Friday the 4th of December would be an easy day for me. I had
to write a management summary for a customer and I would be attending a
top-secret meeting in the afternoon (details of which I will not make known
here and now). When getting up in the morning it had been snowing and freezing
severely, so the traffic situation was worse than ever. I left my home
at about half past nine and struggled my way to the office.
Getting there I hooked up Jadzia to the office LAN and started working.
One of my customers is selecting a package for Sales Force Automation (SFA)
and I am responsible for evaluating and advising on the client architecture
of the various packages at hand. Friday was the day we would have to hand
in our findings regarding the top two contenders. In my e-mail inbox I
found the management summary of one of my collegues on the project. The
document was in Microsoft Word 95 format, which is the customer's standard
(as you can see, I still have some evangelising to do here :-). I imported
it into Applix in order to review it. Applix loaded the file without any
problems.
Again using Applix, I wrote down my findings on the SFA packages, resulting
in a 2-page document (only a 9 Kb file by the way). Once finished, I wanted
to send this document to my collegues at the project. Obviously (unfortunately)
they do not "understand" the native Applix Words format. I exported the
document to RTF (Rich Text Format, only a 5 Kb file) and attached it the
e-mail message in which I announced the availability of my management summary
document. Just for fun, I also attached the Applix Words (".aw") file.
I was to hear more from this later that day!
Following this "hard labour" I had a lunch date with Marielle
Klatten, the pretty (good) office manager of the Dutch Unix User Group
(NLUUG). She is always smiling, good
humoured, and generally fun to be with. The NLUUG offices are located inside
the UUNET building in Diemen, which is right around the corner from my
office. I walked to the parking garage, jumped in my car and attempted
to start it. Unfortunately, for the first time since I owned this car,
it failed to start :-(.
Scheisse (bin ich wieder das Englandische Wort fuer "shit" vergessen)!
I concluded that I had most likely run out of gas. My car is dual powered:
it contains a tank for regular (unleaded) gas and a pressurised barrel
for LPG (a form of liquified gas). LPG is much cheaper and I normally
use that tank only. However, the engineers of my LPG installation figured
that it would be best to start the car using normal gas, and automatically
switch to LPG after a short while. As a consequence, I use a small amount
of normal gas each and every day (maybe only 100 ml). That tank was now
completely empty! So although I had almost 40 liters of LPG on-board, I
could not start.
I jumped out and walked the short distance to the NLUUG office . There
I met Marielle and we drove to our local Italian restaurant in her car.
Following a pleasant (if somewhat hasty) lunch and a productive meeting,
Marielle drove me to the local gas station where I picked up 5 liters of
normal gas. We threw some in the tank and the car started like never before!
The biggest and best printer we have at the office is a network
connected HP Laserjet 4000 (hp4000.osp.nl). It understands both PCL6 and
PostScript so it seems a perfect match to Applix Words' printing capabilities
(which are PCL5 and PostScript). Hewlett-Packard obviously ships printer
drivers for all DOS, Windows and Netware versions in the known universe.
Our Windows machines print to the HP4000 either directly across the LAN (using
HP's supplied printer driver) or through a Windows NT server that shares
a printer spooler queue that is mapped on the network printer.
How should I print to this printer from Jadzia (my laptop)?
Because the HP4000 understands PostScript, I can beam PostScript to
it directly, without any need for translation. We used to own a Minolta
network laser printer which understood the FTP protocol. You could send
it a file through FTP which it would subsequently print. Maybe the HP4000
was this smart as well? I tried to FTP to the printer but I got a "Connection
Refused". Obviously our HP4000 does not understand FTP. I then tried to
telnet to the printer, which succeeded. I landed in a sort of printer configuration
menu in which I could set the printer host name, default gateway and other
printer parameters. Unfortunately, the menu did not contain any hints on
how to print to it.
To get some information about what the printer did, and did not, understand,
I decided to perform a port scan. The "Satan" program (by Dan Farmer and
Wietse Venema) contains a program called "tcp_scan" that you can use to
scan for TCP ports which accept network connections. I performed a scan
on ports 1 to 1000. "tcp_scan" immediately returned that the printer accepted
connections on port 23 (telnet) and, ........., 80, the port of the World
Wide Web protocol HTTP! I interrupted the port scan and fired up Netscape
Navigator to connect to the printer (http://hp4000.osp.nl). I was immediately
redirected to a web application running on one of our Windows NT servers.
This web application turned out to be a very general network printer (JetDirect)
configuration program. Again, no pointers on how to print from UNIX.
Since the HP4000 is shared from our main Windows NT server, I contemplated
using "smb_print" for a while. This utility can be used to print data from
UNIX (Linux) to a Lan Manager, OS/2 or Windows NT shared printer.
My reflections on this were very brief: no way!
