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From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: (was RAMSEY) 2nd SCSI controller
Message-ID: <20994@cbmvax.commodore.com>
Date: 27 Apr 91 06:01:23 GMT
References: <1991Apr12.002442.3871@minyos.xx.rmit.oz.au> <1991Apr23.010944.10776@ariel.unm.edu> <20874@cbmvax.commodore.com> <41588@cup.portal.com> <20912@cbmvax.commodore.com>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 49

In article <20912@cbmvax.commodore.com> daveh@cbmvax.commodore.com (Dave Haynie) writes:
>In article <41588@cup.portal.com> FelineGrace@cup.portal.com (Dana B Bourgeois) writes:
>>Dave, 
>
>Who, me?  Is this comp.sys.amiga.haynie or something :-)

	Heh, heh...

>Not usually.  For kicks, I ran an A3000 set up with A2091, Hardframe, and
>internal SCSI drive all going at once.  It ran for over two weeks, basically
>until I had to take it down for other purposes.

	Note: most a2000-era DMA scsi controllers either need an updated
rom, and/or nofastmem and/or a mask to restrict them to chip memory for
DMA.  When joanne dow said that microbotics wasn't doing an A3000 version,
I think she mainly meant they weren't doing a Z-III board, and without ability
to DMA anywhere it's pretty silly (for 99.99% of people) to put another
controller in an A3000 (just plug the drive into the A3000 - that's what
the hardblocks.h standard is about).  Because of that, they probably don't
plan to do new ROMs, though I'm sure you can get one up and running with
some trouble (which may include pulling a ram chip and running without
fastram...).

>From what I recall (software types feel free to correct this), the

	No problem, dave.  It's dangerous to let you HW types near SW, just
like it's dangerous to let us play with HW (as the 6" puff of smoke from a
power supply in my office yesterday attests to....)

>unit number in this case is a natural extension to scsi.device.  You normally
>get units from 0 through 7, corresponding to the traditional 8 physical SCSI
>devices.  The 10's place digit, though, can also range from 0 through 7,
>indicating logical unit numbers.  And finally, the 100's digit indicates which
>controller to address.  So unit 0 is physical unit 0, LUN 0, on the first 
>A2091, unit 100 is physical unit, LUN 0, on the second A2091.  Or something
>like that...

	Well, yes, but only if a single driver handles more than one board.
The a590/2091 driver handles only one board, and subsequent baords use
different device names (2nd.scsi.device, 3rd.scsi.device - don't blame me,
blame steve... ;-) ).

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.commodore.com  BIX: rjesup  
Disclaimer: Nothing I say is anything other than my personal opinion.
Thus spake the Master Ninjei: "To program a million-line operating system
is easy, to change a man's temperament is more difficult."
(From "The Zen of Programming")  ;-)