SCSI Transfer Rate

Elliott, Robert Robert.Elliott at
Tue Dec 5 12:36:03 PST 2000

* From the T10 Reflector (t10 at, posted by:
* "Elliott, Robert" <Robert.Elliott at>
> * From the T10 Reflector (t10 at, posted by:
> * "Hartling, Sean" <Sean_Hartling at>
> *
> Does anyone have any idea how to obtain the bus type and bus 
> speed from a scsi device?  I have a U-160 drive connected to 
> a Adaptec AHA2940 and I need to obtain the Bus speed and the 
> bus type from the device.  
> Looking through the SCSI-2 specs the inquiry data of a 
> device doesn't contain this information.  It appears that the 
> information is obtained by the host adapter at boot up time 
> and there doesn't appear to be a way of obtaining
> this information after boot.  Any help would be 
> greatly appreciated.
> Sean K. Hartling
> Adaptec Inc.
> Management Software
> wk:(303)684-4879
> Home:(970)532-1180
> seanh at

A proposal was accepted at the Novemeber T10 plenary to
solve that problem:
	00-397r1 Reporting currently negotiated settings

It defines a parallel-SCSI specific mode page for targets
to return their current bus speeds and other information.
You won't find any devices supporting this yet, though.

The host adapter driver knows the information, but there is
no standard API across HBA vendors for applications to 
retrieve this information.  The Fibre Channel world recently 
created a "management API" to communicate this type of 
information - something similar for parallel SCSI would
be helpful.  T10 doesn't have much expertise in 
standardizing APIs, though.

PC: Robert.Elliott at
UNIX: relliott at
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