heiser@tdw201.ed.ray.com (08/29/90)
I have a 386 machine running Unix (Esix); the system has an Adaptec
1542b SCSI controller and a CDC Wren IV drive. I also have an mfm
drive that I may take out of another machine, to be used as a backup
medium while I'm saving my pennies to buy a tapedrive.
Can I use an MFM card along with the SCSI card? I would want to keep
the scsi drive as the "primary drive" (LUN 0), and have the mfm
drive something after that. (is this possible?)
Anyone there with this config doing this? If so, what kind of mfm card
should I get, and how do you have your adaptec & mfm cards configured?
Thanks in advance,
Bill
--
Bill Heiser
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Other: heiser@world.std.com (Public Access Unix)rose@sunset.sedd.trw.com (08/29/90)
> Can I use an MFM card along with the SCSI card? I would want to keep > Bill Heiser In addition to MFM would there be any problem with an RLL drive and SCSI drive in the same computer. Also, why are SCSI drives so much cheaper (at least some are)? There's an 84 MB with kit for less than $400. Thanks Marc Rose
poffen@sj.ate.slb.com (Russ Poffenberger) (08/29/90)
In article <2247@sud509.ed.ray.com> heiser@tdw201.ed.ray.com writes: > >I have a 386 machine running Unix (Esix); the system has an Adaptec >1542b SCSI controller and a CDC Wren IV drive. I also have an mfm >drive that I may take out of another machine, to be used as a backup >medium while I'm saving my pennies to buy a tapedrive. > >Can I use an MFM card along with the SCSI card? I would want to keep >the scsi drive as the "primary drive" (LUN 0), and have the mfm >drive something after that. (is this possible?) > >Anyone there with this config doing this? If so, what kind of mfm card >should I get, and how do you have your adaptec & mfm cards configured? > >Thanks in advance, > >Bill > > Yes, the AHA 1542B can co-exist with an MFM controller, I have done it with a Western Digital WD1003. The only problem is that the 1542 can no longer be the boot drive, the MFM becomes the boot drive. This is not a limitation of the 1542, but because of the way the system BIOS works. The system BIOS will probe for things it knows about (ie MFM controllers, video cards, etc) before probing for BIOS extensions (such as the one on the 1542), this means that upon finding the MFM controller, it is assigned as the first hard disk, then later, as the 1542 BIOS is invoked, it will install any SCSI drives after the MFM drives. Just make sure that the BIOS addresses for the controllers are at different places. The 1542 can be re-configured, many MFM controllers cannot, so they sit at C800, you will probably want to put the 1542 at CC00 or D000. (check for video bios conflicts here). Russ Poffenberger DOMAIN: poffen@sj.ate.slb.com Schlumberger Technologies UUCP: {uunet,decwrl,amdahl}!sjsca4!poffen 1601 Technology Drive CIS: 72401,276 San Jose, Ca. 95110 (408)437-5254
rcollins@altos86.Altos.COM (Robert Collins) (08/30/90)
In article <2247@sud509.ed.ray.com> heiser@tdw201.ed.ray.com writes: > >Can I use an MFM card along with the SCSI card? I would want to keep >the scsi drive as the "primary drive" (LUN 0), and have the mfm >drive something after that. (is this possible?) > It is possible for SCSI and ST506 to coexist. If both controllers have adaptor ROMs then one will have to be jumpered so it doesn't interfere with the other. As for the SCSI LUN=0, that will have no effect on which device appears as device 80. If the ST506 is supported by the BIOS, then the MFM will appear first as device 80. This is because ST506 gets installed before adaptor ROMs. If however both the ST506 and SCSI are on cards that have adaptor ROMs, I think if you jumper the SCSI before the ST506, then the SCSI would be device 80. But, the monkey wrench is that I seriously doubt the ST506 code is on adaptor ROM -- as all 386 BIOSs support ST506. At my work, I wrote the entire SCSI code, and encorporated it into the Phoenix BIOS. I deviced a technique known here as "drive mapping" that allows you to map the SCSI as device 80 and make ST506 the next logical device. The answer to your question is that it is possible, but you would most likely have to modify the BIOS -- which would require the source code. -- "Worship the Lord your God, and serve him only." Mat. 4:10 Robert Collins UUCP: ...!sun!altos86!rcollins HOME: (408) 225-8002 WORK: (408) 432-6200 x4356