Xref: utzoo comp.sys.ibm.pc:47119 comp.periphs.scsi:236
Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!cs.utexas.edu!usc!sdsu!crash!pnet01!jca
From: jca@pnet01.cts.com (John C. Archambeau)
Newsgroups: comp.sys.ibm.pc,comp.periphs.scsi
Subject: Re: MFM and SCSI together ?
Message-ID: <1969@crash.cts.com>
Date: 25 Mar 90 20:16:02 GMT
Sender: root@crash.cts.com
Organization: People-Net [pnet01], El Cajon CA
Lines: 79

iverson@xstor.UUCP (Tim Iverson) writes:
>>>tmottonen@cc.helsinki.fi writes:
>>>
>>> [paraphrased]	is it possible to have both a SCSI-adapter
>>>			and an MFM-controller in the same machine?
>>>
>>>    Thanks, Teemu.
>
>>jca@pnet01.cts.com (John C. Archambeau) replies:
>>
>>I don't know the idiosyncrasies of how a SCSI host adaptor works in a
>>PC/AT/386, but I'm willing to bet that the host adaptor and ST412/506 MFM
>>controller would have IRQ and port address wars ...
>>... I personally wouldn't do it.  With respect to controllers, the rule of
>>thumb is this...assume the manufacturer is stupid (or arrogant) and will not
>>allow any way for you to have more than one drive controller in your machine.
>>[... more mis-information deleted ...]
>I just couldn't pass this one up.  The scsi h/a would have IRQ and port wars
>with an ST506 controller?  This is pure bullshit.  Most scsi host adapters
>are *designed* to work in systems with existing ST506 controllers.  SCSI H/A
>manufacturers are not arrogant idiots trying to lock you into their own
>platform - for the most part they actually go out of their way to make sure
>that their boards are comptible with existing platforms.  Because of this,
>most H/As are easier to install and more reliable than their ST506
>counterparts.
>
>I have used Storage Dimensions' Data Cannon 800, Future Domain's TMC 830 and
>MCS 350, and Adaptec's 1540 derivatives extensively.  I have played with
>many others, but I do not posses sufficient information on them to provide
>a recomendation.  This is what I can attest to:
>
>	DC800	- very good for supported OSes.  SDI drivers support DOS
>		and Novel only.  Low overhead, but no 1st party DMA.  DOS
>		can run w/o SDI's SpeedStor driver, but you don't get added
>		features (Erasable Optical support, fast compare after write,
>		automatic reallocation of bad blocks on write, etc...).
>		[BTW: I wrote the SpeedStor driver for the DC800 :-)].
>
>	FutDom	- all products have serious bugs that require special driver
>		workarounds (verify function doesn't work, randomly pokes
>		bytes into memory under certain conditions, etc.)
>
>	Adaptec	- high overhead (1ms per command?), but has 1st party DMA
>		(good for UNIX - Novel support unknown) and is reliable.
>		On board BIOS supports only 2 drives, but Adaptec driver
>		will support 7.  SDI is working on adding 1540/1640 support
>		to SpeedStor.

I based my assertion on trying to hang an ESDI and ST412/506 controller
at the same time on the same machine.  Doesn't work too hot.  Also, I don't
care for Adaptec's products since they have lousy tech support.  You might
have good luck with them, but I personally stick with only Western Digital, is
the same true for the WD7000 SCSI Host Adaptor?  If so, then I'd love to hear
it.  Also, I didn't say that what I said was the gospel truth, just an
educated guess considering I know some of the horrors of SCSI and the IBM
compatable domain.  I am not convinced that it is fully implemented or
supported as well as it should be which is why I stay away from SCSI with
respect to IBM compatables.  I also based my assertion of the KISS philosophy
of system configuration (keep it simple, stupid).  Granted, you may be able to
do it, but also think from the practical standpoint, why would you want to? 
You have this slow drive that's running ST412/506 MFM and a SCSI controller
with possibly a Wren IV to VI running like a bat out of hell.  I wouldn't do
it just for the sake of system performance if I knew 100% in my mind that I
wasn't going to have any problems with the SCSI host adaptor and the IBM
compatable in question.

As for Novell, the only thing that is 100% Novell approved is Novell's DCB
board.  It's also the only thing that currently works with NetWare 386.
 
     // JCA

 /*
 **--------------------------------------------------------------------------*
 ** Flames  : /dev/null                     | My opinions are exactly that,
 ** ARPANET : crash!pnet01!jca@nosc.mil     | mine.  Bill Gates couldn't buy
 ** INTERNET: jca@pnet01.cts.com            | it, but he could rent it.  :)
 ** UUCP    : {nosc ucsd hplabs!hd-sdd}!crash!pnet01!jca
 **--------------------------------------------------------------------------*
 */