Asking someone about a floppy disk is cause for sexual harassment these days.

-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]] On Behalf Of Eric Oyen
Sent: Tuesday, November 3, 2015 10:37 PM
To: [log in to unmask]
Subject: Re: Useless Knowledge (was Laser Light)

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...