[comp.sys.next] Answer to External MO Disk Drive question.

mat@zeus.opt-sci.arizona.edu (Mat Watson) (06/28/91)

I have finally gotten what I consider to be an authoritative
answer on the 3rd party optical disk question.

First the question:
   Can I use a 3rd party SCSI optical drive on my NeXTstation?

Then the answer:
   Yes.

Another person I've talked to at NeXT (who impressed me as knowing
what he was talking about) has obtained and installed a Canon 512MB
external SCSI OD on his NeXT.  He told me the insallation process he
went through:

1. Connect the OD to the SCSI port using shielded (like Sun, unlike
   Mac) SCSI cables.
2. Boot the computer.
3. When you insert an unformatted optical disk into the Canon
   drive, an allert panel will pop up offering to initialize
   the disk.  Answer yes.

Done!

Important note: THE EXTERNAL CANON DRIVE IS UNABLE TO READ DISKS
WRITTEN WITH THE INTERAL CANON DRIVE FOUND ON THE CUBES.  THIS
INCLUDES SOFTWARE RELEASED BY NEXT ON MAGNETO-OPTICAL DISKS.  The low
level format for the internal disk is different than that used by the
newer external SCSI drives even though the optical drive unit itself
is essentially the same.


I hope this clears up any confusion people (like me) had about
being able to use 3rd party MO drives on their NeXTstations.

--Mat    mat@zeus.opt-sci.arizona.edu

izumi@mindseye.berkeley.edu (Izumi Ohzawa) (06/28/91)

In article <MAT.91Jun28063750@zeus.math.arizona.edu> 
mat@zeus.opt-sci.arizona.edu (Mat Watson) writes:
>
>Another person I've talked to at NeXT (who impressed me as knowing
>what he was talking about) has obtained and installed a Canon 512MB
>external SCSI OD on his NeXT.  He told me the insallation process he

[deleted...]
>
>Important note: THE EXTERNAL CANON DRIVE IS UNABLE TO READ DISKS
>WRITTEN WITH THE INTERAL CANON DRIVE FOUND ON THE CUBES.  THIS
>INCLUDES SOFTWARE RELEASED BY NEXT ON MAGNETO-OPTICAL DISKS.  The low
>level format for the internal disk is different than that used by the
>newer external SCSI drives even though the optical drive unit itself
>is essentially the same.

Does this incompatibility have to do with OD formatting
changes Canon made in Japanese NeXT OS 2.1J, rendering
2.1J OD incompatible with 2.1 system?  Someone from
Japan posted such a note in several postings back.

By any chance then, are OD's initialized on 2.1J compatible
with the Canon's external SCSI OD drive?
Is that why Canon changed OD filesystem for 2.1J?


Izumi Ohzawa             [ $@Bg_78^=;(J ]
USMail: University of California, 360 Minor Hall, Berkeley, CA 94720
Telephone: (415) 642-6440             Fax:  (415) 642-3323
Internet: izumi@violet.berkeley.edu   NeXTmail: izumi@pinoko.berkeley.edu 

izumi@mindseye.berkeley.edu (Izumi Ohzawa) (06/28/91)

In article <1991Jun28.145106.17420@agate.berkeley.edu> izumi@mindseye.berkeley.edu (Izumi Ohzawa) writes:
>In article <MAT.91Jun28063750@zeus.math.arizona.edu> 
>mat@zeus.opt-sci.arizona.edu (Mat Watson) writes:
>>
>>Another person I've talked to at NeXT (who impressed me as knowing
>>what he was talking about) has obtained and installed a Canon 512MB
>>external SCSI OD on his NeXT.  He told me the insallation process he
>
>[deleted...]
>>
>>Important note: THE EXTERNAL CANON DRIVE IS UNABLE TO READ DISKS
>>WRITTEN WITH THE INTERAL CANON DRIVE FOUND ON THE CUBES.  THIS
>>INCLUDES SOFTWARE RELEASED BY NEXT ON MAGNETO-OPTICAL DISKS.  The low
>>level format for the internal disk is different than that used by the
>>newer external SCSI drives even though the optical drive unit itself
>>is essentially the same.
>

I forgot to ask a few more things.
Are the media (optical disk cartriges) the same for this external
SCSI drive, and double sided OD's sold for NeXT?

Can they be made compatible if NeXT modifies their software?

I understand that magneto-optical's low-level format is
done at factory and not re-doable by user on OD drives.
If the difference is actually in low-level format, then
the media themselves may be incompatible.

Could someone clarify these points, and those in the previous posting?


