Balloon Help (choose Show Balloons from the ^A icon in the upper right corner of the screen or from the Help menu) is also available for DeskTape windows and menus.
What is DeskTape?
DeskTape is a system extension that allows you to copy files to a mounted Tape. This means you can use the Finder to copy files to or from a tape right from the desktop.
Installing DeskTape
DeskTape requires System 7 or later. To install DeskTape, drag the DeskTape icon to your System folder. A dialog box will appear asking if you want to place it in the Control Panels folder. Press OK, then restart your Macintosh.
If you are using DeskTape with a third-party tape drive you will need to use the installation tape to complete the installation. Refer to the DeskTape User's Guide for instructions on using the installation tape.
Protecting Your Data
To protect against data loss, always maintain two separate copies of your data. If you plan to delete data from your hard drive, first make sure you have two other copies. Also, never turn off your tape drive while writing to a tape. It's also a good idea to activate the write-protect tab on the tape until you actually plan on adding more data to it.
You should perform the following integrity test after installing DeskTape on a new CPU or System folder:
1) Use the Finder to copy 10 MB on a new tape.
2) Copy a different 10 MB on a second tape.
3) Mount the first tape and check to make sure that the data on the tape is correct.
4) Mount the second tape and check to make sure that the data on the tape is correct.
If error dialogs appear, or the data read back from either tape is not correct, DO NOT continue to use DeskTape until these problems are resolved.
Initializing a Tape
There are several ways to initialize a tape:
• When you insert a blank tape into the drive, the initialize dialog automatically appears allowing you to initialize the tape.
• To initialize a mounted tape, choose Erase Disk from the Finder's Special menu.
• To force a tape to be initialized, hold down the <option> and <delete> keys when inserting it.
It takes 2 to 3 minutes to initialize a DAT tape. You must copy at least one file to a newly initialized tape, otherwise you will have to initialize it again the next time it is inserted.
Copying to a Tape
Once a tape is mounted, you can use the Finder to drag files and/or folders to it just like you would to a hard disk. You can also rename or delete files and folders on the tape. Note that the space occupied by deleted files is not reused until the next time you erase the tape.
Ejecting a Tape
When you are done copying files to a tape, simply drag it to the trash to unmount it. After the directory is written, the tape should automatically eject from the drive.
It's best to drag the tape to the trash and wait for it to eject before restarting or shutting down your Macintosh. This allows you to respond to any errors that may occur while writing the directory to the tape (see Tape Directory below).
To eject a tape that is not mounted, choose Eject from the Utilities menu.
Mounting a Tape
Tapes automatically mount when they are inserted in your drive. It's best to wait until after your Macintosh starts up before inserting a tape.
The DeskTape control panel has a “Mount” control that you can use to prevent a tape from mounting. This allows you to use the Utilities or Directory menu functions that are normally not available when the tape is mounted. To toggle the “Mount” control, click on the Mounted status indicator in the main DeskTape window. If Mount is underlined, the tape automatically mount when inserted in the drive.
Locking a Tape
Tapes can be locked by activating the write-protect tab on the tape. Sometimes a tape will mount locked ^C even though the write-protect tab is not activated. This can occur if the tape was mounted using the DeskTape Directory menu Mount command or the tape is so full that there is not enough room to write another directory. The lock condition may also be caused by Mac OS Easy Open. Try removing Mac OS Easy Open from the Control Panels folder then restart your Macintosh.
Hardware Data Compression
HDC is a lossless data compression technique that increases the data capacity and speed of a tape. The preferred compression format is DDS-DC which is based on the Lempel-Ziv algorithm. Some tape drives have non-standard compression formats and you may have problems interchanging tapes with these drives. Also, compressed tapes cannot be used with non-compression drives.
^B There may be cases where HDC actually causes data to expand on the tape. Data expansion reduces tape performance and available capacity and is most likely to happen if the data is pre-compressed (like QuickTime movies). It's best to turn compression off when working with pre-compressed data.
