The answer was only a man page away (man tz).
Writing to a tz89 with rmt0l will yield somewhere between 20 and 40GB depending on compression, which is tz88 mode, and hence is readable on the other system's tz88.
Thanks to each of you who responded:
Horsnell T. <tsh_at_mrc-lmb.cam.ac.uk>
"Dr. Tom Blinn, 603-884-0646" <tpb_at_doctor.zk3.dec.com>
Bruce Senn <sennb_at_union.edu>
"Lavelle, Bryan" <Bryan.Lavelle_at_COMPAQ.com>
<alan_at_nabeth.cxo.dec.com>
Details of some of the responses are as follows:
++++++++++
The books you are looking for are the TZ89 DLT Series Tape Drive User's
Guide and the TZ88 DLT Series Tape Drive Owner's manual.
If you write a DLT IV in a TZ89 with rmt0l it is in tz88 format and should
hold 40 Gb.
You can then read the tape on the TZ88 with rmt0h.
HTH.
Bruce.
++++++++++
According to the tz(7) manual page from a V4.0D system:
a = 20 GB (compression off)
l = 40 GB (compression on)
As always, any numbers involving compression depend on
2:1 compression of the data. In practice this can vary
both up and down. For non-compression, the data and
error rates can influence capacity.
++++++++++
Original question follows:
>>> Scott Mutchler <smutchler_at_gfs.com> 11/09/00 02:00PM >>>
Hello all,
Perhaps someone on this list either knows details of drives and densities or knows where I can find those details.
I need to write data onto a tz89 that will in turn be readable on a tz88.
Now, I can write to the tz89 (using vdump) with any of the four devices: nrmt0h, nrmt0m, nrmt0l, and nrmt0a. Those all work fine.
However, I cannot read from the tz88 using tapes written with the nrmt0h or nrmt0m devices (I expected it to fail on the h device; I was not sure if the m device would work or not).
I am able to read tapes written using the "l" (lower case L) and the "a" devices. So, my question is this: how much data can I expect to write to a DLT IV in a tz89 using /dev/nrmt0l or /dev/nrmt0a?
Thanks in advance
Scott Mutchler
Gordon Food Service/Marketplace
Outlline of test methods (if the detail matters here):
on a tz89 using DLT IV and vdump, one fileset per tape cartridge
# vdump -0v -f /dev/nrmt0h
# vdump -0v -f /dev/nrmt0m
# vdump -0v -f /dev/nrmt0l
# vdump -0v -f /dev/nrmt0a
Take the tapes to the tz88 and read them one at a time, using
# vrestore -xv -f /dev/nrmt0h (used the h device each time for consistency)
The "h" and the "m" tapes caused vrestore to complain as follows:
vrestore: unable to use save-set: invalid or corrupt format
******* PROGRAM ABORTED *********
vrestore: unable to obtain fileset attributes
The "l" and the "a" devices happily restore files as described previously.
Received on Fri Nov 10 2000 - 14:08:45 NZDT