Analysis of information sources in references of the Wikipedia article "Floppy disk" in English language version.
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Turns out the obsolete floppy is way more in demand than you'd think. ... I expect to be in this business for at least another four years.
Information Systems – Unformatted Flexible Disk Cartridge for Information Interchange, 5.25 in (130 mm), 96 Tracks per inch (3.8 Tracks per Millimeter), General, Physical, and Magnetic Requirements (includes ANSI X3.162/TC-1-1995) Specifies the general, physical, and magnetic requirements for interchangeability for the two-sided, 5.25 in (130 mm) flexible disk cartridge
GCR disks cannot be read by standard PC disk controllers.
Wozniak's technique would allow the drive to do self-synchronization ("soft sectoring"), not have to deal with that little timing hole, and save on hardware.
Shugart is one of the major subscribers to the 31⁄2-inch micro-floppy standard, along with Sony and 20 other company ... Its single-sided SA300 micro-floppy drive offers 500K of unformatted storage. Shugart's Kevin Burr said the obvious next step is to put another 500K of storage on the other side of the diskette and that the firm will come out with a double-sided 1-megabyte micro-floppy drive soon.
So the short story is don't write a double density diskette in a high density drive and then expect a double density drive to be able to read it. The narrower write head overwriting the wider preexisting data can confuse the wider drive head
ISO 838 specifies that, for filing purposes, two holes of 6±0.5 mm diameter can be punched into the sheets. The centers of the two holes are 80±0.5 mm apart
Forecasts indicated that only 10% of the total number of flexible disk drives marketed in 1997 would be of the high-capacity or superfloppy type.
Floppy disk drives for Macintosh computers have an electric ejecting mechanism, so there is no eject button on Macintosh floppy disk drives
A system of levers that opens the little protective window on the diskette to allow the read/write heads to touch the dual-sided diskette media
Forecasts indicated that only 10% of the total number of flexible disk drives marketed in 1997 would be of the high-capacity or superfloppy type.
A floppy disk drive mechanism includes a clamping lever which is turned to align the floppy disk with a drive spindle and clamp it thereto
SuperDisk is a type of high-capacity floppy disk that provides increased storage compared to traditional floppy disks. It can store up to 120MB of data, a significant upgrade from the older 1.44MB floppy disks. [...] The backward compatibility with standard floppy disks added convenience, allowing users to access old data without maintaining separate devices.
Extra Density (ED): Consists of 3 μm barium ferrite
[…] The Brier ... can store 20 megabytes, increase the number of tracks. […] In Brier's Flextra system, a low-frequency magnetic homing signal is embedded at the bottom of the barium ferrite coating after the disk is manufactured. Later, the data are recorded in the top of the layer, using a higher-frequency signal. The Brier system cannot read and write lower-capacity disks, although the company says it will introduce a model that can do that later this year. […] Brier has designed its system from scratch to achieve higher speeds.
Because of spring loading, the linkages involved with insertion and clamping of the disk provide a force, upon release, by pushing the release button, that strikes against the rear edge of the cartridge containing said disk and applies an ejection force thereto
{{citation}}: CS1 maint: deprecated archival service (link)It's not a mechanical eject button - it's an electrical switch, so the Mac itself has to "respond" not the drive
data frequency 250Kbps, MFM double density DD / 500Kbps, MFM high density HD / 1Mbps, ?MFM?? 2.88M extended density ED
Single-sided double-density (SSDD) systems used original media, 40 tracks and MFM encoding for a capacity of around 160 KB/diskette. Double-sided double-density (DSDD or sometimes "2D") systems obviously doubled the above to about 320 KB/diskette.access-date=20 November 2024
There were in fact 'hard' protected disks - such that simply had no write protect hole. These were used by software distributions
It is also a good idea on real hardware to retry a disk operation a few times if it fails. You can do that by calling BIOS function Int 13h/AH=0 (Disk Reset) before retrying the operation again. If it fails more than a few times then you can abort
The diskette is about 8" (20 cm) square and has a net capacity of 1898 128-character records – about one day's data entry activity. Each of the diskette's 73 magnetic recording tracks available for data entry can hold 26 sectors of up to 128 characters each.
Information Systems – Unformatted Flexible Disk Cartridge for Information Interchange, 5.25 in (130 mm), 96 Tracks per inch (3.8 Tracks per Millimeter), General, Physical, and Magnetic Requirements (includes ANSI X3.162/TC-1-1995) Specifies the general, physical, and magnetic requirements for interchangeability for the two-sided, 5.25 in (130 mm) flexible disk cartridge
The diskette is about 8" (20 cm) square and has a net capacity of 1898 128-character records – about one day's data entry activity. Each of the diskette's 73 magnetic recording tracks available for data entry can hold 26 sectors of up to 128 characters each.
Wozniak's technique would allow the drive to do self-synchronization ("soft sectoring"), not have to deal with that little timing hole, and save on hardware.
Enhanced electronics permit the BR-3225 to read IBM formatted 3.5 inch floppy disks. The drive automatically identifies 1 MB, 2 MB, or 25 MB disks… Servo: magnetically embedded (buried).
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