UNIBUS mapalloc

[utzoo!duke!decvax!ucbvax!woods at LL-ASG]

From: woods at LL-ASG (John Woods)
     I now have completed the UNIBUS map which I was working on (and announced
a trial version of).  Mapalloc now hands the unibus out in 8K chunks (one map
register at a time), and though I haven't been able to run any conclusive
benchmarks, it seems to provide some improvement.  There have been some
problems with asking RL02 drives to share the UNIBUS; their marginal design
causes them to fail in the presence of any contention for the attention of
the UNIBUS.  Devices with reasonable buffering and/or no time constraints
should experience no problems at all.

Happy Hacking!
	-- John Woods

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