[alt.next] The NeXT Cache

pchris@monet.Berkeley.EDU (Chris Perleberg) (10/17/88)

(Sorry if this is a repost)

Does the NeXT computer have a cache external to the processor?  I know the
68030 has on-chip data and instruction caches, but their small size leads to 
high miss rates.  If NeXT does have an external cache, what is its size,
organization, replacement algorithm, "average" miss rate, etc.?

	Thanks,

		Chris  Perleberg
		pchris@ucbarpa.berkeley.edu

c152-tb@cory.Berkeley.EDU (Chris Perleberg) (10/18/88)

Does the NeXT computer have a cache external to the processor?  I know the
68030 has on-chip data and instruction caches, but their small size leads to 
high miss rates.  If NeXT does have an external cache, what is its size,
organization, replacement algorithm, "average" miss rate, etc.?

	Thanks,

		Chris  Perleberg
		pchris@ucbarpa.berkeley.edu

brown@hpccc.HP.COM (Jeffrey L. Brown) (10/21/88)

/ hpccc:alt.next / pchris@monet.Berkeley.EDU (Chris Perleberg) /  9:39 am  Oct 17, 1988 /
(Sorry if this is a repost)

Does the NeXT computer have a cache external to the processor?  I know the
68030 has on-chip data and instruction caches, but their small size leads to 
high miss rates.  If NeXT does have an external cache, what is its size,
organization, replacement algorithm, "average" miss rate, etc.?

	Thanks,

		Chris  Perleberg
		pchris@ucbarpa.berkeley.edu
----------

I watched a talk that someone from NeXT gave at Stanford yesterday.  Someone
asked a question very similar to this on.  The guy from NeXT gave a definitive
"NO" answer:  the 68030 has internally caching of both busses; other than that
there is no caching in the system.

On a completely different topic (yet slightly related in a upside-down-and-
backwards sort of way... :-) ), a few people wanted to know how the box was
doing its graphics.  The guy from NeXT (I wish I remembered his name) said
there is hardware support for what he called compositing.  I'm not a graphics
guru; from what he said it has something to do with making things transparent
when objects pass over each other.  Anyway, all other graphics ops are done in
software--no other hardware support.

I had hoped he would have a machine present to demo stuff, "but this is a
technical talk..."

Now that I'm done rambling idly on....

Jeff Brown
HP Corp. Computing
brown%hpccc@hplabs.hp.com
It just doesn't matter....