Tuesday, October 13, 2009

Salient Features of Unix ... continued

Unix has excellent provision for communicating with fellow users. The communication may be within the network of a single main computer, or between two or more such computer networks. The users can easily exchange mail, data, programs through such networks. Distance poses no barrier to passing information or messages to and fro. You may be two feet away or at two thousand miles, your mail will hardly take any time to reach its destination.

Unix allows sharing of data, but not indiscriminately. Had it been so, it would be the delight of mischief-mongers and useless for any worthwhile enterprise. Unix has three inherent provisions for protecting data. The first is provided by assigning passwords and login names to individual users ensuring that not anybody can come and have access to your work.

At the file level, there are read, write and execute permissions to each file which decide who can access a particular file, who can modify it and who can execute it. You may reserve read and write permissions for yourself and leave others on the network free to execute it, or any such combination.

Lastly, there is file encryption. This utility encodes your file into an unreadable format, so that even if someone succeeds in opening it, your secrets are safe. Of course should you want to see the contents, you can always decrypt the file.

One of the main reasons for the universal popularity of Unix is that it can be ported to almost any computer system, with only the bare minimum of adaptations to suit the given computer architecture. As of today, there are innumerable computer manufacturers around the globe, and tens of hundreds of hardware configurations. More often than not, Unix is running strong on each one of them. And lest we forget, due credit for this feat must be given to the Dennis Ritchie's prodigy, C, which granted Unix this hardware transparency. Unix, in fact, is almost entirely written in C.

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