Date   : Wed, 05 Jul 2006 20:05:09 +0100
From   : Mike Tomlinson <mike@...>
Subject: Re: Stacking wedges and multiple TUBE connections (Was: Re: Cheese Wedge Dating)

In article <4484374D.4030103@...>, Jules Richardson <julesrichar
dsonuk@...> writes

>1) offer flat-topped upper portions of the cheese wedge cases so that they 
>could be stacked?

Cable length.  The Tube's unbuffered, so the cable has to be kept short.

> It seems obvious that people could easily end up with more 
>than one, and the things just don't stack or spread along the desk well!

IIRC, some Acorn publicity shots showed beebs with more than one cheese
wedge alongside (e.g. one copro and a Teletext adapter - this
combination wouldn't be subject to cable length restrictions as they
used different interfaces.)  I thought they looked quite good spread out
as opposed to stacked.

>2) Design the TUBE interface so it could handle multiple devices (connected up 
> and selectable from the beeb - not necessarily switchable without a machine 
>restart though, which would be more work).

The Tube was originally intended to be daisy chained, which is why some
cheese-wedge copros have pins for another 40-pin socket on the
underside.  As far as I know, the sockets were never actually fitted to
production machines.  Perhaps Acorn realised they wouldn't be reliable
with the lack of buffering.

-- 
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.