While trying to help new users install Linux, questions relating to the
>64MB RAM problem occurs quite frequently. Although the solution is well documented, the reason why it occurs is not.
While trying to find an explanation, I found this at
http://www.meangene.com/notes/memory.html
"Just FYI, the problem /w Linux not knowing the real amount of memory is
due to a BIOS limitation, and not a software limitation. The BIOS can
not properly report memory over 64MB, and this information must be known
before the kernel is loaded into memory. Hence, this info is passed to
the kernel as a boot command line argument, so that the reliability of
the system will not be dependent on a flaky BIOS report."
But I contrast I found this in the Brief Linux FAQ
(http://metalab.unc.edu/pub/Linux/docs/faqs/BLFAQ)
"Linux uses the BIOS to detect the amount of available RAM. At the
present time there are two separate function calls available to do the
job. Any version of Linux prior to 2.1.x uses the old call which is
limited to 64M.
The newer call (used by 95/NT and Linux 2.1.x) can return more than 64M.
This problem should be fixed in the next stable release of the Linux
kernel
(release 2.2.0)."
And I know some users who still have this problem using kernel 2.2, so
why does this bug occur?
I say bug because new users are convinced that this is a Linux bug,
since Windows 95 or greater detects all of their RAM just fine.
So, which is it? A Linux problem or a BIOS problem. If it is a BIOS
problem, how does Windows properly detect the amount of RAM.
I've also heard that 2.4 solves this problems. How hard would it be to
"back-port" the solution to 2.2?
"Why?", you may ask.
Should the correct detection of RAM depend on the user? If so, then why
fix the problem in 2.4?
Answers to these questions will be relayed to new users in the form of a
FAQ, so hopefully they will only have to be answered once.
Please CC: me (tcrompton@home.com) any responses to this post.
Thank you for your time.
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