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Linux Tech Support

© Ian Carr-de Avelon

Support for Windows software normally comes in the form of a telephone number which you ring and either quote your license number or you pay by the minute on your telephone bill. Someone is at the other end, maybe even 24 hours a day and they will ask you questions (especially if you pay by the minute) and guide you though tests and steps which will hopefully help you. There are companies which will offer you this for Linux too, either for the specific software they write, or for general problems you may have, but in the main it goes quite differently.

The first thing to understand is that a PC running Linux is not running software from a single organisation like a Windows PC would probably be. If we take an example of one of my customers ringing in with a modem to my company for a connection to the Internet. When the the telephone line has a ring signal on it, a modem at my end sends a message into a Linux PC. A piece of software called the kernel (which comes from http://www.kernel.org) receives that and passes it into a program which has registered itself as being responsible for the modem (in my case portslave http://www.linuxrouter.org/portslave/). That program is only concerned with working out what is happening. If for example it decides that someone is trying to send a fax, it will start a program for receiving that fax (written by someone else), give it the modem and end itself. In this case it sees someone trying to login, so it will check the username and password, which it does sending a request through the kernel to the network card and across the net to another Linux PC where the other PC's kernel (http://www.kernel.org again) passes it through to a program (from http://www.cistron.nl) which knows all the users and passwords.

I'll leave the details at this point, although we still have not sent one bit of information in our out of the Internet. What we see is lots of separate programs from different developers, they each do something which you may not be familiar with, but you can understand if you take the time to read a little. They also fit together in a logical manner, so if you need to you can follow the whole process as they are running and find any problems. All of these programs work together, but each can work with a different set of programs. I use Linux, so all the data moving in and out of programs passes through the Linux kernel, but all the other software would happily run on a kernel from FreeBSD, Santa Cruz Operation, IBM, SUN, Hewlett Packard etc.

The copyright of the article Linux Tech Support in Linux is owned by Ian Carr-de Avelon. Permission to republish Linux Tech Support in print or online must be granted by the author in writing.