Single Density

Single Density ( single density ), abbreviated as SD or 1D, is a name for the recording density on older disks and magnetic tapes. For encoding the FM method is used. SD disks are available in sizes 8 ", 5.25 " and rarely even 3.5 "and 3". SD disks are the first generation computer disks and came 1971 ( 8 ") or 1976 ( 5.25") on the market. 8 " - and 5.25" SD disks are available in single-sided ( single sided, SS) and two-sided (double sided, DS ) version.

8 " SD disks have nominally more than 77 tracks at a track density of 48 tpi, the number of sectors and thus the capacity are variable within wide ranges. Had the original format of a capacity of 180 KB.

5.25 " SD disks have nominally more than 40 tracks with 4 sectors in a track density of 48 tpi, which corresponds to a capacity of 80 KB ( one-sided) or 160 KB ( two-sided). The data transfer rate is 125 kb · s- 1

The rare 3.5 " SD disks have nominally more than 40 tracks with 9 sectors with a track density of 67.5 tpi what ( two-sided) corresponds to a capacity of 360 KB.