SCSI Information
I. SCSI Terminology:
Here is a table of SCSI terminology and what it means.
II. Pictures of Connectors
Here are some pictures of SCSI connectors and info on how they are used.
III.Types of SCSI on our Systems
Some
Architecture Model Hostnames Card Types
------------ -------------- ------------ -------------------------------
HP 9000/800 A180C CAS3 (1) SCSI Single Ended
(2) Fast Wide SCSI (Differential)
------------------------------------------
| | |=======| | |
| | (2) | |
| ------------- |
| |===| (1)|
------------------------------------------
D250 NETDB, (1) SCSI (Single Ended)
NETMGT2, (2) ESIA/SCSI (Single Ended)
------------
| |===||
| (2) |
| -- |
| || |
| || |
| -- |
| (1) |
| |
| |
| |
| |
| |
| |
------------
G30 SPOOL1 (1) SCSI (Single Ended)
-------------------
| |
| |
| |
| -- |
| || |
| || |
| -- |
| (1) |
| |
| |
| |
| |
-------------------
K2XX DEVELOP2, (1) SCSI (Single Ended)
ASUF1 (2) Fast Wide SCSI (Differential)
K3XX CAS3
CORE
HP-PB I/O HSC Power
-----------------------------
| | | | | | | |
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| | -| -| -| | | |
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| | || || || - - | | |
| | -| -| -| | | | | |
| | 2| 2| 2| | | | | |
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|-----------| - - | | |
| | | 1| 1| 2 2 | | |
| | | -| -| | | |
| | | || || | | |
| | | || || | | |
| | | -| -| | | |
-----------------------------
HP 9000/7XX 712/80 TRANSX (1) SCSI (Single Ended)
-----------------------------
| (1) |
| |===| |
| |
-----------------------------
735 STATS1,2,4 (1) SCSI (Single Ended)
(2) Fast Wide SCSI (Differential)
-----------------------------
| (1) (2) |
| |===| == |====| |
| FDDI |
-----------------------------
C160 STATS3 (1) SCSI (Single Ended)
(2) Fast Wide SCSI (Differential)
-----------------------------
| |
| (2) (1) |
| |====| |===| |
-----------------------------
C240 STATS5 (1) SCSI (Single Ended)
(2) Ultra Wide SCSI (Single Ended)
-----------------------------
| |
| (2) (1) |
| |====| |===| |
-----------------------------
AIX RS6000 250 SOFT3 (1) SCSI (Single Ended)
-----------------------------
| |
| (1) |
| |===| |
-----------------------------
43P-140 DCE1 (1) Fast Wide SCSI (Single Ended)
43P-240 DCE4
-----------------------------
| (1) | |===| | ||
| ||===||| (1)
| ||===||| (1)
| ||===||| (1)
| |
-----------------------------
390 RESEARCH2,3 (1) Fast Wide SCSI (Single Ended)
-----------------------------
| |
| |
| |
| |====| (1) |
-----------------------------
520H FILESRV2 (1) SCSI (Single Ended) (These are plugged into Old 2g (Legsys) Disk,)
530H Y2K (2) Fast Wide SCSI (Single Ended) (These are plugged into Old 2g (Legsys) Disk,)
570 FILESRV3 (3) Fast Wide SCSI (Differential) (These are plugged into STK (Clarrion) Raid Disks)
590 COMPUTE1,2,3
-------------------------
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| | ||
| | ||
| | |==| ||(1) (There is a mix like
| ||====|||(2) this but all are not the same...)
| | ||
| | |==| ||
| | ||
| | ||
| ||====|||(3)
| ||====|||(3)
-------------------------
F30 FILESRV6 (1) Fast Wide SCSI (Single Ended) (These are plugged into Old 2g SCSI (Legasys) Disk,
Or New IBM 4g 7204-114 disks )
F40 FILESRV7 (2) Fast Wide SCSI (Differential) (These are plugged into STK (Clarrion) Raid Disks)
-------------------------
| | | |
| | | |
| ||===|| | (1)
| | | |
| ||===|| | (1)
| | | |
| | | |
| ||===|| | (2)
| ||===|| | (2)
| ||===|| | (2)
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-------------------------
Sun Sparc 10 TRANS19 (1) SCSI (Single Ended)
Sparc 20 HESIOD1
-----------------------------
| |
| (1) |
| |===| |
-----------------------------
Sparcsrver 1000 IMAP1,2,3,4 (1) SCSI (Single Ended) (These are plugged into External Sun 2G Disks)
(2) Fast Wide SCSI (Differential) (These are plugged into STK (Clarrion) Raid Disks)
Ultra1 LDAP1 (1) SCSI (Single Ended) (Some Ultras have this interface)
EUltra1 ASUDNS2 (2) Fast Wide SCSI (Single Ended) (Others Ultras have this interface)
-----------------------------
| |
| |
| |===| |
-----------------------------
EUltra2 FW1 (1) Ultra Wide SCSI (Single Ended)
-----------------------------
| |
| (1) |
| |====| |
-----------------------------
E250 ASUDNS4 (1) Ultra Wide SCSI (Single Ended)
------------
| |
| |
| |
| |
| |
| -- |
| || (1) |
| || |
| || |
| -- |
| |
| |
| |
| (1) |
| |====| |
| |
---------------
E450 WEB1,2,3 (1) Ultra Wide SCSI (Single Ended)
(2) Ultra SCSI (Single Ended) PCI Narrow connection
----------------------
| |
| -- |
| || (1) |
| || |
| -- |
| |
| |
| | ||
| | ||
| | ||
| | ||
| | ||
| | ||
| | ||
| | -- -- || (2) Short PCI/Ultra Wide SCSI (Single Ended)
| | ||
----------------------
IV. Notes on Compatability / Termination
A. Device Compatability.
Device to Host Adapter Compatible Notes
--------------------- --------------------- ---------- -------------------------------------------------------
SCSI (SE) SCSI (SE) YES
SCSI (SE) Fast Wide SCSI (SE) YES Runs at SCSI FAST (10mb/s) speed. (Look Cabeling/Termination
Notes Below on how to connect)
SCSI (SE) Ultra Wide SCSI (SE) ?
