Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 18 Jan 1996 23:57:40 +0100 (MET)
From:      J Wunsch <j@uriah.heep.sax.de>
To:        dutchman@spase.nl (Kees Jan Koster)
Cc:        freebsd-hackers@FreeBSD.ORG
Subject:   Re: Above286 board
Message-ID:  <199601182257.XAA29440@uriah.heep.sax.de>
In-Reply-To: <199601181416.OAA01326@phobos.spase.nl> from "Kees Jan Koster" at Jan 18, 96 02:16:06 pm

next in thread | previous in thread | raw e-mail | index | archive | help
As Kees Jan Koster wrote:

[EMM board]

> I'd like to use it as a ram disk for FreeBSD, to have 2MB of fast swap
> space. But for that I'll have to write a device driver.
> 
>  1) Has anyone heard of this board? Does anyone use it? Is there
>     source of a device driver for it? (Any system)

EMM should be fairly well documented.  It's being addressed in
segments, where the active segment is being mapped at some address in
the ``ISA hole''.

>  2) Can a non-kernel process address the ISA memory space? To
>     experiment I'd like to be able to write to it's addresses without
>     rebuilding the kernel.

It could, via /dev/[k]mem.  An alternative is writing a kernel driver,
and hooking it into the kernel as an lkm.  See /usr/share/examples/lkm.

> The docs tell me that the board can be used to supply _conventional_
> memory via a setup program. That's odd. I didn't think an XT could
> address memory via the ISA bus? Or can it?

It can, in the ISA hole (0xa0000 ... 0xfffff), though fairly slow.

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199601182257.XAA29440>