[IP] more on Patent issued for Web caching

[David Farber <dave@xxxxxxxxxx>]

Begin forwarded message:

From: Dave Crocker <dcrocker@xxxxxxxx>
Date: October 23, 2006 9:51:06 AM EDT
To: dave@xxxxxxxxxx
Cc: ip@xxxxxxxxxxxxxx, petri.tuomola@xxxxxxxxxxxxx
Subject: Re: [IP] more on Patent issued for Web caching



David Farber wrote:
> It seems to me that the real "invention" they claim is a proxy that
> manages its own mass storage directly (rather than relying on the
> operating system/file system to do so). They claim that the use of
> system calls by other proxy designs to manipulate the cached data
> results in "...several sources of delay, caused primarily by the  
> proxy's
> surrendering control of its storage to its local operating system and
> local file system".


(IANAL.  But they sometimes let me play in their infringement sandbox.)

It would be interesting to see the USPTO file history for this patent.

Claim 1 of the patent has no text that matches what Petri says:

"1. A method, including steps of: receiving a set of network objects  
in response to a first request to a server from a client; and  
maintaining said network objects in a cache memory in a cache engine,  
said cache engine connected via a network to the server and the  
client, said cache memory including mass storage; wherein said step  
of maintaining includes steps of recording said network objects in  
said cache memory and retrieving said network objects from said cache  
memory, so as to substantially minimizes a time required for  
retrieving said network objects from said mass storage."

The phrase "minimizes a time required for retrieving said network  
objects from said mass storage" might imply the technique of  
bypassing the o/s calls, but it does not state it.

A patent is supposed to say how something is done.

This one gives no detail about the "how" of the minimization.  To the  
extent that the "minimizes" clause is the distinctive part of the  
claims, it is difficult to imagine more generic -- and therefore less  
helpful -- language in a patent.

For that matter, the sub-task of minimizing delay is inherent in the  
construction of any production query system, so that clause is, in  
fact, not even slightly distinctive.  Further, the performance  
technique of bypassing the overhead of operating system calls is  
probably not less than 30 years old.

Where the heck is the innovation, in this claim?


So indeed, the claims language is exactly as broad as the notes on IP  
have worried about.


Upon expending the considerable dollars needed to dispute an  
infringement assertion of the patent, the defendant will typically  
note the absence of precise description in the claims. The fallback  
is to resort to the section on "Detailed Description of the Preferred  
Embodiment".

Here we see some reference to the caching being done by a dedicated  
engine that does not have a distinction between user and operating  
system.  I seem to recall at least one such dedicated engine dating  
back to the early 1970s. Along with doing serious database research,  
their demonstration machine was a repository for the world's best  
collection of dirty limericks.

More generally, the Embodiment section is little more than a tutorial  
on storage and retrieval performance basics.  I do not see any  
techniques described that are less than 20 years old, and the  
combination of them is a very long way from innovative.

d/
--

  Dave Crocker
  Brandenburg InternetWorking
  bbiw.net


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