Dell 3 User Manual

Page 28

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PERC 3/SC has one ultra-high-density 68-pin external connector for the
external storage subsystem and one high-density 68-pin internal connector.

Single-Ended and LVD SCSI Buses

The SCSI standard defines two electrical buses: a single-ended bus and an
LVD bus. PERC 3 supports both standards.

Maximum Cable Length for SCSI Standards

Table 1-1 displays the maximum length of cable that you can use for various
SCSI standards.

SCSI Bus Widths and Maximum Throughput

Table 1-2 displays the SCSI bus widths and maximum throughput for each
of the SCSI standards.

Ta b l e 1 - 1 . M a x i m u m C a b l e L e n g t h f o r S C S I S t a n d a r d s

SCSI Standard

Single-ended

LVD

Maximum # of
Drives

SCSI I

6 m

12 m

7

Fast SCSI

6 m

12 m

7

Fast Wide SCSI

6 m

12 m

15

Ultra SCSI

1.5 m

12 m

7

Ultra SCSI

3 m

12 m

3

Wide Ultra SCSI

N/A

12 m

15

Wide Ultra SCSI

1.5 m

12 m

7

Wide Ultra SCSI

3 m

12 m

3

Ultra 2 SCSI

N/A

25 m

1

Ultra 2 SCSI

N/A

12 m

7

Wide Ultra 2 SCSI

N/A

25 m

1

Wide Ultra 2 SCSI

N/A

12 m

15

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