mainframe data compression

PRESSTO is a high-performance data compression package for IBM and program-compatible mainframes. It consists of record compression subroutines, as well as stand-alone file compression utilities. Transparent PRESSTO interfaces exist for most major databases.

With any compression technique there is a balance between storage saved, CPU time spent, and simplicity of use. The relative importance of these factors will vary from case to case. In view of this, PRESSTO offers four compression methods, each providing a different balance. Its weakest method offers the fastest execution times and simplicity of use, while still achieving good compresson on most files. Its strongest method offers compression ratios at least as good as any other currently available data compression product.

Unlike the mainframe ZIP programs, PRESSTO can compress and re-expand individual records as well as whole files. This makes its compression suitable for databases, archiving, and bulk data transmission.

PRESSTO is generally used to reduce disk space. Other uses include:


Files can be copied, archived, loaded and unloaded in compressed form. Throughput and CPU overhead for these functions are significantly improved as a result of this compression.

Data Transmission

Transmission times are reduced in proportion to the amount of compression obtained.


PRESSTO allows sort keys to be left uncompressed. Thus files can be sorted in compressed form, reducing sort times and sort work space.

Faster Throughput

PRESSTO can exempt selected fields from compression, thereby allowing retrieval and selective updating without compression/expansion overhead.

Data Security

A level of encryption is obtained as a by-product of compression.

Database interfaces

PRESSTO has acheived universal acceptance and is the data compression engine for the following database interfaces:

Product Name Marketed By
CA-Datacom Presspack Option CA Technologies, Inc.
CA-IDMS Presspack Option CA Technologies, Inc.
E-NET7 E-Net Corporation
PRESSTO Ironwood Software, Inc.
PRESSTO/IMS Ironwood Software, Inc.
PRESSTO/DB2 Ironwood Software, Inc.
Capacity Plus for VSAM Softworks, Inc.