Computer in 1900, was RE: Oldest operational computer was Re: cctalk Digest , Vol 54, Issue

[Roy J. Tellason]

On Friday 15 February 2008 10:48, William Donzelli wrote:
(Snip)
> >  I seem to recall that this was about the biggest problem in getting
> > Colossus to work in the 1940s; the technology for doing the optical
> > detection of the tape data just wasn't really 'there' yet, not at any
> > speed. I think the maximum they managed to get was around 8KHz, but it
> > wasn't particularly reliable (I think 5KHz was the norm, and it took an
> > awful lot of initial effort to get that working properly).
>
> I am not sure what the photocells of 1920 were up to, but by 1940 they
> were not half bad, with so many being used for FAX service. 8 KHz may
> be about right for off the shelf tubes.

For some reason when I read "photocell" earlier on in this thread I started 
thinking about CdS and similar stuff,  not thinking about _tubes_ per se,  
until I hit the last paragraph of this post...

There are a number of different photocell datasheets on my tubes page:

http://www.classiccmp.org/rtellason/tubes.html

Perhaps this info might be useful  Some of those real early audio and other 
tubes are in there too,  though I don't recall offhand if that stuff is dated 
or not.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin