From: Dave Emery <die@pig.die.com>
Date: Sat, 25 Apr 1998 12:36:13 -0700 (PDT)
To: jim@mentat.com (Jim Gillogly)
Subject: Re: IRS cratering
In-Reply-To: <9804251705.AA06849@mentat.com>
Message-ID: <19980425153547.A6607@die.com>
MIME-Version: 1.0
Content-Type: text/plain


On Sat, Apr 25, 1998 at 10:05:09AM -0700, Jim Gillogly wrote:
> 
> > Similar efforts in the past to modernize the FAA have failed...as someone
> > noted, the FAA and control towers are still dependent on vacuum tube
> > computers. The problem lies not with finding newer computers, but with the
> > software for the many subsystems, displays, communcations links, radars,
> 
> Is this really true?  They do have obsolete vacuum tube equipment, but
> I thought it was all radars and radios rather than computers.  The up-side
> of it is that vacuum tubes are more resistant to EMP than silicon... but
> I'm pretty sure that's not why they're still using them.
> 
	IEEE Spectrum of ran a story on this last year.  Apparently they
do have some vacuum tube radio, audio and radar gear, but all the
computer systems in use are solid state such as antique 360s and the
like with lots of custom interfaces that can't be readily replaced.  And
much of the software is such patched spaghetti that nobody has been able
to reimplement it.   But telling is the fact that most of the radar
display consoles are late 60s designs manufactured in the early 70s with
a 5-10 year expected lifetime, and wires and connectors and other parts
not normally replaced in the field are getting brittle with age after
20-25 years of continuous operation at temperature.  And maintaining them
and the computers is made harder each year by the increasingly total 
unavailibility of electronic components of the types used back then...


-- 
	Dave Emery N1PRE,  die@die.com  DIE Consulting, Weston, Mass. 
PGP fingerprint = 2047/4D7B08D1 DE 6E E1 CC 1F 1D 96 E2  5D 27 BD B0 24 88 C3 18