2M (DOS)


2M is a DOS program by the Spanish programmer Ciriaco García de Celis. It enables higher than normal capacity formatting of floppy disks. 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++ 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 KB, 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 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. 2MGUI utilized bit banging and tricked the floppy controller into some kind of "pass-through" mode allowing direct manipulation of the low-level bitstream. A similar technique was also used by Vincent Joguin's Disk2FDI for Amiga floppies.
Formatting program5.25", DD5.25", HD
FORMAT 368,640 bytes 1,228,800 bytes
FDFORMAT 1.8 839,680 bytes 1,427,456 bytes
2MF 3.0 /F 839,680 bytes 1,511,424 bytes
2MF 3.0 /M 923,648 bytes 1,595,392 bytes
2MGUI 1.0 1,000,064 bytes 1,679,104 bytes
blank disk ~1,025,000 bytes ~1,708,224 bytes

Formatting program3.5", DD3.5", HD3.5", ED
FORMAT 737,280 bytes 1,474,560 bytes 2,949,120 bytes
FDFORMAT 1.8 839,680 bytes 1,763,328 bytes not supported
2MF 3.0 /F 1,007,616 bytes 1,847,296 bytes 3,694,592 bytes
2MF 3.0 /M 1,091,584 bytes 1,931,264 bytes 3,862,528 bytes
2MGUI 1.0 1,204,224 bytes 2,019,328 bytes 4,038,656 bytes
blank disk ~1,230,000 bytes ~2,050,000 bytes ~4,100,000 bytes