You Can Teach an Old Chip

Kudos (again) to Tom Halfhill for his detailed yet clear explanation of how the MMX instructions work with Intel-type CPUs ("x86 Enters the Multimedia Era," July). The article's nuts-and-bolts focus typifies why BYTE is a valuable resource for all of us.

First, if my browser requests <URL:http://www.some.company/directory>, an HTTP_error_302 is raised, resulting in an extra transaction between browser and server to correct the URL to <URL:http://www.some.company/directory/> .

It works, but it generates extra traffic, which contributes to an already crowded Net. Second, consider a Web server, like Zeus ( http://www.zeus.co.uk/ ), that actually does content negotiation. You don't, for example, put extensions on image files. Instead of <IMG SRC="/images/mypic.gif">, you would write <IMG SRC="/images/mypic">.

The server looks at the HTTP_ACCEPT string and determines whether the browser can display GIF, JPEG, XBM, etc., then serves the best or smallest image accordingly. So, if we have a directory called /images/mypic/ but refer to it as /images/mypic, aren't we potentially in trouble?

Adam Shaun Nealis
adam@lbs.lon.ac.uk

I think you're right on both scores. I do try to include the trailing slash to avoid the extra bit of negotiation you describe. That's pretty well known. But the second case you bring up is really interesting. I've been only vaguely aware of progress in standards for content negotiation, but if it ends up working in the way you describe (i.e., no file extension means negotiate best type), then that wou ld certainly be another reason we should all try to be more precise about trailing slashes. -- Jon Udell, executive editor