28 Oct
2010
28 Oct
'10
3:06 p.m.
On 10/28/10 2:55 PM, William Donzelli wrote:
In many cases, DEC's wider racks had no interconnect reduction
benefits, at least none that I can identify. For example, the 11/750 is
(more or less) a 19" rack machine in a rack with a wide cableway on the
left side. It'd have the same number of connectors with or without that
extension.
The DECdatasystem-570 configuration of the PDP-11/70 is more of the
same, just a lot more air in the box. Same connectors.
The DECsystem-2020 contains card cages which don't appear to be
helped really at all by the wider rack. The CPU/memory card cage
(bottom) has big gaps on both sides, and the Unibus card cage (top) has
a big gap to its right. It makes cabling more convenient, sure, but I
fail to see how it reduces interconnects.
The PDP-11/60 is similar, with lots of air surrounding fairly
ordinary rack-width card cages.
I can see your point where machines like the VAX-11/780 and larger
8000 series are concerned, though.
-Dave
--
Dave McGuire
Port Charlotte, FL
The extra-wide
cabinet always seemed out of place next to all the 19-inch
rack equipment and I wondered why DEC went to the trouble to make it that
way. I never knew about the regular rack-width 751 until now.
DEC and IBM and many others went to wider cabinets to keep costs
lower. Less interconnections, basically, and connectors cost real
money.