Disk Drive Data and Parameters

08/06/2001


Floppy Disk Drives

* Special Note: There were quite a number of different Floppy Disk-Drive Configurations, and as time went on there were a number of new Drive Manufacturers that entered the fray. Please understand that this list is not complete, by any means. It is presented here as only to show some of those initial concepts in those early days.

Some Descriptive Terms

Single-Sided (SS/density)Single-Density (sides/SD)Quad-Density (sides/QD) Extended-Density(sides/ED) Double-Sided (DS/density)Double-Density (sides/DD)High-Density (sides/HD) Grandiose-Density (sides/GD)

Prior to the IBM PC:

Date Size Model Encoding Method Type Capacity Tracks Sectors per Track Bytes per Sector Mech'sm
Apr,'73 8" SA801 FM SS/SD 77 32/16/8 128 Stepper
8" SA801 MFM/M2FM SS/DD 77 32/16/9 128 Stepper
 
8" SA800 FM SS/SD 262 Kb 77 26 128 Stepper
8" SA800 FM SS/SD 315Kb 77 32 128 Stepper
8" SA800 MFM/M2FM SS/DD 473Kb 77 48 128 Stepper
8" SA800 MFM/M2FM SS/DD 572Kb 77 52 128 Stepper
 
May,'79 8" SA851 MFM SS/SD 243Kb 77 26 128 Stepper
8" SA851 MFM/M2FM SS/SD 486Kb 77 52 128 Stepper
8" SA851 MFM DS/SD 486 Kb 77 26 128 Stepper
8" SA851 MFM/M2FM DS/DD 972 Kb 77 (2+75) 52 128 Stepper
8" SA851 MFM SS/ED 600 Kb 77 8 1024 Stepper
8" SA851 MFM/M2FM DS/ED 1200 Kb 77 (2+75) 8 1024 Stepper
 
8" SA851 MFM/M2FM SS/GD 710Kb 77 9 1024 Stepper
8" SA851 MFM/M2FM DS/GD 1420Kb 77 9 1024 Stepper
 
8" SA861 MFM DS/ED 600 Kb 77 8 1024 Stepper
8" SA861 MFM/M2FM DS/ED 1200 Kb 77 8 1024 Stepper
 
Oct,'77 8" PerSci 277 FM SS/SD 243 Kb 77 26 128 Voice Coil
8" PerSci 277 MFM SS/DD 800 Kb 77 26 512 Voice Coil
 
5.25" SA400 FM SS/SD 92 Kb 40 18 128 Stepper
5.25" SA400 MFM SS/DD Kb 40 9 256 Stepper
 
5.25" T100 FM SS/SD 180 Kb (172) 40 9 256 Stepper
5.25" T100 MFM SS/SD 340 Kb (344) 40 17 256 Stepper
5.25" T100 MFM SS/SD 400 Kb (404) 40 5 1024 Stepper
 
5.25" Micropolis FM DS/SD 180Kb (177) 77 18 128 Stepper
5.25" Micropolis FM DS/SD 180Kb (177) 77 9 256 Stepper
5.25" Micropolis MFM SS/DD 354Kb (335) 77 17 256 Stepper
5.25" Micropolis MFM DS/DD 800Kb (710) 77 9 1024 Stepper

With IBM's release of their PC, and their initial attempt at standardization:

Date Size Model Encoding Method Type Capacity Tracks Sectors per Track Bytes per Sector Mech'sm
Aug, '81 5.25" MFM SS/DD 160Kb 40 8 512 Stepper
5.25" MFM SS/DD 180Kb 40 9 512 Stepper
5.25" MFM DS/DD 320Kb 40 8 512 Stepper
5.25" MFM DS/DD 360Kb 80 9 512 Stepper
5.25" MFM DS/QD 720Kb 80 15 512 Stepper
5.25" MFM DS/HD 1.2Mb 80 15 512 Stepper
 
3.5" MFM DS/DD 720Kb 80 9 512 Stepper
3.5." MFM DS/HD 1.44Mb 80 18 512 Stepper

Special Notes