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From: neese@adaptex.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: MFM and SCSI together ?
Message-ID: <25100008@adaptex>
Date: 26 Mar 90 16:16:00 GMT
References: <9@cc.helsinki.fi>
Lines: 88
Nf-ID: #R:cc.helsinki.fi:9:adaptex:25100008:000:4518
Nf-From: adaptex.UUCP!neese    Mar 26 10:16:00 1990


>>>>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.

I am sorry you and others have had tech support problems.  I am always
here for those who can afford to use E-mail for answers and questions.

>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.

I would watch out for IBM machines.  I know of one machine IBM makes
(PS/2 Model 30) that will not allow anything but an IBM drive/controller
to be used.  In this instance, the number of drives allowed to be used is
hard coded in the system BIOS.

>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.

The AHA-154xA Novell 286/386 drivers have been fully certified by Novell.
To my knowledge, no other SCSI drivers have been certified by Novell.


			Roy Neese
			Adaptec Central Field Applications Engineer
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