Are there any known web browser implementations (or browser options) that explicitly do not cache pages (and other data) to disk?
I'm looking for an implementation that only caches to memory (obviously the cache is discarded when the process exits). I'm ignoring external disk write factors such as OS paging.
it's possible to disable the cache in every major browser, wich solves your first problem.
if you want to cache to memory, you have to turn caching on again, configure a ramdisk and then set the caching-path to that ram-disk. in firefox, for example, you have to change Browser.cache.disk.parent_directory in about:config to achive this - and i'm pretty sure other major browsers will have similar options.