List of floppy disk formats: Difference between revisions
m Dating maintenance tags: {{Citation needed}} |
MoS prefers traditional KB/MB (and previous version preferred whatever was originally used in the article). |
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| align="center" | 1,212,416 |
| align="center" | 1,212,416 |
||
|- |
|- |
||
! bgcolor="#C0C0C0" | Formatted ( |
! bgcolor="#C0C0C0" | Formatted (KB) |
||
| align="center" | 79.75 |
| align="center" | 79.75 |
||
| align="center" | 237.25 |
| align="center" | 237.25 |
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! bgcolor="#C0C0C0" rowspan="2" | Capacity |
! bgcolor="#C0C0C0" rowspan="2" | Capacity |
||
<!-- ! bgcolor="#C0C0C0" | Unformatted ([[To be confirmed|?]]) |
<!-- ! bgcolor="#C0C0C0" | Unformatted ([[To be confirmed|?]]) |
||
| align="center" | 500 |
| align="center" | 500 KB |
||
| align="center" | 1 |
| align="center" | 1 MB |
||
|- --> |
|- --> |
||
! bgcolor="#C0C0C0" | Formatted (bytes) |
! bgcolor="#C0C0C0" | Formatted (bytes) |
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Line 286: | Line 286: | ||
| align="center" | 512,512 |
| align="center" | 512,512 |
||
|- |
|- |
||
! bgcolor="#C0C0C0" | Formatted ( |
! bgcolor="#C0C0C0" | Formatted (KB) |
||
| align="center" | 250.25 |
| align="center" | 250.25 |
||
| align="center" | 500.5 |
| align="center" | 500.5 |
||
Line 298: | Line 298: | ||
!Form factor<ref>Floppy disk sizes are almost universally referred to in inch measurements, even in countries where [[SI|metric]] is the standard, and even when the size is in fact defined in SI; for instance, the 3½-inch floppy is defined as 90 mm.</ref> |
!Form factor<ref>Floppy disk sizes are almost universally referred to in inch measurements, even in countries where [[SI|metric]] is the standard, and even when the size is in fact defined in SI; for instance, the 3½-inch floppy is defined as 90 mm.</ref> |
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!Year introduced |
!Year introduced |
||
!Formatted<br>Storage capacity<br>(in [[ |
!Formatted<br>Storage capacity<br>(in [[kilobyte|KB]] = 1024 bytes if not stated) |
||
!Marketed<br>capacity¹ |
!Marketed<br>capacity¹ |
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|- |
|- |
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Line 328: | Line 328: | ||
|5¼-inch (35 track) |
|5¼-inch (35 track) |
||
|align="center"|1976<ref>{{cite journal | last = Sollman | first = George | title = Evolution of the Minifloppy (TM) Product Family | journal = Magnetics, IEEE Transactions on | volume = 14 | issue = 4 | pages =160–166 | date = July 1978 | doi = 10.1109/TMAG.1978.1059748}} "In September, 1976, the first minifloppy disk drive was introduced by Shugart Associates."</ref> |
|align="center"|1976<ref>{{cite journal | last = Sollman | first = George | title = Evolution of the Minifloppy (TM) Product Family | journal = Magnetics, IEEE Transactions on | volume = 14 | issue = 4 | pages =160–166 | date = July 1978 | doi = 10.1109/TMAG.1978.1059748}} "In September, 1976, the first minifloppy disk drive was introduced by Shugart Associates."</ref> |
||
|align="right"|87.5<ref>[http://www.swtpc.com/mholley/SA400/SA400_Index.htm Shugart SA 400 Datasheet] Formatted with 256 byte sectors and 10 sectors per track the capacity is 89.6 Kbytes (256 x 10 x 35 = 89,600), or 87.5 |
|align="right"|87.5<ref>[http://www.swtpc.com/mholley/SA400/SA400_Index.htm Shugart SA 400 Datasheet] Formatted with 256 byte sectors and 10 sectors per track the capacity is 89.6 Kbytes (256 x 10 x 35 = 89,600), or 87.5 KB</ref> |
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|align="right"|110 kB |
|align="right"|110 kB |
||
|- |
|- |
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Line 418: | Line 418: | ||
