Actually, that's incorrect. Board manufacturers are required, at a minimum, to provide the Baseboard information. As for the system-level strings, most board manufacturers provide tools (or a capability via BIOS Setup) that will allow (at a minimum) certain system and chassis strings to be entered.
Note: when looking for these tools, there's something to understand: When it was originally invented, Intel called this table the DMIBIOS structure table. This name was chosen so that DMI tools could get the information about the hardware that they needed to document the system properly. Later on, when Intel released this table into the public domain, the industry working group (and eventually, the DMTF) that took over its control renamed it to the SMBIOS (System Management BIOS) structure table. Because of the original name, however, many of the tools used to query or manage this structure table still use the old DMI name. This includes the standard tool on Linux, for example. It is still referred to as DMI in some of the board manufacturer's BIOSs as well.
Hope this helps,
...S
