Newsgroups: comp.os.minix
Subject: Re: Minix on Sun?
References: <6FrzSGA6SkE3EwCh@dbqa.demon.co.uk> <slrn7h4jfc.gbg.pino+comp_os_minix@mud.stack.nl> <37128886.0@isc-newsserver.isc.rit.edu> <+Q3RDBA983E3EwzB@dbqa.demon.co.uk>
Organization: Rochester Institute of Technology, Rochester, NY
From: aje9383@osfmail.isc.rit.edu (Andrew Erickson)
NNTP-Posting-Host: grace.isc.rit.edu
X-Original-NNTP-Posting-Host: grace.isc.rit.edu
Message-ID: <3713902c.0@isc-newsserver.isc.rit.edu>
Date: 13 Apr 1999 14:42:52 -0500
X-Trace: 13 Apr 1999 14:42:52 -0500, grace.isc.rit.edu
Lines: 81
XPident: Unknown
X-Original-NNTP-Posting-Host: 129.21.3.100
XPident: Unknown
Path: star.cs.vu.nl!newsfeed.amsterdam.nl.net!sun4nl!newspump.monmouth.com!newspeer.monmouth.com!netnews.com!news-peer1.sprintlink.net!news-in-west1.sprintlink.net!news.sprintlink.net!isc-newsserver.isc.rit.edu!aje9383
Xref: star.cs.vu.nl comp.os.minix:35226

In article <+Q3RDBA983E3EwzB@dbqa.demon.co.uk>,
Tom Bird  <hamster@nospam.demon.co.uk> wrote:
>In article <37128886.0@isc-newsserver.isc.rit.edu>, Andrew Erickson
><aje9383@osfmail.isc.rit.edu> writes
>>
>>Is that the FreeBSD (or maybe NetBSD--I get them confused) X terminal setup? 
>>If so, ordinary [Free|Net]BSD should work, too.  (At any rate, their is an
>>apparently stable port).
>
>The X server I have currently appears to be based around SunOS 4.1.1
>although I hear there is a FreeBSD that should run on the native
>hardware.  I do have a SCSI box for mounting hard disks and tape drives
>in although the SCSI hard drive in it appears to be deader than a dead
>thing.  There was also a rather curious looking piece of hardware that
>looked to be a SCSI -> MFM converter.  I have an old MFM hard drive from
>my similarly aged IBM XT model 286 but that didn't work either.  And
>yes, the SCSI bus was properly terminated.  The hard drive didn't work
>on my Diamond FirePort 40 either.  It wouldn't even detect it.  I should
>be able to install it over NFS though.

Hmmm...probably about time to get a (relatively) cheap little SCSI drive. 
Around here, at least, it's fairly easy to find used ones for very little
money (under $50 US, or...erm...25ish pounds?  Don't have the exchange rate
handy.)

NetBSD is the BSD I was thinking of--http://www.netbsd.org/

>
>>>> I have no idea what CPU these things use.
>>>
>>>a Motorola 68030, IIRC.
>>
>>Close--a 68020 with a 68881 FPU and a SUN/3 MMU (which is quite unlike a
>>Motorola MMU).  The /110 runs at 16.67 MHz, is rated at 2 MIPS, and has a
>>memory cycle time of 270 ns.  (This from the Sun-3 Product Family
>>Configuration Guide, dated October, 1986.)
>
>Sounds right, this Sun is dated December 1986.
>
>>From a software standpoint, the MMU is the only real difference between a
>>SUN 3 and a 68030-based system.  For user-level programs, this is not an
>>issue.
>
>What does MMU stand for?

"Memory Management Unit"; the device which allows paging and memory
protection.  Essentially, it converts virtual addresses from a process to
physical address in RAM.

>>Minix can run under SunOS (or could at one point) but has not been ported to
>>the bare SUN 3 hardware.
>
>But since there are Mac and (afaik) Amiga versions, it shouldn't be too
>difficult, right...?  If attempting something like that, I suppose it
>would be a good idea to get the Minix book.  Besides, it'll be useful
>for the university course I hope to get into next year.

Yes, the book would be essential.  You'd also need some sort of technical
information on the hardware, which is sometimes difficult to find.  (For a
SUN 3, probably not impossible to find--unlike, say, some things about
Macintosh computers.)

No, the port would not be extremely easy (although certainly not
impossible).  You would need to write drivers for all the hardware you
wanted supported--at least the keyboard, disk, and display.  You'd also
probably want to write in support for the MMU on some level to avoid having
to use shadowing.

Targeting a different processor is only one minor detail in porting Minix;
the drivers are generally the biggest hurdle.  Switching processors merely
means using a different C compiler (and rewriting a small amount of
assembly, but that often needs tweaking, anyhow).

The Mac, and AFAIK Amiga, ports are only at version 1.5; the rest of the
world is using 2.0.  If you do port, you probably would want to start from
the Amiga setup, as MacMinix makes heavy use of MacOS.

>
>TB

--Andrew Erickson, aje9383@grace.isc.rit.edu
