html - Why width 960px?

Question

I have a question regarding fixed layout. It has two parts, closely related, so I'm putting in one question.

Part (a) Why 960px is suggested for the website layout? I understand that it is optimized for the most common screen resolution (1024px). But why exactly 960px? Won't the 1000px be as good?

Part (b) What exactly is Grid system? I did check 960.gs but didnt get the idea of columns. Is it better to use grid system (using the template from 960.gs, which looks so messy) or should i stick with traditional way, like:

<div id="wrap">
     <div id = "left-column">..</div>
     <div id = "center-column">..</div> 
     <div id = "right-column">..</div>     
</div>

Answer 1

1024px is the max screen width it's aiming at. We need to allow some window chrome, so it needs to be less. We'd ideally like it to have lots of factors, allowing us to split it into equal size columns with integer widths.

960 has lots of factors:

echo factors(960);
1  2  3  4  5  6  8  10  12  15  16  20  24  30  32  40  48  60  64  80  96  120  160  192  240  320  480  960 

1000 doesn't have as many

echo factors(1000);
1  2  4  5  8  10  20  25  40  50  100  125  200  250  500  1000  

Specifically, you can easily split 960 into 2,3,4,5,6 and 8 columns.