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SCSI Information

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=== Single Ended (SE)=== === Single Ended (SE)===
<ul><ul><li>Positive data bits are referenced to ground</li><li>Maximum cable length is 6 meters</li> <li>Externally terminate bus with an active terminator.</li></ul></ul> <ul><ul><li>Positive data bits are referenced to ground</li><li>Maximum cable length is 6 meters</li> <li>Externally terminate bus with an active terminator.</li></ul></ul>
-<strong><em>Differential (Diff)</em></strong>+ 
 +=== Differential (Diff) ===
<ul><ul><li>Positive data bits are referenced to negative data bits</li><li>Maximum cable length is 25 meters</li><li>Must use a differential terminator.</li></ul></ul> <ul><ul><li>Positive data bits are referenced to negative data bits</li><li>Maximum cable length is 25 meters</li><li>Must use a differential terminator.</li></ul></ul>
-<strong><em>Narrow devices</em></strong>+ 
 +=== Narrow devices ===
<ul><ul><li>3 address bits for target id's</li><li>4 2 1</li><li>Supports target id's 0-6 and the controller is target id7.</li></ul></ul> <ul><ul><li>3 address bits for target id's</li><li>4 2 1</li><li>Supports target id's 0-6 and the controller is target id7.</li></ul></ul>
-<strong><em>Wide devices</em></strong>+ 
 +=== Wide devices ===
<ul><ul><li>4 address bits for target id's</li><li>8 4 2 1</li><li>Supports target id's 0-6, 8-15 and the controller is target id7.</li></ul></ul> <ul><ul><li>4 address bits for target id's</li><li>8 4 2 1</li><li>Supports target id's 0-6, 8-15 and the controller is target id7.</li></ul></ul>
-<br>+ 
-<u><strong>SCSI Rules</strong></u>+== SCSI Rules ==
<ul><li>Never mix Single-ended and differential devices on a SCSI bus.</li> <ul><li>Never mix Single-ended and differential devices on a SCSI bus.</li>

Revision as of 00:03, 12 April 2006

In the event you find that your backups are not operating as expected, for example, lower than expected throughput or SCSI errors in your System Messages file, refer to the tables below to confirm your SCSI configuration.

Contents

SCSI Chart

Pins
 
Bus Speed
MHz
Bits
 
Throughput
MB/sec
Max. Cable
Length
SCSI-1 50 5 8 5 SE - 6m
HVD - 25m
SCSI-2 Fast 50 10 8 10 SE - 3m
HVD - 25m
Wide 68 5 16 10 SE - 6m
HVD - 25m
Fast Wide 68 10 16 20 SE - 6m
HVD - 25m
SCSI-3 Wide Ultra 68 20 16 40 LVD - 12m
HVD - 25m
Wide Ultra2 68 40 16 80 LVD - 12m
HVD - 25m
Ultra3 68 40 16 160 LVD - 12m
Ultra320 68 80 16 320 LVD - 12m


Definitions

Single Ended (SE)

Differential (Diff)

Narrow devices

Wide devices

SCSI Rules