Method for Manipulating Deleted Members of a Partitioned-Data-Set File (01-Oct-2009)

Method for Manipulating Deleted Members of a Partitioned -Data-Set File

A Partitioned-Data-Set (PDS) file, in a mainframe computing system, is divided into sequentially organized members, each described by one or more directory entries. In an interactive mainframe environment, the Member-Selection-List (MSL) facility is enhanced to support the new MAPPDS (abbreviated to MAP) main command. When a PDS is displayed in "MAP mode", each deleted member is assigned a unique sequence number and a unique "synonym name" which consists of a 2-character prefix followed by the 6-character unique address, in the form of "TTTTRR", also known as "relative track address". TTTT are 4 hexadecimal digits of the position of the track relative to the first track allocated to the PDS. RR are 2 hexadecimal digits of the block position on the track. From the "MAP mode" display, a user can examine (browse/edit) the contents of
a deleted member and restore it with any specified (unique for the PDS) name. In one command, the user may restore a range (from-to sequence numbers) or all deleted members by giving them (by default) names equal to their "synonym names". This technique provides the user an easy mechanism to examine deleted members before deciding which deleted members should be restored. It also provides an expedited way to restore any number of deleted members, in a crisis situation, and postpone the tedious process of manipulating each one of them to a more convenient time. Once deleted members are restored, they can be manipulated by any of the existing on-line or batch PDS utility functions. The following logic is used to implement the MAPPDS command:

M1 The user selects a PDS to be displayed by the MSL facil...