What's the difference between I686 and I586 machines?

This refers to the architecture.

Remember when you used to have a 386, then 486?

The difference between a 586 and a 686 is a semantic rather than real architectural difference. The 'Pent' in Pentium means 5 hence 586.

Eg. 386 was the first Intel (hence I386) to have 32-bit data and address busses and emulates a degree of concurrency (windows 3.1 for example could run literally hundreds of windows at the same time). 486 was a complex instruction reduced register computer (more operations using less memory) and a few other minor enhancements.

In short, from what I can see the difference between 586 and 686 is basically the difference between PII and PIII (or celeron if you're a cheapskate). PII with MMX is called I686 because Intel thought they could sell more computers if they incremented the identifying architecture number. (Hey it worked for Sun and Java!).

It's therefore probably got more to do with marketing than innovation.

Bert

Good explanation "Bert"!.
I586 processors are like AMD K5's and compatible.
I686 started at the AMD K6's and the P II's and we still see them today.

no, cos SQL used to be called SeQueL (by the developers i think), but eventually just gave in and called it SQL, and it's pronounced esskewell now in general ;-)

personally i tink it should have been called SQuirreL. seems nicer to me.

Thanks very much guys, those were great answers.

i thought 586 uses mmx optimizations and therefore would not run on earlier models (ie a 486), and i thought 686 uses sse optimization. and when you are configuring your kernel, i think the 'Athlon' option uses 3dnow! optimizations. i don't think code compiled for a specific processor feature set, like sse or 3dnow, will work correctly on a chip that is lacking that feature set. but using the optimizations allows the compiled program to run faster on machines that support it. so if you have a 486, binaries that say '586' in their name probably won't work on your computer. for ultimate compatibility, i believe many programs are still compiled for i386, or 'x86' so that they can run on any pc. but maybe i am mistaken.

I prefer 'sequential query language' (SQurreLs good too though!) as there's nothing 'structured' about Structured Query Language.

yeah i see what you mean about the sequential bit, i find that with MySQL

why doesn't it do constraints? how else am i meant to do it? why doesn't it comply to the sql api? how come it just crashed? where's that oracle download site?