|3½-inch |
|3½-inch |
||
|align="center"|1996 |
|align="center"|1996 |
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|align="right"|120.375 |
|align="right"|120.375 MB |
||
|align="right"|120 MB |
|align="right"|120 MB |
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|- |
|- |
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Line 424: | Line 424: | ||
|3½-inch |
|3½-inch |
||
|align="center"|1997 |
|align="center"|1997 |
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|align="right"|240.75 |
|align="right"|240.75 MB |
||
|align="right"|240 MB |
|align="right"|240 MB |
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|- |
|- |
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Line 483: | Line 483: | ||
|74 |
|74 |
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|1 |
|1 |
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|250.25 |
|250.25 KB |
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|360 |
|360 |
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|FM |
|FM |
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Line 495: | Line 495: | ||
| 40 |
| 40 |
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| rowspan=2 | 1 |
| rowspan=2 | 1 |
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| 100 |
| 100 KB |
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| rowspan=5 | 300 |
| rowspan=5 | 300 |
||
| rowspan=2 | FM |
| rowspan=2 | FM |
||
|- |
|- |
||
| 80 |
| 80 |
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| 200 |
| 200 KB |
||
|- |
|- |
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| rowspan=3 | double |
| rowspan=3 | double |
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Line 507: | Line 507: | ||
| 40 |
| 40 |
||
| rowspan=2 | 1 |
| rowspan=2 | 1 |
||
| 160 |
| 160 KB |
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| rowspan=3 | MFM |
| rowspan=3 | MFM |
||
|- |
|- |
||
| rowspan=2 | 80 |
| rowspan=2 | 80 |
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| 320 |
| 320 KB |
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|- |
|- |
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| 2 |
| 2 |
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| 640 |
| 640 KB |
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|- |
|- |
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| rowspan=3 | 3½ in (90 mm) |
| rowspan=3 | 3½ in (90 mm) |
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Line 522: | Line 522: | ||
| rowspan=3 | 80 |
| rowspan=3 | 80 |
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| rowspan=3 | 2 |
| rowspan=3 | 2 |
||
| 640 |
| 640 KB |
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| rowspan=3 | 300 |
| rowspan=3 | 300 |
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| rowspan=3 | MFM |
| rowspan=3 | MFM |
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Line 528: | Line 528: | ||
| rowspan=2 | 1024 |
| rowspan=2 | 1024 |
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| 5 |
| 5 |
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| 800 |
| 800 KB |
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|- |
|- |
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| high |
| high |
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| 10 |
| 10 |
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| 1600 |
| 1600 KB |
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|- |
|- |
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| rowspan=7 | [[Apple II]] |
| rowspan=7 | [[Apple II]] |
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Line 541: | Line 541: | ||
| rowspan=4 | 35 |
| rowspan=4 | 35 |
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| 1 |
| 1 |
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| 113.75 |
