[SCC_Active_Members] Test summary of Xerox and SRI keysets in the CHM collection

[Ed Taft]

On 5/19/2006 10:45 AM, Philip Gust wrote:
> The only problem encountered was that our custom adapter cable was 
> wired backwards, so key0 registered as key4, an so forth.  The cable 
> was built from Xerox Alto schematics, and we need to determine whether 
> the problem was how the cable was wired or the schematics.  In any 
> case we were still able to complete the tests, and we can easily 
> rewire the cable to set things right.
Here is a possible explanation for this discrepancy --

The Alto, like most machines designed at Xerox PARC, was a big-endian 
machine. It was PARC custom to number bits on such a machine 
left-to-right, so that the high-order bit is numbered 0. This is in 
contrast to today's almost universal industry practice of numbering bits 
right-to-left, so that the low-order bit is numbered 0. This might have 
caused confusion in interpreting the Alto schematics.

Ed Taft