DLT Density Setting question 1

[bjverzal]

I have a DLT 7000 drive that I want to run in 20GB (DLT 4000) mode. Which (if any) /dev/rmt0 device would I use to force the lower density setting ? If I can't get the density lowered via a /dev/rmt0 device, what automated method can I use to accomplish this ?

TIA, Bill.

 

[aixqueen]

Not sure the 7000 can do the density of another drive you are seeking?
Here is general info that may assist you.......Sorry if I misunderstood you.

It would be in smitty devices .....under the tape drive
the 7000 is

Default Density #1 27 ( 70GB )
Default Density #2 26 ( 40GB )

Don't know if you have a choice for another density setting?

DLT Tape Interchange Information

IBM 7205-311 35GB

The following is a chart that shows the interchange using the IBM 7205-311 tape drive.

--------------------------------------------------------------
|Type of | | | SMIT |
|Cartridge | | Compressed | Density |
|Supported | Density | Data Capacity* | Setting |
|-------------+---------+----------------------------+---------|
|DLTtapeIII | 2.6GB | 2.6GB (No Compression) | 23 |
| | 6GB | 6GB (No Compression) | 24 |
| | 10GB | 20GB (Default for drive) | 25 |
|-------------+---------+----------------------------+---------|
|DLTtapeIIIxt | 15GB | 30GB (Default for drive) | 25 |
|-------------+---------+----------------------------+---------|
|DLTtapeIV | 20GB | 40GB | 26 |
| | 35GB | 70GB (Default for drive) | 27 |
--------------------------------------------------------------

Notes:

The 7205 Tape drive only supports the data densities listed in the table.
Supported data cartridges written in other densities will not be recognized by
the drive and these cartridges will not be readable by this drive.
The 7205 will treat these cartridges as blank cartridges.

If a DLT IV data cartridge written in 40GB mode is attempted to be read
on the 35GB drive the tape will appear to be a blank data cartridge.
Interchange of data between the 35GB drive and the 40GB drive can
only be done on supported data cartridges with a density setting
common between the drives.
The drive does an automatic determination of the density setting when
reading a data cartridge, but for write operations you must set a writing
density that matches the data cartridge you are using.

If an unsupported write density is requested, the density will default
to the highest supported density for the currently loaded data cartridge.
* Compression will depend upon the type of data. A compression
ratio of 2:1 is assumed for this compression capacity.

DLTtapeIII, DLTtapeIIIxt, and DLTtapeIV are trademarks of Quantum
Corporation.

IBM 7205-440 40GB

The following is a chart that shows the interchange using the IBM 7205-440 tape drive.

--------------------------------------------------------------
|Type of | | | SMIT |
|Cartridge | | Compressed | Density |
|Supported | Density | Data Capacity* | Setting |
|-------------+---------+----------------------------+---------|
|DLTtapeIII | 10GB | 20GB | 25 |
|-------------+---------+----------------------------+---------|
|DLTtapeIIIxt | 15GB | 30GB | 25 |
|-------------+---------+----------------------------+---------|
|DLTtapeIV | 20GB | 40GB | 26 |
| | 35GB | 70GB | 27 |
| | 40GB | 80GB | 65 |
--------------------------------------------------------------

Notes:

The 7205 Tape drive only supports the data densities listed in the table.
Supported data cartridges written in other densities will not be recognized
by the drive and these cartridges will not be readable by this drive. The
7205 will treat these cartridges as blank cartridges.
The drive does an automatic determination of the density setting when
reading a data cartridge, but for write operations you must set a writing
density that matches the data cartridge you are using.

If an unsupported write density is requested, the density will default
to the highest supported density for the currently loaded data cartridge.
* Compression will depend upon the type of data. A compression
ratio of 2:1 is assumed for this compression capacity.

DLTtapeIII, DLTtapeIIIxt, and DLTtapeIV are trademarks of Quantum Corporation.

DLT Significant Item

The DLT drive is sensitive to the delivery of data to the tape drive.
Some applications take the blocksize and block
the data block into larger blocks for transfer to the tape drive.
Some applications call this the blocksize, or the buffer
size or blocking factor. Whatever it is called you need to understand
that this tape drives performance(data rate)is
greatly effected when the system sends small blocks of data.
Try setting the tape drive block size to a large block
size and large blocking factor. You will need to test your application
to see at what blocking you get the best
performance for your tape drive. The minimum recommended
blocking for this drive is 32k. Some AIX commands
already use 32k or larger blocks when writing, some do not.
The following are a few of the AIX commands and blocking information:

backup <- will either use 32k or 51.2k as default depending if backup
by name or not. N/S customer change required.
tar <- default is 10k (error in tar manual stating 512kb)
tar needs the customer to use at minimum -N64
mksysb <- uses backup on AIX 4.1 N/S customer change required.
dd needs the customer to use at minimum bs=32k
cpio needs the customer to use at minimum -C64

Users should insure the blocksize they select is supported by the users application.

As an example: Using a blocksize of 1024 and backing up 32GB of data will take
approximately 22 hours. Same 32GB of data backed up at a block size of 32k
will take approximately 2 hours. Small blocksizes have a significant
impact on performance but only a minimal impact on capacity. However 2.6
format(density) and 6 format(density)are significantly impacted in capacity
by using small blocksizes, they don't pack the data in the drives internal 8k
block.



rmt retension/rewind settings

-----------------------
RMT D1/D2 | Retension*| rewind** | D1 = density 1 used
-----------------+-----------+------- ----| D2 = density 2 used
| rmt0.0/4 | no | yes | * 4mm & 8mm ignore this.
|-----------------+-----------+-----------| ** Rewind on open, does not
| rmt0.1/5 | no | no | control on insertion.
|-----------------+-----------+-----------|
| rmt0.2/6 | yes | yes |
|-----------------+-----------+-----------|
| rmt0.3/7 | yes | no |
-----------------------------------------

 

[aixqueen]

http://www.rs6000.ibm.com/support/micro/tapewhdr.html#Header_101

 

[bjverzal]

This looks exactly like what I was looking for aixqueen. Thanks for the info.

Bill.

 

[bjverzal]

P.S. If it is right, I'll give you a gold star.

BV

 

[tomfay]

Is a Magstar 3570 dual C01 the same as the C02 are they compatiable?

 

[aixqueen]

http://www2.ibmlink.ibm.com/cgi-bin...-C01&xhi=usa.main|usa.main|salesmanual^&xfr=N

http://www2.ibmlink.ibm.com/cgi-bin...-C02&xhi=usa.main|usa.main|salesmanual^&xfr=N

http://www2.ibmlink.ibm.com/cgi-bin...3570&xhi=usa.main|usa.main|salesmanual^&xfr=N

Model Abstract 3570-C01
The IBM 3570 Model C01 is a Library Subsystem with 1 tape drive and a cartridge
capacity of 20. The tape drive data rate is 7.0 MB/sec and the case is stand-alone.

Model Abstract 3570-C02
The IBM 3570 Model C02 is a Library Subsystem with 2 tape drives and a
cartridge capacity of 20. The tape drive data rate is 7.0 MB/sec and the case is stand-alone.

Model Conversions - done by IBM....
C01 to C02