does windows read ibm format floppy disks

Using larger sectors increases the memory requirements when reading from or writing to disks DOS used two buffers by default on the PC, which would have meant going from 1KiB for buffers, to 2KiB. See also What is between the sectors of floppy disks? for details of floppy disk layouts (in particular, their capacity needs to be considered in terms of reversals per unit of time, not bytes or anything like that). Some copy-protection techniques also relied on non-standard sector sizes. Later disk formats such as XDF and 2M used varying sector sizes to increase storage capacity, but they are more CPU-intensive and not appropriate for a 4.77MHz 8088. 1024-byte sectors were used on other computers, and on IBM’s own 8” disks. So while this addresses your question, it doesn’t explain why 512-byte sectors were chosen. (Since the tracks are circular, having gaps between the logical sectors isn’t sufficient, so counting 10 sectors and 9 gaps doesn’t work - a gap is also needed between the last and first sectors.) However it would technically be possible to store 5 1024-byte sectors, for a total capacity of 200KiB per side, 400KiB per disk. The headers and gaps result in an overhead of 114 bytes per sector, so a track can store 9 512-byte sectors, but not quite 10 - at least not safely, on all drives. Sector sizes are assumed to be the same throughout a track.Īs Tim Paterson explains, the IBM PC can write at most 6250 bytes per track in total (including gaps, which don’t store data). The size is specified as a bit shift applied to 128, so sector sizes are of the form 128 × 2 n (usable values go from 128 to 4096 on the original PC there isn’t enough time to fit an 8KiB sector in a track using the IBM PC’s single-density 5.25” drives). Every FDC command involving sectors or tracks takes the sector size as a parameter.

Yes, the sector size is software-controlled, to a certain extent.

Does windows read ibm format floppy disks