Conference hydra::amiga_v1

5074.0. "LZ version 1.92 Warning" by DECWET::DAVIS (Mark W. Davis 206.865.8749) Tue Sep 24 1991 14:07

    Here is something I pulled off USEnet...I encountered this problem
    while testing LZ version 1.92.
    
    -------------------------------------------------------------------
Article 2439 of comp.sys.amiga.datacomm:
From: [email protected] (Jim Shaffer)
Subject: LZ BUG WARNING [was Re:  what is .lha]

In article <[email protected]> [email protected] (John 'Vlad' Adams) writes:
>LHA is the new version of LHarc for both the Amiga and the IBM.  It
>is -lh5- instead of -lh1- and offers tighter compressions at a faster
>speed.  The *program* you need is LZ, version 1.92, which I think is
>on ab20 as well.  LZ is Jonathan Forbes' freely distributable
>archiver/dearchiver.  You want to run this over Lharc 1.30.

There was a bug report recently on FidoNet and CompuServe.  I haven't seen
it here yet (it would've been in AMReport 1.11 but I didn't get around to
posting it yet -- more on this later) so here it is:

LZ WARNING!
~~~~~~~~~~~
The following message was posted by Chet Solace (The Final List) on
FidoNet.

From: CHET SOLACE
  To: ALL
Subj: URGENT FILE ALERT! PLEASE READ
**********************************************************************
URGENT FILE WARNING:  "LZ" v1.92 - DO NOT USE "LH5" MODE ON LARGE
FILES UNLESS YOU ARE WILLING TO KQC( A BACKUP OF THE ORIGINAL ARCHIVE
UNTIL SURE EACH "LHA" ARCHIVE IS NOT CORRUPT! FEST ANY EXISTING
ARCHIVES OVER 100k IN SIZE BEFORE UPLOADING TO OTHER BBS's!! READ
ENTIRE TEXT. DON'T PANIC, I WILL NOTIFY AUTHOR PERSONALLY OF PROBLEM.
..
.     Ok. Here's what's real. There have been a number of messages
warning of corrupt archives created by the new versions of Jonathan
Forbes' "LZ" file compression utility; specifically versions 1.91 and
1.92.  I did not become alarmed earlier, since random testing of
various sized archives revealed no 'apparent' problems. Now, after
converting umpty-ump megs to LHA, I have - ahem - had personal contact
with the problem. LISTING OF LHA ARCHIVES DOES *NOT* DETECT BAD ONES!!
The problem ONLY shows up when you actually, physically decompress
the archive; which means that EACH of the 1,200 new files will have
to be individually unarced to insure it's ok. The problem may or may
not exist in the 'default' lh1 mode, but ABSOLUTELY exists in lh5
mode. I noticed a few corrupt 'lh1'-compressed files showing up on
Smorgasboard, so Dick, if you're using LZ, please let me know a.s.a.p.
Anyway, the problem is severe enough and not likely to be detected
easily enough to get by with a standard warning.. hence this BIG ONE.
I'm calling Jonathan as soon as I post this. Meanwhile, until the
problem has been traced down and fixed, I urge ALL sysops who have
been using LZ (and everyone ELSE, too) to check the integrity of
those archives and NOT upload any bad ones - including re-archived
files with the corrupted ones missing. I've also seen more and more
incomplete archives appearing randomly across the country.. This may
be the reason. Until this problem is fixed, I recommend use of either
the regular lharc, or the new zoo v2.10 which is MORE efficient than
lharc, and only a few bytes away from lz in 'lh5'(LHA) mode.. although
slower..  good luck..

Chet


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