On Fri, 16 Oct 1998, Todd Vierling wrote:

> On Fri, 16 Oct 1998, Wally Hinson wrote:
> 
> : Hey, out of curiosity, how much of a difference is there between the
> : SS1+/SS2 onboard SCSI controllers?  I've been running NetBSD on an SS1+
> : with what the esp driver reports to be the original revision of the chip,
> : and it's *slow* -- I seem to spend a lot of time waiting for the disk.

The SS2 uses the ESP100A part. The SS1 and SS1+ use the ESP100 part.
Minor differences.

> 
> That depends how much disk activity you do on a regular basis and how many
> physical disks you have.
> 
> My own subjective use shows the SS2 as having better performance on the
> scale of 40-50% extra, but it seems to be more CPU than disk, truly.  

It has a hardware VAC flush. That's a big difference. It has
twice the number of h/w contexts and PMEGS. That's an even
bigger win. It has a processor that's nearly twice that of
an SS1+ (40Mhz IU vs. 25Mhz IU). It has 3 full master/slave
SBus ports (the SS1 and SS1+ only have 2- the third is
slaveonly).