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

----- Original Message -----
From: "Peter Dow" <pcdow@yahoo.com>
To: <midrange-l@midrange.com>
Sent: Wednesday, December 05, 2001 5:43 PM
Subject: Re: Writing multiple CD volumes for the AS/400?


> Hi Brad,
>
> No problem (about the thinking out loud), I think this is
interesting.

I know when a vendor speaks, some people thnk every word is a
sales message. With me it's only every other word. I'm one half
programmer.

> I don't know what format you're storing the data on the CD with
your virtual
> tape drive, but if was simply SAVF format in a .zip file, I
personally would
> have no problem using OS400 facilities to unzip the save file
and restore
> from that.

Actually it will be savlib format, not SAVF. At least that is the
plan.

It's actually a couple of years since I last worked with the
format for our AS/400 CD Recorder, but I think it was SAVLIB
because that could be loaded directly ont he AS/400 CD reader, and
it's also the easiest way to save the objects int he first place,
since it doesn't have to be written to the AS/400 DASD first.

As I remember it, we do a savlib to the pae drive, capture it on
the PC's hard drive, massage it very slightly and put it on the
CD. (We have our own CD writer routines.)

So it's a hand's freee operation - you put a blank CD-R int he
CD-writer, do your savlib to the Niagra CD Recorder, and when it
is done the CD is recorded and ready to pop into an AS/400 CD
reader.

At the time we developed the CD Recorder, the RISC machines were
fairly new, and there wasn't a whole lot of demand for the
product. Now I suppose it is something I should be promoting. I
think we sold 4 or 5 of them, Computer Associates bought 1 and
then a year later bought another. (I have records on all this of
course, but not at hand.)

It costs 5K - the peripheral IBM forgot.

I sure wish I could figure out how to do multiple CD saves. Aren't
there any IBMers on this list who know the right people's email
address? Have pity on a poor independent developer.

We copied some big spool files to databases, then savlibed them to
our VTS, and zipped them - 94% compression. That means a 650MB CD
will store 10.8 gigabytes (about 16 uncompressed CDS) of spool
file data. That's a lot.

Of course we could set this thing to save anything a tape can
save. When I made the first version of this thing, I thought
people might use it for job step backups.

My CPA - my CPA! suggested writing the compressed files to DVD.
But DVD is too slow - 1.3 MB a second transfer rate. Actually I
supposed for compressed files, such as databases and spool files,
it would match a tape drivein throughput.

Another thing you could do with a CD is verify it - read it and
compare it to the disk image of the CD on the VTS. Remember when
we use to save and verify backup tapes?

> However, I can see that it might be a problem for people who
simply want to
> use RSTLIB or RSTOBJ.

Well, even if you could save to uncompressed CDs, you would not
want to. It could take 20 to 40 CDs to back up a decent sized
AS/400, and there is really no reason to do it except when the IBM
tape interface fails. And that is just not likely to happen. In
that case, you can create your 20 cads - but as of yet you can't
reload them to the IBM.