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Last modified on 28 July 2018, at 13:40

IBM System 34 double density format

Revision as of 13:40, 28 July 2018 by Arnoldemu (Talk | contribs) (Created page with "The IBM System 34 double density format is a structure used by NEC765 compatible disc controllers when writing in MFM mode. The data has this form: The track starts with thi...")

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The IBM System 34 double density format is a structure used by NEC765 compatible disc controllers when writing in MFM mode.

The data has this form:

The track starts with this: 

Gap 0 (80 bytes of data 4E)
Sync (12 bytes of 0)
Index mark IDAM which contains 3 bytes of C2 (this has a missing clock) followed by 1 byte FC.
Gap 1 (50 bytes of data 4e)