Some other trivia about DEVTYPE in catalog entries...

The first two bytes are "feature" bits. For modern disk, it will always be x'3010'. These bits represent obsolete and now-standard functions that were once features, namely burst mode (obsolete), data chaining (now standard), and rotational position sensing (now both standard *and* obsolete!).

The next byte is the device class, x'20' for direct access.

The last byte, represents the device, and as others have posted x'0F' is set for 3390.

(Wayne Rhoten had the feature bit mapping when I looked for this a couple months back!)

John Eells
IBM Poughkeepsie

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