LLXX said:
No, the 1.68 DMF format is explained here:
http://www.winimage....lp/wini1a1y.htm
There are actually three 1.68 formats, all have geometry 2x21x80 and thus have a total of 1,720,320 bytes:
1) "normal" has 1 sector (512 bytes) cluster and 1 sector for boot, 2x10 sectors for FAT and 14 sectors for dirs, which allows for max 224 files in root, usable size is 1,702,400
2) DMF 1.68 "1024" has 2 sectors (1024 bytes) cluster and 1 sector for boot, 2x5 sectors for FAT and 1 sectors for dirs, which allows for max 16 files in root, usable size is 1,714,176
2) DMF 1.68 "2048" has 4 sectors (2048 bytes) cluster and 1 sector for boot, 2x3 sectors for FAT and 1 sectors for dirs, which allows for max 16 files in root, usable size is 1,716,224
Then there is the 1.72 format:
geometry 2x21x82, total size 1,763,328 bytes, 1 sector (512 bytes) cluster and and 1 sector for boot, 2x10 sectors for FAT and 14 sectors for dirs, which allows for max 224 files in root, usable size is 1,745,408
I suppose we can call the format you mentioned a "1.76 DMF", just like:
1,474,560/1024/1000=1.44
1,720,320/1024/1000=1.68
1,763,328/1024/1000=1.72
we have:
1,806,336/1024/1000=1.76
I think this is the biggest format that does not use some "trick" like the 2m formats or the IBM XDF 1.84 format.
RJARRRPCGP said:
Actually, strange as it might seem, the opposite of "normality" is true.
Going beyond the 80th or in some cases 81th track appears to be a major problem with "brand name" drives, whilst "no name" ones behave better.
However these formats do push the drive to (and beyond) design limits, so they are not dependable.
Moreover, due to the drop in price of floppies (the media I mean), they appear to be of lesser quality than they used to be.
I have used for a certain period the Naslite software that uses a 1.72 floppy and I was able to get about one working floppy out of three using new "brand name" media, whilst I had about 90% success with a few years old "recovered from gargage bin" used floppies.
jaclaz



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