At 16:34 -0600 12/08/2002, Blair Stilwell wrote:
>Jeff Walther wrote:
>
>>  So, on the older PowerSurge machines there is a MESH SCSI bus 
>>which is internal only and supports 10 MB/s.  On the Beige G3 the 
>>only SCSI is MESH based, but it only supports 5 MB/s and has both 
>>internal and external connectors.    I think this change in what 
>>MESH does, and step backwards in performance also led to a lot of 
>>confusion about the Beige G3's capabilities when it was released.
>
>
>I got the number from an old Mac user web site, and figured the 
>10MB/s was right based on the boot messages on a Beige G3 running 
>Linux PPC (2.2.20).  I haven't run Linux on a Beige G3 in quite some 
>time, so I'm not sure if that was an error or hack.  Is Ben 
>Herrenschmidt still reading this list?  I admit the 10MB/s internal 
>vs. 5MB/s external seemd odd to me (I thought maybe it was a 
>stability issue or something), and now seeing the Mesh history, I 
>can see that the Mac user pages were just confused by the MESH on 
>older PowerMacs.  It looks like they help spread confusion well ;-).


Yes, the Mac sites spread the confusion very much.   When the Beige 
first came out there was a lot of confusion about what the SCSI was 
capable of.  Many of the sites settled on believing 10 MB/s based on 
the fact that it was SCSI-II, because they didn't understand that 
SCSI can be SCSI-II without being Fast.  You'll find such wrong 
information pretty widespread.

The Apple Hardware Developer Notes for various models are usually 
reliable, though I think the PM7200 doc may have some errors in its 
PCI section.

Jeff Walther