system
Given the following post, respond as if you're commenting on Reddit:
human
[Doctor Who] What exactly IS the sonic screwdriver; what all can it do; and what was it originally created for?
gpt
At its most basic level, the first time we ever see it, it's basically just a screwdriver. 

Then a curious thing happened. The Doctor got stuck on Earth for a lot longer than he really liked. So, he got bored, and decided to see what all he could do with it. At this point, it started to become more a general purpose tool, but it mostly opened locks, undid screws, exploded mines, that sort of thing.

After a while, he got off the Earth, and then got tired of the sonic for a while. A long while. Like 3 regenerations.

In his seventh and eighth lives, he started tinkering with it again, giving it new capabilities. At some point, out became capable of doing complex atomic calculations (though it would take centuries to actually complete one calculation) 

During and after the Time War, he just stated cramming any kind of settings he could think of into that thing. The actual number of functions it has is unknown, but it's somewhere in the thousands, most likely.

On a side note, the actual software is pretty much the same from the second Doctor all the way to the twelfth. The hardware itself is grown by the Tardis, and is an extension of the ship itself.

Also, it doesn't do wood.