Xref: utzoo comp.dcom.modems:3596 comp.protocols.appletalk:1679 comp.sys.mac:28672
Path: utzoo!attcan!uunet!lll-winken!xanth!ukma!rutgers!cmcl2!ccnysci!alexis
From: alexis@ccnysci.UUCP (Alexis Rosen)
Newsgroups: comp.dcom.modems,comp.protocols.appletalk,comp.sys.mac
Subject: Re: Liason network bridges vs. Telebit TrailBlazer Plus modems
Summary: THIS IS A FALSE RUMOR!!!
Message-ID: <1422@ccnysci.UUCP>
Date: 19 Mar 89 01:32:17 GMT
References: <22320@coherent.com>
Reply-To: alexis@ccnysci.UUCP (Alexis Rosen)
Organization: City College of New York
Lines: 48

In article <22320@coherent.com> dplatt@coherent.com (Dave Platt) writes:
>According to the "Mac the Knife" column in the 3/14 issue of MacWeek,
>there's a design peculiarity in the Liason network bridge software that
>can have severe repercussions if you use this software with a Telebit
>TrailBlazer Plus.
>
>It seems that the software periodically sends a modem-configuration
>command string to the modem.  According to the article, this occurs once
>per minute [etc.]   This
>configuration command includes an "&W" sequence, which instructs the
>modem to write the configuration information into its nonvolatile
>memory.
>
>The TrailBlazer Plus's nonvolatile memory is (according to the article)
>implemented in EEPROM, which has a life expectancy of 10,000 write
>cycles.  At 1 write per minute, Liason could run through this lifecycle
>in less than a week!  The results would be bad... you might find
>yourself unable to change the configuration of your TrailBlazer, or find
>that the modem had gone entirely belly-up due to inconsistent EEPROM
>settings.

THIS RUMOR IS ENTIRELY FALSE.

I don't know how "Mac the knife" heard this, or why MacWeek was irresponsible
enough to print this without verifying it. Liason is an extraordinary
product, and this rumor may cause great damage to a company which is doing
wonderful and unique things for Mac networking.

To Summarize: your Telebits are not at risk.

The detail: That command string is necessary to make the modem remember to
autobaud. Telebits are shipped so that they default to high-speed mode, which
is not what you generally want for a bridge. The write-to-prom command is
given ONLY on reset, which generally happens when you reboot your mac. If
you reboot five times a day (my gateway, with a telebit, gets rebooted maybe
once a week) you won't have to start worrying for about seven years. Long
before then Telebit will change their setup. (But before that, you'll likely
be on ISDN or some other faster technology [Telebit T5000?].)


If any of you remember the horror of dealing with MacServe, you'll know how
bad networking can get. As a user of both Liason and (formerly) MacServe, I
feel that InfoSphere has more than redeemed itself for that abortion of a
disk server. Liason is every bit as good as MacServe was bad. And with version
2.0, which is now in Beta, is will be even better.

Alexis Rosen
alexis@ccnysci.uucp