|Before I joined TradeSignals.com in
June 1998 the company was well on its way
to becoming a purely Windows shop. All the computers in the building (shared
with 2 other companies) ran either Win9x or WinNT and there was no mention of
Unix anywhere. |
I've been described jokingly as a Linux virus by others in the company.
Once anyone in the office saw my cool looking desktop and what I could do
with a few lines of script they wanted to try it! People tend to look at
Windows in a different light when they see Linux working well.
During that summer I helped convince my boss that Unix, and specifically Linux,
was the way to go for further development of our website. I also convinced
him to let me use Linux on my desktop machine, something I really needed if I
was to be more productive.
At the time, we were using an NT server and ISDN line owned by a sister
Solas Data, for our email addresses and Internet connectivity. A new version
of our site went live during the summer and I could concentrate on getting our
LAN into shape.
We needed several machines:
An NT box to run a program called Goldmine to handle email correspondence with
customers and partners, and NT would handle network logins.
A Linux box to act as a mirror of our webserver (which would be in Dublin,
160 miles away)
At this time I applied for 16 IP addresses to cope with any further future
expansion but we were refused and were allocated 8 addresses instead.
Thankfully, I was aware of the IP masquerading facilities of Linux and
convinced my boss that it was a viable way of getting all our machines on the
Originally, the NT machine was going to handle email services for the company
but there would be trouble if the NT machine was behind a masqueraded
gateway/firewall. At the time I didn't know Sendmail very well but after a
weekend in Galway at Intersocs '98(1) and a brilliant
presentation(2) by Kenn
Humborg I saw it was simplicity itself to configure Sendmail! Once I figured
that out I started on a Perl script(3) to configure
Sendmail which has proved
very popular. After I figured out how to get Samba and Sendmail working our
website mirror machine became a mail machine, smb/nfs file server that allows
us to alter website files easily and directly, DNS server, squid proxy for web
browsing, as well as a database server mirroring the data held in Dublin. The
machine had 32MB RAM originally, but I upgraded to 64MB mainly for Squid. The
mail machine has now been happily working for 101 days.
Our NT machine is used to host Goldmine, (I figured out I could host Goldmine
off the mail machine too - all it requires is a file server) and as backup
storage for the LAN. It's a 128MB machine so it's quite stable, only crashing
We now have a spare Linux box on which further development is done, mainly
pretty intensive cgi stuff which the 64MB mail machine might have a few
troubles with and certainly doesn't have the hard drive capacity for.
Just recently I was at home recovering from an operation in hospital.
Sometimes a problem popped up that needed immediate attention. When that
happened, I was able to connect to our mail machine and do maintenance and
write/debug scripts. I was even able to then connect onto our machine in
Dublin and correct a few bugs in some house-keeping programmes there.
All through a simple telnet connection over a 56k modem connection.
Has Linux helped us work better?
- Yes, because the Win95 clients can access the web server through Samba and
by using PHP, scripts can be written in notepad and saved on the webserver to
be tested straight away. Yes, I'm amazed at what a 64MB Linux box can do. It's
been very stable, and I don't remember the last time it crashed.
- Yes, the support given by the ILUG(4) mailing list
has been invaluable and I try and give back as much as I get from them. It's
true what they say about support from the Internet and mailing lists. It's
great and it works!
- Yes, our servers don't have monitors, I can just telnet into any of them
and do any administration required. If my own desktop machine freezes for some
reason (Netscape is the usual fault.) I can go to any of the Win95 boxes and
telnet to it and "killall X" and start my desktop again. Real simple, real
- Yes, the power of telnet enables me to configure and fix problems in
Dublin from my desktop as if the remote machine were in the same room.
- Yes, the group permissions in Unix allowed me to give access to only
certain people to the web server files. This is possible in NT as well, but in
Unix permissions are a lot more visible to the user.
(do an "ls -l" Vs "Right-Click and select properties")
- Yes, using Linux as my desktop OS gives me access to virtual desktops, The
GIMP, Netscape as well as the powerful text manipulation tools and stability
of Unix. I find it handy to have a few telnet sessions open to other machines
on the LAN in case remote admin is required. I could do the same on Win95 but
it really isn't as nice.
- Yes, using the command line offered by Linux I had to be sensible in how
we organized the website. Giving sub-directories in different sections the
same filenames made it very easy to navigate with filename completion.
- Yes, it allows the company to become familiar with Unix concepts required
if we move to larger "Enterprise Class" Unix systems such as AIX or Solaris.
- Yes, Linux is free. I was hired because I knew the web and systems stuff.
I was there already as part of the expansion of the company. OS costs was a
part of the decision process to go for Linux. We're using RH5.2 on a
development machine in-house that I installed off a PCPLUS cover CD.
- No, it took some time to figure out how Sendmail, Samba, BIND and various
utils such as procmail were configured. Now I know how, I understand not just
the basic facilities of the services offered but also got some insight into
some of the neat things they can do. I've taken advantage of this knowledge
several times and it's something I won't forget. (yes/no kind of answer
- No, the power that remote administration gives to the user through telnet
can cause huge problems if the user isn't very careful. I'm speaking from
- No, Exchange would have been a lot easier to setup I suspect than
Sendmail. Certainly, file sharing would be. This is in the days before SWAT(5) for Samba.
- No, NT recovers very well from crashes whereas Linux really needs more
work in this area.
NT vs Linux.
We have a very small LAN at Tradesignals.com, and even when we used the
facilities of our sister company their NT machine was stable practically all
the time. It was running Exchange server as well as acting as a file server
for 10 users. Since Tradesignals.com separated from them, MS DNS server was
setup on it and it still runs fairly happily on an old 64MB machine. I still
prefer Linux but sometimes when I read Slashdot(6) I
wonder if people who post there
have worked in a real life office yet.
Our local Linux servers never did crash without a good reason,(can't remember
the last time) but NT did a few weeks ago and displayed a blank screen for no
apparent reason. Everyone was off for the day and only one or two in at the
Our webserver in Dublin did crash once, on Good Friday. We had to get tech
support to reboot the machine. Besides that one crash we've had next to no
problems with it.
Trade Signals Corporation Ltd was founded in 1997. The company's
mission is to bring cutting edge systematic trading systems and
analysis to professional and private futures investors using the
Internet as a cost efficient delivery mechanism.
Its unrivalled online trading systems and charting software provide
traders with a level of analysis previously only available to fund
managers and full time professional traders. The company also
provides futures charting services for many US brokerage houses.
About the Author
Donncha O Caoimh is a
graduate of the Cork Institute of Technology.
He runs DemoNix, a site
about the Linux demoscene as well as lots of utilities and programs for
He can be reached at donncha@NOSPAMlinux.ie. Just remove
the word NOSPAM from the address.
(warning: lots of graphics!)
and look for mention of Install-Sendmail