Chapter 10. The ZAP Service Program
Introduction
The ZAP service program (DMSZIP) executes
under the centrol of CMS via the ZAP command. It performs three functions for
LOADLIB, TITLlE, and MODULE files residing
on direct access storage devices. The functions are: • DUllp • Verify • Replace DUMP The dump function reads all or part of a
specified CSECT, or an entire lIember or • odule, formats the dump, and prints it at
the system printer (133-character lines,
each containing 32 bytes in hexadecimal,
plus the translation) or displays it at the terminal (SO-character lines, each
containing 16 bytes in hexadecimal, plus
the translaticn). If more than one CSECT is dUllped, the CSECT nalle appears before each dump. VERIFY The verify function compares sFecified data
with the data at a specified address in a If the data is the a replace operation (if one is specified) is
permitted; otherwise, an errcr message is
issued. REPLACE The replace function replaces data at a
specified address in a CSECT with the data
specified in a control The changed
record is then written back te the file • Chapter 10. The ZAP Serwice Proqra8 195

Method of Operation
The method of operation diagrams describe
the execution of the ZAP program and show
the processing associated with: • Verifying and replacing data in a CSECT. • Dumping a CSECT, member, or module.
The relationship of the method of
operation diagrams is shown in Figure 10-1. Diagram 10-1 describes the execution of
the ZAP program.
Diagram 10-2 shows the ZAP command and
control record processing.
Diagram 10-1
Overview of the
ZAP Program l Diagram 10-2
ZAP Initialization and Control Record Processing I .- • • • Diagram 10-3 describes tbe Frocessing of
the DUMP function.
Diagrams 10-4 and 10-5 describe the
processing for modifying data in a CSECT.
Diagrams 10-6 and 10-7 proper CSECT is located
modifying.
describe how the
for dumping or
Diagram 10-8 shows how a file is read
for dumping or modifying. Diagram 10-9 describes how a dump is
printed. • Diagram 10-3 Diagram 10-4 Diagram 10-4 Diagram 10-5 Diagram 10-5 DUMP Control BASE Control NAME Control END Control VER!VERIFYor Record Processing Record Processing Record Processi ng Record Processing REP Control Record Processing I • • Diagram 10-6 Diagram 10-8 Diagram 10-6 Diagram 10-8 Opening the Reading the Opening the Reading the File Text File Text 1 1 1 Diagram 10-7 Diagram 10-9 Diagram 10-7
Finding the Printing the Finding the CSECT Dump CSECT Figure 10-1. Key to the ZAP Program Method of operation Diagrams
196 IBM VM/370 Service Routines Program Logic