Anne & Lynn Wheeler wrote:
the result was that w/o stringently enforced microkernel standards ... the
micro-kernel tended to become extremely bloated, starting to resemble
the kernels of more traditionally implemented operating systems ...
becoming more and more bloating and much more difficult to maintain and
modify (the ease of modification somewhat leading to its own downfall).
ref:
http://www.garlic.com/~lynn/2006p.html#10 What part of z/OS is the OS?
this brings to my mind somebody's line that goes something like "it
isn't done when there is no more to add, it is done when there is no
more to take away"
applied to micro-kernel efforts ... with somebody's related observation
that maintaining a KISS implementation can actually be significantly
more difficult than doing a complex implementation.
however, there is a corollary about KISS implementation being applicable
to the situation. recent posts mentioning how simple handling of FINWAIT
processing in tcp session close ... made some implicit assumptions about
the environment that were violated with HTTP use of TCP sessions.
http://www.garlic.com/~lynn/aadsm25.htm#17 Hamiltonian path as
protection against DOS
http://www.garlic.com/~lynn/aadsm25.htm#19 Hamiltonian path as
protection against DOS
the mention of the spool file system rewrite in the previous posts
http://www.garlic.com/~lynn/2006e.html#36 The Pankian Metaphor
http://www.garlic.com/~lynn/2006k.html#51 other cp/cms history
http://www.garlic.com/~lynn/2006o.html#64 The Fate of VM - was: Re: Baby
MVS???
addressed a problem similar to what showed up with FINWAIT handling on
heavily loaded webservers in the mid-90s. native vm spool processing had
a linear list of all spool files ... and all spool file operations
involved searching the linear list. this had non-linear increase in
overhead as systems scaled. this is also similar to the original cp67
kernel storage management that used a single linear list ... before
subpool logic was introduced to cp67 kernel in the early 70s.
in any case, my pascal/vs spool file rewrite introduced both a hash
table and a tree structure for managing spool files.
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