[wplug] 4GB Ram not seen by Linux kernel

[Tom Rhodes]

On Wed, 6 Feb 2008 23:36:19 -0500
"Mackenzie Morgan" <macoafi at gmail.com> wrote:

> You're running a 32bit kernel, then?  You could theoretically address all
> 4GB (and not a bit more) on 32bits, except that'd assume you had no drivers
> or firmware or anything.  It varies by hardware just how much you'll see on
> a 32bit OS.  Install 64bit, and you'll be good because that can
> address....umm....Wikipedia says 16 exbibytes (1 exbibyte = 1024 pebibytes,
> 1 pebibyte = 1024 tebibytes, 1 tebibyte = 1024 gibibytes).

Yea, it's 32-bit.  From what I can tell, PAE (physical address
extentions) exist in the kernel file (perhaps I could rebuild and
try) and should, theoretically, give me access to the larger
amount of RAM.  I was also thinking that the OS needs upgraded
to the 64-bit version; however, I need to double check and make
sure that the CPU will actually run it.  I doubt a 64-bit
version will run on a 32-bit CPU, but I've been told (may not
be correct) that a 64-bit CPU will run either or.  On that,
as I've not tested either, I reserve the right to be wrong.

Maybe it's likely that even though PAE seems enabled in the
source (seen with make menuconfig), it's not enabled in the
default kernel - a rebuild, as noted above, may just fix this
entire issue.

> 
> The IEEE caved to the hard drive manufacturers and decided 1024 megabytes
> are not a gigabyte.  1000 megabytes is a gigabyte.  We have to call them
> gibibytes if we mean 1024.  The "bi" is for binary.  That also means that
> when you have "kibibit" data transfer rates, it's kilo binary binary digit
> since "bit" is short for "binary digit".  Sounds stupid, eh?

This has bitten me so many times it's annoying.  It was yet
another mistake by the wonderful IEEE ... like a64l() et. al.

This becomes even more aggravating when you edit the partition
table in vi(1).

Anyway, luckily, they're not in eight bit bytes, but I couldn't
see the valid point since the last bit would be mostly unused
since a drive should never have a negative value, it'd always
start with 0.  :P


[Context lost from top posting, original mail below]

> 
> On Feb 6, 2008 7:51 PM, Tom Rhodes <trhodes at freebsd.org> wrote:
> 
> > Hi,
> >
> > I've got a machine here that doesn't like to see the 4GB RAM.  It
> > appears to only see 3/4th of it.
> >
> > New kernel does nothing.  This is the uname:
> >
> > Linux tornado 2.6.20-1.2320.fc5smp #1 SMP Tue Jun 12 19:40:16 EDT 2007
> > i686 i686 i386 GNU/Linux
> >
> > I've noticed that some Linux distro's have a BIGMEM kernel, but
> > am not sure if fc5 has it.  If so, is there a safe way to use
> > yum to get and install everything I need?  Thanks,
> >
> > --
> > Tom Rhodes
> > _______________________________________________
> > wplug mailing list
> > wplug at wplug.org
> > http://www.wplug.org/mailman/listinfo/wplug
> >
> 
> 
> 
> -- 
> Mackenzie Morgan
> Linux User #432169
> ACM Member #3445683
> http://ubuntulinuxtipstricks.blogspot.com <-my blog of Ubuntu stuff
> apt-get moo
> 


-- 
Tom Rhodes