Software Licensing Description Table
A Software Licensing Description Table ( SLIC ) is a digital signature in a computer's BIOS . In most cases, this is placed in the ACPI table by the manufacturer and does not represent executable code. PC manufacturers who sell OEM versions of Microsoft Windows and other Microsoft products with their products can use the SLIC to authenticate the license of Use the supplied software. Systems with a SLIC can be preactivated with a special OEM key without an internet connection. The key is checked and a corresponding verification for the executing hardware takes place via a certificate (in XML format) from the manufacturer together with the data in the SLIC. Pre-activation is only possible when reinstalling an unchanged Windows installation if the user has both the OEM key and the certificate. However, this is rarely the case, since in most cases a Windows installation that has already been modified by the manufacturer is provided with additional information (logo, support information) (mostly as a hidden partition on the hard drive or on an external medium such as a DVD), which already contains the certificate.
The SLIC table may also be important for the product activation of volume licenses from Windows using the KMS server: If the main board of the PC is an OEM board and the BIOS contains an ACPI-SLIC, then this must be intact, and a Windows on it -Marker must be set, otherwise activation via the KMS server will fail. In this case, a Windows volume license can only be activated using MAK instead of KMS (the respective volume license agreement may not allow this). If the SLIC table is defective or the Windows marker is missing, a BIOS upgrade to a standard BIOS without a SLIC table may help if one is available for the respective board (the basic license required by the license agreement is required for missing SLIC table can only be detected if required, but not entered in the BIOS).