Zoo Z format

Revision as of 17:07, 8 January 2021

Zoo Z format is an obscure compressed file format associated with the Zoo archive format. Though "Z format" seems to be its name, the Zoo source code often uses the word "Tiny" to refer to it.

The file naming convention is to replace the middle character of the extension with a "Z", much like Crunch format does.

One use for Z format is to efficiently copy a compressed member file from one Zoo archive to another, without decompressing and recompressing it.

The format is not necessarily portable. You should probably assume that a Z file can only be read by the same Zoo program that created it.

Z format is supported by Zoo 2.00 through 2.10 for DOS. (It might work in some earlier versions, or on other platforms, but that hasn't been verified.)

Z format is distinct from Zoo filter format.

Identification

The files produced by Zoo for DOS start with bytes fe 07 01.

Examples

These examples use DOS/DOSBox.

To create a Z format file

Given a file (example.txt) to compress, add it to a new temporary Zoo archive in the normal way:

> ZOO.EXE -add temp1.zoo example.txt
Zoo:  example.txt --  added

This creates temp1.zoo. The use the "z" option to extract it in "Z format":

> ZOO.EXE xz temp1.zoo example.txt
Zoo:  example.txt  ==> example.tzt  -- extracted

This creates example.tzt.

To decompress a Z format file

Given a file (example.tzt) in Z format, add it to a new temporary Zoo archive, and use the "z" option.

> ZOO.EXE az temp2.zoo example.tzt
Zoo:  example.txt  <== example.tzt -- added

Then extract it in the normal way:

> ZOO.EXE -extract temp2.zoo
Zoo:  example.txt  -- extracted

Software

• Zoo 2.10 for DOS