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...
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