Basic System DMS PROC › SELECT Command › DSCL SELECT CRITERIA Field Name Descriptions › F1USEDT — Format-1 DSCB last used date (date format)

F1USEDT — Format-1 DSCB last used date (date format)

Comparison dates can be entered in any acceptable CA Disk format. For all data set processing, the value F1USEDT is set to the location indicated by the CA Disk system parameter DSCBLUSD in the format-1 DSCB of each data set or VSAM data component. For more details, see the system parameter description for DSCBLUSDnnnk in the Systems Guide. Missing or invalid values are assigned a value of 2155366. For more information, see Midnight "Rapid Aging" Problems. The last used date is not set in the format‑1 DSCB of VSAM index components.

Note: There are restrictions involving special expiration date and Year 2000 processing. For details, see Year 2000.

Under SCAN REALVOLS, the F1USEDT selection criteria will give increased performance over the USEDT selection criteria due to eliminating the need for CA Disk to access the catalog to retrieve the cluster name for VSAM components that do not meet this USEDT test.

This selection criteria is only valid when using SCAN REALVOLS, it is ignored for SCAN CAT, unlike the USEDT selection criteria, which is valid for both. Another difference between F1USEDT and USEDT selection criteria is that F1USEDT can allow your CA Disk job to process more quickly. This is because F1USEDT is set up to allow CA Disk to bypass some catalog processing.

For more information, see Midnight "Rapid Aging" Problems.