os/doc
3
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

BIOS detecting an absurdly low amount of memory is no longer a concern.

Browse source 
Approved by:	bcr (mentor)
This commit is contained in:
Eitan Adler 2012-10-29 04:28:28 +00:00
parent b92b172364
commit 69d37341d7
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=39834
1 changed files with 0 additions and 30 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

30
en_US.ISO8859-1/books/faq/book.xml
View file

@ -3140,36 +3140,6 @@ quit</programlisting>
</answer> </answer>
</qandaentry> </qandaentry>
<qandaentry>
<question id="reallybigram">
<para>Why does &os; only use 64&nbsp;MB of RAM when my system
has 128&nbsp;MB of RAM installed?</para>
</question>
<answer>
<para>Due to the manner in which &os; gets the memory size
from the BIOS, it can only detect 16&nbsp;bits worth of
Kbytes in size (65535&nbsp;Kbytes = 64&nbsp;MB) (or less...
some BIOSes peg the memory size to 16&nbsp;MB). If you have
more than 64&nbsp;MB, &os; will attempt to detect it;
however, the attempt may fail.</para>
<para>To work around this problem, you need to use the kernel
option specified below. There is a way to get complete
memory information from the BIOS, but we do not have room in
the bootblocks to do it. Someday when lack of room in the
bootblocks is fixed, we will use the extended BIOS functions
to get the full memory information... but for now we are
stuck with the kernel option.</para>
<programlisting>options MAXMEM=<replaceable>n</replaceable></programlisting>
<para>Where <replaceable>n</replaceable> is your memory in
Kilobytes. For a 128&nbsp;MB machine, you would want to use
<literal>131072</literal>.</para>
</answer>
</qandaentry>
<qandaentry> <qandaentry>
<question id="kmem-map-too-small"> <question id="kmem-map-too-small">
<para>My system has more than 1&nbsp;GB of RAM, and I'm <para>My system has more than 1&nbsp;GB of RAM, and I'm