VSE/VSAM for VM Version 6 Release 1 (5686-081)


VSE/VSAM (5686-081) was with withdrawn from marketing September 30, 2005.

VSE/VSAM (5686-081) ends service February 28, 2007.

  • Supports data compression for VSAM datasets
  • Improves system performance through hardware data compression
  • Reduces the processor time required to perform data compression
  • Requires no changes to application programs
  • Provides additional CMS virtual storage constraint relief below the 16MB line
  • Supports RAMAC** Array Family

Data compression for VSAM datasets

VSE/VSAM for VM Version 6 Release 1 supports data compression for VSAM datasets. You can easily select which datasets to store and hold in memory as compressed datasets, and which datasets should remain expanded. VSAM will exploit the S/390 hardware-assisted compression feature, if available on the processor; otherwise data compression is provided by software algorithms. Data compression provides the following benefits:

  • Requires significantly less disk space
  • Reduces channel traffic
  • Stores more data records within a 4GB file

    Most application programs can use data compression. No changes are required to realize the benefits of data compression and improved exploitation of 31-bit addressing. You only need to specify which files are to be compressed.

    Further 31-bit exploitation

    The exploitation of 31-bit addressing, which was introduced with VSE/VSAM Version 2 Release 2, is continued and provides additional CMS virtual storage constraint relief below the 16MB line. The following VSAM control blocks are moved above the 16MB line:

  • Place Holder (PLH)
  • Buffer Control Block (BCB)
  • Buffer Subpool Header (BSPH)
  • Buffer Header (BHD)

    Device Support - IBM RAMAC array family

    The IBM RAMAC Array DASD and Subsystem are high-performance RAID-5 (redundant array of independent disks -- level five) fault tolerant disk arrays. Earlier levels of VSE/VSAM for VM support both the RAMAC Array DASD, model 9391, and the RAMAC Array Subsystem, model 9394. VSE/VSAM for VM Version 6 Release 1 provides performance enhancements for the RAMAC Array DASD, model 9391.

    Overview of VSAM releases supported on VM releases

    VM Release VSE/VSAM
    VM/ESA Rel 1.5 (370 Feature) YesNo(*) No
    VM/ESA Rel 1.1 YesNo(*) No
    VM/ESA Rel 2.0YesNo(*)No
    VM/ESA Rel 2.1YesYesNo
    VM/ESA Rel 2.2 NoYesNo
    VM/ESA V2 Rel 1 No Yes Yes

    Note (*)

    When VSE/VSAM V2.2 or V6.1 or VSE/ESA is licensed, VSE/VSAM V2.1 can be ordered without charge.

    For additional information refer to IBM Announcement Letter 295-244 dated June 12, 1995.