| 113.75 KB |
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| rowspan=4 | 300 |
| rowspan=4 | 300 |
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| rowspan=4 | [[Group Code Recording|GCR]] |
| rowspan=4 | [[Group Code Recording|GCR]] |
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Line 547: | Line 547: | ||
|- |
|- |
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| 2 |
| 2 |
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| 227.50 |
| 227.50 KB |
||
|- |
|- |
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| rowspan=2 | 16 |
| rowspan=2 | 16 |
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| 1 |
| 1 |
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| 140 |
| 140 KB |
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|- |
|- |
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| 2 |
| 2 |
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| 280 |
| 280 KB |
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|- |
|- |
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| rowspan=3 | 3½ in (90 mm) |
| rowspan=3 | 3½ in (90 mm) |
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Line 562: | Line 562: | ||
| rowspan=2 | 80 |
| rowspan=2 | 80 |
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| 1 |
| 1 |
||
| 400 |
| 400 KB |
||
| rowspan=2 | [[Constant linear velocity|CLV]] |
| rowspan=2 | [[Constant linear velocity|CLV]] |
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| rowspan=2 | GCR |
| rowspan=2 | GCR |
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Line 568: | Line 568: | ||
|- |
|- |
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| 2 |
| 2 |
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| 800 |
| 800 KB |
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|- |
|- |
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| high |
| high |
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Line 575: | Line 575: | ||
| 80 |
| 80 |
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| 2 |
| 2 |
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| 1440 |
| 1440 KB |
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| 300 |
| 300 |
||
| MFM |
| MFM |
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Line 587: | Line 587: | ||
| rowspan=2 | 80 |
| rowspan=2 | 80 |
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| 1 |
| 1 |
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| 400 |
| 400 KB |
||
| rowspan=2 | CLV |
| rowspan=2 | CLV |
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| rowspan=2 | GCR |
| rowspan=2 | GCR |
||
|- |
|- |
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| 2 |
| 2 |
||
| 800 |
| 800 KB |
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|- |
|- |
||
| high |
| high |
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Line 599: | Line 599: | ||
| 80 |
| 80 |
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| 2 |
| 2 |
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| 1440 |
| 1440 KB |
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| 300 |
| 300 |
||
| MFM |
| MFM |
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Line 610: | Line 610: | ||
|rowspan=3|40 |
|rowspan=3|40 |
||
|rowspan=3|1 |
|rowspan=3|1 |
||
|90 |
|90 KB |
||
|rowspan=3|288 |
|rowspan=3|288 |
||
|FM |
|FM |
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Line 618: | Line 618: | ||
|128 |
|128 |
||
|26 |
|26 |
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|127 |
|127 KB |
||
|rowspan=2|MFM |
|rowspan=2|MFM |
||
|- |
|- |
||
Line 624: | Line 624: | ||
|256 |
|256 |
||
|18 |
|18 |
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|180 |
|180 KB |
||
|- |
|- |
||
|rowspan=5|[[Commodore International|Commodore]] (8-bit) |
|rowspan=5|[[Commodore International|Commodore]] (8-bit) |
