On 4/30/2013 9:52 PM, Dave Dunfield wrote: I tried reading and then recreating a DOS 360K disk. Worked fine. It even seemed to read a known good Kaypro disk. But, I tried writing it out with no luck. It did, though, write it out with no errors, so I think I have two issues. One is that the K10FLOAD.TD0 file that I converted to an IMD did not convert correctly, and the other is a lack of correct settings on IMD. When I read my known good DSDD Kaypro boot disk, I set tracks to 80, stepping to double, and sides to 2. But, IMD tries to read all the way up to track 80, when I thought it would stop at 40 (80 tracks, double stepped). But, when I set retry to 0, and it goes all the way up there, I still don't have a good copy. Jim -- Jim Brain brain at jbrain.com www.jbrain.com

On Tue, 30 Apr 2013, Jim Brain wrote: WHOA! You asked for 80, and it tried to do 80. You seem to be assuming that it would divide by the double-stepping and do 40. (Actually, it is prob'ly planning to stop at #79, V #39) 1) When IMD asks "tracks", is it asking A. Cylinders of the disk format (AKA "tracks [per side]") B. number of cylinders TIMES number of heads C. cylinders of the DRIVE Kaypro is 40 tracks [per side] You obviously understand that for an 80 track DRIVE, that requires "double stepping" But, are you sure that IMD is counting both sides of a cylinder as separate tracks? When dealing with hardware, it is not uncommon [albeit inaccurate] to treat "track" and "cylinder" identically. "1.2M drives are 80 track" V "360K drives are 80 track (40*2)" "Directory is on track 4" usually does NOT mean cylinder#2, side B If retry is set to 0, then it won't even try again when it hits an error, which is VERY common with floppy drives. NOT GOOD for getting usable disks. A good default is 5 - 10 In SOME programs, NO RETRIES is useful for TESTING, as ANY error, no matter how soft will be reported. In SOME programs, 1 - x are the normal values, and 0 is treated as a special case, either as '0' means "never stop trying until you succeed", which is useful for desperate recovery, or in SOME programs, '0' is a special case, and just means 256, 65536, or 4294967296 (DEC CX JNZ...) NOTE: PLEASE, EVERYBODY, talking about head 0 and head 1 is obvious and correct. So is talking about head 1 and head 2, although 0 and 1 is what the hardware expects. But, that leads to LOTS of confusion. Calling them "head [or side] A" and "B" eliminates that confusion and ambiguity. On MS-DOS DPB on the boot sector of floppy disks, there is a field for number of heads. I have seen values ON FLOPPIES of 0, 1, 2! 0 obviously is intended to mean single sided - "highest head number" 2 obviously is intended to mean count of heads. 1 is EITHER double-sided highest head number, OR singel sided. Likewise, although it's PC-CENTRIC, and thus OFFENSIVE to many, I use "360K" and "1.2M" to refer to the 2 most common groups of 5.25" drives (and "720K, "1.4M" for 3.5"). What is an "80 track drive"? What is a "4 MegaByte drive" (on NeXT) What is "HIGH density"? What is "EXTENDED density"? Kaypro is "360K", with an actual used capacity of 200K or 400K BTW, Kaypro puts an INCORRECT value in the "Head Number" field of the sector headers of all of the sectors on side B. Fortunately, like the extraneous SD track that Dave encountered on the 41st cylinder (#40), it is ignored in use. Both are irrelevant to the current project, but quite important if you want to use INT13h to read, write, or format Kaypro diskettes. -- Grumpy Ol' Fred cisin at xenosoft.com