Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!cs.utexas.edu!hellgate.utah.edu!jaguar.utah.edu!mike
From: mike%jaguar.utah.edu@cs.utah.edu (Mike Hibler)
Newsgroups: comp.sys.hp
Subject: Re: HPUX 7.0: Was Re: HP Optical When???
Message-ID: <1990Jan3.135237.4355@hellgate.utah.edu>
Date: 3 Jan 90 20:52:37 GMT
References: <13002@cit-vax.Caltech.Edu> <-286539972@hpcupt1.HP.COM>
Organization: University of Utah CS Dept
Lines: 27

In article <-286539972@hpcupt1.HP.COM> tsu@hpcupt1.HP.COM (Stanley Tsu) writes:
>Wayne Schlitt asks about MO:
>> 1)  do you have to physically remove the disc and flip it over to get,
>> or does it just act like two different discs?
>> 
>> 2)  how do you know which side is which?  
>
>You don't have to flip it over and you don't have to know which side 
>is which.  You mount each side as a file system.  Everything else is 
>functionally transparent to the user.  The driver takes care of all 
>the details.

Are you sure about this?  The "HP Series 6300 Model 650/A Rewritable Optical
Disk Drive User's Guide" says:

	"Because the disk drive contains only one read/write head
	assembly, the cartridge must be ejected, turned over, and
	re-inserted to access the second side."

Empirical evidence seems to back this up.  I have tried various minor device
numbers (with different volumes, different units) under HP-UX 6.5 and it
certainly appears that you cannot get to the other side.  Maybe its different
under 7.0?

I have seen documentation for the autochanger (20GB/A) which says that it
has two drive mechanisms and hence you could mount two "surfaces" at once.
Is that what you are refering to?