Zip Built-in Function Notes

The ZIP BIFS utilise Info-ZIP's compression and uncompression 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 Internet/WWW sites, including Please refer to Info-ZIP's WWW site(s) for further 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:



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 GB

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.*).