin[1] rather than by software, and I'd be prepared to bet that the Sam hardwires it to double density. If not, it will depend on the capability of the drive. I'd say you're probably out of luck. > However, I remember picking up a SAM disk magazine at an All Formats >show which came on single density floppies, and so I am aware that the >SAM disk interface has no such problems. Yes, but was it *formatted* as single or double density? Using inferior disks may well tend to cause errors, but the formats certainly don't necessarily need to match. For example, I often use HD disks formatted as DD, just because I can't find DD any more. I was not aware that SamDOS was written to cope with anything other than 800K disks, although someone else who has hacked about with it more than I have may know different (Edwin?) > Therefore, is there any tool available for my 256kb SAM that will copy >such a disk for me? > > I'm also aware that KE-Disk (since I owned it twice counting the later >distribution with Fred) was a BASIC program that could read non-SAM >format disks. So perhaps there is a place somewhere where I could just >read up on the correct commands to write such a program? Most of the meat of KE-Disk was actually written in machine code, for speed. Anything more complicated than sector reads and writes you will not be able to achieve in BASIC. Andrew [1] 26 -- -- Andrew Collier ([EMAIL PROTECTED]) -- My other -- http://mnemotech.ucam.org -- .sig is a -- Part 3 Materials Science, Cambridge -- PDF file --
