HP Ultrium Tape Drive manual Glossary

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Single-Ended and Low Voltage Differential SCSI

These terms define how the signals are transmitted along the cable.

With single-ended (SE) SCSI, each signal travels over a single wire and each signal’s value is determined by comparing the signal to a paired ground wire. Signal quality tends to decrease over longer cable lengths or at increased signal speed.

With low voltage differential (LVD) signaling, signals travel along two wires and the difference in voltage between the wire pairs determines the signal value. This enables faster data rates and longer cabling with less susceptibility to noise than SE signaling and reduced power consumption.

Narrow and Wide, Fast, Ultra and Ultra2 SCSI

Narrow SCSI devices can transfer data one byte at-a-time (and are sometimes called “8-bit SCSI” devices). They can conform to either the SCSI-2 or SCSI-3 protocols. They have a 50-pin connection to the SCSI bus.

Wide SCSI devices can transfer two bytes of data simultaneously (“16-bit SCSI”). They usually have a single, 68-pin connection to the SCSI bus. (This physical arrangement is part of the SCSI-3 specification.) They may support either SCSI-2 or SCSI-3 protocols. Wide and narrow devices can simultaneously be connected to the same bus without problem, provided certain rules are followed.

Fast SCSI can transfer data at up to 10 MB/sec, using a cable of up to 6 meters total length.

Ultra SCSI can transfer data at up to 20 MB/sec, but the cable length cannot exceed 3 meters (it is also known as “Fast20”).

Ultra2 SCSI can transfer data at up to 80 MB/sec, using a cable of up to 12 meters.

Ultra160 SCSI can transfer data at up to 160 MB/sec, using a cable of up to 12 meters.

Ultra320 SCSI can transfer data at up to 320 MB/sec, using a cable of up to 12 meters.

Ultra SCSI supports both SE and LVD interfaces. Although Ultra2 SCSI and above can support SE devices, this is not recommended as the whole bus is slowed to Ultra speeds; instead, use LVD devices only.

HP’s Ultrium drives are Ultra-320 compatible devices. They should be used only on LVD host bus adapters for maximum performance.

Glossary

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Contents Generation 3 drives Version Date Changes Contents Verifying the Installation Related documents Purpose of this manualDocuments specific to HP Ultrium drives Documentation mapDrives-general Interface General documents and standardization How error correction worksIrvine, CA Tel 800 854 7179 or 714 261Page Introduction Backup ApplicationsUltrium Drives in a Library IntroductionHP-UX AIX HP Servers and Workstations-HP-UX HP-UX SystemsIntroduction Determining the Scsi ID HP-UX SystemsFor an HP Ultrium drive, execute the following Creating the Device FilesSelect the following Where When you have exited sam, run ioscan to see the tape driveRun insf as follows To create a device file with the following characteristicsWhat Next? For compressed mode defaultHardware path can be found from previous ioscan output HP-UX Systems HP Alpha Unix HP Alpha UnixHP Alpha Unix Add the following entry to your /dev/ddr.dbase fileWhat Next? Determining the Scsi ID Configuring the Device FilesThis will produce output that looks similar to Device Filenames under AIX Linux Configuring on Linux SystemsDetermining the Scsi ID Linux LinuxThis should find a number of lines. One should look like Where /dev/stp is the device file Using the Seek and Tell Features of mtLinux Sun Systems, Solaris 8, 9 Sun Systems, Solaris 8, 9This will produce output similar to the following This produces a list similar toLs -l /dev/rmt/*m grep st@X Determine the device file by typingWhen the system is down, reboot Do a reconfigure bootHP-Data Values Specifies the Scsi ID target of the device Values for the parameters for name are as followsSpecifies the LUN for the device Verifying the Installation of the Drive Unix Verifying the InstallationTo verify the installation Verifying the InstallationRead the file back from tape File The name of the file to archive, prefixed with ‘./’Change to the temporary directory Compare the original with the restored versionExtract the file from the tape Verifying the Installation Glossary GlossaryFibre Channel switching technology Response to a filemark commandFeatures required by that standard Point-to-point connection between itself and the fabricGlossary Glossary Index IndexAIX Index
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