Eric,
Got my first programming job in 1968 writing Autocoder for an IBM 
1400 series box with 80K of storage, half of which was available for 
us to use.  A far cry from the 4k 1401 I learned to program 
on.  Evolved in to DOS/360 and all its offspring until 1995 when I 
left the ineustry for other interests.  All good stuff and fond 
memories! And yes, JCL was always a large pain in the ass!!
pat, K9JAUAt 09:37 PM 11/3/2015, you wrote:
>thats almost as bad as knowing job control language for an IBM AS/360 =
>Mainframe. :) Also, working on reel to reel tape machines. Its really =
>too bad that most people these days don't remember the technology that =
>was the predecessor to the current media. You ask a kid today what a =
>floppy disk is and they might look at you like a deer caught in the =
>headlights. Or how about coders these days that couldn't conceive of a =
>program written in basic and having to work tightly in only 8k of ram. =
>Pretty soon, I imagine, keyboards are going to be quaint reminders of an =
>old computing past.
>
>DE n7zzt Eric
>
>On Nov 3, 2015, at 8:11 PM, Tom Fowle wrote:
>
> > Knowing how things work, or used to work is never useless.
> > At the least it's interesting.
> >=20
> > Used to run 16 MM projectors in highschool in the 60s, but don't =
>remember
> > the filter. Maybe those school units didn't have the freeze frame.
> > thanks for the fun
> > tom Fowle WA6IVG
> >=20
> > On Tue, Nov 03, 2015 at 02:22:44PM -0600, Martin McCormick wrote:
> >>      A lot of what is left of my brain is useless knowledge by
> >> today's standards. When I worked as a technician with the OSU
> >> Audio Visual Center in the eighties, I repaired 16-millimeter
> >> film projectors among many other things and I have a whole
> >> treasure trove of trivia in my head that doesn't get you very far
> >> today.
> >>=20
> >>      Did you know, for instance, that if the film stops moving
> >> for even a fraction of a second that the heat from the projection
> >> lamp is sufficient to melt it? Most projectors had a freeze-frame
> >> function but it only worked because a special piece that greatly
> >> reduced the amount of heat/light was supposed to drop down
> >> between the film gate and the film, itself.
> >>=20
> >>      We had a few machines that came in because a mechanical
> >> part that held the filter piece up and out of the way failed and
> >> the piece would slowly swing down and cause the light output to
> >> appear to go very dim.
> >>=20
> >>      How does a person who is blind work on a film projector?
> >> Most of the mechanical failures that befall 16-millimeter
> >> projectors cause audible issues also.
> >>=20
> >>      Sound film projectors must yank the film through the gate
> >> in a series of 24 very fast jerks per second so that each frame
> >> of the picture is still for 1/24 of a second. When the film
> >> reaches the sound pickup, it must not have any trace of the jerky
> >> motion and moves as smoothly as audio tape. There are failure
> >> modes that cause the film to move more smoothly than it should
> >> through the film gate and other failures that make it move in a
> >> jerky manner through the sound pickup. Those usually make the
> >> machine clatter with an extra loud sound or the sound has a
> >> terrible flutter in the speed which is unacceptable. It is
> >> necessary to examine the film transport to diagnose the problem
> >> and fix the broken parts.
> >>=20
> >>      There is a Walt Disney movie which I think might be
> >> "Bambee" in which there is a scene where animals are talking to
> >> each other while under water. Their voices all sound fluttery
> >> like someone with water in their throat. One time, my wife and I
> >> watched this film because she wanted to see it again after many
> >> years and I had never watched it at all. I almost fell out of my
> >> chair when that scene came on. Some technician simply blocked the
> >> rotation of the sound drum and fed that audio in to the movie as
> >> a special effect. I thought it was brilliant and never imagined
> >> that someone would actually want that sound to appear, but it was
> >> perfect for the scene.
> >>=20
> >>      I remember running across many weird problems that were
> >> usually the fault of wear and tear on belts, gears and clutches.
> >> That's where I accumulated all this useless knowledge.
> >>=20
> >>      So, what makes the film stop and melt? Ripped out sprocket
> >> holes along the edge. That will turn torn-up film in to torn-up
> >> melted film. If this had been back in the really old days, the
> >> film which used to be made of celluloid would have burst in to
> >> flame and started a real fire.
> >>=20
> >> Martin
> >>=20
> >> Colin McDonald <[log in to unmask]> writes:
> >>> ah, I love teachable moments!!!
> >>> They call me a walking encyclopedia of mostly interesting, but =
>useless
> >>> facts...