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Line 633: | Line 633: | ||
|rowspan=2|35 |
|rowspan=2|35 |
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|1 |
|1 |
||
|170 |
|170 KB |
||
|rowspan=5|300 |
|rowspan=5|300 |
||
|rowspan=4|GCR |
|rowspan=4|GCR |
||
Line 639: | Line 639: | ||
|- |
|- |
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|2 |
|2 |
||
|340 |
|340 KB |
||
|- |
|- |
||
|rowspan=2|quad |
|rowspan=2|quad |
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Line 645: | Line 645: | ||
|rowspan=2|77 |
|rowspan=2|77 |
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|1 |
|1 |
||
|521 |
|521 KB |
||
|- |
|- |
||
|2 |
|2 |
||
|1042 |
|1042 KB |
||
|- |
|- |
||
|3½ in (90 mm) |
|3½ in (90 mm) |
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Line 656: | Line 656: | ||
|80 |
|80 |
||
|2 |
|2 |
||
|800 |
|800 KB |
||
|MFM |
|MFM |
||
| |
| |
||
Line 667: | Line 667: | ||
|rowspan=2|80 |
|rowspan=2|80 |
||
|rowspan=2|2 |
|rowspan=2|2 |
||
|880 |
|880 KB |
||
|300 |
|300 |
||
|rowspan=2|MFM |
|rowspan=2|MFM |
||
Line 674: | Line 674: | ||
|high |
|high |
||
|22 |
|22 |
||
|1760 |
|1760 KB |
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|150 |
|150 |
||
|- |
|- |
||
Line 684: | Line 684: | ||
|rowspan=3|77 |
|rowspan=3|77 |
||
|1 |
|1 |
||
|250.25 |
|250.25 KB<ref name="fat12">The calculated formatted capacity is based on [[FAT12]] format.</ref> |
||
|rowspan=3|360 |
|rowspan=3|360 |
||
|rowspan=3|MFM |
|rowspan=3|MFM |
||
Line 690: | Line 690: | ||
|- |
|- |
||
|2 |
|2 |
||
|500.5 |
|500.5 KB<ref name="fat12"/> |
||
|- |
|- |
||
|double |
|double |
||
Line 696: | Line 696: | ||
|8 |
|8 |
||
|2 |
|2 |
||
|1232 |
|1232 KB<ref name="fat12"/> |
||
|- |
|- |
||
|rowspan=7|5¼ in |
|rowspan=7|5¼ in |
||
Line 704: | Line 704: | ||
|rowspan=4|40 |
|rowspan=4|40 |
||
|1 |
|1 |
||
|160 |
|160 KB<ref name="fat12"/> |
||
|rowspan=4|300 |
|rowspan=4|300 |
||
|rowspan=7|MFM |
|rowspan=7|MFM |
||
Line 710: | Line 710: | ||
|- |
|- |
||
|2 |
|2 |
||
|320 |
|320 KB<ref name="fat12"/> |
||
|- |
|- |
||
|rowspan=2|9 |
|rowspan=2|9 |
||
|1 |
|1 |
||
|180 |
|180 KB<ref name="fat12"/> |
||
|- |
|- |
||
|2 |
|2 |
||
|360 |
|360 KB<ref name="fat12"/> |
||
|- |
|- |
||
|rowspan=2|unknown |
|rowspan=2|unknown |
||
Line 723: | Line 723: | ||
|rowspan=2|80 |
|rowspan=2|80 |
||
|1 |
|1 |
||
|320 |
|320 KB<ref name="fat12"/> |
||
|rowspan=2|unknown |
|rowspan=2|unknown |
||
|- |
|- |
||
|2 |
|2 |
||
|640 |
|640 KB<ref name="fat12"/> |
||
|- |
|- |
||
|high |
|high |
||
Line 733: | Line 733: | ||
|80 |
|80 |
||
|2 |
|2 |
||
|1200 |
|1200 KB<ref name="fat12"/> |
||
|360 |
|360 |
||
|- |
|- |
||
Line 742: | Line 742: | ||
|rowspan=3|80 |
|rowspan=3|80 |
||
|1 |
|1 |
||
|320 |
|320 KB<ref name="fat12"/> |
||
|rowspan=7|300 |
|rowspan=7|300 |
||
|rowspan=7|MFM |
|rowspan=7|MFM |
||
|- |
|- |
||
|rowspan=6|2 |
|rowspan=6|2 |
||
|640 |
|640 KB<ref name="fat12"/> |
||
|- |
|- |
||
|9 |
|9 |
||
|720 |
|720 KB<ref name="fat12"/> |
||
|- |
|- |
||
|rowspan=3|high |
|rowspan=3|high |
||
|18 |
|18 |
||
|80 |
|80 |
||
|1440 |
|1440 KB<ref name="fat12"/> |
||
|- |
|- |
||
|rowspan=2|21 |
|rowspan=2|21 |
||
|80 |
|80 |
||
|1680 |
|1680 KB<ref name="fat12"/> |
||
|rowspan=2|[[Distribution Media Format|DMF]]<ref>These variations are known as [[Distribution Media Format|DMF]] diskettes, used for a time to pack more data on to each disk for software distribution.</ref> |
|rowspan=2|[[Distribution Media Format|DMF]]<ref>These variations are known as [[Distribution Media Format|DMF]] diskettes, used for a time to pack more data on to each disk for software distribution.</ref> |
||
|- |
|- |
||
|82 |
|82 |
||
|1720 |
|1720 KB<ref name="fat12"/> |
||
|- |
|- |
||
|extended |
|extended |
||
|36 |
|36 |
||
