(Updated 2000 Nov 16)

The basics:

• Gear is a text-driven CD-writer for SGIs, i.e. munich.rose.brandeis.edu
• For commands that require multiple arguments, (i.e. 'newvol VOL1999 74 iso') if you don't specify them all on the command line, don't worry; Gear will ask for them one by one.
• Gear creates an "image" that contains either the locations (a virtual image) or a physical image copy of files specified by the user
• The Gear manual is available in Adobe Acrobat format by typing gearhelp at a Unix prompt. You can also type help within Gear itself to get a list of all the commands.

Compact disk capacity:

• A 74-minute CD holds 640 megabytes of data.
• To check how much space a single file or directory takes up, see the sections from the Unix page on 'ls -l' or 'du -k', respectively.
• To increase the amount of data you can fit on a CD, gzip can compress data by up to 50% but usually less.

My conventions here:

• Entries below to be typed in by the user are written in bold code font.

An example:

• insert CD
  • there should be a CD-ROM icon on the desktop that shows a disk in 5-10 seconds
  • if an error appears when a blank disk is inserted, ignore it and click it away
• gear
  • typing this at a Unix prompt starts up Gear
  • don't be in a directory you're backing up when you run Gear; be a directory up for example -- Gear writes some temporary files which won't exist when you come to write the CD, which will cause problems if they're in the file list
• newvol VOL1999 74 iso
  • newvol -- creates a new volume
  • VOL1999 -- the name of the volume -- must be all capital letters and numbers
  • 74 -- the length of the CD in minutes -- usually printed on the CD package
  • iso -- file format
• gettrackparms -- read the track header of the CD. Check for:
  • name-handling level: do not translate
    • this allows long filenames containing special characters
    • the default is always to change to ISO format level 1 -- if you need to change this setting in settrackparms, it's option one out of five
• settrackparms -- use if you need to change one of the settings seen in gettrackparms -- the defaults never change, so allowing long filenames, for example, always needs to be set
• cp -r src_directory direct1
  • 'src_directory' -- the name of the directory on disk
  • 'direct1' -- the name of the directory on CD. There potentially can be issues with directory names being truncated on certain operating systems. Directory names up to eight characters long with only letters, numbers, and underscores should always work.
  • you can substitute a period (.) for 'direct1' if you want to keep the directory name -- if so, be sure to include a space between 'src_directory' and the period
  • the flag '-r' will copy 'src_directory' and all of its subdirectories
  • make sure the track parameters are okay, as changing them later won't affect a pre-existing image (as I learned the hard way)
  • repeat this command, with the appropriate changes, for all the directories you are writing
• physvol -- copies the contents of the volume into one, big file.
  • CD-writing session is more likely to succeed if the files are on a locally mounted disk or a physical image of the files is made. The CD writer has a limited ability to wait for traffic over the network or the read-write head searching over the disk. Lumping the files in one place gets around this potential problem.
  • I recommend creating a physical volume if the files are not on a local disk.
  • If you are making a physical image of your files, make sure there is room on the disk. (To check free disk space, see the section about 'df' on the Unix page.)
• getcdrparms -- get settings for CD writer. Check specifically for:
  • virtual vs. physical image
  • verify after write
  • recording of disc enabled
  • track at once writing
  • 4X recording speed
  • 4X reading speed
  • disc fixaton enabled
  • multi-session writing
    • enabled if you plan on adding more volumes, disabled if it's a one-time shot
    • multi-session CDs are subject to different compatibilities on different platforms --I don't recommend multisession CDs for critical data
    • reading the CD is quicker is there is only one volume
• setcdrparms -- use if you need to change one of the settings seen in getcdrparms
• writecd -- writes the CD -- progress is monitored at the bottom of the screen
• exit

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