This document addresses some common questions about tape drives, densities, and rmtX.Y special files. This document is applicable to AIX versions 3.2 and 4.1. For detailed information concerning all supported tape drives, see Chapter 10 of the IBM RS/6000 System Management Guide, SC23-2457.
The following table lists tapes that can be used with the IBM 7207-001 (QIC-150), 7207-011 (QIC-525), and 7207-012 (QIC-1000) tape drives.
Tape Type Model 001 Model 011 Model 012 DC300XLP R R R DC600A R/W (15) R * R * DC6150 R/W (15,16) R/W (15,16) R/W (15,16) DC6250 R/W (15,16) R/W (15,16) R/W (15,16) DC6037 R/W (15,16) R/W (15,16) R/W (15,16) DC6320 R/W (15,16) R/W (15,16) R/W (15,16) DC6525 R ** R/W (15,16,17) R/W (15,16,17) DC9100 N/A N/A R/W (21) DC9120 N/A N/A R/W (21)
Note:
R Read Only
R/W Read and write
N/A Not compatible
* Not recommended -- will cause excessive wear to read/write head
** Not recommended -- will clog read/write head
( ) Numbers in parenthesis are allowable density settings. For greatest capacity,
use the highest number.
Density Tape Format
15 QIC 120
16 QIC 150
17 QIC 525
21 QIC 1000
You can predefine two writing-density settings which you can later choose by specifying the Y extension of the rmtX.Y special file. If you do not define the settings, the default settings for the tape drive will be used.
The following charts in the left-hand column show possible values for the density settings with various tape drives. The charts in the right-hand column show the tapes that can be used with the drives.
Density Setting Description
19 Writes in DDS (Digital Data Storage)
format (not mofifiable for 4mm)
00 Factory power-on default of DDS format
(not modifiable for 4mm)
Note: Less than 324 listed as "other SCSI Tape Drive." 324 and greater: 4mm listed as either 2.0 GB 4mm tape drive or 4.0 GB 4mm tape drive.
Note: The drive is always in compression mode.
Part Number Cartridge Type 4mm Usage 21F8758 Data 21F8763 Cleaning 50 cleanings
Note: Be sure to use data dat tapes instead of voice dat tapes with the 7206 4mm tape drive. Voice tapes will not work. Data dat tapes are marked "DDS ||||" on the cartridge.
Density Setting Description
16 Writes in QIC 150 format
15 Writes in QIC 120 format
00 Factory power-on default for QIC 150
or last saved permanent MODE select
density as set by using system
Part Number Cartridge Type 1/4" Usage
21F8588 Data QIC-150 or QIC-120
21F8570 Cleaning 50 cleanings
Density Setting Description
17 Writes in QIC 525 format
16 Writes in QIC 150 format
15 Writes in QIC 120 format
00 Factory power-on default for QIC 525
or last saved permanent MODE select
density as set by using system
Part Number Cartridge Type 1/4" Usage 21F8587 Data QIC-525 21F8588 Data QIC-150 or QIC-120 21F8570 Cleaning 50 cleanings
Density Setting Description
21 Writes in QIC 1000 format
17 Writes in QIC 525 format
16 Writes in QIC 150 format
15 Writes in QIC 120 format
00 Factory power-on default for QIC 1000
or last saved permanent MODE select
density as set by using system
Part Number Cartridge Type 1/4" Usage 21F8732 Data QIC-1000 21F8587 Data QIC-525 21F8588 Data QIC-150 or QIC-120 21F8570 Cleaning 50 cleanings
Density Setting Description
00 Drive is single density - 2.3GB;
There is no Density 1 and 2 for this drive.
00 Factory power-on default
Part Number Cartridge Type 8mm Usage 21F8595 Data 2.3 GB 21F8593 Cleaning 12 cleanings
Density Setting Description
140 Writes in 5.0GB mode and will enable data
compression; also, to do compression you must
use "DATA COMPRESSION = yes"
21 Writes in 5.0GB mode and will NOT do data compression
20 Writes in 2.3GB mode and will NOT do data compression
00 Factory power-on default for 5.0GB data
compression mode
Part Number Cartridge Type 8mm Usage
21F8595 Data 2.3 & 5.0 GB, 112M length
21F8593 Cleaning 35 cleanings
Data 7.0 GB 160m length
Density Setting Description 2 Writes in 1600 bits per inch 3 Writes in 6250 bits per inch
For a listing of possible values for the density settings for various tape drives see "Densities and Tapes."
smit tape
DENSITY setting #1 { }
DENSITY setting #2 { }
To select a writing density, type in the number which corresponds to the
desired density for the tape drive model you have.
Notes:
The rmtX.Y file is used in commands, such as backup, to specify the tape drive device. For example,
backup -0 -u / /dev/rmt0
The X part of the rmtX.Y file name specifies which tape drive is used. The first tape drive connected is rmt0, the second is rmt1, etc. The Y extension on the file name specifies the tape drive action and writing density as shown in the following chart:
Special File Retension Rewind Density Setting rmtX no yes 1 rmtX.1 no no 1 rmtX.2 yes yes 1 rmtX.3 yes no 1 rmtX.4 no yes 2 rmtX.5 no no 2 rmtX.6 yes yes 2 rmtX.7 yes no 2
Suppose you have a 7207 1/4" tape drive and you have set Density #1 = 16 and Density #2 = 15.
If you use special file rmt0.3, the drive will write in QIC 150 density, will not rewind, and will retension.
If you use special file rmt0.6, the drive will write in QIC 120 density, rewind, and retension.
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