Controlling Compression
If your drive has built-in DDS-DC hardware data compression, you can control it with the HDC check box in the main DeskTape window or by using the compression check box in the “Tapes” window.
If the tape is not mounted, use the HDC check box in the main DeskTape window to control compression.
DeskTape allows you to specify the compression setting when initializing tapes. Note that tapes always mount with the compression state they were initialized under.
Tape Directory
DeskTape creates a file in the System folder of your startup drive called DeskTape.dir. This file is a place holder for the tape's directory and allows dynamic interaction with files and folders on a tape.
When a tape is loaded, DeskTape transfers the directory from the tape to the DeskTape.dir file and then mounts the tape. Any changes to the tape directory are first made to the DeskTape.dir file on your startup drive. When the tape is ejected, DeskTape writes the directory to the tape.
The size of the DeskTape.dir file determines how big the tape directory can grow. The tape directory contains entries for each file on the tape and applications use up more directory space than documents. The default size is 8 MB but can be changed through the Utilities menu Configure window. Depending on the types of files on the tape, a 8-MB directory can hold 8,000 to 25,000 files.
^B Since the tape's directory is temporarily stored on your startup drive, it is very important that your startup drive is in proper working order. Use Norton Disk Doctor to verify your startup volume, and a low-level disk utility like DiskArray to verify the startup drive's media. Do not use Norton Disk Doctor to repair a tape volume.
Tape Handling Guidelines
• Clean your drive mechanism once a month with an approved cleaning tape.
• Use only data tapes and cleaning tapes labeled DDS with DAT drives.
• Keep tapes within the temperature range of 5°C to 45°C (41°F to 113°F).
• Allow tapes to equalize in temperature when changing environments.
• Store and use tapes in a clean place. Dust, dirt, and smoke decrease tape life and increase data errors.
Mounting Problems
There are several reasons a tape may not mount:
• The tape is blank.
• The tape was not created by DeskTape.
• The tape has a damaged End Of Data (EOD) marker.
• A directory could not be found at the end of the tape.
• The tape was written using hardware data compression and you have a non-compression drive.
• You have a SCSI hardware problem (cable, termination, or ID conflict).
• You have a software compatibility problem (see Compatibility Issues below).
To determine if a tape is blank or was not created by DeskTape, choose Header Info from the Directory menu in the DeskTape control panel. In some cases, tapes not created by DeskTape will cause a "-7932" error when running a Read test.
If you choose Find Last from the Directory menu and the message "Last session not found." appears, then the tape has a damaged EOD marker or the tape does not contain a valid last directory. Try mounting this tape by choosing <option> Find Log from the Directory menu. You can verify that the EOD marker is good by running a Read test on the tape.
If you run a quick Read test and an error occurs at block 0, it may indicate the tape was created using compression (or an incompatible compression format).
SCSI problems most likely show up as computer freezes or erratic behavior. To help isolate the problem, run a Write/Verify test. If your computer freezes or an error is displayed, try disconnecting all other SCSI devices except your startup drive and tape drive to help isolate the problem.
Compatibility Issues
DeskTape is designed to allow you to use the Finder to save files directly to a tape. Third-party software, like automatic compressors and copy accelerators, that modifies how the Finder interacts with mounted volumes may interfere with DeskTape. The Allow Random Writes option in the Configure window allows you to save data directly to tape from most applications. Keep in mind that random writes use large amounts of the tape directory and you may have to increase the directory size. Use the Finder to save files to tape that become too fragmented or require large amounts of the tape directory.
If you are having problems using the Finder to copy files to or from a tape, use the Extensions Manager and choose "Mac OS All" then add DeskTape. After restarting, verify proper operation then add additional extensions and control panels one at a time until the problem recurs.
About Optima Technology
Optima Technology is a quality manufacturer of high-performance hard disk, optical, tape, array, and CD subsystems, including:
• 2-GB to 23-GB hard disk (both 8 bit and Fast/Wide/Ultra)
• 3.5- and 5.25-inch ISO compatible magneto-optical (read/write)
