ECMA-34

ECMA TC19 was set up by ECMA in January 1970 with aim to identifying and standardizing the physical properties and the relevant data format of a magnetic tape cassette for digital applications – below the performance range of existing magnetic tape standards – in order to ensure interchangeability.

It appeared to be a fact that the 3,81 mm tape cassette was already used and will be more used in computer applications.
The urgent need for a standard for this type of cassette was therefore recognized and-TC19’s first efforts were directed to setting up the present Standard ECMA-34, which was issued in September 1971.

This Standard was presented to ISO/TC 97 as a proposed draft for an international standard. Similar work was also in progress in the American National Standard Institute (ANSI). As a result ISO/TC97/SC11 eventually adopted a final draft for an international standard at their April 1973 meeting. The 2nd Edition of Standard ECMA-34 was in its content identical to this draft.

When it was finally edited at the July 1975 meeting of SC11, a few changes were introduced. The present 3rd Edition of ECMA-34 reflects these changes.

Essentially they concern two points:

• magnetic properties can be checked on the same relative pass,
• the integrity of gaps is defined as a number of flux transitions instead a length of tape.

Furthermore, a recommendation for the hub diameter has been introduced in this 3rd Edition to ensure exchangeability in case of reel- to-reel drives.