SCSI (SE) Fast Wide SCSI (DFl) NO
Fast Wide SCSI (SE) SCSI (SE YES Runs at SCSI FAST (10mb/s) speed. (Look Cabeling/Termination
Notes Below on how to connect)
Fast Wide SCSI (SE) Fast Wide SCSI (SE) YES
Fast Wide SCSI (SE) Ultra Wide SCSI (SE) YES Runs at SCSI Fast/Wide (20mb/s) speed)
Fast Wide SCSI (SE) Fast Wide SCSI (DFl) NO
Fast Wide SCSI (DFl) SCSI SE NO
Fast Wide SCSI (DFl) Fast Wide SCSI (SE) NO
Fast Wide SCSI (DFl) Ultra Wide SCSI (SE) NO
Fast Wide SCSI (DFl) Fast Wide SCSI (DFl) YES Runs at SCSI Fast/Wide/DIff (20mb/s) speed)
Ultra Wide SCSI (SE) SCSI SE ?
Ultra Wide SCSI (SE) Fast Wide SCSI (SE) YES Runs at SCSI Fast/Wide (20mb/s) speed)
Ultra Wide SCSI (SE) Ultra Wide SCSI (SE) YES Runs at SCSI Ultra/Wide (40mb/s) speed if cable length is
correct otherwise it will reset to (20mb/s speed)
Ultra Wide SCSI (SE) Fast Wide SCSI (DFl) NO
-----------------------------------------------------------------------------------------------------------------------
(SE) Single Ended
(DF) Differential
B. Cabeling and Termination
- There is a difference between a Fast Wide Differential Terminator and Fast Wide Single
Ended Terminator.They are not compatible. (The terminators are all labeled so you can
tell the difference since they look very much the same.)
- Some Disks are Self Terminating. For those disks that are there is a light in the back i
to show the termination.
- If connecting 68 pin (Fast Wide SCSI SE ) amd 50 pin ( SCSI SE ) do the following:
1. If the system connection is 50 pin, put all 50 pin devices before the 68 pin Devices on
the bus and then terminate the 68 pin device.
2. If the sytem connection is 68 PIN, put all the 68 pin devices before the 50 pin devices on
the bus and then terminate the 50 pin device.
- Here is a diagram of 60 pin, 50 pin, and Self Terminating Devices and how they need to be hooked
up:
----------------- ---------------- ------------------ ------------------
| | | | | | | Autoterminating|
| SYSTEM | | 68 Pin DEV. | | 68 Pin DEV. | | 68 Pin DEV. |
| | | | | | | |
----------------- ---------------- ------------------ ------------------
| | | | | |
------------------ ------------- -------------
68-68 68-68 68-68
----------------- ---------------- ------------------ ------------------
| | | | | Autoterminating| | |
| SYSTEM | | 68 Pin DEV. | | 68 Pin DEV. | | 50 Pin DEV. |
| | | | | | | |
----------------- ---------------- ------------------ ------------------
| | | | | | |
------------------ ------------- ------------- Terminator
68-68 68-68 68-50
----------------- ---------------- ------------------ ------------------
| | | | | | | |
| SYSTEM | | 50 Pin DEV. | | 50 Pin DEV. | | 50 Pin DEV. |
| | | | | | | |
----------------- ---------------- ------------------ ------------------
| | | | | | |
------------------ ------------- ------------- Terminator
----------------- ---------------- ------------------ ------------------
| | | | | | | |
| SYSTEM | | 50 Pin DEV. | | 50 Pin DEV. | | 68 Pin DEV. |
| | | | | | | |
----------------- ---------------- ------------------ ------------------
| | | | | | |
------------------ ------------- ------------- Terminator
C. Bus Length Rules:
1. Differential Host Adapter
The differential host adapter can support up to 15 devices per port on a SCSI bus
lenght of 24 meters (78.74 feet)
2. Single Ended Host Adapter
For UltraSCSI performance, you must adhere to the following cable length restrictions:
- For 1 to 3 devices, the maximum bus length per port is 3 meters (9.84 feet)
- For 4 to 7 devices, the maximum bus length per port is 1.5 meters (4.92 feet)
If you exceed these bus length restrictions, the UltraSCSI devices may operate at less
than 40 mbytes/sec. And UltraSCSI devie on the bus may experiance errors that eventually
cause it to reset and operate at 20Mbytes/sev.
Here is a table showing the bus length of each type of SCSI bus.
SCSI Type Bus Width Number of Devices SCSI Bus Length (1)
---------------- ------------- ------------------- --------------------
SCSI-2 Fast SE 8 bits 1-7 6.0 meters (19.7 feet)
SCSI-2 Fast/Wide SE 16 bits 1-15 6.0 meters (19.7 feet)
UltraSCSI SE 16 bits 1-3 3.0 meters (9.84 feet)
4-7 1.5 meters (4.92 feet)
SCSI-2 FAST/Wide Diff, 16 bits 1-15 24 meters (78.74 feet)
V. SCSI Information Sources and FAQ's
T10 Committee Web Site
SCSI Trade Association Technical Web Page
SCSI FAQ at support.quantum.com
Another SCSI FAQ
Created Thu Feb 13 18:03:08 MST 1997 by Greg