|80 |
|80 |
||
|2880 |
|2880 KB<ref name="fat12"/> |
||
|- |
|- |
||
|rowspan=11|[[NEC]] [[NEC PC-9801|PC98]] |
|rowspan=11|[[NEC]] [[NEC PC-9801|PC98]] |
||
Line 777: | Line 777: | ||
|77 |
|77 |
||
|1 |
|1 |
||
|250.25 |
|250.25 KB<ref name="fat12"/> |
||
|rowspan=2|360 |
|rowspan=2|360 |
||
|FM |
|FM |
||
Line 787: | Line 787: | ||
|77 |
|77 |
||
|2 |
|2 |
||
|1232 |
|1232 KB<ref name="fat12"/> |
||
|MFM |
|MFM |
||
|- |
|- |
||
Line 796: | Line 796: | ||
|rowspan=3|80 |
|rowspan=3|80 |
||
|rowspan=4|2 |
|rowspan=4|2 |
||
|640 |
|640 KB<ref name="fat12"/> |
||
|rowspan=4|360 |
|rowspan=4|360 |
||
|rowspan=4|MFM |
|rowspan=4|MFM |
||
|- |
|- |
||
|9 |
|9 |
||
|720 |
|720 KB<ref name="fat12"/> |
||
|- |
|- |
||
|rowspan=2|high |
|rowspan=2|high |
||
Line 810: | Line 810: | ||
|8 |
|8 |
||
|77 (80)<ref name="77_80_tracks"/> |
|77 (80)<ref name="77_80_tracks"/> |
||
|1232 (1280) |
|1232 (1280) KB<ref name="fat12"/><ref name="77_80_tracks"/> |
||
|<ref name="77_80_tracks">Inner 3 tracks of 8 sectors/track format are unused.</ref> |
|<ref name="77_80_tracks">Inner 3 tracks of 8 sectors/track format are unused.</ref> |
||
|- |
|- |
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Line 819: | Line 819: | ||
|rowspan=3|80 |
|rowspan=3|80 |
||
|rowspan=5|2 |
|rowspan=5|2 |
||
|640 |
|640 KB<ref name="fat12"/> |
||
|rowspan=4|360 |
|rowspan=4|360 |
||
|rowspan=5|MFM |
|rowspan=5|MFM |
||
|- |
|- |
||
|9 |
|9 |
||
|720 |
|720 KB<ref name="fat12"/> |
||
|- |
|- |
||
|rowspan=3|high |
|rowspan=3|high |
||
|15 |
|15 |
||
|1200 |
|1200 KB<ref name="fat12"/> |
||
|rowspan=2|[[3mode]]<ref>The PC98 3½" (90 mm) formats are also known as "3 Mode" floppy disks, usable on IBM PC compatibles with a 3-mode floppy drive.</ref><ref name="77_80_tracks"/> |
|rowspan=2|[[3mode]]<ref>The PC98 3½" (90 mm) formats are also known as "3 Mode" floppy disks, usable on IBM PC compatibles with a 3-mode floppy drive.</ref><ref name="77_80_tracks"/> |
||
|- |
|- |
||
Line 834: | Line 834: | ||
|8 |
|8 |
||
|77 (80)<ref name="77_80_tracks"/> |
|77 (80)<ref name="77_80_tracks"/> |
||
|1232 (1280) |
|1232 (1280) KB<ref name="fat12"/><ref name="77_80_tracks"/> |
||
|- |
|- |
||
|512 |
|512 |
||
|18 |
|18 |
||
|80 |
|80 |
||
|1440 |
|1440 KB<ref name="fat12"/> |
||
|300 |
|300 |
||
|- |
|- |
||
Line 849: | Line 849: | ||
|rowspan=2|77 |
|rowspan=2|77 |
||
|rowspan=2|2 |
|rowspan=2|2 |
||
|rowspan=2|1232 |
|rowspan=2|1232 KB<ref name="fat12"/> |
||
|rowspan=2|360 |
|rowspan=2|360 |
||
|rowspan=2|MFM |
|rowspan=2|MFM |
Revision as of 18:16, 7 September 2012
This article needs additional citations for verification. (August 2010) |
This is a list of different floppy disk formats.
IBM 8-inch formats
This is a list of 8-inch floppy diskette 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 (sides) | 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 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | |
Sector size (bytes) | 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 | 74 | 74 | 74 | 74 | 74 | 74 |
Sectors per track | 8 | 26 | 15 | 8 | 26 | 15 | 26 | 15 | 8 | |
Number of sectors | 256 | 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 (KB) | 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 |
DEC 8 inch formats
Digital Equipment Corporation used the following formats on 8-inch disks:
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 (KB) | 250.25 | 500.5 | |||
SS = Single Sided; SD = Single Density; DD = Double Density; TPI = Tracks per Inch; BPI = Bits per Inch |
Other manufacturers
Disk | Form factor[1] | Year introduced | Formatted Storage capacity (in KB = 1024 bytes if not stated) |
Marketed capacity¹ |
---|---|---|---|---|
IBM 23FD[2] | 8-inch | 1971 | 79.75 | ? |
Memorex 650 | 8-inch | 1972 | 175 | 1.5 megabit[3] [unformatted] |
