The story of a company replacing Windows systems with Linux to obtain better speed and greater reliability.
Linux is the best tool I have found for facilitating the expansion of Internet and Intranet systems throughout the company, Stocks & Stocks I.T., that employs me.
Upon arriving in South Africa from Australia, my first task was to develop and implement a system which would allow general Internet users to obtain accurate, real-time hotel room availability details from the company's chain of hotels and game resorts. This is a list of what I had to work with:
WAN spanning South Africa
System protected by firewall
TCP/IP as the primary protocol
The immediate problems to deal with were:
Each hotel/resort used Novell Netware 3.12 running only IPX/SPX.
Each hotel/resort room database was approximately 300KB in size.
Each hotel/resort was linked using a 64KB line (at best).
Everyone was running around with Windows in their mind.
The first prototype system I set up was a central Linux web server as follows:
Pentium 133 64MB RAM, S3-Trio 64 with 4MB RAM, ADI 17-inch monitor (Microscan), 1.2GB EIDE HDD, 8x CD-ROM, 3Com 3C509b NIC (network interface card), Ergo keyboard/mouse (Microsoft)
Linux Slackware 1.2.13, NSCA HTTPd v1.10
The reason for having 64MB RAM, a 17-inch monitor and other “niceties” was so this system could also be used for web development of any home pages/Intranet pages.
At each of the hotels the only system available to me was Windows 95 on which I used a scheduling system to send the room database to the central web server every morning at about 6AM. The Windows 95 machines were also being used to act as a bridge between Novell and TCP/IP. This gave the Internet user statistics on room availability that could be up to 24 hours old. The room databases were in DBase-IV format, for which I wrote a C application to search and return statistics given desired room and date details.
The system seemed fine for a while, until the Windows 95 machines mysteriously started to shut down, lock up, etc. for no apparent reason. It was also about this time that the “higher management” decided that the ability to obtain “real-time” room availability statistics was a priority.
I felt real-time statistics would be an impossibility with the current setup, as it meant sending 300KB of data to the central Linux server over a 64KB line in less time than it takes for the average person to get bored and move on to another web page.
For the current prototype, the whole process was turned upside down. While still retaining the central web server, I replaced the Windows 95 machines with small, highly effective Linux machines (2.0.29). These Linux machines now process availability requests locally via a secure shell from the central web server.
In order to provide a backup, I left the existing Windows 95 system on each machine and used FIPS (First Interactive Partitioning System) to create a new partition on which I installed Linux. Details of the “remote” machines are as follows:
Pentium 100 (Generic Clone), 8MB RAM, 800MB HDD, 3Com 3C509b NIC (no monitor, no keyboard, no mouse)
Linux 2.0.29 (Slackware), Secure Shell (ssh), ncpfs (network file system that supports the NCP protocol used by Novell)
ncpfs is used to mount a Novell Netware volume containing the room availability database to a local directory at boot time. It should be stressed that without ncpfs, there is no way this project would have gotten into the “real-time” phase successfully.
The process of checking room availability for hotels is now as follows (Local = central web server, Remote = Linux system at required hotel):
Local: Get room/date details (HTML POST form).
Local: CGI application processes POST data and executes.
Local: Use ssh to log in to the appropriate remote Linux machine.
Remote: Search database located on Novell Netware server.
Remote: Exit search with 0 = Success, 1 = Failure.
Local: ssh returns the result of the search through its exit value.
Local: CGI application generates an HTML file with the correct response, depending on the database search result.
This whole process has been timed to take less than 10 seconds which I believe is an acceptable figure (given that there is a great deal of existing traffic on the lines). Something worth noting is that using ssh in order to remotely execute processes greatly improved operations. ssh offers public key encryption for all transactions and is effectively easier to setup than rsh.
Now that the Hotel reservation system was up and running in a manner that pleased management, it was time to start working on the Intranet. Our primary objectives were:
Gains in productivity
Ease of use
Improvements in speed
The applications the Intranet could be used to accomplish were:
Training course enrollment
All the applications were written in ANSI-C. No actual HTML files exist for these applications, as the HTML is created dynamically through the application. Although this increases the time required to update the pages (having to edit, compile, etc.), it's a small tradeoff compared to the resultant simplicity. As a minor alternative I have enabled some applications to read an external file, parse it (for any replaceable tokens) and redirect it to stdout. This too produces more overhead, but offers easier HTML page maintenance.
In order to provide database functions and non-trivial HTML POST/GET form handling, two ANSI-C object/libraries were created. All the libraries were written in ANSI C and compiled with gcc.
After a couple of weeks, it was time to upgrade the web server to Apache 1.2b10 giving better speed and security. The upgrade to Apache from NSCA was relatively painless, with a few alterations made to the /conf/*.conf files to reflect my new directory structure.
Java was the next item on the list of “things to think about”. To me, Java is a great idea offering what C has almost been offering for a long time. However, the thought of going back from thin client into “medium-thin” was not something that interested me much. Linux is a reliable, powerful OS. I have full confidence in its ability to handle the load of the CGI applications we run. The reduction in administration by sticking with thin-client applications far outweighs the increase in server load from having to process every application transaction—this is why we chose Java.
Next, there was the need for an FTP-type file warehouse. Since most of the clients that are running within the Intranet are Windows-based, few are keen on using FTP. Samba was installed in order to alleviate this “barrier”. Samba enabled all Windows 3.1, 95, NT and OS/2 users to gain access to their files, applications, drivers and utilities. Of course, anonymous FTP was still set up, just in case I wasn't the only one of my kind in this company.
My most potent Linux machine is now being used to churn out images and animations using POV-Ray 3.0 which have markedly improved the appearance of the Intranet pages. I am currently working on a small (15-second) animation to be used as an “introduction” to Stocks & Stocks. To date, these are the Linux installation statistics for the company:
Seven machines doing hotel remote access support/availability response
Two for web application and graphic development
While a total of twelve machines may not seem like many for a company the size of Stocks, one must consider that there are only five NT boxes and one AS/400. (Okay, one AS/400 is often enough.)
The failure rate of the Linux systems has effectively been 0%. To date there has been only one failure, caused only by a power supply getting friendly with a bolt of lightning. Once I've installed a Linux machine, providing the user (me) doesn't do anything malicious (such as remove agetty or getty--another story), there's little cause to worry.
Some may feel Linux (and any UNIX system for that matter) has a somewhat less “user-friendly” interface when compared to Windows. However, Linux was chosen by Stocks & Stocks because it offers one thing that Windows does not—dependability. For me, Linux is “admin-friendly”.