Subject: Re: various scsi questions
To: None <firstname.lastname@example.org>
From: Justin T. Gibbs <gibbs@FreeBSD.org>
Date: 02/08/2000 21:32:38
>This is 'Low Voltage Differential' and requires special negotiations.
>> does it uses the same cables as Ultrawide ?
>No. It needs those twisted pair flat cables.
Although LVD requires higher quality cables, the physical connections
are the same for LVD, SE, and HVD cables. This means that you can use
SE cables to perform LVD transfers, but you may see corrupted transfers
at the higher speeds.
>Note that 80MB/s (or 160MB/s for Ultra3- I'm about to check in support for
>this) is still only in DATA PHASE. Command/Status/Message phases are still
>async mode. With Fibre Channel, you get maybe nearly twice the effective IOPs
>because command/status stuff gets shipped at the same data rate as data
I would have thought that QLogic would support "information unit transfers"
on their U3 products. This allows all information to be transmitted at
the negotiated synchronous rate.