Re: [9fans] third edition, installation experiences

["rob pike" <rob@plan9.bell-labs.com>]

	/dev/draw seems slower than /dev/bitblt.  I wonder if the difference is
	from not doing runtime code generation.

Perhaps.  Draw() is also a much more general operator, which causes it to be
slower in the worst case.  On the other hand, we (well, Russ) worked on getting
draw() to talk to the graphics accelerator on some of the cards, and there are
simple examples like catting /dev/words where the new system is *much*
faster (factors of 10 or more) than even bitblt was.  I hope folks will
connect the code to the hardware on more graphics cards so the speedups
will be more widely available.

On the issue of run-time code generation, we abandoned it because it was
too hard to write portable code to handle the synchronization of instruction
and data caches.  The problem is not processors so much as systems; the
details of cache management in different architectures are often delegated
to motherboard makers who choose widely varying ways to handle cache
flushing and make it very hard for a portable program to divine what to do.
If you're just on PCs, it's not so hard, but we use a lot of non-PC machines.
Also, it's possible that the rise of JITs will help this situation, but if the
VGA industry is anything to go by...

	Plumbing is... interesting.  I normally like to have several editors
	running, keeping different work in different contexts.  The new system
	makes that difficult, because when one editor opens a file, the
	others want to open it too.

There was a long discussion about how and whether to handle fan-out in
the plumber.  What we did reflects our style of use.  If it doesn't suit your
needs, you have the source...  Also of course it's mostly controlled by
configuration files, so you might be able to try another arrangement just
by using different plumbing rules.  (The fan-out isn't explicit in the
configuration, but I suppose on reflection it could be made to be.) I've
also done tricks where I've rebound things to rearrange plumbing ports
for temporary purposes; that might work well for you.

Failing that, B is a shell script that could easily be adapted to use other
information to direct the file to a port other than edit, or to add
attributes that different editors could check.

-rob