The Menu Interface (TSO/ISPF Panels) › Send MVS File To Another System Screen › Parameter Fields › Compression Mode

Compression Mode

This parameter specifies whether CA XCOM Data Transport compresses the data being transferred and decompresses it on the remote system. Compressing the data decreases the transmission time on lower‑speed lines.

YES

Provides Run‑Length Encoding (RLE) for blanks and binary zeros only.

NO

No data compression.

RLE

Provides complete Run‑Length Encoding for all characters.

COMPACT

Provides full RLE (as in RLE) plus a byte compaction scheme that is suitable for uppercase English text.

COMPACTL

Same as COMPACT, only the compaction scheme is most beneficial for lowercase English text.

LZSMALL

Lempel‑Ziv 77 compression with a small memory allocation scheme.

LZMEDIUM

Lempel‑Ziv 77 compression with a medium memory allocation scheme.

LZLARGE

Lempel‑Ziv 77 compression with a large memory allocation scheme.

HUFFMAN

Greater compression than RLE but not as much as the Lempel‑Ziv 77 modes.

LZRW3

General‑purpose algorithm that runs fast and gives reasonable compression.

ZLIB(n)

Greater compression than LZRW3 but less than LZSMALL, LZMEDIUM, and LZLARGE. The n value can be 1 through 9.

Default: YES

Notes:

• Specifying a value other than NO enables use of zIIP to perform the compression function. zIIP processing is used for compression only if the buffer size to compress is >= 4096 bytes. Specifying PACK=LENGTH and use a high MAXPACK value (>= 4096) for TCP/IP transfers or RUSIZE (>=4096) for SNA transfers to use zIIP.
• Not all compression modes are supported on all platforms.