File organization on direct access disk device

Abstract

Abstract A TECHNIQUE IS DISCLOSED FOR UTILIZING ALL AVAILABLE WORK SPACE ON DIRECT ACCESS DISK DEVICES WITHOUT REGARD TO THE A LOGICAL ADDRESS NAMING CONVENTION FOR AVAILABLE WORK SPACE AND AN AUTOMATIC TRANSLATION OF PHYSICAL ADDRESS TO LOGICAL ADDRESS. THE TRANSLATION IS AUTOMATICALLY MACHINE CALCULATED ACCORDING TO M=MMM(V) H=HHH(V)+XX-VVV(V) C=CCC(V)+YY XX=FLOOR(RT//(TPC.NWK)) YY=FLOOR(RT/(TPC.NWK)) WHERE M IS THE PHYSICAL MODULE NUMBER, H IS THE PHYSICAL TRACK (HEAD) NUMBER, C IS THE PHYSICAL CYLINDER NUMBER, MMM, HHH, AND CCC ARE PHYSICAL MODULE, HEAD AND CYLINDER NUMBERS AT PREDETERMINED BREAK POINTS SELECTED BY THE USER, XX AND YY ARE PARAMETERS, AND X IS A PARAMETER EQUAL TO THE LOWEST POSSIBLE VALUE OF V AT WHICH VVV(V) $XX$WWW(V) WHERE VVV IS EQUAL TO THE FIRST LOGICAL TRACK OF A GROUP AND WWW IS EQUAL TO THE LAST LOGICAL TRACK OF THAT GROUP, A GROUP COMPRISING ALL LOGICAL TRACKS BETWEEN TWO OF THE PREDETERMINED BREAK POINTS, AND WHERE A BREAK POINT IS THE TRANSFER FROM ONE PHYSICAL CYLINDER TO ANOTHER PHYSICAL CYLINDER. A TRACK INTERLEAVING TECHNIQUE IS ALSO DISCLOSED FOR COMBINATION WITH THE WORK SPACE TECHNIQUE TO ACHIEVE RAPID COMPARISON OF PARALLEL FILES.

Inventors

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