InstallShield installer archive

File Format
Name	InstallShield installer archive
Ontology	Electronic File Formats Archiving InstallShield installer archive
Extension(s)	.ex_

InstallShield installer archive is what we're calling the format of the _INST32I.EX_ file included in many Windows software distributions that use the InstallShield installation software. It appears to be a general-purpose compressed archive format, though it's not clear whether it has been used in any other way.

Disambiguation

It is not to be confused with InstallShield CAB, InstallShield Z, or MS-DOS installation compression.

Discussion

Based on unconfirmed information, the 16-bit SETUP.EXE program detects the user's platform, and extracts the appropriate platform-specific installer programs from _INST32I.EX_.

Identification

Files begin with bytes 2a ab 79 d8.

At offset 8 is the message "Copyright (c) 1990-1995 Stirling Technologies, Inc. All Rights Reserve".

Sample files

• Examples of software with such a file: [1], [2], [3]
• https://telparia.com/fileFormatSamples/archive/installShieldInstallerArchive/

Links

• FILExt page about the ??_ file extension pattern (Look for "InstallShield")