Today's Exciting Acquisition & Microvax 3100 Question

From: Eric Dittman <>
Date: Mon Jun 18 23:28:19 2001

> >> The expansion box appears to contain a TK50 drive as it had a TK50
> >> tape in it. To be honest, I've never seen a TK70. So could it be a
> >> TK70 with a TK50 tape in it? Can a TK70 read/write a TK50 tape?
> >
> >I'm assuming it's a Half-Hieght drive? If so it's a TZ30. I'm not aware of
> >there ever having been a SCSI TK70.
> >
> It's a half height drive. Ah, so a TZ30 is just a SCSI TK50? Can I use the
> tapes I write in my TK50 on my MVax II? (I lost track of DEC stuff after
> the MVax II. Kinda sad really.)

The TZ30 is compatible with the TK50. There are also SCSI TK50 drives,
but they are full-height. I never got around to using a TZ30, even
though there are a couple around at work. We just don't have anything
on TK50-formatted tapes. I went from a TK50 to a TK70 to an Exabyte
8200 to a TLZ04 to a DLT4000, so I don't know how the TZ30 is in terms
of speed and reliability compared to a TK50. I remember going through
a few TK50 drives, most of which where due to people abusing the drives.
The 8200 drive seemed to wear out about every six months, even with
proper cleaning. I never had a problem with my TLZ04 or my DLT4000.
At work we have TZ867 and TZ877 drives, and it seems we have about one
replaced every three months, but they get a LOT of use, and if we have
any glitches that can't be explained on a bad tape or operator error
the drive gets replaced.

If the TZ30 is anything like the TK50 I'd limit using it to just
reading existing TK50-formatted tapes and get a cheap TLZ04 or
TLZ06 from eBay for backups.

> I suppose I'm not completely against running VMS on it though I can't
> afford the hobbyist license right now. ($100 isn't it? Or is that for the
> Unix hobbyist license?) I used to do ALOT of stuff on VMS Vaxen and have
> even toyed with the idea of having a nice one around to telnet into just
> to say I can. I'm just not sure I'd want to USE it for anything, however.

The OpenVMS Hobbyist program is free. The Tru64 Enthusiast program costs
$100. I have one VAX system (and one Charon-VAX emulator) and three Alphas
running VMS and one Alpha running Tru64 V5.1. I only have the Alpha running
Tru64 for keeping up with Tru64. I really prefer VMS.

> I suppose I feel the same way about Vaxen that I do about Intel boxes.
> Perfectly acceptable hardware, horrible default operating systems.
> Intel - Linux
> Vaxen - NetBSD =-)

Horrible default operating system? Hah!

A VAX should only run VMS or, if necessary, VAXELN.

[warning, topic drift ahead!]

I haven't had to deal with ELN for a couple of years now. I never
got deep into ELN on purpose, but where I used to work we had a
Schlumberger S90 memory tester that was MVII-based running an old
version of ELN. We were having performance problems getting some
vectors generated quickly during test (the parts were taking several
minutes to test) so it was decided to try to port the software to
a new version of ELN so it would run on a VAX 4000-105A with a
QBUS adapter. Unfortunately, I only had a month to get the port
working and it took a long time to just get the sofware modified
to compile with the new version. I ran out of time to get any
timing problems fixed as I could only have the tester at limited
times to debug.

Rather than go ahead and buy the 4000 management decreed we return
the demo unit. The manager acted like any money spent in the
department came out of his personal bank account. He used to
gloat about how he was the only manager that always had a surplus
in the budget every year, while those of us working in the
department had to deal with obsolete equipment and limited supplies.

If the porting project would have been impossible due to the
timing issues we still would have had a huge performance increase
over our host MV3900. On the 3900 compiling the S90 test programs
(written in VAXELN Pascal) took about 15 minutes. On the 4000
the time went down to about 2 minutes.
Eric Dittman
Received on Mon Jun 18 2001 - 23:28:19 BST

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