[comp.os.minix] Will Minix 1.5.10 work on an XT

eb@beach.cis.ufl.edu (Edmund Bernard) (08/22/90)

Hello,

	I'm wondering if Minix 1.5.10 can operate on an IBM XT with an 8088.
If so, how can I get it up and running?  I've seen it come up on a Zenith 386
in protected mode.  Does this imply that it won't come up on the 8088.


Thanks in advance!!

Eddie Bernard
eb@beach.cis.ufl.edu

windy@charm.informatik.rwth-aachen.de (Andrew John Stuart Miller) (08/22/90)

eb@beach.cis.ufl.edu (Edmund Bernard) writes:

>Hello,

>	I'm wondering if Minix 1.5.10 can operate on an IBM XT with an 8088.
>If so, how can I get it up and running?  I've seen it come up on a Zenith 386
>in protected mode.  Does this imply that it won't come up on the 8088.


>Thanks in advance!!

>Eddie Bernard
>eb@beach.cis.ufl.edu

No - minix runs in protected mode if it is possible, othewise in real mode!

I have 1.5.10 up and running on my 8088 compatible (NEC V20 to be more accurate)
Configuration 8MHZ 1Mb, though only 640K currently useful to Minix - 8088
cannot address more than a megabyte. IBMs silly addressing scheme basically
forbids all programs and data fom being at addresses between 640K and 1M. DOS
can only manage store in big coniguous blocks, if you have ever unloaded
"memory resident" programs from a PC in the wrong order you will know what I
mean! If you have a 286 or better, then Minix will make use of store whereever
it is, as long as it is not sideways. I have 384k of sideways store, and want
to write a device driver to put /dev/ram, the ram disk there, freeing up memory
elsewhere under 640k and giving me a larger ramdisk than otherwise - faster
compiling!

We also have a 386 machine, which is used to generate Kernels and for the more 
complicated development work. If you want to use minix seriously then an 8MHZ V20 
is adequate procesor power. Since installing minix, the speed of operation has
increaasesed, as minix does not waste time doing buisy waits. I currently have a 20Mb
65ms Winchester, which is now three years old, and showing its age --- the minix 
file system is fussier (and therefore safer) than DOS's, and refuses to talk to
half the disk due to too may retries (DOS Didn't care a damn!) 10Mb is enough to
work with if you have to. With this slow disk, the CPU spends a great deal of
time waiting! My friends in the DOS world think that im am crazy to want to
add a faster disk to an XT as "The machine can't use all that speed" -- it can!
DOS just does loads of bussy wait whilst the DMA hardware transfers the data to
or from disk. Minix just gives the otherwise lost time to any other tasks in
the system.

An 8088 or 8086 (or better V20 or V30) can really be used as a development
system for a single user to learn about operating systems, ot to work on at
home, especially with a hard disk. I also have a VT100 terminal connected!

Don't think that installing  minix is as easy as installing DOS. It isn't, but
it also works much better than DOS: you pays your money, you takes your choice.

Happy hacking everyone

	Andrew Miller

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snail: Ruetscherstr 165  D-5100 Aachen
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ast@cs.vu.nl (Andy Tanenbaum) (08/24/90)

In article <24170@uflorida.cis.ufl.EDU> eb@beach.cis.ufl.edu () writes:
>	I'm wondering if Minix 1.5.10 can operate on an IBM XT with an 8088.

Yes. It works fine on a plain vanilla 8088.  It figures out the CPU type
by itself by sniffing around.

Andy Tanenbaum (ast@cs.vu.nl)