Date: Fri, 20 Jan 95 10:03:00 PST From: Plyaskin Sergey <splyaski@cmp.com> To: "'freebsd-questions@freebsd.org'" <freebsd-questions@FreeBSD.org> Subject: Extra RAM? Message-ID: <2F1FFB10@mailgate.cmp.com>
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Hi everybody,
My question isn't really pure BSD question, but since I'm installing FreeBSD
2.0 on my machine, it is somehow related to FreeBSD :-)
I'm installing FreeBSD 2.0-950112-SNAP on an Mitac 486DX33 w/ EISA bus and
Phoenix 1.0 BIOS. CMOS reports 640k of base memory, 15MB of extended, and
20MB of extra RAM (in total 36MB). The Microsoft Diagnostics (msd) under DOS
detects only 15 MB (I think 1MB is relocated via BIOS). Windows NT
installations detects all 35 MB. FreeBSD only sees 15 MB.
I believe I've read somewhere that the amount of handled RAM depends on
which disk controller I use (ISA, or Local Bus). In case of ISA, it is
impossible to address more than 16MB because of DMA limitations. However, in
the FAQ for 2.0 I read:
1.5: I have 32MB of memory, should I expect any special problems?
No. FreeBSD 2.0 comes with bounce buffers which allows your
bus mastering controller access to greater than 16MB.
So, I have 3 questions:
1. Please someone explain what is *extra* RAM means. Is that expanded memory
or somethinfg else?
2. Right now, I temporarily use AHA 1542CF SCSI host adapter (ISA) but I
still have a hope to be able to use my EISA AHA 1740. Does it matter?
3. Anyway, how to make FreeBSD to see this extra memory?
Thanks in advance.
__________________________________________________________
Serge Plyaskin, CMP Publications splyaski@cmp.com
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