Table of 8-inch floppy formats
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This is a table of 8-inch diskettes floppy formats as introduced by IBM:
| Category | Drive designation | 23FD | 33FD | 43FD | 53FD | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Media designation | N/A (read only) | Type 1 | Type 2 | Type 2D | ||||||
| App. size | 80 KB | 242 KB | 284 KB | 303 KB | 492 KB | 568 KB | 985 KB | 1,136 KB | 1,212 KB | |
| Drive | Heads (data surfaces) | 1 | 1 | 1 | 1 | 2 | 2 | 2 | 2 | 2 |
| Spindle motor speed (RPM) |
90 | 360 | 360 | 360 | 360 | 360 | 360 | 360 | 360 | |
| Controller | Transfer rate (kbit/s) | 33.333 | 250 | 250 | 250 | 500 | 500 | 500 | 500 | 500 |
| Encoding | FM | FM | FM | FM | FM | FM | MFM | MFM | MFM | |
| Media | Track density (TPI) | 32 | 48 | 48 | 48 | 48 | 48 | 48 | 48 | 48 |
| Bit Density (BPI) | 1,594 | 3,268 | 3,268 | 3,268 | 3,408 | 3,408 | 6,816 | 6,816 | 6,816 | |
| Density designation | SS SD | SS SD | SS SD | SS SD | DS SD | DS SD | DS DD | DS DD | DS DD | |
| Geometry of the index cylinder (0) |
Sectors | N/A | N/A | 26 | 26 | 26 | 26 | 26 | 26 | 26 |
| Sector size (bytes) | N/A | N/A | 128 | 128 | 128 | 128 | (side 0:128 1:256) |
(side 0:128 1:256) |
(side 0:128 1:256) |
|
| Size (bytes) | N/A | N/A | 3,328 | 3,328 | 6,656 | 6,656 | 9,984 | 9,984 | 9,984 | |
| Geometry of remaining cylinders |
Usable cylinders | 32 | 73 (74) | 75 | 75 | 75 | 75 | 75 | 75 | 75 |
| Sectors per track | 8 | 26 | 15 | 8 | 26 | 15 | 26 | 15 | 8 | |
| Number of sectors | 640 | 1,898 | 1,110 | 592 | 3,848 | 2,220 | 3,848 | 2,220 | 1,184 | |
| Sector size (bytes) | 319 | 128 | 256 | 512 | 128 | 256 | 256 | 512 | 1024 | |
| Capacity | Formatted (bytes) | 81,664 | 242,944 | 284,160 | 303,104 | 492,544 | 568,320 | 985,088 | 1,136,640 | 1,212,416 |
| Formatted (KiB) | 79.75 | 237.25 | 277.5 | 296 | 481 | 555 | 962 | 1,110 | 1,184 | |
| SS = Single Sided; DS = Double Sided; SD = Single Density; DD = Double Density; N/A = Not Applicable; TPI = Tracks per Inch; BPI = Bits per Inch | ||||||||||
In addition, Digital Equipment Corporation introduced their own floppy formats:
| Category | Drive designation | DEC RX01 | DEC RX02 | ||
|---|---|---|---|---|---|
| App. size | 250 KB | 500 KB | |||
| Drive | Heads (data surfaces) | 1 | 1 | ||
| Spindle motor speed (RPM) | 360 | 360 | |||
| Controller | Transfer rate (kbit/s) | 250 | 500 | ||
| Encoding | FM | FM/MFM | |||
| Media | Track density (TPI) | 48 | 48 | ||
| Bit density (BPI) | 3,200 | 6,400 | |||
| Density designation | SS SD | SS DD | |||
| Geometry | Cylinders | 77 | 77 | ||
| Sectors per track | 26 | 26 | |||
| Total sectors per disk | 2,002 | 2,002 | |||
| Sector size (bytes) | 128 | 256 | |||
| Capacity | Formatted (bytes) | 256,256 | 512,512 | ||
| Formatted (KiB) | 250.25 | 500.5 | |||
| SS = Single Sided; SD = Single Density; DD = Double Density; TPI = Tracks per Inch; BPI = Bits per Inch | |||||
