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Reports › CIA Report Description › Description of Data Component Graphic Headings

Description of Data Component Graphic Headings

The following table describes different data component graphic headings:

REC TOTAL

This is the total number of data records found in the control interval. When the CI contains a portion of a spanned record, the literal SPAN will appear in front of the record count. A value of zero is displayed for the first and any intermediate segments of the spanned record, and a value of one is displayed for the last segment.

BYTE TOTAL

This is the total number of characters found in all of the data records in this control interval.

FREE SPACE

This is the amount of unused space in the control interval. It can be used to add new records or to expand records in a file that can contain variable-length records.

DEAD SPACE

This is the number of bytes that CA Disk considers unusable in the control interval.

OVERHEAD

This is the number of bytes required to hold the system control information.

% USED

This is the percentage of the cluster currently being used. For the purposes of this figure, used space can either be space used to hold data records or space required by VSAM for control information.

% DEAD

This is the percentage of the control interval considered to be unusable. It is calculated by dividing the number of dead bytes by the control interval size.

REL SEQ

This value represents the relative order of each control interval in the control area by key sequence. In a control area that has all of its control intervals in key sequence, this value will always be incremented by one for each line in the graph.

REL DEV

This value represents the relative deviation between the current control interval and the one that preceded it in key sequence. In an organized cluster, this value will be 1. Since this value is normal it is suppressed on the report so you will see blanks instead. If the value is other than 1, the control interval does not physically reside next to the control interval beneath it in key sequence. This normally would have no impact on the performance of the cluster. The only exception to this would be when the control area size is less than one cylinder and the deviation would cause the DASD device to have to shuttle between two different cylinders to read the control intervals in keyed-sequence mode.