As budgets continue to get squeezed, IT departments look for cheaper alternatives to expensive operating systems and Linux, being open source, is an excellent option. For those running Unix, migrating to the Linux platform can be viewed with trepidation. It need not be!

A Uni/Linux migration can be a much more pleasant experience than many expect and, provided the software being hosted is mostly off-the-shelf – then the process is really quite simple (but not fool proof). COTS software is painless to migrate and causes few problems. Issues do arise, however, when bespoke applicants have to migrate.

Common considerations or issues that arise include:

* Compiler issues
* Standard library issues
* Endian considerations
* Threading issues
* Database variations
* Issues involving 32-bit versus 64-bit systems
* Operating-system calls
* Memory-management considerations

The above may seem a little academic if one is not familiar with the differences in Unix and Linux, so let us enlighten you. Unix was developed in the 1970s for AT&T and quickly evolved into the standard operating system for academic institutions. As a commercial operating system it was available at a cost. Linux was developed as the free alternative to Unix and, although sharing common ground, the two systems offer very different options.

The first difference to note is that Linux runs on more hardware platforms than the restricted Unix, which is limited to one architecture. The second difference is in the way the two systems have been developed. Unix, as a commercial OS, utilises developers with very specific skills and commercial goals, whereas Linux, being open source, has evolved with a combination of development skills from a wide variety of people with differing ideas, designs and inputs.

One issue that arises from Linux (and its open source nature) is the lack of standardisation in terminology and documentation. Different suppliers have different ways of cataloguing and naming features and modules. With Unix, on the other hand, when a new version is released, so do new operating manuals and comprehensively documented changes. In turn this standardised process makes a Unix administrator’s skills upgrade much simpler than those administering a Linux OS.

Because of the limited architecture applications of Unix, Linux wins big when it comes to hardware adaptability. It has the ability to be used for endless architectures on a limitless number of devices, Unix is very much restricted. However, Unix users have available to them all the tools and features that have been designed for them, they know their boundaries and limitations and can exploit them fully. Linux users are unable to optimise features in the same way due to not being able to ascertain whether certain features have been installed.

Patching kernels and drivers for Unix and Linux really highlights the differences in operating systems. Unix test, test and test again, only releasing kernels in binary code, thus preventing changes and requiring users to have to wait for Unix for updates. Linux kernels are released in source code form, allowing users to modify and install what they choose. The real differences arise from support – Unix administrators can be confident a release has been thoroughly tested, Linux users have to rely on others to flag issues.

The differences continue, but require considerably more space than this article permits. Unix and Linux share common roots, although from very different sides of the fence. If you’re considering the move from Unix to Linux, economically and technically it could be the best decision you make, just ensure you have the skills and support in-house to administer your new operating system!