Izumi Ohzawa             [ $@Bg_78^=;(J ]
USMail: University of California, 360 Minor Hall, Berkeley, CA 94720
Telephone: (415) 642-6440             Fax:  (415) 642-3323
Internet: izumi@violet.berkeley.edu   NeXTmail: izumi@pinoko.berkeley.edu 

mat@zeus.opt-sci.arizona.edu (Mat Watson) (06/29/91)

izumi@mindseye.berkeley.edu (Izumi Ohzawa)
> mat@zeus.opt-sci.arizona.edu (Mat Watson) writes:
> >
> >Important note: THE EXTERNAL CANON DRIVE IS UNABLE TO READ DISKS
> >WRITTEN WITH THE INTERNAL CANON DRIVE FOUND ON THE CUBES.  THIS
> >INCLUDES SOFTWARE RELEASED BY NEXT ON MAGNETO-OPTICAL DISKS.  The low
> >level format for the internal disk is different than that used by the
> >newer external SCSI drives even though the optical drive unit itself
> >is essentially the same.

> Does this incompatibility have to do with OD formatting
> changes Canon made in Japanese NeXT OS 2.1J, rendering
> 2.1J OD incompatible with 2.1 system?  Someone from
> Japan posted such a note in several postings back.

> By any chance then, are OD's initialized on 2.1J compatible
> with the Canon's external SCSI OD drive?
> Is that why Canon changed OD filesystem for 2.1J?

> I forgot to ask a few more things.
> Are the media (optical disk cartridges) the same for this external
> SCSI drive, and double sided OD's sold for NeXT?

> Can they be made compatible if NeXT modifies their software?

> I understand that magneto-optical's low-level format is
> done at factory and not re-doable by user on OD drives.
> If the difference is actually in low-level format, then
> the media themselves may be incompatible.

> Could someone clarify these points, and those in the previous posting?

The media in both cases is the same, with the exception that the newer
media is double sided.  The formatting differences arise from hardware
differences between disk controllers.  I'm told that NeXT had to use a
custom chip set to implement its internal optical drive system when it
did.  Now the disk controllers work of of the SCSI buss and use
different (standard?) chip sets, hence the different low level format.

As far as 2.1 vs. 2.1J goes, I would be quite surprised if that format
difference occurs at this level, if in both cases you use the same
type of drive (external SCSI for example). Just my own impression
here; I'm really not an expert on this.  More likely, the two differ
in file format (contents).  If this is the case, then formatting a
disk under one OS version produces a disk usable by the other, and
(in principle) one should be able to write software that converts
between the different file formats.

--Mat    mat@zeus.opt-sci.arizona.edu

lee@pipe.cs.wisc.edu (Soo Lee) (06/29/91)

In article <MAT.91Jun28063750@zeus.math.arizona.edu> mat@zeus.opt-sci.arizona.edu (Mat Watson) writes:
>
[stuff deleted]
>
>Important note: THE EXTERNAL CANON DRIVE IS UNABLE TO READ DISKS
>WRITTEN WITH THE INTERAL CANON DRIVE FOUND ON THE CUBES.  THIS

Of course they are different.

>INCLUDES SOFTWARE RELEASED BY NEXT ON MAGNETO-OPTICAL DISKS.  The low
>level format for the internal disk is different than that used by the
>newer external SCSI drives even though the optical drive unit itself
>is essentially the same.
    ~~~~~~~~~~~~~~~~~~~~
Great! Could you explain more specifics like connector pin layout, etc?

I believe that the base mechanism is the same but the control signals to
OD Drive(ODD) are different to make its performance better than SCSI
oriented installation. BTW, is there anyone verified this *wonderful*
experiment recently?
Could anyone tell me the *best* price of DS OD now?
>
>I hope this clears up any confusion people (like me) had about
>being able to use 3rd party MO drives on their NeXTstations.
>
>--Mat    mat@zeus.opt-sci.arizona.edu

Don't throw away your OD yet!

Soo	lee@cs.wisc.edu

erik@zeus.opt-sci.arizona.edu (Erik Schumacher) (06/29/91)

Nice summary, Mat. But how much is the dammned thing?? (Do you by me one??:-))
Erik

raymond@picasso.cs.unc.edu (Will Raymond) (06/30/91)

In article <1991Jun28.213641.25266@spool.cs.wisc.edu> lee@pipe.cs.wisc.edu (Soo Lee) writes:

>Could anyone tell me the *best* price of DS OD now?

I don't know if this is the best price but a local vendor is willing
to sell single DS OD's for $169 and for lots of 5-10 we have discussed
pricing of $155.

The DS OD's are used in a document system that Canon is pushing "bigtime".
The vendor said that Canon recently asked if vendors wanted lower prices on
DS OD's or more capacity with prices of OD's the same.

I told him I hope Canon goes with a cheaper , same capacity, DS OD.

I figure I'll buy one every three months for the next 1.5 years.
That oughta handle my backup problem for the life of my cube. ;-).

Will 



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