Allocating Datacom data sets using DSNTYPE=LARGE

Products

• Datacom
• DATACOM - AD
• Datacom/AD

Issue/Introduction

Does Datacom support allocating large format sequential data sets greater than 65,535 tracks with DSNTYPE=LARGE?

Environment

Datacom/AD 14.0 and higher

Resolution

Datacom supports the use of large format sequential data sets which can be larger than 65,535 tracks  (4369 cylinders) per volume. 

Allocate a large format data set by using the DSNTYPE=LARGE parameter on the DD statement in the JCL. 

However, extended format data sets defined with DSNTYPE=EXT, DSNTYPE=EXTREQ or DSNTYPE=EXTPREF  are not supported because they cannot be accessed using the EXCP access method which is used by Datacom.