Floppy disk variants
The prospective users, both inside and outside IBM, preferred standardization to what by release time were small cost reductions, and were unwilling to retool packaging, interface chips and applications for a proprietary design.
[10] A magnetic disk in a hard plastic shell was invented by Marcell Jánosi [hu], who was working at the Hungarian Budapest Radio Technology Factory (Budapesti Rádiótechnikai Gyár, BRG), in 1973.
[11][12] In 1982, such a product, the 3-inch MCD-1 was announced internationally and Jack Tramiel showed interest in using the technology in his Commodore computers, but negotiations fell through.
[13] Versions of the floppy drive were released in minimal quantity for the ZX Spectrum and Commodore 64, and some computers made in East Germany were also equipped with one.
It was also adopted by some first-party manufacturers/systems such as Sega, Yamaha, the Oric, the Tatung Einstein, and Timex of Portugal in the FDD and FDD-3000 disk drives and a number of third-party vendors such as Amdek, AMS, and Cumana who provided drives for use with the Apple II, Atari 8-bit computers, BBC Micro, and TRS-80 Color Computer.
[21][22] Many Smith Corona "CoronaPrint" word-processor typewriters used a proprietary double-sided 3-inch diskette format named "DataDisk".
This was due in part to the scarcity of other devices using this drive making it impractical for software transfer, and high media cost which was much more than 3½-inch and 5¼-inch disks of the time.
IBM developed, and several companies copied, an autoloader mechanism that can load a stack of floppies one at a time into a drive.
[28] None of these ever reached the point where it could be assumed that every current PC would have one, and they have now largely been replaced by optical disc burners and flash storage.
The main technological change for the higher-capacity formats was the addition of tracking information on the disk surface to allow the read/write heads to be positioned more accurately.
One major goal was that the to-be-developed standard drive be backward compatible: that it be able to read 720 KB and 1.44 MB floppies.
[30] In 1991, Insite Peripherals introduced the "Floptical", which uses an infra-red LED to position the heads over marks in the disk surface.
Eventually the falling prices of compact disc optical media and, later, flash storage, along with notorious hardware failures (the so-called "click of death"), reduced the popularity of the Zip drive.
[35] LS in this case stands for LASER-servo,[36] which uses a very low-power superluminescent LED that generates light with a small focal spot.
This worked very well at the time and as a result failures associated with magnetic fields wiping the Zip drive alignment Z tracks were less of a problem.
Although by this time the LS-120 had already garnered some market penetration, industry observers nevertheless confidently predicted the HiFD would be the real standard-floppy-killer and finally replace standard floppies in all machines.
After only a short time on the market the product was pulled, as it was discovered there were a number of performance- and reliability problems that made the system essentially unusable.
Sony then reengineered the device for a quick rerelease, but then extended the delay well into 1998 instead, and increased the capacity to "200 MB" (approximately 210 decimal megabytes) while they were at it.
Another more-common early copy-protected scheme simply does not record important sectors as allocated in the VTOC, so the DOS Utility Package (DUP) does not duplicate them.
Well-known 3rd party Atari DOS products include SmartDOS (distributed with the Rana disk drive), TopDos, MyDos and SpartaDOS.
Because of this, foreign formats such as the IBM PC compatible's can be handled with ease (by use of CrossDOS, which was included with later versions of AmigaOS).
With the correct filesystem driver, an Amiga can theoretically read any arbitrary format on the 3½-inch floppy, including those recorded at a slightly different rotation rate.
On the PC, however, there is no way to read an Amiga disk without special hardware, such as an Individual Computers Catweasel, and a second floppy drive.
It is simple STM32 based USB to FD interface adapter capable of reading magnetic flux image.
The Amiga HD disks can handle 1760 KB, but using special software programs they can hold even more data.
The DiskMasher format is copy-protected and has problems storing particular sequences of bits due to bugs in the compression algorithm, but was widely used in the pirate and demo scenes.
The proprietary IPF files were created to allow preservation of commercial games which have copy protection, which is something that ADF and DMS cannot do.
Post-1991 machines including the A5000 and Risc PC add support for high-density disks with F format, storing 1,600 KB.
However, the PC combo IO chips used are unable to format disks with sector skew, losing some performance.
Computer Concepts released a package that implements an image filing system to allow access to high density Macintosh format disks.
