2M (DOS)
Encyclopedia
2M is a DOS
DOS
DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...

 program by the Spanish programmer Ciriaco García de Celis. It enables higher than normal capacity formatting
Disk formatting
Disk formatting is the process of preparing a hard disk drive or flexible disk medium for data storage. In some cases, the formatting operation may also create one or more new file systems...

 of floppy disk
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...

s. It saw active development from 1993 to 1995. The last version, v3.0, was released on March 6, 1995. It was written in C and assembler and compiled using Borland C++
Borland C++
Borland C++ is a C and C++ programming environment for MS-DOS and Microsoft Windows. It was the successor to Turbo C++, and included a better debugger, the Turbo Debugger, which was written in protected mode DOS....

 3.1.

The program consisted of two major components: 2M and 2MGUI. Of these, 2M was the main program enabling the formatting, reading and writing of high density 3.5" disks formatted to a capacity of either 1804 KiB or 1886 KiB, and 2MGUI was a proof-of-concept program that demonstrated the ability to format any normal high density 3.5" disk to a capacity of over two million bytes (1972 KiB) on any disk drive. Both programs implemented disk I/O speedups in the form of "Sector Sliding" and "DiskBoost", which work on the principle of ordering the physical sectors on the disk to facilitate pauseless reading over track changes.
Formatting program 5.25", DD
Double density
Double density, often shortened DD, is a capacity designation on magnetic storage, usually floppy disks. It describes the use of an encoding of information, which can encode on average twice as many bits per time unit compared to single density...

5.25", HD
FORMAT (40/80 track
Cylinder-head-sector
Cylinder-head-sector, also known as CHS, was an early method for giving addresses to each physical block of data on a hard disk drive. In the case of floppy drives, for which the same exact diskette medium can be truly low-level formatted to different capacities, this is still true.Though CHS...

s)
368,640 bytes (360 KiB) 1,228,800 bytes (1200 KiB)
FDFORMAT 1.8 (82 tracks) 839,680 bytes (820 KiB) 1,427,456 bytes (1394 KiB)
2MF 3.0 /F (82 tracks) 839,680 bytes (820 KiB) 1,511,424 bytes (1476 KiB)
2MF 3.0 /M (82 tracks) 923,648 bytes (902 KiB) 1,595,392 bytes (1558 KiB)
2MGUI 1.0 (82 tracks) 1,000,064 bytes (976 KiB) 1,679,104 bytes (1639 KiB)
blank disk (82 tracks) ~1,025,000 bytes (1001 KiB) ~1,708,224 bytes (1668 KiB)

Formatting program 3.5", DD
Double density
Double density, often shortened DD, is a capacity designation on magnetic storage, usually floppy disks. It describes the use of an encoding of information, which can encode on average twice as many bits per time unit compared to single density...

3.5", HD 3.5", ED
FORMAT (80 track
Cylinder-head-sector
Cylinder-head-sector, also known as CHS, was an early method for giving addresses to each physical block of data on a hard disk drive. In the case of floppy drives, for which the same exact diskette medium can be truly low-level formatted to different capacities, this is still true.Though CHS...

s)
737,280 bytes (720 KiB) 1,474,560 bytes (1440 KiB) 2,949,120 bytes (2880 KiB)
FDFORMAT 1.8 (82 tracks) 839,680 bytes (820 KiB) 1,763,328 bytes (1722 KiB) not supported
2MF 3.0 /F (82 tracks) 1,007,616 bytes (984 KiB) 1,847,296 bytes (1804 KiB) 3,694,592 bytes (3608 KiB)
2MF 3.0 /M (82 tracks) 1,091,584 bytes (1066 KiB) 1,931,264 bytes (1886 KiB) 3,862,528 bytes (3772 KiB)
2MGUI 1.0 (82 tracks) 1,204,224 bytes (1176 KiB) 2,019,328 bytes (1972 KiB) 4,038,656 bytes (3944 KiB)
blank disk (82 tracks) ~1,230,000 bytes (1201 KiB) ~2,050,000 bytes (2002 KiB) ~4,100,000 bytes (4004 KiB)

See also

  • fdformat
    Fdformat
    Fdformat is the name of two unrelated programs:* A command-line tool for Linux that "low-level formats" a floppy disk.* A DOS tool written in Pascal by Christoph H. Hochstätter that allows users to format floppy disks to a higher than usual density, enabling the user to store up to 300 kilobytes...

    , a similar program that offers less capacity
  • DMF
    Distribution Media Format
    Distribution Media Format is a format for floppy disks that Microsoft used to distribute software. It allowed the disk to contain 1680 KB of data on a 3½-inch disk, instead of the standard 1440 KB. As a side effect, utilities had to specially support the format in order to read and write the...

    , a high-density diskette format used by Microsoft
  • XDF
    IBM Extended Density Format
    The IBM eXtended Density Format is a way of formatting standard high-density 3.5" and 5.25" floppy disks to larger-than-standard capacities...

    , a high-density diskette format used by IBM

External links

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