A&J Micro Drive

1050 East Duane Ave., Suite I, Sunnyvale, CA 94086
Owner(s): Jim Howell

A&J Micro Drive was a spin-off of Exatron, the company that manufactured and marketed the Exatron Stringy Floppy (ESF). The Exatron Stringy Floppy was a continuous loop tape cartridge (โ€œwaferโ€) that had some advantages over traditional cassette tapes.

Exatron also manufactured the tape drive mechanism and sold it via mail order to home computer owners. The first ESF drives were made for the TRS-80 Model I. Wafers were available in several lengths, from 5 feet (which could store 4K of data) to 75 feet (up to 64K).

By 1983, Exatron needed additional capital to improve the overall performance and quality of the wafer drives and wafers. With new investors came the name change to Entrepo (a word close to the French word for warehouse). Exatron focused on large OEM accounts and Jim Howell, son of the Exatron founder, took over the mail-order stringy floppy business with his company, A&J Micro Drive.

One investor, BSR Ltd., the Hong Kong-based electronic components and consumer electronics company, acquired a third of the equity in Entrepo. BSR finalized the R&D on the wafer drive which it also manufactured. The BSR drive was used in the Rototronics Wafadrive.



Low cost, high-speed mass storage system that uses on “wafers” (endless loop tapes). Data transfer rate is many times faster than cassette and more reliable. Loads a 28k program in 24 seconds. Micro drive controller attaches to the expansion connector on the back and peripherals attach behind it. Most programs will run with little or
TS 1000
The TS2068 version of the A&J Micro Drive has all the features of the original and includes a Centronics printer interface.
TS 2068
Supplemental Exatron Stringy Floppy drive.
TS 1000 TS 2068
The ESF/81 monitor program will allow you to program your Sinclair ZX81 at the most elementary level, in “machine language.” In. addition, the ESF/81 monitor will let you back up other machine-language programs stored on ESF wafers for extra security.
TS 1000
Continuous loop tape (“stringy floppy“) for the A & J Microdrive.
TS 1000 TS 2068



Computer Media


Scroll to Top