I knew that my collegue Wout could print to the HP4000 from the Linux
workstation that he uses for software development. He had obviously configured
his Linux printing subsystem (printer spooler) to print to the HP4000,
so I decided to check his printer configuration. Linux contains a version
of the BSD printer spooler system in which users use the "lpr" command
to send files to the printer spooler. The printer spooler optionally performs
translations (such as ASCII to PostScript) and sends the file to the printing
device. The entire subsystem is configured using the configuration file
"/etc/printcap". In addition, the command "lpc" is used to control the
printer spooler.
Although I had used and configured BSD printer spoolers before, I am
not a real BSD printing expert. Now was obviously the time to become one.
The "/etc/printcap" contains printer destination configurations. Each destination
has a name and a bewildering array of options that can be used to specify
things like the destination spool queue directory, the device file of the
printer and the translation scripts to run. Wout's "/etc/printcap" entry
for the HP4000 looked pretty simple. For one thing it did not contain an
"lp" configuration entry (which denotes the device file of a local printer).
I found this logical since we should be printing to a network connected
printer. It did however contain an "rm" and an "rp" entry. These are used
to denote printing to a remote BSD printer spooler. The "rm" entry contained
the name of the HP4000 printer, and the "rp" entry contained the name "lp".
This seemed to suggest that the HP4000 understood the BSD remote printing
protocol all by itself! This would be good! I looked up the TCP port number
used by BSD remote printing in "/etc/services". It turned out to be 513.
I then used "tcp_scan" again to do a port scan of TCP ports 500 to 520.
"tcp_scan" immediately reported that the printer was willing to answer
connections on port 513! Hurrah, one hurdle taken!
I would now have to setup Jadzia's "/etc/printcap" to contain a remote
BSD printer on "hp4000.osp.nl". On Wout's machine the printcap entry of
the HP4000 also contained an "if" entry which is used to denote a
filter script that has to run on the printed data. This "if" entry pointed
to a script called "filter". I looked at the script but could not immediately
determined what it did. I suspected it to be part of the "apsfilter" package,
which can perform all kinds of conversions on data before it is printed.
Maybe I would have to setup "apsfilter" as well? As it turned out, I had
installed the "aps" package on Jadzia. I reviewed some of the package documentation
(in "/usr/doc/packages/aps") and it turned out there was a "SETUP" script
to setup printer destinations using "apsfilter". I started the "SETUP"
script but found out that it could only setup local parallel or serial
printers. (Later I thought up that I could have used this setup script
and modified the resulting "/etc/printcap" entries manually).
Hmmm, maybe YaST could help? I started YaST, but was unable to find
an option for configuring printers. (I later discovered that there is
support for creating printers, but I had overlooked the option. Again,
it can only be used to configure local serial or parallel printers. Using
this and then manually editing the printcap configuration seems viable
to me as well).
I then realised that I probably did not need a filter script. Applix
Words generates PostScript and the printer understands PostScript, so I
saw no need to process the data before it was sent to the printer. I decided
to create a very simple entry in "/etc/printcap":
hp4000_ps:\
:sd=/var/spool/lpd/hp4000_ps:\
:mx#0:\
:sh:\
:rm=hp4000.osp.nl:\
:rp=lp:
The printer destination name is "hp4000_ps", it stores its spool files
in "/var/spool/lpd/hp4000_ps", it does not have a maximum size for print
jobs (the "mx" option), it does not print a burst page header ("sh") and
the real printing destination is the BSD remote printer "lp" at host
"hp4000.osp.nl". Obviously, the printer spooler directory does not magically
appear out of nothing, so I created it manually. After editing the "/etc/printcap"
I started the printer spooler subsystem with the command "lpc start all".
Ok, all things set up, let's print! I switched back to Applix Words
and chose "File->Print". The "hp4000_ps" printer appeared in the list of
printers allright. I selected it and pressed "Ok". Nothing happened.
Right. Disappointed!
A messy debugging cycle then started. Did the spool directory exist?
Was the "printcap" entry correct? Did the printer daemon run? As it turned
out, I had made some syntax errors in the printcap entry (the one showed
above is the correct one). After I had corrected these I found out that
I had forgotten to change the ownerships of the spooler directories to
"lp". Once that was all corrected I manually cleaned the spooler directories,
stopped the "lpd" daemon, removed the lock files and restarted the "lpd"
daemon ("lpc restart hp4000_ps"). I printed the document again (from Applix
Words), and voila, before I could see what had happened, the document rolled
out the printer. Success at last!
I
am a registered member of ArtToday (http://www.arttoday.com),
one of the biggest collections of clip art, web art and digital photos
on the Internet. I decided to browse through their database to look for
a picture the correct size. This was easily found and I downloaded it into
my "/home/josv/tmp" directory. From there I included it in my document.
Applix Words has a handy "frame" feature that can be used to divide
your page in separate independently positioned frames so that text and
pictures do not interfere with one another. Once I finished the information
bulletin, I hit the "File->Print" option again and requested that Applix
print 80 copies of the document. To my surpise, Applix gave an error message
saying that it could only print from 1 to 20 copies! Why this silly maximum?
Why not 6, 99 or 64? Obviously, there are no prizes for the workaround,
I hit "File->Print" 4 times, printing 20 copies at a time.