Subject: Re: Another changer, another changer problem
To: NetBSD-current Discussion List <>
From: Greg A. Woods <>
List: current-users
Date: 10/12/1998 22:02:02
[ On Sat, October 10, 1998 at 00:48:03 (-0700), John Nemeth wrote: ]
> Subject: Re: Another changer, another changer problem
> } > tagged onto the end of the list.  Why should I have to remember to use
> } > 'mount /dev/dsk/c1t2d0 /cdrom' (taken from an HP-UX system just now; I
> } > had to use ioscan to remind myself where the cdrom drive is) as
> } > opposed to simply 'mount /dev/cd0a /cdrom' in order to view a cdrom?
> } 
> } That begs the question:  Why didn't you just type "mount /cdrom"?????
> } 
> } Surely c1t2d0 is no more meaningful to a naive user than cd0a is.  The
>      No, but the latter is a heck of a lot easier to type and
> remember.  And, I would argue the latter is more meaningful, since it
> contains the string "cd" and that's the kind of device they want;
> whereas, the former is just a collection of random characters.

And if you have 15 SCSI buses with a total of 30-odd CD-ROM devices and
you're just trying to find the one on the third bus that's attached to
the single drive set to target 6 beside your console?  I.e. c3t6d0s0
vs. cd17a, or whatever.

(yes, finding which cable is the "third" bus is still a trick, but let's
not digress too far again...)

>      I wouldn't use any version of UNIX to run a CO.  This is a hard
> real-time application, which requires a real-time OS.  The only CO's
> with which I have direct experience is Northern Telecom DSS'es.  I
> couldn't tell you what runs a 5ESS, but I doubt very much that it is
> UNIX.  I also doubt that UNIX runs their billing systems; MVS is a far
> more likely answer.  Until recently, there weren't very many UNIX
> boxes that had the horsepower to do the job.  Do you have any
> references to back up your claims?

I guess you've never seen a 3B2/4000 in operation.  In a common
configuration it might have four main CPU boards, each with four CPUs
running at probably 8 MIPS each (not bad for their day), and on top of
that it used several 3B2/600's (quite beefy machines on their own)
internally for disk controllers.  I don't remember the
transactions/second it ran with Tuxedo, but it wasn't slow.  It sucked
rocks vs. it's price as a general purpose computing machine, but that's
because it wasn't designed as one.

I don't know all the details on the various incarnations of 5ESS
switches and the computers used to control them, but they definitely
used 3B processors and something at least distantly related to Unix.
Even the secound round of Unix articles in Bell System Technical Journal
talked about some of this stuff (my copies are still in boxes or I'd
have looked up the details).

(BTW, I didn't mean by "biling systems" the machine actually tracking
customer data and printed bills for mailing, but rather the machines
that collate call detail records and thus feed the bill printing

							Greg A. Woods

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