Discussion Groups / English Usage / November 2006

 Modification OF the electric/magnetic field? need more context.

Buckwheat Soba wrote, in <ejrqvp$mcl$2@news.wss.yale.edu>
on Mon, 20 Nov 2006 09:02:49 +0000 (UTC):

That is how I understand it, sometimes with the implication that it is a
temporary fix which will be replaced by a formal manufacturer-supplied
change at a later date.  I was responsible for such a couple of times
during my days as an IBM Customer Engineer.  One of them never was
formally fixed and I was sorely tempted to remove it when I left.

} Is the term "field modification" a standard term in one or more
} engineering disciplines or otherwise, and, if so, how would you define it
} (I assume it means "modification in the field" rather than, I suppose, on
} the premises of the manufacturer or other originator of the thing in
} question)?

I suspect that it has military origins that suggest actual outdoor fields.  
At first a number of usages flitted past, but they elude me just now, but
there is at least the concept of "field-grade officer" (major and above)
who are expected to function autonomously if necessary.

My own background is as a fixed-station radio transmitter repairman back
in the early sixties.  In effect I was a draft dodger, but I did it by
enlisting in the Regular Army with a guarantee of the longest school
available to repair the biggest, warmest equipment I could find in the
catalog to avoid both combat and Greenland-like weather.  The Army has a
tradition of training people for one thing and assigning them to do
something else, and their leverage in my case was to give me a choice
between volunteering for retraining as a fixed station communications
technical controller or being sent to Vietnam (pre-Tonkin) to repair
mobile equipment.  So it was, let's see, cushiest job in the army in a
nice place near Tokyo or field work in Vietnam.  Irregardless of *some*
people's impressions, I'm not entirely stupid, so I ended up spending a
couple of years in Japan, both pre- and post-Tonkin.  Just as later as a
computer systems analyst when I wasn't actually supposed to be doing any
programming, as a controller I wasn't supposed to be doing any repairing,
but I wasn't above doing some field modifications when necessary.

There are also "field commissions" and "field expedients" and so on, but I
would be surprised if any engineering applications weren't military
metaphors.

I think you've got it.   Here's a good example:

http://www.cr.nps.gov/nr/publications/bulletins/aviation/nrb_aviation_IV.htm

where it states:

Distinctive aircraft markings such as nose art should be considered
examples of workmanship. Other field modifications should fall under
this category. An F4F squadron stationed on aircraft carrier CV-6 in
1942, installed steel boiler plate to protect its pilots in a time prior
to factory installation of aircraft armor plate on F4Fs. This
modification is an example of field response to an immediate need.

"Field modification" sounds like a modification made in the field
rather than at a factory or repair facility.

In the days of mainframe computers, the term "Field Mod" could have
both an official meaning and a euphemistic one.

Official field mods tended to be minor hardware changes (usualy
in the backplane wiring that connected all the boards together) to
improve reliabilty ar correct an outright error in the original design
of the machine as originaly shipped from the factory. Or it might be
the installation of a higher capacity fan to do a better job of
cooling down some component where the original fan was
insuffient. Something of that ilk.

The euphemism referred to local modifications that were
(usualy) done to circumvent some safety feature or other
damn nuisance which made it difficult to get the job done.

On big high speed printers there was frequently a safety switch
that caused operation to halt when the main hood was opened
to gain accress to the paper feed mechanism. But sometime
it was necessary to run with the hood open in order to facilitate
correct tracking of the fanfold paper. In this case a "field mod"
was devised to jam the safety switch - completely against
the rules and known only to the operators on graveyard shift.

That's just one example of the euphemistic use. Another
example had to do with the environmental sensors on the mainframe
which constantly monitored voltage, pressure and temperature of
the chilled water supply, air humidty, smoke. etc. At one particular
site we had a problem where the machine would do an emergency
shut-down when it sensed water pressure loss due too many loos
being flushed simultaneously. This happened very regularly when
the "girls in the punch room" (Yes - that's what they were called)
broke simultaneously for mid-morning coffee. Accordingly
a "field mod" was fitted so that the sensor would always report
"OK" no matter what. This recipe for disaster was fulfilled
one Christmas when the site shut down their main hot-water supply
to save energy over the holidays. So the dehumidifiers failed, and
we returned after New Year's to find the mainframe sporting a
magnificent coat of icicles. Some thousands of boards had
to be replaced before we had the beast up and running again.

Jitze

It's probably not directly relevant to your question, but in
meteorology (and in some other scientific disciplines too)
"field modification" is what you do to make minor changes to the
initialised (geographical) field of a given parameter when running
a sequence of prediction routines. The action is also called
"bogusing" (although most meteorologists insist on spelling it with
two esses), and the whole process is often called "ensemble
forecasting".

Philip Eden