Attributes for 525 MB 1/4-inch tape drives (type 525mb)

The following are attributes for 525 MB 1/4-inch tape drives (type 525mb).

Block size
The default block size is 512. The other valid block sizes are 0 for variable length blocks, and 1024.
Device buffers
The general information for this attribute applies to this tape drive type.
Extended file marks
Writing to a 1/4-inch tape can only occur at the beginning of tape (BOT) or after blank tape is detected. If data exists on the tape, you cannot overwrite the data except at BOT. If you want to add data to a tape that has been written and then rewound, you must space forward until the next file mark is detected, which causes the system to return an error. Only then can you start writing again.
Retension
Writing to a 1/4-inch tape can only occur at the beginning of tape (BOT) or after blank tape is detected. If data exists on the tape, you cannot overwrite the data except at BOT. If you want to add data to a tape that has been written and then rewound, you must space forward until the next file mark is detected, which causes the system to return an error. Only then can you start writing again.
Density setting #1 and density setting #2
The following settings apply:
Setting Meaning
17 QIC-525*
16 QIC-150
15 QIC-120
0 Default (QIC-525), or whatever was the last density setting by a using system.
* QIC-525 is the only mode that supports the 1024 block size.

The default values are 17 for Density Setting #1, and 16 for Density Setting #2.

Attributes with fixed values
If a tape drive is configured as a 525 MB 1/4-inch tape drive, the Extended File Marks, Reserve Support, Variable Length Block Size, and Data Compression attributes have predefined values which cannot be changed.