Thanks to the people who corrected my mistake.  One can indeed have a
DLT4000 SE-SCSI on a 3000.  Indeed over the years, several people have
reported that you can even boot from a DLT4000 drive, even though this is
not officially supported.  I have never tried this, but I always thought
that perhaps one of the reasons you could boot from a 4000 but not a 7000 or
8000 was the fact the 4000 was NOT connected to a FWD-SCSI card but that it
was indeed connected via Fast SCSI-2.  Then again, people have reported
problems booting or updating on a DDS-3 using a DDS-1 tape or some such
thing.

Has anyone ever successfully booted from a DLT7000/8000?  Has anyone ever
successfully updated from a DLT4000?

As for LTO Vs SDLT, we have been testing LTO for over a year now and several
customers have it in production on either HP-UX or NT.  Finally, they are
working well.  We have experience only with the Ultrium format, not the
Accelis format.

The main attraction of the SDLT is the fact these drives will be able to
read from, but not write to, DLT4000/7000/8000 but only on DLT IV tapes.
And there are a lot of DLTs out there.  The DLT cartridge holds about 10%
more than the Ultrium cartridge, but the SDLT is slower than the Ultrium.


Denys

-----Original Message-----
From: HP-3000 Systems Discussion [mailto:[log in to unmask]]On Behalf Of
Jeff Woods
Sent: Saturday, May 04, 2002 5:01 AM
To: [log in to unmask]
Subject: Re: Thinking about a new tape drive

At  12:05 PM 5/2/2002, Chuck Ryan wrote:
>I have a 939ks-020 running 6.0pp2 with a DDS3 DAT drive. Currently backups
>are taking a little over 3 hours to run which is killing me when I try and
>squeeze my nightly production run around it.
>
>What would be a good upgrade to the DAT that my system can keep a steady
>stream of data into? I don't want to spend a ton of cash on a drive my
>3000 cannot keep busy.

DDS was a great technology 10 or 12 years ago.  Today, it's barely "good
enough".  DLT is the current sweet-spot in storage for most HP3000
systems.  And DLT4000 drives can be quite
affordable.  http://www.pricewatch.com shows me multiple vendors selling
DLT4000 drives from US$295.00 (a refurbished internal SE-SCSI, but with
free shipping) or US$300.00 (new, internal, SE-SCSI, plus $20.00 shipping)
and up.

BTW, the DLT4000 stores 20GB native (plus whatever compression it achieves,
depending on your data) at 1.5MB/s on a DLT-IV tape (presently about
US$51.00 *each* and up), but it stores 15GB native (plus compression) at
1.25MB/s on a DLT-IIIxt tape (presently about US$25.00 each).

[Warning:  Generalizations and simplifications abound in the following.]

DDS drives all seem to have a duty-cycle rating of "one tape per day".  DLT
drives have a duty cycle rating that basically says "use them all day long
if you want".  And it's been a few years but the last time I looked at the
specs DLT drives were literally 1000 times (3 orders of magnitude) less
likely to have unrecoverable data errors than DDS drives.

For folks looking for high-capacity drives, LTO/Ultrium drives look like
they might steal the limelight over DLT's successor, SDLT, but it's too
early to see which format will become dominant in that performance range.

--
Jeff Woods
[log in to unmask]
[log in to unmask]
Quintessential School Systems

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