IBM 33FD / Shugart 901 | 8-inch - SSSD | 1973 | 237.25[4][5] | 3.1 Mbits unformatted |
IBM 43FD / Shugart 850 | 8-inch - DSSD | 1976 | 500.5[6] | 6.2 Mbits unformatted |
Shugart SA 400 | 5¼-inch (35 track) | 1976[7] | 87.5[8] | 110 kB |
IBM 53FD / Shugart 850 | 8-inch DSDD | 1977 | 980 (CP/M) - 1200 (MS-DOS FAT) |
1.2 MB |
5¼-inch DD | 1978 | 360 or 800 | 360 KB | |
HP single sided | 3½-inch | 1982 | 280 | 264 kB |
3-inch | 1982[citation needed] | 360[citation needed] | ? | |
3½-inch (DD at release) | 1984 | 720 | 720 KB | |
5¼-inch QD | 720 | 720 KB | ||
5¼-inch HD | 1982 YE Data YD380[9] | 1155 | 1.2 MB | |
3-inch DD | 1984[citation needed] | 720[citation needed] | ? | |
Mitsumi Quick Disk | 3-inch | 1985 | 128 to 256 | ? |
2-inch | 1985[citation needed] | 720[citation needed] | ? | |
5¼-inch Perpendicular | 1986[citation needed] | 100 MB[citation needed] | ? | |
3½-inch HD | 1987 | 1440 | 1.44 MB | |
3½-inch ED | 1987[10] | 2880 | 2.88 MB | |
Floptical (LS) | 3½-inch | 1991 | 20385 | 21 MB |
LS-120 | 3½-inch | 1996 | 120.375 MB | 120 MB |
LS-240 | 3½-inch | 1997 | 240.75 MB | 240 MB |
3½-inch HiFD | 1998/99 | 150/200 MB[citation needed] | 150/200 MB | |
Abbreviations: DD = Double Density; QD = Quad Density; HD = High Density; ED = Extended Density; LS = Laser Servo; HiFD = High capacity Floppy Disk; SS = Single Sided; DS = Double Sided | ||||
¹
The formatted capacities of floppy disks is less than the unformatted capacity, which does not include the sector and track headings required for use of the disk. The amount of capacity lost to this overhead depends on the application of the drive and is beyond the manufacturer's control. Mixtures of decimal SI-style prefixes and binary record lengths required care to properly calculate total capacity. Unlike semiconductor memory, which doubled in size each time an address pin was added to an integrated circuit package and so naturally favored counts that were powers of two, the capacity of a disk drive was the product of the sector size, number of sectors per track, number of tracks per side, (and in hard drives, the number of disk platters in the drive). Individual formatted sector lengths are arbitrarily set as powers of 2 (256 bytes, 512 bytes, etc.), and disk capacity is naturally calculated as multiples of the sector size. This led to an impure combination of decimal multiples of sectors and binary sector sizes. The "1.44 MB" value for the 3½-inch HD floppies is the most widely known example; where the "M" prefix is peculiar to the context of the disk drive and represents neither a decimal million nor a mebibyte 2 ^20. See Ultimate capacity and speed. | ||||
Dates and capacities marked ? are of unclear origin and need source information; other listed capacities refer to: Formatted Storage Capacity is total size of all sectors on the disk:
Marketed Capacity is the capacity, typically unformatted, by the original media OEM vendor or in the case of IBM media, the first OEM thereafter. Other formats may get more or less capacity from the same drives and disks. |
Physical composition
Size | Density | Tracks | TPI | BPI | Coercivity | Unformatted capacity per side |
---|---|---|---|---|---|---|
3½ in | single | 40 | 67.5 | 600 Oe | 250 KB | |
double | 80 | 135 | 8.717 | 600 Oe (300 Oe) | 500 KB | |
high | 80 | 135 | 17.434 | 750 Oe (600 Oe) | 1000 KB | |
extended | 80 | 135 | 900 Oe | 2000 KB | ||
5¼ in | single/double | 40 | 48 | 5.876 | 300 Oe | 250 KB |
quad | 80 | 96 | 5.876 | 300 Oe | 500 KB | |
high | 80 | 96 | 8.646 | 600 Oe | 750 KB | |
8 in | single/double | 77 | 48 | 300 Oe | 1000 KB |
Known disk logical formats
Throughout the 1970s and 1980s, many different logical disk formats were used, depending on the hardware platform.
