Some tape drives are capable of doing quick fast forwards. A quick fast forward means that the tape drive is able to find the start of the next volume even when in the middle of the previous volume. Drives based on ftape are NOT capable of doing this, however, zftape, is able to do quick fast forwards, as are most SCSI drives.
With ftape, therefore, the only way to find the next volume is to rewind the tape to the beginning, and then forward to the desired volume. As you can imagine, this constant rewinding and forwarding can take quite a while.
By default, taper assumes that zftape, SCSIs and IDE tape drives can do a quick fast forward, while removable and ftape tape drives cannot.
To test whether your drive can do quick fast forwards, go into the utilies menu and run the Test fast fsf program which will tell you if your drive supports quick fast forwards or not. Note that taper will overwrite all the data on the tape used for the test.
If you find that your tape drive doesn't support quick fast forwards, you will have to change the appropriate preference.