Exatron Stringy Floppy

An Exatron Stringy Floppy (cover removed) designed for use with the TRS-80 Model 1

The Exatron Stringy Floppy (or ESF) is a continuous loop tape drive developed by Exatron.

The company introduced an S-100 stringy floppy drive at the 1978 West Coast Computer Faire, and a version for the Radio Shack TRS-80 in 1979. Exatron sold about 4,000 TRS-80 drives by August 1981 for $249.50 each, stating that it was "our best seller by far". The tape cartridge is about the size of a business card, but about 316 inch (4.8 millimetres) thick.[1] The magnetic tape inside the cartridge is 116 inch (1.6 millimetres) wide. There is no single catalog of files; to load a specific file the drive searches the entire tape, briefly stopping to read the header of each found file. The tape loop only moves in one direction, so a file that starts behind the current location cannot be read until the drive searches the entire loop for it.[2]

According to Embedded Systems magazine, the Exatron Stringy Floppy uses Manchester encoding, achieving 14K read-write speeds and the code controlling the device was developed by Li-Chen Wang, who also wrote a Tiny BASIC, the basis for the TRS-80 Model I Level I BASIC.

In the July 1983 issue of Compute!'s Gazette the Exatron Stringy Floppy for the Commodore VIC-20 and the 64 was reviewed. Calling the peripheral "a viable alternative" to tape or disk, the magazine noted that "under ideal conditions, a Stringy Floppy can outperform a VIC-1540/1541 disk drive". Texas Instruments licensed the Stringy Floppy as the Waferdrive for its TI 99/2 and CC-40 computers.[2]

Exatron pitched the ESF as "The viable alternative". The ESF was faster and more reliable than a data cassette, and half the price of a floppy disk.

Cartridges, or "wafers", were available with tape lengths ranging from 5 to 75 feet.[1] Known data capacities/tape length are: 4 kB/5 feet, 16 kB/20 feet, 48 kB/50 feet, and 64 Kk/75 feet.[3] One complete cycle through a 20-foot tape takes 55 to 65 seconds, depending on the number of files on it.[2]

See also


  1. 1 2 Barry, John (1981-08-31). "Stringy Floppy from Exatron". InfoWorld. pp. 47–48. Retrieved 15 February 2015.
  2. 1 2 3 Halfhill, Tom R. (July 1983). "Exatron Stringy Floppy for VIC-20 and 64". Compute!'s Gazette. pp. 58–62. Retrieved 6 February 2016.
  3. Reed, Matthew. "The Exatron Stringy Floppy". Retrieved 23 March 2014.

External links

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