Can someone explain how our LaTeX problems are possible?

[Fredrik]

Physics Forums has had problems with LaTeX for 10 months now. I'm just wondering if someone can explain what's causing it, or at least how it's possible at all. The problem and some of my thoughts are summarized in this quote:

There's probably 20 threads about this already, but most of them just say that the workaround is to refresh and resend after each preview. It appears that we've had this problem since April 13, 2010. According to our LaTeX guy, chroot, nothing changed on the server around that time. The problem is essentially the same in all versions of all browsers, on all operating systems. This strongly suggests that the service provider started doing some weird caching around then. Has anyone been in contact with them? Maybe Greg just needs to ask them to configure an exception.

I don't know this web stuff well enough to know if something can be done on the server. Is it possible to configure the web server software to instruct proxies to not cache images?

It seems to me that something else must be wrong, in addition to the fact that somebody is caching something. How does a transparent proxy know what image to use from the cache? Isn't the image identified by a file name or something? When I previewed these four LaTeX images, I got the two images from my previous post instead of 1 and 2, but 3 and 4 were fine.

$$1$$

$$2$$

$$3$$

$$4$$

Can someone explain how that's possible?

 

[Greg Bernhardt]

Fredrik, I understand your frustration. What I can say is that once MathJax 1.1 is released from beta we will be begin seriously looking at switching over. This will solve the preview problems for good.