[Ilugc] Does the Linux kernel rely upon BIOS?
- From: siva@xxxxxxxxxxx (Sivasankar Chander)
- Date: Fri Aug 6 08:31:19 2004
To what extent does the Linux kernel rely upon BIOS?
The kernel itself has very minimal dependancies on the BIOS. As of
2.4, only APM, ACPI and ISAPnP had any dependancy on ROM and/or ROM
extensions on the system board. A number of drivers including net,
scsi, RAID, etc. may have dependancies on ROM extensions on adapter
cards, but these are optional and can be config'ed out.
The only critical component that needs the BIOS, and only to boot
the kernel, is LILO or any other boot manager. Of course, this
isn't part of the kernel.
Check out the LinuxBIOS and ROMDOS projects for different approaches
to get around BIOS limitations. There are many trends in progress:
1) A minimal BIOS that only loads and starts something else (Open
Firmware, etc.).
2) A maximal BIOS that includes an OS in it, so it can correctly
recognize and configure a wide range of devices (LinuxBIOS, EFI, ...).
3) A (traditional closed-source) Award/AMI-like BIOS that is customized
for each board by modularization, allowing some degree of upgradability.
For instance, it is possible to upgrade an Award BIOS for i440LX/BX PII slot-1
boards to support later slot-1 or socket-370 Intel CPUs, including
all Celerons, PIIs and PIIIs up to the last Coppermine-core CPU.
(I'm inclined to stick with this tried-and-tested approach.)
-Siva
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