Yet more questions/problems with Interactive UNIX

Raymond Nijssen raymond at ele.tue.nl
Fri Jul 27 21:03:21 AEST 1990


In article <1091 at ke4zv.UUCP> gary at ke4zv.UUCP (Gary Coffman) writes:
>In article <821 at digi.lonestar.org> kcantrel at digi.lonestar.org (Keith Cantrell) writes:
>>  2) In my system I have 4 meg of memory, but when I boot up I get the
>>     following message:  (The numbers are correct, I am not exactly sure
>>     what the verbiage said) 
>>
>>Real memory 3801088
>>Available memory 3031040
>>
>>     Is it really not seeing all of the 4 meg?  Am I correct in assuming
>>     that the reason why all the memory is not "Available" is that the
>>     kernel is taking a 770048 bytes?
>
>Another "frequently asked question", the memory area from 640k to 1024k
>is mapped out due to the PC architecture and the kernel takes over half
>a megabyte for itself. 

Very close. Not all of the 384k is lost. Depending on which chipset and
adapters you have, you can reclaim some of it. Generally, segments 0x0D and
0x0E are free. To make it available to unix, do the following:

- Find out which address ranges between 640k and 1M containing RAM do not
  contain ROM (main/vga/fdd) BIOS ROMs.
- Use the extended setup to enable these ranges.
- edit the file in /etc/conf/ .... (I can't recall it exactly) containing
  a line which looks like:
   0-640k:0;1M-4M:0;   (syntax is self-explanatory)
  and insert in case you want to reclaim the 128k mentioned above the range:
   832k-960k:0;
- rebuild the kernel.

I don't know if this works on all unixes. I use ISC on a 386DX with a non-NEAT
C&T chipset. It doesn't make much of a difference, but we've a saying here:
If you don't appreciate small things, you're not worth the big things.

______________________________________________________________________________
Raymond X.T. Nijssen  / Don't speak if you  / Oh VMS, please forgive me all
raymond at ele.tue.nl   / speak for yourself  / unfriendly things I said about you



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