Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!well!nlane
From: nlane@well.sf.ca.us (Nathan D. Lane)
Newsgroups: comp.os.coherent
Subject: Re: Coherent questions
Message-ID: <25052@well.sf.ca.us>
Date: 26 May 91 19:32:11 GMT
References: <1991May24.033415.23636@risky.ecs.umass.edu>
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 52

In article <1991May24.033415.23636@risky.ecs.umass.edu> kimmel@ganzer.ecs.umass.edu (Mathew Kimmel) writes:
>I just bought Coherent 3.1.0 and I think it's the greatest thing ever.
>Imagine, Unix for $100!  Anyway, I have a couple of questions:
>
>1. Is it possible to access expanded memory from Coherent, a la EMM.SYS
>   in DOS?  It's kind of demoralizing to see Coherent boot with 455K
>   of memory free, when I have a megabyte of RAM.
>
>2. Is there an improved version of the shared memory driver and
>   corresponding lib functions that implements shmat() and shmdt()?
>   ftok() would be nice too, although I guess I could hack that myself.
>
>3. Is there any way at all to get around the 64K code segment limit?
>   Does this new kernel that keeps being mentioned on this group solve
>   the problem?
>
>Any and all answers would be much appreciated...
>
>-Matt
>
>
>-- 
>Matt Kimmel          University of Massachusetts          Amherst, Mass.
>
>Internet: kimmel@umvlsi.ecs.umass.edu              Bitnet: KIMMEL@UMAECS


Coherent questions:

1. EXPanded memory is not accessible to Coherent.  EXTended memory is.
Notice when you boot, the kernel gives a message "protected mode: mem=
xxxK" - when my machine boots I get 4276K or so.  The kernel does
take some memory for itself!  Also, I have a 512K ramdisk and a 256K
ramdisk that eat some memory too.  Generally, the memory on your
motherboard is either real or EXTended memory.  Memory on an add-in
card for DOS is EXPanded memory.  Check your manual.

2. 2. I don't know about the shared memory semaphores and the like.  They
are compatible enough for me and do what I need them to do and I haven't
heard of any enhancements for them.

3.  The 64K+64K is hard-coded in the kernel memory management routines
and the "p3" release kernel does not solve that problem.  So far, I haven't
run into the problem yet, even in my initial compile of tcp/ip (it
still won't link and still doesn't have any ethernet driver support,
though).  Look into accessing a large ramdisk - it's amazing what one
of those can do.

-Nathan Lane
Digital Technology Service
Santa Barbara
Authorized Esix Resllers