Re: Caching Servers Considered Harmful (was: Re: Finger URL)

Marc VanHeyningen (
Mon, 22 Aug 1994 20:35:48 +0200

> Because anyone running a caching server runs the dual risk of presenting
> out-of-date information to their users and can be in direct violation of
> international copyright law.

So, it's not just caching servers per se but any form of shared, persistent
caching that you object to. Yes?

> The first point is by far the most important in my mind. As more and
> more professional publishers come online, you will see this becoming
> much more of an issue.
> The publisher holds complete responsibility over their product, in
> content, presentation, timeliness and distribution. By running a caching
> server on my content, you are robbing me of any control I might have over
> the timeliness and distribution.
> You can provide no guarantee that the versions that you present to your
> users are accurate or timely. Further, I have no idea of the number of
> consumers who view my content through your cache or what they view, how
> and when.

It depends how the cache is implemented. If it checks currency with the
original (e.g. via a HEAD or a conditional GET) it can indeed make such a
guarantee, and the original server still has an accurate record of how
often pages are being viewed. Of course, such a system makes the cache
less of a win because only bandwidth time, rather than round-trip-times,
is heavily saved. Any reasonable cache would behave in this way given
an appropriate expiration time.