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Wide Ultra2 SCSI speed?

Ayman Altounji
Valued Contributor

Wide Ultra2 SCSI speed?

When the server was purchased, it was bought with a Wide Ultra2 SCSI card for the extra speed of 80 MPS. Exploring the Compaq Web management interface, it states that the Ultra2 card and hard drives, BB01813467, are only exchanging data at 40 MPS and 16 bit. This should be 32 bit and 80 MPS, why not?
The drivers are CPQSCSI.HAM v1.43 and CPQSHD.CDM v1.50i.
1 REPLY
Ayman Altounji
Valued Contributor

Re: Wide Ultra2 SCSI speed?

Hello,

I am not sure where you have located your information, but I do understand that SCSI is a bit confusing at the best of times.

The hard drive that you mention [Compaq Module: BB01813467] with [Compaq Spare: 104633-0012 Option:388144-B22] is a UNIVERSAL form fitting drive. The Interface is WIDE ULTRA2 SCSI with a SCA-2 (SCA-2 [enhancement that allows hot plugging]), 80 PIN connector (68 PIN).
If we look at the SCSI standards and their descriptions we will see that this SCSI connector indicates that this drive will communicate with SCSI transfer speeds of Up to 80 MB/s (This is a WIDE [16 BIT] not a NARROW [8 BIT] drive SCSI form factor)

NOTE:
To assist with the PIN configuration and the finer points that I have pointed out in this response please feel free to look at http://www.transintl.com/technotes/scsi.htm. There is other SCSI explanation sites but this one assist with the SCA and PIN discussion.

Fuzzy about SCSI?

SCSI (Small Computer Systems Interface) is a high-speed, general-purpose peripheral interface. Over the years, it has expanded to offer a variety of data transfer rates and an increased bus bandwidth. Today, SCSI is now more a family of interfaces than a single interface.

Bandwidth: The bandwidth is how many bits can be transmitted on the bus at the same time. SCSI has only two bandwidth options, Narrow 8-Bit and Wide 16-Bit. The number of bits on the bus also define how many devices can technically be added to the SCSI bus. On 8-Bit busses, 8 devices can be added (including the host adapter) and on 16-Bit busses up to 16 devices can be used.

Speed: This is how fast the data transfers on the SCSI bus and is closely tied to Bandwidth.

Narrow 8-Bit SCSI-1 up to 5MB/Sec
Narrow 8-Bit SCSI-2 up to 10MB/Sec
Wide 16-Bit SCSI-2 up to 20MB/Sec
Narrow 8-Bit Ultra SCSI up to 20MB/Sec
Wide 16-Bit Ultra SCSI up to 40MB/Sec
Narrow 8-Bit Ultra2 SCSI up to 40MB/Sec
Wide 16-Bit Ultra2 SCSI up to 80MB/Sec
Narrow 8-Bit Ultra3 SCSI up to 80MB/Sec*
Wide 16-Bit Ultra3 SCSI up to 160MB/Sec*

Further where are you basing your SCSI TRANSFER concerns? Form within the information contained under Compaq insight manager or from a base line, or network tester or some type?

After all that information over load, your drive should be communicating Up to 80 Mb/s, when connected to the Ultra2 SCSI controller that was added to your ProLiant 1600.

Jason