Review this topic for information on differences between the various tape devices.
When removing the floppy disk from the drive, the device light must be off and the floppy must be detached (unloaded). Otherwise, the system reports parity errors. This is not the case in multiple floppy save/restore.
t-rew or set-floppy does not actually access the drive. Therefore, the diskette drive light does not go on, but it does work properly.
After a file-save or after the last t-dump on a tape, always do a t-rew or t-unld to ensure that a second file mark is written to the tape, making a logical end-of-tape marker. Without this precaution, only one file mark is written at the end of the tape. This might cause problems when restoring the tape on some non-D3 systems, or will cause the system to prompt for an additional, nonexistent reel when doing a selective restore or an account restore from a tape on which the account is not saved. Even without doing the t-rew or t-unld, a restore from the tape will work properly.
Detaching the tape may force a rewind.
t-rew waits until the tape is rewound, instead of returning immediately to TCL.
If a sel-restore or account-restore on a full file-save tape was made on an older version of AP or a non-AP system, and that tape does not contain the specified account, the system asks for one more than the actual number of reels. If this creates a problem, use the (f option to force reading all files.
After a file-save or after the last t-dump on tape, a dummy label is added after the two file marks by the t-rew or t-unld. Since this block is beyond the logical end of tape, it should not create a problem. However, if the tape is read using readt in FlashBASIC, and if the double file mark is ignored by the program, this block becomes visible.
Executing a t-det can force a rewind.
t-rew waits until the tape is rewound before returning to TCL.
t-unld executes a rewind only. The tape has to be unloaded manually. This is also the case when changing reels on a multireel save or restore.
On the IBM tape drive, only two densities are supported:
1600 bpi (rmtX.5)
6250 bpi (rmtX.1)
On the Cipher tape drive with the appropriate Dickens Data Systems Driver and Cipher SCSI interface CSC100, three densities are available:
1600 bpi (rmtX.1)
3200 bpi (rmtX.3)
6250 bpi on the model 990 (rmtX.5)
Some D3 Licensees write the D3 label inside an 80 byte block, while D3 expects the label to be written at the beginning or at the end of a 512 byte block. When trying to read this kind of tape, tape format errors occur because the label is not understood and some data is rejected by the tape handler. To resolve this problem, and to write 80 byte label blocks, use the chg-device command. See the D3 Reference Manual for more information. Remember to set the 512 byte block format after using the tape; if a file-save is done with an 80 byte label, it is not possible to do a full file restore from this tape.