I have read about a technique involving writing to disk a rendered dynamic page and using that when it exists using mod_rewrite. I was thinking about cleaning out the cached version every X minutes using a cron job.
I was wondering if this was a viable option or if there were better alternatives that I am not aware of.
(Note that I'm on a shared machine and mod_cache is not an option.)
You could use your cron job to run the scripts and redirect the output to a file.
If you had a php file index.php, all you would have to do is run
php index.php > (location of static file)
You just have to make sure that your script runs the same on command line as it does served by apache.
Does the page need to be junked every so often because it just has to? Or should it be paralleled with a static version after an update to the page?
If the latter, you could try and write a script that would make a copy of the just edited page and save it to its static filename version. That should lighten the write load since in that scenario you wouldn't need to have a fresh static copy unless there was a change made that needed some show time.
I would use a cache on application level. Because the application knows best when the cached version is out of date and is more flexible and powerful in the matter of cache negotiation.