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  2. List of floppy disk formats - Wikipedia

    en.wikipedia.org/wiki/List_of_floppy_disk_formats

    5 14 inch High 2 77 8 1,024 1,232 kB [NB 11] 360 MFM 3 1 ⁄ 2 inch SHARP CE-1600F, CE-140F: 2 1 ⁄ 2 inch [2] [3] Single drive: 1, diskette: 2 16 8 512 2× 64 kB 270 GCR (4/5) Internally based on FDU-250 Micro Floppy Disk Drive Unit [2] Thomson: 5 14 inch Single 1 40 16 128 80 kB 300 FM Thomson UD90.070 Double 2 256 320 kB MFM

  3. Floppy disk - Wikipedia

    en.wikipedia.org/wiki/Floppy_disk

    8-inch floppy disk, inserted in drive, (3½-inch floppy diskette, in front, shown for scale) 3½-inch, high-density floppy diskettes with adhesive labels affixed The first commercial floppy disks, developed in the late 1960s, were 8 inches (203.2 mm) in diameter; [4] [5] they became commercially available in 1971 as a component of IBM products and both drives and disks were then sold ...

  4. Frequency modulation encoding - Wikipedia

    en.wikipedia.org/wiki/Frequency_modulation_encoding

    As each bit of data requires two transition periods in the FM system, it makes use of only half the potential storage capacity of the disk. This led to a series of more advanced encodings that make better use of the available space. The most widely used replacement was modified frequency modulation, or MFM. This system recorded only a single ...

  5. Floppy disk format - Wikipedia

    en.wikipedia.org/wiki/Floppy_disk_format

    Variables included the size of media (nominal 8-inch, 5 + 14-inch, 3 + 1 ⁄ 2-inch and others), encoding of data on the media (FM, MFM, M²FM, GCR), the number of disk tracks, one or two sides, the number of sectors in each track, and hard- or soft-sectoring. Even media that was physically interchangeable between two systems might not ...

  6. Floppy disk variants - Wikipedia

    en.wikipedia.org/wiki/Floppy_disk_variants

    A Maxell-branded 3-inch Compact Floppy Disk. The floppy disk is a data storage and transfer medium that was ubiquitous from the mid-1970s well into the 2000s. [1] Besides the 3½-inch and 5¼-inch formats used in IBM PC compatible systems, or the 8-inch format that preceded them, many proprietary floppy disk formats were developed, either using a different disk design or special layout and ...

  7. Commodore 1541 - Wikipedia

    en.wikipedia.org/wiki/Commodore_1541

    The best-known floppy disk drive for the C64, the 1541 is a single-sided 170-kilobyte drive for 5¼" disks. The 1541 directly followed the Commodore 1540 (meant for the VIC-20). The disk drive uses group coded recording (GCR) and contains a MOS Technology 6502 microprocessor, doubling as a disk controller and on-board disk operating system ...

  8. 40-track mode - Wikipedia

    en.wikipedia.org/wiki/40-track_mode

    A disk sector (7) on a floppy diskette. A 3.5 inch 1.44MB mini-floppy diskette contains 80 tracks, 18 sectors per track, and 512 bytes per sector. A 3.5 inch 720k diskette contains 80 tracks, 9 sectors per track, and 512 bytes per sector. This technique refers to formatting an 80-track 1.44MB diskette as a special 40-track 720KB diskette.

  9. Group coded recording - Wikipedia

    en.wikipedia.org/wiki/Group_coded_recording

    The Durango Systems F-85 (introduced in September 1978 [20] [21]) used single-sided 5¼-inch 100 tpi diskette drives providing 480 KB utilizing a proprietary high-density 4/5 group coded encoding. The machine was using a Western Digital FD1781 floppy disk controller, designed by a former Sperry ISS engineer, [17] with 77-track Micropolis drives ...