Platform | Size | Density | Bytes/ sector | Sectors/ track | Tracks/ side | Sides | Capacity | RPM | Encoding | Note |
---|---|---|---|---|---|---|---|---|---|---|
IBM (3740 format) | 8 in | single | 128 | 26 | 74 | 1 | 250.25 KB | 360 | FM | [11] |
Acorn | 5¼ in | single | 256 | 10 | 40 | 1 | 100 KB | 300 | FM | |
80 | 200 KB | |||||||||
double | 256 | 16 | 40 | 1 | 160 KB | MFM | ||||
80 | 320 KB | |||||||||
2 | 640 KB | |||||||||
3½ in (90 mm) | double | 256 | 16 | 80 | 2 | 640 KB | 300 | MFM | ||
1024 | 5 | 800 KB | ||||||||
high | 10 | 1600 KB | ||||||||
Apple II | 5¼ in | double | 256 | 13 | 35 | 1 | 113.75 KB | 300 | GCR | [12] |
2 | 227.50 KB | |||||||||
16 | 1 | 140 KB | ||||||||
2 | 280 KB | |||||||||
3½ in (90 mm) | double | 512 | Variable (8-12) | 80 | 1 | 400 KB | CLV | GCR | [13] | |
2 | 800 KB | |||||||||
high | 512 | 18 | 80 | 2 | 1440 KB | 300 | MFM | [14] | ||
Apple Macintosh | 3½ in (90 mm) | double | 512 | Variable (8-12) | 80 | 1 | 400 KB | CLV | GCR | |
2 | 800 KB | |||||||||
high | 512 | 18 | 80 | 2 | 1440 KB | 300 | MFM | |||
Atari 8-bit | 5¼ in | single | 128 | 18 | 40 | 1 | 90 KB | 288 | FM | [15] |
enhanced | 128 | 26 | 127 KB | MFM | ||||||
double | 256 | 18 | 180 KB | |||||||
Commodore (8-bit) | 5¼ in | double | 256 | Variable (17-21) ZCAV | 35 | 1 | 170 KB | 300 | GCR | [16] |
2 | 340 KB | |||||||||
quad | Variable (23-29) ZCAV | 77 | 1 | 521 KB | ||||||
2 | 1042 KB | |||||||||
3½ in (90 mm) | double | 512 | 10 | 80 | 2 | 800 KB | MFM | |||
Commodore Amiga | 3½ in (90 mm) | double | 512 | 11 | 80 | 2 | 880 KB | 300 | MFM | [17] |
high | 22 | 1760 KB | 150 | |||||||
IBM PC compatibles[18] | 8 in | single | 128 | 26 | 77 | 1 | 250.25 KB[19] | 360 | MFM | [20] |
2 | 500.5 KB[19] | |||||||||
double | 1024 | 8 | 2 | 1232 KB[19] | ||||||
5¼ in | double | 512 | 8 | 40 | 1 | 160 KB[19] | 300 | MFM | ||
2 | 320 KB[19] | |||||||||
9 | 1 | 180 KB[19] | ||||||||
2 | 360 KB[19] | |||||||||
unknown | 8 | 80 | 1 | 320 KB[19] | unknown | |||||
2 | 640 KB[19] | |||||||||
high | 15 | 80 | 2 | 1200 KB[19] | 360 | |||||
3½ in (90 mm) | double | 512 | 8 | 80 | 1 | 320 KB[19] | 300 | MFM | ||
2 | 640 KB[19] | |||||||||
9 | 720 KB[19] | |||||||||
high | 18 | 80 | 1440 KB[19] | |||||||
21 | 80 | 1680 KB[19] | DMF[21] | |||||||
82 | 1720 KB[19] | |||||||||
extended | 36 | 80 | 2880 KB[19] | |||||||
NEC PC98 | 8 in | single | 128 | 26 | 77 | 1 | 250.25 KB[19] | 360 | FM | |
double | 1024 | 8 | 77 | 2 | 1232 KB[19] | MFM | ||||
5¼ in | double | 512 | 8 | 80 | 2 | 640 KB[19] | 360 | MFM | ||
9 | 720 KB[19] | |||||||||
high | 15 | 1200 KiB[19] | ||||||||
1024 | 8 | 77 (80)[22] | 1232 (1280) KB[19][22] | [22] | ||||||
3½ in (90 mm) | double | 512 | 8 | 80 | 2 | 640 KB[19] | 360 | MFM | ||
9 | 720 KB[19] | |||||||||
high | 15 | 1200 KB[19] | 3mode[23][22] | |||||||
1024 | 8 | 77 (80)[22] | 1232 (1280) KB[19][22] | |||||||
512 | 18 | 80 | 1440 KB[19] | 300 | ||||||
SHARP X68000 | 5¼ in | high | 1024 | 8 | 77 | 2 | 1232 KB[19] | 360 | MFM | |
3½ in (90 mm) |
Notes and references
- ^ Floppy disk sizes are almost universally referred to in inch measurements, even in countries where metric is the standard, and even when the size is in fact defined in SI; for instance, the 3½-inch floppy is defined as 90 mm.
