|
STA Terms
|
Bus Speed,
MBytes/Sec. Max.
|
Bus Width,
bits
|
Max. Bus Lengths, Meters (1)
|
Max. Device
Support
|
|
Single-ended
|
LVD
|
HVD
|
|
SCSI-1(2)
|
5
|
8
|
6
|
(3)
|
25
|
8
|
|
Fast SCSI (2)
|
10
|
8
|
3
|
(3)
|
25
|
8
|
|
Fast Wide SCSI
|
20
|
16
|
3
|
(3)
|
25
|
16
|
|
Ultra SCSI (2)
|
20
|
8
|
1.5
|
(3)
|
25
|
8
|
|
Ultra SCSI (2)
|
20
|
8
|
3
|
-
|
-
|
4
|
|
Wide Ultra SCSI
|
40
|
16
|
-
|
(3)
|
25
|
16
|
|
Wide Ultra SCSI
|
40
|
16
|
1.5
|
-
|
-
|
8
|
|
Wide Ultra SCSI
|
40
|
16
|
3
|
-
|
-
|
4
|
|
Ultra2 SCSI (2,4)
|
40
|
8
|
(4)
|
12
|
25
|
8
|
|
Wide Ultra2 SCSI (4)
|
80
|
16
|
(4)
|
12
|
25
|
16
|
|
Ultra3 SCSI or Ultra160 SCSI (6)
|
160
|
16
|
(4)
|
12
|
(5)
|
16
|
|
Ultra320 SCSI (6) |
320
|
16
|
(4)
|
12
|
(5)
|
16
|
Notes:
(1) The listed maximum bus lengths may be exceeded in Point-to-Point
and engineered applications.
(2) Use of the word "Narrow", preceding SCSI, Ultra SCSI, or
Ultra2 SCSI is optional.
(3) LVD was not defined in the original SCSI standards for this speed.
If all devices on the bus support LVD, then 12-meters operation is possible
at this speed. However, if any device on the bus is singled-ended only,
then the entire bus switches to single-ended mode and the distances in
the single-ended column apply.
(4) Single-ended is not defined for speeds beyond Ultra.
(5) HVD (Differential) is not defined for speeds beyond Ultra2.
(6) After Ultra2 all new speeds are wide only.
SCSI Terms - STA overview of the different
SCSI Standards and Cables.
|
