From: lawries@btinternet.com
Date: Thu Feb 19 2004 - 05:19:56 EST
Admins,
This info from Overland EMEA Support.
The file, ddr.dbase, is used by TRU64 UNIX to mainly add density support for
Tape Devices and to specify special values* for a Tape Devices via Mode
Pages. Since LTO Ultrium 1 or 2 are essentially 'single' density devices,
where the density is determined by the cartridge type loaded, TRU64
automatically creates the devices necessary to support writing compressed or
uncompressed data (to the specific cartridge type loaded, Ultrium 1 or 2).
Densities that a device can read need not be specified.
*Special values for Mode Pages are used to specify unique characteristics of
the Tape Device. If the Tape Device defined in the dd.dbase file matches
the Vendor name, and has special values for the Mode Pages defined, then the
OS will expect the Tape Device to respond to all special values, and the
Mode Page requests, as defined in dd.dbase. A new dd.dbase has been
implemented by HP that affects ALL HP Ultrium Tape Devices. Only HP branded
Ultrium Tape Devices will respond to the new Mode Page requests. OEM
versions of HP Ultrium Tape Devices will not respond and will not work under
TRU64 UNIX where this new dd.dbase has been implemented. Note: The error
that will appear when accessing an OEM LTO Tape Device, when using the
unmodified new dd.dbase, is of the form; "Error on device named
/dev/tape/tapexx_d1 - Place Ultrium 2(or 1)-SCSI tape drive unit #xx ONLINE"
The new ddr.dbase has an entry for HP Ultrium that looks like this:
SCSIDEVICE
#
# Matches "Ultrium"
#
Type = tape
Name = "HP" "Ultrium"
#
#
PARAMETERS:
TypeSubClass = lto # Linear Tape Open
TagQueueDepth = 0
MaxTransferSize = 0x0ffffff # (16MB - 1)
ReadyTimeSeconds = 120 # seconds
# Ultrium mode select parameters for rewind after reset behavior
MODESELECT:
ModeSelectNumber = 0
SavePage = No
PageFormat = scsi2
BlockDescriptor = yes
TransferLength = 16
Hdr.Tape.BufferMode = 0x1
Data.UBYTE[0] = 0x3D #Vendor Unique Page Code 0x3D
Data.UBYTE[1] = 0x02
Data.UBYTE[2] = 0x01
Data.UBYTE[3] = 0x00
To modify this file so Overland LTO Tape Devices will work with the OS,
every line below "# Ultrium mode select parameters" should be commented out
by putting the '#' sign in front of each. The entry would then look like:
SCSIDEVICE
#
# Matches "Ultrium"
#
Type = tape
Name = "HP" "Ultrium"
#
#
PARAMETERS:
TypeSubClass = lto # Linear Tape Open
TagQueueDepth = 0
MaxTransferSize = 0x0ffffff # (16MB - 1)
ReadyTimeSeconds = 120 # seconds
#
# Ultrium mode select parameters for rewind after reset behavior
#
# MODESELECT:
# ModeSelectNumber = 0
# SavePage = No
# PageFormat = scsi2
# BlockDescriptor = yes
# TransferLength = 16
# Hdr.Tape.BufferMode = 0x1
# Data.UBYTE[0] = 0x3D #Vendor Unique Page Code 0x3D
# Data.UBYTE[1] = 0x02
# Data.UBYTE[2] = 0x01
# Data.UBYTE[3] = 0x00
For Density Code support; there are a total of 8 device names that will map
to a combination of density and compression variables. TRU64 will
automatically create the 8 devices, for single density devices, whose only
variable is writing compressed or uncompressed. For a device, such as LTO,
that only supports 1 density and compressed or uncompressed, the devices
will be created 'as if' an entry were made, in ddr.dbase, as follows:
DENSITY:
#
DensityNumber = 0,2,4,6
DensityCode = default
CompressionCode = 0x0
Buffered = 0x1
DENSITY:
#
DensityNumber = 1,3,5,7
DensityCode = default
CompressionCode = 0x1
Buffered = 0x1
Note that the (new) ddr.dbase entry above (shown as it actually appears)
does not include these DENSTIY entries. This is because they are implied.
So the tape devices' (which will be created automatically) tapexx_0, 2, 4 or
6, will write uncompressed, and, tapexx_1, 3, 5 or 7 will write compressed,
where 'xx' represents the device number TRU64 UNIX assigns when it creates
the device. LTO Ultrium 2 can write 2 densities dependent on whether an
'Ultrium 1' or an Ultrium '2' cartridge type is loaded. Since an Ultrium 2
drive knows which cartridge is loaded it will write the appropriate default
density for that cartridge (Ultrium 1 or 2).
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