Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!pcrat!rick
From: rick@pcrat.uucp (Rick Richardson)
Newsgroups: comp.unix.i386
Subject: Re: Use a 386 unix as a home machine?
Message-ID: <1989Dec30.071817.3232@pcrat.uucp>
Date: 30 Dec 89 07:18:17 GMT
References: <1557@aber-cs.UUCP> <1989Dec25.164606.1072@ddsw1.MCS.COM> <818@chinacat.Lonestar.ORG>
Reply-To: rick@pcrat.UUCP (Rick Richardson)
Organization: PC Research, Inc., Tinton Falls, NJ
Lines: 42

In article <818@chinacat.Lonestar.ORG> chip@chinacat.Lonestar.ORG (Chip Rosenthal) writes:
>karl@mcs.MCS.COM (Karl Denninger) writes:
>>>[re: HP LJ IIP printer]
>>Especially if you don't mind doing a little hacking.  I understand that the
>>IIP can take LZW compressed input
>
>I don't have the techinical manual for the IIP.  If anybody out there does,
>how about posting some info on the compression formats?

The compression mode refered to as TIFF 4.0 on the IIP is the PackBits
compression mode.  It is a straightforward extension to simple run length
encoding.  Each 'run' is preceeded by a control byte.  A value of -1 to
-127 means repeat the next byte abs(control) times.  A value of 0 to 127
means the next control+1 bytes are uncompressed.  A value of -128 is a
NOP.

This scheme actually gets pretty good compression on images, and is
much simpler than LZW.  We provide this as an output option in our
FAX package, and it makes the IIP print faster than the II (since
FAX is image, and the bottleneck is the communication to the printer).

We have one site that runs three FAX boards, incoming (!) only, and
are using the IIP to print the FAXes.  They plan on eventually
replacing a total of eight FAX machines with two 386's, two IIP's,
eight FAX boards, and two ISC runtime licenses.  I believe the
cost justifaction is that they need plain paper output and plain
paper FAX machines are very pricey. (NOTE: two systems are used
for reliability concerns, not performance; these folk's business
depends on receiving a continuous stream of incoming FAX
'information' from their customers).

The IIP is the fastest parallel interface laserprinter for this
type of application.  It also happens to have the best price,
which is just icing on the cake.

-Rick

-- 
Rick Richardson |       Looking for FAX software for UNIX/386 ??????     mention
PC Research,Inc.|                  WE'RE SHIPPING			 your
uunet!pcrat!rick|    Ask about FaxiX - UNIX Facsimile System (tm)        FAX #
(201) 389-8963  | Or JetRoff - troff postprocessor for the HP {Laser,Desk}Jet