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First look at Linux

Who’s it for?
Linux is a very efficient, multi-user, multi-tasking operating system and is used particularly for database servers and Internet servers.

Traditionally it has been used by students and other people who enjoy playing with new technologies, but is now used by web site hosting companies, ISPs., educational establishments, hospitals, etc. Large, conservative (non technology) companies are also starting to evaluate and use Linux.

Many of the big computer companies, including IBM, already offer Linux on their servers as an alternative to their own version of UNIX or other operating systems.

Like other versions of UNIX, Linux is scalable from a small system right up to a mainframe-class system (all you need to do is add extra hardware), which makes it suitable for anyone looking for a low cost, reliable operating system. For programmers it has a wonderful set of utilities and a straight forward structure that makes it easy to produce quite complex programs in a relatively short time and is very much like other versions of UNIX. For end users, it has a friendly graphical interface (called X Windows) and many business applications such as spread sheets, databases, word processors, etc.

Hardware Requirements
As it is very light on resource requirements it will run on old 386 or 486 computers with 2Mb RAM and 40Mb of disk space. The GUI (X-Windows) requires another 2Mb RAM. Therefore a 386-based computer with 4 Mb of RAM is all that is needed to run both Linux and X-Windows. There is also a cut-down version which will run on a Psion 3a with 512kb RAM!As always, the more memory the better, but Linux makes efficient use of resources, so this is not as important as it would be for Windows 95/98/NT/2000.

How To Improve Performance
As with other versions of UNIX, there are kernel parameters which may need to be tweaked to run heavy duty applications such as Oracle (these will be specified in the installation guide), but generally they should be left alone.

The key to improving performance is to know how the system is performing currently and which of the three main resources (cpu, memory, i/o) is under the most load.

Linux provides performance monitoring and statistics gathering tools which you can run to determine current loads and thus the limiting factor. Generally, though, in descending order of cost effectiveness, the things that you can do are:

* add more memory
* use a faster i/o bus technology (eg. SCSI instead of IDE) or use a RAID device.
* replace the cpu (the processor chip) with a faster one (e.g. Pentium III instead of a Pentium II). This may mean that the motherboard has to be replaced as well as all the memory chips.

Other options may be to:

* schedule some jobs to run over night
* restrict access to certain applications (e.g. games), if they consume a lot of resources unnecessarily
* tune and optimise in-house written applications For those who are really keen, Linux comes complete with source code which means you can build your own kernel and have it finely tuned to the type of applications you run. This is not recommended, though, unless you know a lot about operating system kernels and C programming or employ someone who does.

Distributors
Linux is a free version of UNIX, but it may be bundled with applications and support and sold commercially. In strict terms, Linux means the just kernel of the operating system, therefore excluding all applications and utilities provided with it. Commercial organisations that sell Linux are entitled to add whatever utilities and applications they like to go with the kernel. Naturally each company has it’s own set of applications/utilities, so the different companies offerings are called distributions. There are many distributions available but the main ones are SuSE from Germany and Red Hat, Caldera and Corel in the U.S. These companies provide the kernel, the utilities and applications and provide support.

Advantages
Linux is widely supported especially on the Internet, as well as by many smaller companies (such as ourselves) and many recent graduates will have used it extensively during their courses. This means that there is plenty of support and help available for anyone that needs it. The other advantages already mentioned are that it is stable, scalable and makes efficient use of resources. Also, it can be downloaded for free from the Internet, or bought at low cost (which usually includes support) from any of the distributors.

It is compatible with MS Windows, in that it will support full access to Windows file systems and with the help of emulators will run Windows software (some better than others).

There are also plenty of native applications available, including databases, compilers, office applications, networking software, etc. These applications will run unchanged from a single-user system up to an enterprise-wide system.

Disadvantages
Linux doesn’t support quite such a wide range of hardware as Windows 95/98 (for example – the winmodems that come with most pcs). At the moment there is no IRDA (infrared) support, but this should changed in the next release of the kernel sometime later this year.

Conclusion
Linux is a stable, efficient operating system that is widely supported and provides all the tools and applications that any business could want.

However if you have IRDA devices you have a slight problem as Linux doesn’t support these directly. You could keep one PC running MS Windows to access those devices, but that’s an unnecessary expense.

You could have a dual-boot system with Linux and MS Windows, but it can be a pain to keep re-booting your PC.

You could use WINE (a free MS Windows emulator available from www.winehq.com), which should allow you to access these devices. Or you could create an MS Windows vrtual machine that runs under Linux by using something like VMWARE (available from www.vmware.com). This is available for a free 30-day trial and aims to provide an environment for Windows programs that is as close as possible to the environment that would exist if they were actually running under Windows. There is also software available to allow MS Windows to read from and write to Linux disk partitions available from http://uranus.it.swin.edu.au/~jn/linux/.