Talk:List of floppy disk formats

8-inch table comfusing
haywire 8" disk info. The table is very confusing, for most disk it lists formatted capacity in bytes.  but for 8" it gives UNformatted capacity in BITS. this is very misleading. I used to have a pair of 8" floppy drives (late 70's) and what I distinctly remember is that the formatted capacity was 1.44 kB. codeslinger at compsalot.  —Preceding unsigned comment added by 63.229.4.234 (talk) 00:17, 20 February 2011 (UTC)

IBM and DEC 8-inch formats
The first table in this article is very confusing, and some explanation may be warranted. Here's what I'm inferring from this table.

The first read/write floppy drive was the 33FD, which initially supported a geometry format that used 73 tracks, divided into 26 sectors per track, composed of 128 bytes per sector. Two additional formats were added, which used 15 sectors of 256 BPS (increasing capacity using less than half the sectors and doubling the capacity of each sector) or 8 sectors of 512 BPS (again, less than half the sectors and doubling the capacity of each sector). For compatibility, every new 8" floppy disk format had to keep the first track formatted at 26 sectors of 128 bytes per sector, which became the "geometry cylinder" (cylinder 0). The geometry cylinder is lost for capacity purposes, and is used to store information about the disk geometry. At the same time, all new 8" floppy disks increased the number of tracks from 73 to 75, leaving 74 usable tracks (cylinders 1 to 74).

The 43FD supported 26 sectors of 128 bps, or 15 sectors of 256 bps, and doubled capacity over the previous generation by adding a second read/write head to allow recording on both sides of the disk. The 53FD also supported 26, 15, or 8 sectors per track, but doubled the number of bytes per track to 256 BPS, 512 BPS and 1024 BPS, respectively.

With the exception of the one oddball 33FD format, IBM 8" floppy disks can be regarded as having 74 usable tracks per side, and either 26, 15, or 8 sectors per track, and can be either single sided (Type 1) or double sided (Type 2), single density (26/128, 15/256, 8/512) or double density (Type 2D: 26/256, 15/512, 8/1024).

I'm not adding this information to the article because it is completely unsourced and based solely on my reading of the table. An expert on the subject is free to add or modify this explanation. DOSGuy (talk) 17:19, 13 March 2011 (UTC)


 * I deleted that table and integrated the information into the physical and logical formats table. Okto8 (talk) 20:25, 15 November 2023 (UTC)

Merger with Floppy disk format
The original proposer did not create the merger section on this talk page to discuss the merger. &sect; Music Sorter &sect;  (talk) 15:08, 29 July 2011 (UTC)

Support the merger proposal since the source article is so small and short. If someone proposed to rewrite that article I would then oppose this merger. &sect; Music Sorter &sect;  (talk) 15:08, 29 July 2011 (UTC)
 * Oppose. List is list, prose is prose. On the other hand, much of prose must be merged from &*Floppy disk per Summary style. Muslim lo Juheu (talk) 15:49, 29 July 2011 (UTC)
 * Let's not. This list needs to cleaned up - how about one table, by disk size, decreasing capacity, and then all the other information (operating system, manufacturer, etc.) References would be nice, too. --Wtshymanski (talk) 18:00, 3 January 2012 (UTC)
 * Oppose - Merging this to the Floppy disk format article would make that article disproportionate in terms of then primarily becoming a list. This is a reasonable content fork. Northamerica1000 (talk) 13:43, 10 January 2012 (UTC)

Physical composition
What are the paranthesized clauses in the Coercivity section of the Physical composition table supposed to mean? Hpa (talk) 19:12, 9 September 2012 (UTC)

12-inch Floppies
Does anyone have information on the 12-inch Floppy Disks from the late 60s? All I can find is that they had a 242 kb capacity and a picture: http://www.dickestel.com/images/expo72.jpg 72.238.84.176 (talk) 22:53, 22 May 2014 (UTC)


 * That looks like one of the transmissive optical video disk systems, circa 1980. Thomson-CSF had a popular (FSVO "popular"), Sony had one as well, I think.  Rwessel (talk) 04:55, 23 May 2014 (UTC)
 * This is almost certainly a Sony CRVDisc of some vintage (there were several slightly different looking models). See and  for example.  The logo markings on the disk in the OP's link are different, but the overall package looks pretty identical.  Google (images) on "sony crvdisc" or "lvm-3aa0" for more examples.  Rwessel (talk) 14:53, 23 May 2014 (UTC)
 * Yep, you nailed it. It's a Sony CRVdisc, a recordable video disc system. --Matthiaspaul (talk) 22:55, 23 May 2014 (UTC)


