28 Sep
2003
28 Sep
'03
3:26 p.m.
I came across a decent stash of 9 track reel tapes during my clean out.
(4 cases, so maybe 50 or so of them)
A while ago, I sold or gave away (don't remember) a whole bunch of the
write protect rings for them. So I'm wondering, do those rings stop you
from writing, or enable you to write when installed? I
want to try
selling the 9 track tapes on ebay, but I want to make sure I specify
the
correct status of the rings (that don't exist).
Also, are these safe to bulk erase with an electromagnet? So far none of
them have any data on them that I am worried about erasing, so I'm not
planning to bother... but I want to know if it is safe or not in case I
find one I need to.
And finally, are all 9 track tapes the same? These were used on our
General Automation Zebra machine. So will they work on any machine that
needs 9 track, or only on other Zebras?
-chris
<http://www.mythtech.net>
29 Sep
29 Sep
3:24 a.m.
. So I'm wondering, do those rings stop you
from writing, or enable you to write when installed? I want to try
selling the 9 track tapes on ebay, but I want to make sure I specify the
correct status of the rings (that don't exist).
Also, are these safe to bulk erase with an electromagnet?
And finally, are all 9 track tapes the same?
The hymn of the day is "no ring, no write".
Yes, you can erase them with a powerful magnet. I dont remember the exact strength the
magnet must have.
In my 30-odd years of IT, I've only come across tapes with a mounting hole of some 9
cm (3.5 inch or so, so physically there is no problem.
However, magtapes come in various densities, and it is very common that tapes certified
for 800 bpi cannot be written succesfully on 6250 bpi drives.
If I were you,I would specificy the reel diameter and the certified density. The tape
I'm looking at at this instant, says on the label "3M Scotch 777 6250 bpi",
so in this case I would say "7 inch reel, 6250 bpi"
Many installations using tapes, have the policy that they have only as many rings as they
have tape drives. This is a very secure way to ensure that tapes are not accidentally
overwritten, as you have mount a ring before you can write, and even todays operators can
think. A bit.
:-)
Nico
3:33 a.m.
So I'm wondering, do those rings stop you from
writing, or enable you to
write when installed?
Write rings enable writing. There are such things as 'write-protect rings'
which when fitted on a reel prvent a write ring from being inserted, but I
haven;t been able to locate any since my mainframe days in the 1970s.
And finally, are all 9 track tapes the same?
From a function perspective yes, from a quality
perspective no.
Lee Courtney
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org]On Behalf Of chris
Sent: Sunday, September 28, 2003 8:26 PM
To: Classic Computers
Subject: 9 track reel tapes
I came across a decent stash of 9 track reel tapes during my
clean out.
(4 cases, so maybe 50 or so of them)
A while ago, I sold or gave away (don't remember) a whole
bunch of the
write protect rings for them. So I'm wondering, do those
rings stop you
from writing, or enable you to write when installed? I want to try
selling the 9 track tapes on ebay, but I want to make sure I
specify the
correct status of the rings (that don't exist).
Also, are these safe to bulk erase with an electromagnet? So
far none of
them have any data on them that I am worried about erasing,
so I'm not
planning to bother... but I want to know if it is safe or not
in case I
find one I need to.
And finally, are all 9 track tapes the same? These were used on our
General Automation Zebra machine. So will they work on any
machine that
needs 9 track, or only on other Zebras?
-chris
<http://www.mythtech.net>
4:09 a.m.
They are actually Write Permit Rings - ie need to be in place to write to a
tape.
Bulk erasing no problem - there may be a few unusual cases where they could
be used with some form of random access with block headers, but such systems
will have their own specialised formatting software.
Although a few drives may be "picky" about taking certain sizes of 9t 1/2"
tape I would expect almost all to take 600', 1200', and 2400' with no
problems (though autoloaders might not like anything not on the 2400'
reels) - the 3600' (thinner tape on 2400' reels - not very common) might
cause problems with some early drives.
Andy
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org]On Behalf Of chris
Sent: 29 September 2003 04:26
To: Classic Computers
Subject: 9 track reel tapes
I came across a decent stash of 9 track reel tapes during my clean out.
(4 cases, so maybe 50 or so of them)
A while ago, I sold or gave away (don't remember) a whole bunch of the
write protect rings for them. So I'm wondering, do those rings stop you
from writing, or enable you to write when installed? I want to try
selling the 9 track tapes on ebay, but I want to make sure I specify the
correct status of the rings (that don't exist).
Also, are these safe to bulk erase with an electromagnet? So far none of
them have any data on them that I am worried about erasing, so I'm not
planning to bother... but I want to know if it is safe or not in case I
find one I need to.
And finally, are all 9 track tapes the same? These were used on our
General Automation Zebra machine. So will they work on any machine that
needs 9 track, or only on other Zebras?
-chris
<http://www.mythtech.net>
6:10 a.m.
At 05:09 PM 9/29/2003 +0100, you wrote:
They are actually Write Permit Rings - ie need to be in
place to write to a
tape.
That reminds me of a true story from my days as an IBM Systems Engineer.
I had a small account that ran CICS on a 9370 or 4370 (don't remember
which) IBM Computer. I was always bugging him to start doing a back up and
also storing it off site. He called me one day to say the system had
crashed and needed to be restored and was going home to get the weekly
backup. I said great you are backing up and storing it offsite. He said
there was one problem, the ICCF Library backup was bad on that backup but
they backed that up every day and the tape was already in the shop. ICCF
was the source code library. He asked me to come over and help if needed.
