A.5. gaps, A-7: self-sync byte – Rana Systems Elite Series User Manual

Page 290

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ELITE SERIES USER MANUAL

APPEN. A - DISK I/O

Normal Byte Hex FF Self-Sync Byte Hex FT

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0

F i g . A - 7 : S e l f - S y n c B y t e

Five self-sync bytes are sufficient to show that

the hardware is reading valid data because the

hardware requires the first bit of a byte to be

a 1 (an Apple-GCR restriction).

As long as the disk is left in read mode, it

will continue to correctly interpret the data

unless there is an error on the track.

A . 5 . G a p s

The size of the three gap types will vary from

drive to drive and even from track to track.

During initialization (INIT) DOS will start with

large gaps and make them smaller until a

complete track can be written without overlap-

ping itself.

P a g e A - 1 9

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