> Johnny Billquist <b...@softjar.se> wrote:

> One thing Cutler did, which you do not find in the predecessors are ACPs.

If so, he may have a claim to inventing (a hint at) a microkernel concept. ;-)

Ironically, while ACPs made a lot of sense in a PDP-11 world due to the 
constraints in address space and kernel memory size, but rolling ACP idea over 
to VMS was much less productive (since these constraints were gone), and 
eventually F11 ACP was replaced with in-process XQP.

I am wondering though if FUSE developers ever heard of ACPs or reinvented the 
concept from scratch.
At least http://en.wikipedia.org/wiki/Filesystem_in_Userspace
claims that "The idea of a filesystem driver living in userspace was originally 
developed in 1995".

It is also curious that ACPs (whether in traditional form or XQP form) allowed 
to do one thing that Unix/Linux interface still does not -- opening files as an 
asynchronous operation -- but ironically the chief utility of this capability 
is mainly for web servers which were not invented back then yet.

P.S. To come think of it, my very first project as a salaried software 
developer (more akin to commercial enterprise of Tom Sawyer in fence painting 
business) at ca. 1984 involved writing an ACP-like structure... not for a file 
system, but for a graphics card, on RSX.
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