thanks for helping me out earlier. One thing i would like to understand is about engines. What exactly are engines. I understand there are backend and frontend engines. Can sum1 clarify this for me

linguistically speaking, saying "engine" is a boast. If used, the person believes that a certain set of programs work together to provide some essential and powerful functionality, usually, to other less-unfied programs (probably user applications).

despite it being a boast, it could very well be true. I'd imagine award winning mplayer can probably be seen as an engine. LAMP could also be seen as a website engine.

The word is especially used in gaming. It's not an exact word so much, because it qualifies or self-rates itself as being very good.

Try this test, imagine a friend calling you an engine, is it an insult? IN SPain at least to call some an engine is highly complimentary. People dream f being called engines around here ... especially by the opposite sex.

It's better to thank people in the thread where they helped you. Here, we don't know who is being thanked--or for what.

I think of an "engine" as a set of functions that does a task behind the scenes. You will read of "graphics engines", "print engines", "gaming engines", etc. The analogy to a car engine is pretty good. From the driver's point of view, the car has a user interface which includes controls to the engine and feedback on how well it is doing. There is no need for the driver to know the number of cylinders, cam profile, or other internal details.

Especially when people talk about media playing applications (on Linux in this case), the words "frontend" and "backend" are widely used. A "backend" is something like an "engine", the set of things that does the "real job" behind the curtains. Sometimes it can be used as such (it also provides a user interface), but sometimes it's easier to have another (perhaps graphical) program with which the user interacts, and which in turn interacts with the "backend". This program is then referred to as the "frontend". Like Totem on Gnome; Totem itself is (in my opinion, at least) a frontend, and it can use more than one backends, or engines (the used backend is selected during program compilation I think, so with Totem you cannot change it on-the-fly like you might be able to do with some other programs) - for example Xine (full player is then "totem-xine") or GStreamer ("totem-gstreamer").

The words aren't really accurate, but that's one way of looking at it. Like pixellany said, the analogy to car is pretty good. But what can/should be called a "backend" or an "engine" is then another matter. On GNU/Linux operating systems, (because this is a Linux forum) for example, a lot of things work with the idea of having something, usually invisible or transparent to the user, that does the "real work" and then having something else that the user interacts with to control the actions. Libraries (which are not engines, if you ask me) are one sort of thing: there can be one library that offers functionality to do something (like libgtkpod to work with iPods), and multiple different programs that can use the library. In the user's point of view there is just a program, maybe graphical, that is used to do different things with the iPod. However the program itself doesn't do everything, some parts of it may use the library which provides the real means of working with the device. This is different from having a graphical Totem which uses Xine "engine" as it's "backend", but still the principle is that not everything is put into one program, but there can be user-transparent pieces of software that other software can use/work with to get a task done.