- ^ James T. Engh (1981). "The IBM Diskette and Diskette Drive" (PDF). IBM Journal of Research and Development. 25 (5): 701–710. doi:10.1147/rd.255.0701. Retrieved 2008-07-14.
{{cite journal}}
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ignored (help) - ^ Memorex 650 Flexible Disc File - OEM Manual
- ^ The IBM Diskette and Diskette Drive, James T. Engh, 1981 - "The user capacity of the diskette was established at 242 944 bytes on 73 tracks with 26 sectors on each track."
- ^ The Evolution of Magnetic Storage, L.D. Stevens, 1981 - "This drive, with a capacity of 243 Kbytes"
- ^ The IBM Diskette and Diskette Drive, James T. Engh, 1981 - "This would double the capacity to approximately 0.5 megabytes (Mbytes)."
- ^ Sollman, George (July 1978). "Evolution of the Minifloppy (TM) Product Family". Magnetics, IEEE Transactions on. 14 (4): 160–166. doi:10.1109/TMAG.1978.1059748. "In September, 1976, the first minifloppy disk drive was introduced by Shugart Associates."
- ^ Shugart SA 400 Datasheet Formatted with 256 byte sectors and 10 sectors per track the capacity is 89.6 Kbytes (256 x 10 x 35 = 89,600), or 87.5 KB
- ^ per 1986 Disk/Trend Report, Flexible Disk Drives
- ^ Mueller, S: "Upgrading and Repairing PCs", p.656, Que Publishing, 2002.
- ^ They have 73 data tracks, 1 index track, 2 spare tracks, 1 reserved track
- ^ 16 sector filesystems require a compatible disk controller (PROM update) and Apple DOS 3.3 or later
- ^ Apple II double-density 3½ inch (90 mm) drives use variable sectors sizes (tracks 00-15: 12 sectors, tracks 16-31: 11 sectors, tracks 32-47: 10 sectors, tracks 48-63: 9 sectors, tracks 64-79: 8 sectors)
- ^ Apple II high-density 3½ inch (90 mm) drives require a compatible disk controller and ProDOS 8.
- ^ Atari XF551 uses 360K, 300RPM, MFM, Double Side/Double Density.
- ^ Commodore floppy drives used a fixed rotation speed with variable sector density (see: Zone bit recording)
- ^ Though the Amiga used MFM, the format places sectors too close together for a standard IBM PC compatible floppy disk controller to read (appearing as one 5632-byte physical sector per track).
- ^ Standard Floppy Disk Formats Supported by MS-DOS
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac The calculated formatted capacity is based on FAT12 format.
- ^ While IBM didn't include an 8" floppy drive option on any of their PCs, MS-DOS supported 8" disks and added support for higher capacities in version 2.0. MS-DOS' predecessor 86-DOS used 8" diskettes. [1]
- ^ These variations are known as DMF diskettes, used for a time to pack more data on to each disk for software distribution.
- ^ a b c d e f Inner 3 tracks of 8 sectors/track format are unused.
- ^ The PC98 3½" (90 mm) formats are also known as "3 Mode" floppy disks, usable on IBM PC compatibles with a 3-mode floppy drive.
- The IBM Diskette General Information Manual (PDF). Product Reference Literature (Fifth ed.). IBM. 1979.
{{cite book}}
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ignored (help) - "RX02 8 inch Floppy Drive Information". David Gesswein. Retrieved 2007-09-21.
External links
- Media related to Floppy disk at Wikimedia Commons