14.2.3 Zip Built-in Functions

The ZIP BIFS utilize Info-ZIP's compression and decompression utilities via unzip32.dll, zip32.dll and unzipsfx.exe. Info-ZIP's software (Zip, UnZip and related utilities) is free and can be obtained as source code or executables from info zip. Also refer to Info-zip's web site for information on the .ZIP file format and functionality of zip and unzip.

PKWARE introduced the .ZIP file format in 1989. According to strict interpretation of the zipfile specification (as specified by PKWARE and amended by Info-ZIP), the following limits apply to all zipfile archives:

Limit Maximum

Number of Files


Uncompressed size of a single file

4 GB

Compressed size of a single file

4 GB

Maximum size of archive that can be created

256 TB

Maximum size of archive that can be extracted

4 GB


Using the wildcard * in file specifications: If you want to include (or ignore) all files that are named readme or readme.* then add readme* to the list (rather than readme.*).