Browse Prior Art Database

USING EXCP TO WRITE AN EOF MARK TO A BSAM DATASET

IP.com Disclosure Number: IPCOM000014323D
Original Publication Date: 2001-Feb-01
Included in the Prior Art Database: 2003-Jun-19

Publishing Venue

IBM

Abstract

In IMS 410, users browse the spool data set via Time Sharing Option(TSO) as it is being written to by IMS. This support consists of writing an end of file (EOF) mark after each message is written to delineate the end of the current data. The EOF marks are overwritten by each write of a new record. The spool data sets are written to using the BSAM access method and the EOF marks are written by issuing a 'Close Type=T' (TCLOSE) macro. This support is especially useful to customer system programmers when the secondary master terminal (MTO) is assigned to a spool line. They can browse the active MTO spool data set to view MTO messages and analyze problems. This support has caused performance degradation in some cases because of the overhead of the 'Close Type=T'. Issuance of a 'Close Type=T' results in extra writes to the Volume Table of Contents(VTOC) to update the Format-1 Data Set Control Block(F1 DSCB), causing up to 4 I/O's to complete