 * (edid conflict) For the records, the photo was shot at the Vintage Computer Festival held on 2005-11-05/06 at the Computer History Museum, Mountain View, CA. The author of that page has no clue what it is: "At 12 inches, the world's largest floppy disk?"
 * To me, this Sony part doesn't look like a floppy disk at all, more like an optical disk in a cartridge with slider. The case and labeling isn't 1960s manufacturing technology, either. Just by the look, Panasonic's PD comes close to it, but is smaller, of course. It could be some over-sized dummy for demo or advertisement purposes of a similar system.
 * The "A" suggests that it has two sides, which might indicate some early video disc system (there were several, including 12-inch-sized cartridged systems, but I don't have an overview about them). But there appears to be a small red slider near one of the corners, which could be a write-protection switch. This would rule out the video disc systems, since they were read-only.
 * What is the source for your "242 KB" figure? Sounds like a 8-inch FM/SD/SS floppy disk (CHS=77/1/26/128) to me (250.25 KiB nominally, but sometimes labelled 243 KB as well, f.e. in DR-DOS). Unrelated to this 12-inch disk.
 * --Matthiaspaul (talk) 08:25, 23 May 2014 (UTC)
 * Small addon: Two links mentioning "12-inch diskettes", but unverified and without any actual information, except for that, according to them, 12-inch flexible disks were used by some mainframes in the 1960s/1970s:, . However, the ones I have seen were single hard-disk platters in removable cartridges (from my memory: much larger than 12-inch) - definitely much bulkier, heavier and older than what is pictured here. --Matthiaspaul (talk) 09:12, 23 May 2014 (UTC)
 * 14 inch single platter hard disks. History_of_IBM_magnetic_disk_drives, these eventually increased to about 5MB in capacity by 1973 (non-IBM versions) Rcgldr (talk) 21:49, 12 July 2018 (UTC)

Deleted Reference Material
The current References 14 and 15 (which are identical), 'Standard Floppy Disk Formats Supported by MS-DOS', has been deleted by Microsoft: https://support.microsoft.com/en-us/help/75131 SandStone (talk) 18:16, 29 April 2017 (UTC)

what about the PC/AT 1200 KB 5-1/4 drive ??
I see the "High Density" 5.25 inch drive for the PC...this actually first appeared in 1985 on the new high end superexpensive Model 5170 PC/AT, the successor to the PC/XT (Model 5160), which became the standard high performance computer in the industry. I came here looking to see if this drive originated with IBM or if it was a technology they borrowed from somebody else.

Anyway, your table here shows this drive is a PC drive, but the AT is distinct. Even the clone makers like Compaq, Zenith and Tandy put the 1.2 MB drive into their AT clones. And it's even more distinct because no other microcomputer (that I am aware of) ever used the 1.2 MB format, since everybody soon switched over to the 3.5 inch drives (like the PS/2s). So it seems this article needs a correction... Wikkileaker (talk) 17:52, 6 July 2020 (UTC)

physical composition table misleading
in the table "physical composition" a distinction is made between SD, DD and QD 5-inch disks.

the disks used are all the same. 158.181.81.216 (talk) 10:27, 13 September 2022 (UTC)


 * Right. And it gets worse; the next table talks about "quad density" 5.25" non-HD floppies, which are the same media (and thus the same flux density) and also the same bit rate and track format as "double density" 5.25" non-HD floppies. So we now have three different uses of the term density here, without much attempt to distinguish between them.
 * I suggest we at least drop the "quad density" term and replace it with "80-track," since it's critical to distinguish between 80-track and 40-track drives: 80-track drives can write 40-track diskettes, but 40-track drives may not be able to read them. Cjs (talk) 05:45, 6 July 2023 (UTC)

Text formatting for disk size?
Using fractions is technically more accurate, since these sizes were defined in fractional inches, but using the fraction template makes the size column sort incorrectly.

Should we use decimal measurements for everything? Is there a way around this I don't know about? Okto8 (talk) 20:05, 15 November 2023 (UTC)

Hard sectoring/different physical formats with same-size platter
My thought is that hard sectoring, being a physical property of the disk, belongs in the Physical Format table, but I am not sure whether to add it as a separate density, or a separate entry in the table (ie, 5.25 Hard Sector in the column that lists sizes). Also, should that table (as well as the Size column in the logical-formats table) distinguish different disk envelopes that share a platter diameter? Examples that come to mind are the IBM 8" and Burroughs 8" floppy formats, both sharing an 8" diameter Mylar disk, but in differently-shaped and incompatible envelopes, and the Apple FileWare/Twiggy disk, which shares a medium with the standard 5.25" disk but also has a different and incompatible envelope. Okto8 (talk) 20:24, 15 November 2023 (UTC)