Python list vs google group

[Gene Heskett]

On Friday 15 June 2018 23:52:12 Gregory Ewing wrote:

> Jim Lee wrote:
> > It was so long ago that I forgot some of the
> > details, but it boiled down to the TWAIN driver pushing the SCSI bus
> > out of spec.
>
> Clearly you didn't sacrifice enough goats!
>
> https://odetocode.com/blogs/scott/archive/2004/09/22/scsi-is-not-magic
>.aspx
>
> --
> Greg

This biggest single thing wrong with any of those old scsi interfaces is 
the bus's 5 volt isolation diode, the designer speced a shotkey(sp) 
diode, and some damned bean counter saw the price diff and changed it to 
a std si power diode in the BOM on the way to the production line, 
thereby destroying the headroom of the logic 1 signal level by lowering 
the supply voltage to the resistive terms used by nominally .6 volts, 
the diff in the forward drop. Back when you could run over to the shack 
and get a shotkey diode, you could make any of them work like a charm.    

The other choice was to find a higher voltage to run the terms on, 5.75 
volts would have been lovely but made of pure unobtainium. But combine 
the si diode, and a psu fading with age and down to 4.85 volts on the 5 
volt line and you were doomed.

-- 
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>