When I got there they had already restored the system tape and were ready
to restore the ICCF libraries from the daily backup. I went in to see the
systems programer to help him with a CICS problem and the DP manager came
running in to say that the operator had goofed and had told the system
backup instead of restore. I told him no problem as long as you didn't have
the ring in the tape you were safe. He said we always keep the ring in the
tapes otherwise we cannot find them when we need them but the backup only
ran for a few seconds when we aborted it.
I told him that the tape may not now be recoverable due to record length
and placement and we can then use the previous days backup and only lose a
few files. He said thats a problem since we always backup on the same tape.
I said if we cannot recover this tape what do we lose. He said all of the
source code that has been created at the company for the past eleven years.
My immediate thought was I wonder if his resume is up to date.
I won't go into the details but was able to finally recover the tape for
him and for years he was my biggest fan.
=================================
Gene Ehrich
gehrich(a)tampabay.rr.com
4:26 p.m.
and the DP manager came
running in to say that the operator had goofed
Which reminds me of a true story too.
When I was an operator on a 360/40, most jobs were done via tape, as we had only 2 or 3x
2311.
All data was saved for 3 generations. Then, at a time, it was discovered that 2
generations of the master member file, were wonky. So, the boss stepped in, took the last
surviving member file and said "I'll keep this one safe", and put it under
his desk phone, one of the phones with a 60V electromagnet in it. I dont have to tell you
what happened when his phone rang....
It took the programmers about 3 months (IIRC) to recreate the member file from other
related files.
Nico
5:11 a.m.
On Sunday, September 28, 2003, at 10:26 PM, chris wrote:
I came across a decent stash of 9 track reel tapes
during my clean out.
(4 cases, so maybe 50 or so of them)
A while ago, I sold or gave away (don't remember) a whole bunch of the
write protect rings for them. So I'm wondering, do those rings stop you
from writing, or enable you to write when installed? I want to try
selling the 9 track tapes on ebay, but I want to make sure I specify
the
correct status of the rings (that don't exist).
No ring, no Write.
IIRC.
:^)
6:36 a.m.
chris wrote:
I came across a decent stash of 9 track reel tapes
during my clean out.
(4 cases, so maybe 50 or so of them)
A while ago, I sold or gave away (don't remember) a whole bunch of the
write protect rings for them. So I'm wondering, do those rings stop you
from writing, or enable you to write when installed? I want to try
selling the 9 track tapes on ebay, but I want to make sure I specify the
correct status of the rings (that don't exist).
No ring-ee, no writ-ee
Also, are these safe to bulk erase with an
electromagnet? So far none of
them have any data on them that I am worried about erasing, so I'm not
planning to bother... but I want to know if it is safe or not in case I
find one I need to.
Yes. They are not pre-formatted. RadioShack at least used to sell a
bulk eraser for video/cassette tapes (44-233A) that can do about 4
or 5 tapes before it overheats (wait 1 hour, and then repeat).
Don't do a quick 'zap' and expect it to be blank. Take your time
and run it over both sides.
And finally, are all 9 track tapes the same? These were
used on our
General Automation Zebra machine. So will they work on any machine that
needs 9 track, or only on other Zebras?
Some tapes were rated for higher density than others.
Common densities were 800, 1600, and 6250 bpi. Others existed
like 100, 200, and 3200. Most tapes were rated at 6250, but
are usable on all the 800+. I don't know about the <800.
Also, you could get tapes with just a few feet (<100) of tape,
up to the common 2400' reels. Some auto-loaders don't like
the shorter tapes.
The seals on the tape varied too. You could get cannisters,
rings that you removed before mounting the tapes, and rings
designed for IBM automatic tape loaders.
Some of the tapes age better than others. I had some that would
lose large amounts of oxide onto the tape heads after just a few
years. Also, some of the tape manufacturers would forget to
put a EOF marker on a large percentage of their tapes.
It depends on what additional "extras" your tape drive required,
but for the most part all of the 9 track tapes were the same.
noon
New subject: 9 track reel tapes [Backup horror stories]
Kevin Handy wrote:
chris wrote:
I had an account that was supposed to do backups every day, and they
did for a long time.
Finally they got enough data that they had to go to two reels to back all
of the data up.
We showed them how to do the backup, and included that they would
have to use the second tape we left for them to finish the saves.
Well, we hit the aformentioned day of 'oh crap we have to do a restore'
and had to get the backup loaded.
We started the restore and everything went fine till we got to the second
reel. it was blank.
mild panic, but who knows, so went to earlier backup. went thru all
backups...
We asked them anything you can tell us about the backup process?
"sure, when we got thru the first reel, it was around 530pm and time to go,
and when it asked if we wanted a second reel, we said N(o). time to go home.
...
never did recover that account
Jim
7:50 a.m.
"chris" <cb(a)mythtech.net> wrote:
A while ago, I sold or gave away (don't remember)
a whole bunch of the
write protect rings for them. So I'm wondering, do those rings stop you
from writing, or enable you to write when installed?
The presence of the ring enables writing.
Also, are these safe to bulk erase with an
electromagnet?
Yes.
And finally, are all 9 track tapes the same?
The tapes and reels normally are. IBM did have some special reels
or cartridges for early autoload equipment, but those are very
uncommon.
The main regard in which the tapes vary is quality. Some of the
tapes shed oxide. Memorex tapes are particularly bad about this.
3M Blackwatch was generally considered to be about the best, IIRC.
9:41 a.m.
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10 comments
10 participants
participants (10)
-
andyh＠andyh-rayleigh.freeserve.co.uk -
ard＠p850ug1.demon.co.uk -
cb＠mythtech.net -
eric＠brouhaha.com -
gehrich＠tampabay.rr.com -
jwstephens＠msm.umr.edu -
kth＠srv.net -
lcourtney＠mvista.com -
nico＠farumdata.dk -
rhudson＠cnonline.net