Re: Writing multiple CD volumes for the AS/400?

[Brad Jensen <brad@xxxxxxxxxxx>]

Peter Dow wrote:
>
> Hi Brad,
>
> Maybe I misunderstood something -- I had the impression your product mimics
> a tape drive.  In which case the AS400 only sees what you let it see, and if
> you unzip the data before passing it to the AS400, how would it know it's
> zipped?

I can do that already. People are telling that theere is an
unzip function on the AS/400, which does not do me any good,
since I won't be zipping or unzipping on the AS/400.

The problem seems to be that you can restore from a multiple-cd
save.

> What exactly does your product do again?

It does pretty much what you think. It looks like a tape file
device that you can do SAVLIBs to, with a large hard drive area
so you can mimick the functions of a tape library system. tape
systems generally compress at 2 to 1, and the data compress
option does up to 2 to 1, whereas the PC can compress up to 16
to 1.

So you can create a CD that could store (theoretically) up to
10.8 GB of data from an AS/400, and duplicate it in five
minutes, for about 50 cents. The media is cheap enough that you
don't have to reuses it, and compact enough to store, and longer
life than anything magnetic. It's feasible to have duplicate
backups, or triplicate backups, with offsite storage.

And it should run faster than a speeding tape drive. Most of the
time you will be backing up to RAM, not disk, and then writing
to disk while the AS/400 is 'thinking'. No rewind, no file mark
seek time.

And of course, no tape swapping, and no tape library robotics to
break. Mechanical stuff breaks much more often than electronic
stuff. Unattended backups - you can even load different 'virtual
tape volumes'on the VTS with CL. Come in the next morning and
write CDs.

There's no tape head to get dirty or out of alignement, no tapes
to break, or accidentally reuse. Like the guy said about the EMC
memory - what are the consequences of it breaking once? The most
likely thing to happen is that you will lose backuop  data
because a tape goes bad, or the head goes bad, or you
accidentally reuse a tape before the exiration date, or you use
it after the expiration date, but while you still really needed
it. VTS with CD output avoides this.

And of course, there is no reason that VTS system couldn't
attach between your AS/400 and your SCSI tape drive - like a
giant tape buffer. Write to the VTS in a fraction of the time,
then write multiple backup tape copies to the tape drive. If the
VTS ever goes bad, reconnect the tape drive directly to the
AS/400. (You won't want to restore from the mag tape directly
unless you have to - the VTS will be much faster on the restore
because there is no seek, mutliple volume load, or rewind times.

The problem is the people who want to restore from the CD to the
AS/400 using the AS/400 CD drive, instead of the virtual tape
system drive. You are correct in thinking that you can put the
compressed CD int he virtual tape system CD drive, read it, and
the VTS decompresses on the fly and present the information,
uncompressed, to the AS/400

But you couldn't put a compressed CD int he AS/400's CD drive
and read it.

Sorry, I'm kind of thinking out loud here.

--
Brad Jensen brad@elstore.com
President
Electronic Storage Corporation Tulsa OK USA
918-664-7276

LaserVault Report Retrieval & Data Mining
www.Laservault.com

www.eufrates.com - Add distance learning to
your site with easy course preparation