Speeding cache scans with a bytemap of active tracks with encoded bits

A computer program product for managing tracks in a cache, the computer program product comprising one or more computer readable storage media having computer readable program code collectively stored on the one or more computer readable storage media, the computer readable program code being executed by a processor of a computer system to cause the computer system to perform a method comprising:

• instantiating cache control blocks to each manage operations for one of the tracks;
• and
• instantiating a bytemap corresponding to each of the cache control blocks, each bytemap comprising:
• an active bit indicating whether the one of the tracks for which the corresponding cache control block manages operations is active;
• and
• additional bits indicating additional characteristics of the one of the tracks for which the corresponding cache control block manages operations.

A computing system comprising:

• a processor;
• a memory coupled to the processor;
• and
• one or more computer readable storage media coupled to the processor, the one or more computer readable storage media collectively containing instructions that are executed by the processor via the memory to implement a method comprising:
• instantiating cache control blocks to each manage operations for one of the tracks;
• and
• instantiating a bytemap corresponding to each of the cache control blocks, each bytemap comprising:
• an active bit indicating whether the one of the tracks for which the corresponding cache control block manages operations is active;
• and
• additional bits indicating additional characteristics of the one of the tracks for which the corresponding cache control block manages operations.