Windows 98 Driver CAB Files and Driver Caching

Microsoft Windows 98 relied on compressed Cabinet (.CAB) files to store system components and device drivers. When users added new hardware, Windows needed access to these files to complete installation. To avoid constantly prompting users to insert the Windows 98 installation CD-ROM, original equipment manufacturers (OEMs) and system administrators routinely cached the installation cabinet files directly to the local hard drive.

The Specific Driver CAB Files

In Windows 98, device drivers were not held in a single consolidated archive. Instead, they were distributed across sequentially numbered CAB files:

  • Hardware Drivers (DRIVER11.CAB through DRIVER18.CAB): Windows 98 First Edition (FE) primarily stored Plug and Play device drivers across DRIVER11.CAB through DRIVER18.CAB. In Windows 98 Second Edition (SE), this sequence expanded up to DRIVER22.CAB to accommodate additional hardware updates.
  • Network Drivers (NET7.CAB through NET10.CAB): Network interface card (NIC) drivers and associated networking protocols were packaged separately in the NET series cabinet files.
  • Core Subsystem Drivers (BASE4.CAB through BASE6.CAB): Foundational system components, display drivers, and baseline controllers were packed within the core system base archives.

How Driver Caching Worked in Windows 98

Unlike Windows 2000 and Windows XP, which automatically generated a dedicated Driver Cache\i386 directory on the system partition, Windows 98 did not automatically cache its driver CAB files during a standard retail installation. Instead, Windows 98 only stored the corresponding driver setup information files (.INF) inside the hidden C:\WINDOWS\INF directory.

To achieve functional driver caching, OEMs and administrators copied the setup cabinet files into a local folder on the hard drive prior to deployment. The standard caching path was typically:

  • C:\WINDOWS\OPTIONS\CABS
  • C:\WIN98

Once these .CAB files were located on the local disk, the Windows registry was configured to reference them. By setting the SourcePath string value in HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Setup to point to the local folder, Windows 98 automatically extracted files from DRIVER*.CAB and NET*.CAB whenever new hardware was detected, completely bypassing the need for physical media.