Tape I/O

  Several tape drives (1/2 inch, QIC, 8mm, DAT) are available on the UNIX system. The tape drives for general usage e.g. Exabyte and DDS/DAT) are installed in the User Room 213.

They can be accessed from any UNIX workstation on the network. The step by step procedure is as follows:

• Login on a UNIX workstation.
• Run MIDAS with inmidas.
• Mount your tape on a drive connected (see below). If you want to write on the tape remember to enable writing.
• Use the intape and outtape commands to access the tape unit using the logical device name e.g. tape0. or the physical device name e.g. /dev/nrst0 or ws1:/dev/nrst0 for a tape unit on remote host ws1. Since the recording density for UNIX tape units is defined by their name, the device name will overrule the density given on the command line! Some 1/2 inch drives require the density to be set manually on the drive as well. During reading the tape drive will itself sense the tape density used. Thus, the generic tape name can normally be given when reading.
• Dismount your tape from the drive so that others can use it.
• Logout from MIDAS with bye and from the workstation.

The logical device names currently defined for magnetic tape drives on UNIX systems with the following generic notes:

1. Tape drives can be selected from any host in the same domain. To get access to drives in other domains you need to have another account with the same name in the remote domain.
2. The temporary register accounts used by visitors belong to domain eso.
3. New tapes are from factory write enable.
4. Tapes can be obtained from the operator, room 220/1, 2nd floor.
5. The MIDAS error Permision denied occurs when the given tape is write protected (check remarks below) or when it is allocated to another user (use deallocate command)

REMARKS:

• For each 1/2 tape drive there is three names but actually only two densities, e.g. tape2 (default: 6250 dpi), tape2h (high density 6250 dpi) and tape2m (medium density 1600 dpi).
• 1/2 inch magtape drives have to be set to enable remote density selection: with the drive OFF-LINE press the button DENSITY until LED "REMOTE DEN" comes on. The MIDAS name as taken from the above table and used with command "INTAPE/FITS" then actually sets the density.
• 1/2 inch magtape drives can read tapes of any density if the drive is set with "REMOTE DEN" on. That is, for reading there is no difference between, e.g. tape2, tape2h, and tape2m.
• 1/2 inch tapes are write enable when they are mounted with the write enable ring and the LED "WRITE ENBL" comes on.

REMARKS:

• 8mm-High drives can also read 8mm-Low density tapes, but not vice versa.
• The 8mm tape is write enable when the red switch in front of the tape is in "REC" position.

REMARKS:

• QIC-150 drives can only write on high density tapes DC600XTD or DC6150 however they can read QIC-24 low density tapes DC300XL or DC600A.
• QIC-24 drives use only low density tapes DC300XL or DC600A.
• QIC tapes are write protected when the round switch in the tape points to the "SAVE" position; write enable otherwise.

REMARKS:

• DDS drives use Sony 60/90/120 min. DAT tapes.
• DAT tapes are write enable when the swith in front of the tape closes the hole.
• An up to date list of available tape drives is posted on the bulletin board in the user room.