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Howdy All:I have to access old data stored on EXABYTE, DAT and DLT 7000 tapes. Originally we had hoped to connect them to my new MAC G5, however the MacOSX version of IRAF does not appear to support tape drives. So now we are installing LINUX on a PC and going for the LINUX version of IRAF, which seems to support tape drives. Can anyone tell us precisely how we should access and edit the TAPECAP file for EXABYTE, DAT and DLT 7000 tape drives? The tapes were made at Kitt Peak and CTIO from 1993-1999 using wfits and mscwfits. Thanks, David Devine

David,Here are some linux tapecap entries that might help:[code:1:711ead2544]
# Unit assignments (Linux).
# ---------------------------mtdat0|mtst0-dat|HP DAT drive unit 0:\
:dt=HP 35480A Helical Scan DAT drive:al=st0 nst0:\
:dv=nst0:lk=st0:tc=generic-dat:
mtdat1|mtst1-dat|HP DAT drive unit 1:\
:dt=HP 35480A Helical Scan DAT drive:al=st1 nst1:\
:dv=nst1:lk=st1:tc=generic-dat:mtexb0|mtst0-exb|Exabyte drive on ST 0:\
:al=st0 nst0:\
:dv=nst0:lk=st0:tc=generic-exabyte:
mtexb1|mtst1-exb|Exabyte drive on ST 1:\
:al=st1 nst1:\
:dv=nst1:lk=st1:tc=generic-exabyte:
mtexb2|mtst2-exb|Exabyte drive on ST 2:\
:al=st2 nst2:\
:dv=nst2:lk=st2:tc=generic-exabyte:mtdlt1|mtst1-dlt|DLT drive on device 1:\
:al=st1 nst1:\
:dv=nst1:lk=st1:tc=generic-dlt:mtdds3|mtst3-dds4|DDS-4 DAT drive on unit 3:\
:al=st3 nst3:\
:dv=nst3:lk=st3:tc=generic-dds4:# Generic device entries.
# -------------------------
dat-60m|Generic DAT/DDS tape drive with 60M tape:\
:tt=DG-90M:ts#1274378:tc=generic-dat:
generic-dat|dat-90m|Generic DAT/DDS tape drive with 90M tape:\
:dt=DAT 4mm Helical Scan tape drive:tt=DG-90M:\
:ts#1911567:bs#0:mr#32768:or#32768:fb#10:fs#127000:mf:fe#2000:
generic-exabyte|Generic Exabyte Model 8500 drive:\
:dt=Exabyte EXB-8500 8mm tape drive:\
:tt=P6-120MP:ts#2347794:\
:bs#0:mr#32768:or#32768:fb#10:rs#2000:fs#188416:mf:generic-lto|lto|Generic LTO tape drive:\
:dt=LTO tape drive:tt=HP-C7971A:\
:se:ts#100000000:bs#0:fb#22:fs#2880:mf:generic-dlt|Quantum DLT-8000 digital linear tape drive:\
:dt=Quantum DLT-8000 :tt=DLT-IV:\
:ts#35000000:bs#0:fb#10:fs#2880:mf:generic-dds4|DDS-4 DAT drive:\
:dt=4mm Helical Scan DDS-4 tape drive:tt=DGP150P:\
:ts#20000000:bs#0:mr#0:or#65536:fb#10:fs#127000:mf:fe#2000:
[/code:1:711ead2544]Note that you'll need to edit the ":al" (device aliases) and ":dv" fields to match the drive number you're trying to access. The ":dv" should refer to the no-rewind device and the drive itself should be configured to use a variable block size (e.g. "mt -f /dev/st0 setblk 0" ). There are tweaks that can be made to fix problems with the drive positioning before/after a tapemark during random seeks but these should work as is.I didn't have access to a tape drive for Mac but tape support under OSX is pretty bad anyway. This has been asked about before in this forum, see e.g. https://iraf.net/phpBB2/viewtopic.php?t=85158&highlight=mac+tapeHope this helps,
Cheers,
-Mike

After ordering a new SCSI card we finally managed to mount the DLT tape drive on the LINUX box. Unfortunately here is what I get when I try to allocate it within IRAF:cl> allocate mtdlt0
rw access to /dev/st0 is deniedI used the tapecap entries as specified. I am guessing there may be some permission problem, as my IT support guy emphasized that I have to log in as root user if I want to extract files from the DLT (we checked with some tarred files to make sure that the tape drive was working). I logged in as root before starting IRAF but that did not help.
Any ideas?

David,Tape devices are assumed to be owned by root with permissions 666 (i.e. rw-rw-rw-), the ALLOC command will change the ownership and permissions to guarantee exclusive access. Logging in as root to use IRAF should never be necessary although some linux systems create the /dev directory at boot time and so setting the /dev/[n]st0 ownership/perms could be done in a /etc/rc.local boot file.
What does an "ls -l /dev/st0" show as the permissions and owner of the file? Can your sysadmin reset this and does the tape then work? -Mike

Hi FitzI logged on as superuser and changed the permission on /dev/st0 in the following: chmod 666 /dev/st0I then logged out as superuser and checked ls -l /dev/st0 and got the following: crw-rw-rw- 1 root disk 9, 0 Mar 9 12:28 /dev/st0I then started up IRAF and attempted to allocate the tape drive:cl> allocate mtdlt0
Error: uid of $hbin/alloc.e must be set to 0 (root)
(rerun install script $hlib/install, or)
(login as root: cd $hbin; chown 0 alloc.e)
ERROR: cannot allocate device mtdlt0
allocate (device=mtdlt0)If I log in as root and then start IRAF, I get the following: cl> allocate mtdlt0
rw access to /dev/nst0 is deniedI am not sure what to do at this point as I do not understand these directions.Ignorance aint bliss!! David

David,Allocating a drive before use isn't strictly required, have you tried just reading the tape?The ALLOCATE binary is in /iraf/iraf/unix/bin.redhat/alloc.e (for a Redhat system),
i.e. the $hbin is $iraf/unix/bin.<arch> You need to be root to run the install script partly because this binary is made setuid root so it can change permissions in the /dev directory on the machine. You can do this manually as root by doing e.g.[code:1:4eed864f75]
# cd /iraf/iraf/unix/bin.redhat
# chown 0 alloc.e <- changes ownership of file to root
# chmod 4755 alloc.e <- makes it setuid root
[/code:1:4eed864f75]Note that the device IRAF actually opens is the no-rewind device name, i.e. /dev/nst0 (the /dev/st0 is an alias). Be sure you've changed the ownership and permissions of this file as well.-Mike