car@trux.UUCP (Chris Rende) (12/19/89)
Summary: Request for information regarding the similtaneous use of 2 hard
disk controllers with 4 hard disks on an XT clone. One controller
and 2 hard disks for DOS - another controller and 2 hard disks for
Minix.
I have a XT clone, MS-DOS 3.2, Minix 1.2 and the following HD configurations:
HD set #1 (DOS): OMTI 5510 HD ctrl, (2) ST-213 10Mb hard disks
HD set #2 (Minix): OMTI 5520 HD ctrl, (1) ST-213 10Mb disk, (1) ST-412 10Mb disk
When I want to run DOS, I plug in the HD controller for HD set #1.
When I want to run Minix, I plug in the HD controller for HD set #2.
Problem: I don't want to keep swapping controllers.
Ray of hope: My HD manual says that the controller's port base can be changed
from 320 to 324, 328, etc.... And that the BIOS ROM can be changed from
C800 to CA00.
Can I change the 2nd controller to use 324 and CA00 and install it?
Will DOS leave the second one alone? (Especially since the disks on
the 2nd controller won't be DOS disks).
Of course I'll have to change the Minix HD driver to use the new base of 324.
Since only one controller will be active for the particular OS, there
shouldn't be any problems with DRQ3 being shared... right? (Each OS would
know how to talk to the appropriate controller when necessary).
car.
--
Christopher A. Rende Central Cartage (Nixdorf/Pyramid/SysVR2/BSD4.3)
uunet!edsews!rphroy!trux!car Multics,DTSS,Unix,Shortwave,Scanners,StarTrek
trux!car@uunet.uu.net Minix 1.2,PC/XT,Mac+,TRS-80 Model I,1802 ELF
"I don't ever remember forgetting anything." - Chris Rendeoverby@plains.UUCP (Glen Overby) (12/19/89)
[I am following up to the net rather than sender since I am asking a question myself] In article <341@trux.UUCP> car@trux.UUCP (Chris Rende) writes: >Summary: Request for information regarding the similtaneous use of 2 hard > disk controllers with 4 hard disks on an XT clone. One controller > and 2 hard disks for DOS - another controller and 2 hard disks for > Minix. I was looking at doing this the other day. If you put the second controler at it's alternate address and on a different interrupt line, then disable the ROM, DOS will never know about it. You will then have to modify xt_wini.c to use the other address and interrupt. I think you will only have to change the #defines, but it could be more subtile than that. It will be a lot more work to support both controlers, but I'd like to see it. Becuase all IBM PC interrupt lines are driven with totem-pole drivers rather than open-collector, you will still not be able to have both controlers on the same interrupt line. It may work, but you will eventually burn out one or both of the driver chips. The ROM in your second controler will be pretty worthless since (I assume) it will assume you want the first drive (0x320), so just disable it. Another problem is that xt_wini (since 1.3, if not earlier) only supports one drive! NEITHER drive is accessable if you change the number of drives in xt_wini to 2. I found this out last night when, after jury-riging the second drive outside the case and accidently grounding out the power supply (fireworks!). At_wini supports two drives (I've seen it work), but that controler is sufficently different that simply stealing code did not work. Did Minix work with the OMTI controler at all?? I tried getting Minix to go with an OMTI a few years ago, but gave up... -- Glen Overby <overby@plains.nodak.edu> uunet!plains!overby (UUCP) ncoverby@ndsuvax, overby@plains (Bitnet)
car@trux.UUCP (Chris Rende) (12/19/89)
In article <3012@plains.UUCP>, overby@plains.UUCP (Glen Overby) writes: > In article <341@trux.UUCP> car@trux.UUCP (Chris Rende) writes: > >Summary: Request for information regarding the similtaneous use of 2 hard > > disk controllers with 4 hard disks on an XT clone. One controller > > and 2 hard disks for DOS - another controller and 2 hard disks for > > Minix. > > I was looking at doing this the other day. If you put the second controler > at it's alternate address and on a different interrupt line, then disable > the ROM, DOS will never know about it. I was just going to use one interrupt line (and one DMA request line: DRQ3) in hopes that everything is open collector. Since the OMTI controller has jumpers to change the I/O port base address and the BIOS ROM base address I would <hope> that they intended to support multiple HD controllers and used open collector drivers. I'll have to give OMTI a call and ask them about this... > You will then have to modify xt_wini.c to use the other address and > interrupt. I think you will only have to change the #defines, but it could > be more subtile than that. It will be a lot more work to support both > controlers, but I'd like to see it. I'm not intending to support both controllers under Minix - just one contoller. But, I need Minix to ignore the controller with the DOS disks. > Becuase all IBM PC interrupt lines are driven with totem-pole drivers rather > than open-collector, you will still not be able to have both controlers on > the same interrupt line. It may work, but you will eventually burn out one > or both of the driver chips. See above. > The ROM in your second controler will be pretty worthless since (I assume) > it will assume you want the first drive (0x320), so just disable it. Yeah, I'll move it to CA000 and hope that it doesn't get in the way. Since I'm using xt_wini and not relying on the BIOS ROM for the HD geometry information, I can do with out the ROM. > Another problem is that xt_wini (since 1.3, if not earlier) only supports one > drive! NEITHER drive is accessable if you change the number of drives in > xt_wini to 2. I found this out last night when, after jury-riging the > second drive outside the case and accidently grounding out the power supply > (fireworks!). At_wini supports two drives (I've seen it work), but that > controler is sufficently different that simply stealing code did not work. Hm. I'm running Minix 1.2 with xt_wini and using 2 hard drives. One is a ST-213 (10Mb: 612 cyl, 2 heads) and the other is a ST-412 (10Mb: 306 cyl, 4 heads). It works great! It is very gratifying to do something like: mount /dev/hd6 /usr mount /dev/hd1 /user cd /user readfs -l /dev/hd6 And watch all the data move from hd6 to hd1 - works great! > Did Minix work with the OMTI controler at all?? I tried getting Minix to go > with an OMTI a few years ago, but gave up... Yes, Minix 1.2 xt_wini worked with my OMTI 5510 controller (with 2 drives - I think both drives have to have the same geometry) and Minix 1.2 xt_wini works with my OMTI 5520 controller (with 2 drives, different geometry, needed a couple small patches to xt_wini). > Glen Overby <overby@plains.nodak.edu> > uunet!plains!overby (UUCP) ncoverby@ndsuvax, overby@plains (Bitnet) car. -- Christopher A. Rende Central Cartage (Nixdorf/Pyramid/SysVR2/BSD4.3) uunet!edsews!rphroy!trux!car Multics,DTSS,Unix,Shortwave,Scanners,StarTrek trux!car@uunet.uu.net Minix 1.2,PC/XT,Mac+,TRS-80 Model I,1802 ELF "I don't ever remember forgetting anything." - Chris Rende