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From: ersys!drin@nro.cs.athabascau.ca (Adrian Smith)
Newsgroups: comp.sys.next
Subject: Re: NeXT's,Disks and Magic
Message-ID: <3V9615w164w@ersys.uucp>
Date: 29 Apr 91 15:29:37 GMT
References: <1991May01.034440.3213@lynx.CS.ORST.EDU>
Organization: Edmonton Remote Systems, Edmonton, AB, Canada
Lines: 38

pvo@sapphire.OCE.ORST.EDU (Paul O'Neill) writes:

> In article <1991Apr19.174923.4113@nntp-server.caltech.edu> anne@nntp-server.c
> >
> >We have an Andataco 1.2 GByte SCSI drive (Wren VII). When it 
> >boots it displays something like:
> >
> >Name of Disk and Model Number, as sd0 at sc0 target 1 lun 0
> >
> >There is NO disktab entry for this drive on my system (yet).
> >So what magical thing does the NeXT do to grab this information?
> 
> Who knows?  But it's pretty cute and it's the reason I've abandoned my
> project to collect and make available disktab entries for 3rd party drives.
> 

 
Isn't the machine just performing a low-level SCSI MODE SENSE command? 
I'm by no means a SCSI or NeXTpert, but in our travails of the past two 
months getting our external Micropolis up on a slab, we learned a few 
things about SCSI. According to what I understand, the machine toggles 
all devices on the bus (which must support rev 17b of the SCSI command 
set) with a MODE SENSE command. The devices then respond with their 
configuration, which includes their manufacturer name, their size in 
bytes, and a bunch of other goodies, which the NeXT mostly ignores. The 
slab then returns this information, along with the appropriate device 
numbers, sd numbers, and lun numbers.
 
(At least, I *think* that's how it works)
 
-drin
 
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Disclaimer: How can I speak for anyone? I don't *work* for anyone!!
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Adrian Smith             ersys!drin@nro.cs.athabascau.ca
Edmonton Remote Systems:  Serving Northern Alberta since 1982