Re: [hylafax-users] Numerous problems with HF4.1 & MicroLink 56kFun IIa

["Jay R. Ashworth" <jra@baylink.com>]

On Tue, May 14, 2002 at 01:59:17PM +0200, Bernd Proissl wrote:
> you may not want to use &F anywhere in you config files, this
> may break your modem.

I want to expand on this, since we don't say it often enough...

(And it's not &F that's the problem, Bernd, it's &W...)

Every once in a while, we'll come across someone who does a bunch of
setup in one of their command strings, and ends it with &W0 (or &W1, I
suppose).  What that AT command does, for those who don't realize it,
is to *write the current settings to NVRAM*.

And therein lies the rub.

NonVolatile RAM is only rated for about 10,000-20,000 write cyucles
before it becomes unwriteable.

If you put &W in, let's say, a string that it sent to the modem every 5
minutes, your modem will become inop in, oh, about 5 to 10 weeks.

Not Good.

Subordinate to this conversation is the "do I use &F and then set
everything manually or set it all in the NVRAM and use ATZ?" topic.

My personal opinion on this as a 10 year system adminstrator is *put
your modem configutations in the setup files of your apps... not in the
modems*.

Sure, it seems a lot easier to only have to put ATZ in your setup
scripts... but there are two flies in that ointment:

1) What happens if you have two apps that need different setups (which
is not at all uncommon), and more importantly

2) you're going to need to document that modem setup anyway; where are
you going to *put* that documentation?  Putting it right there in the
config files for each application violates the Principle of Least
Surprise *much* less, y'know, for that guy who has to take over when
you get hit by a bus...

Cheers,
-- jra
-- 
Jay R. Ashworth                                                jra@baylink.com
Member of the Technical Staff     Baylink                             RFC 2100
The Suncoast Freenet         The Things I Think
Tampa Bay, Florida        http://baylink.pitas.com             +1 727 647 1274

   "If you don't have a dream; how're you gonna have a dream come true?"
     -- Captain Sensible, The Damned (from South Pacific's "Happy Talk")

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