[comp.sys.mac.misc] System 7.0 vs Virtual 2.0

mkelly@cs.uoregon.edu (Michael A. Kelly) (08/31/90)

From the MacWarehouse catalog:

	"Virtual 2.0 gives you the advantages of virtual memory -
	 with System 6.0.  Virtual memory uses your hard disk to expand
	 your RAM without adding memory chips to your Mac.  With
	 Virtual, you can have up to 14 megabytes of memory at your
	 fingertips.  Virtual is fast, offering performance comparable
	 to the usual hardware memory chips."



I seem to remember reading somewhere that System 7.0 will include a similar
utility.  Is this true?  And if so, how does it compare to the aforementioned
product?

And, is Virtual _really_ as fast as the ad claims?


Mike.
--
Michael A. Kelly
mkelly@cs.uoregon.edu

weesh@grymoire.crd.ge.com (Darweesh) (08/31/90)

First, you must realize that Virtual memory of any sort can only be
accessed as fast as the media it's being stored on.  Theoretically,
you could have virtual memory using an audio cassette player, but I would never
use that considering that it may take a couple of years to swap a couple
of megs.  If you have a fast hard drive, virtual will swap faster, but unless
your hard drive is timed in tens of nanoseconds, then it will not be even close
to as fast as real RAM.
I have used Virtual 2.03 and System 7.0 virtual (yea system 7.0 is going to 
support virtual memory).  As I said before, the speed will be dependant on
your hard disk speed, but both seem to work well.  Usually, they just swap
when you are switching between applications in multifinder or when you start up
an application.  It also helps to have some extra real memory so you don't
have an excess of swapping.  I bought virtual because I have a MAc II and
needed the PMMU (connectix has a good deal if you buy the PMMU and the
software).  I have no idea if I answered your question(s)...

-Mike Darweesh
weesh@crd.ge.com

J.Holley@massey.ac.nz (John Holley) (09/01/90)

In article <1990Aug30.211334.2689@cs.uoregon.edu> mkelly@cs.uoregon.edu (Michael A. Kelly) writes:
>From the MacWarehouse catalog:
>	"Virtual 2.0 gives you the advantages of virtual memory -
>	 with System 6.0.  Virtual memory uses your hard disk to expand
>	 your RAM without adding memory chips to your Mac.  With
>	 Virtual, you can have up to 14 megabytes of memory at your
>	 fingertips.  Virtual is fast, offering performance comparable
>	 to the usual hardware memory chips."
>I seem to remember reading somewhere that System 7.0 will include a similar
>utility.  Is this true?  And if so, how does it compare to the aforementioned
>product?
>
>And, is Virtual _really_ as fast as the ad claims?
>

Well I`ve had Virtual on my IIci for a couple of months now and it
seems to work really well i.e. no software problems and doesn't
degrade the performance of the machine too much (hard to tell though
with a IIci :-) ).

Initially my IIci only came with two meg so while I was waiting for my
memory upgrade Virtual was a godsend. Even now with 5 meg of memory I
can see that having another 14 meg on "tap" can be real useful if you
are in to memory intensive applications like image analysis software.

I've played with a System 7 alpha release and it's virtual memory
management is crude to say the lease. I suspect that it's one of the
things Apple is working on at the moment.

When I say crude, I mean waiting several seconds for responses from
software whereas with Virtual you hardly notice any difference at all.
But as I said, this was only an alpha release.

Virtual memory will be a must for many users of System 7 as a two meg
machine basically only has enough real memory to run the System let
alone anything else.

John A. Holley                  | J.Holley@massey.ac.nz         : Internet 
School of Information Sciences  | J.Holley@nz.ac.massey         : Janet 
Massey University               | +64 63 505611                 : Fax
Palmerston North                | +64 63 69099 ext 8616         : Vox
New Zealand                     |  Disclaimer : Sorry! My brain hurts!

clarson@ux.acs.umn.edu (Chaz Larson) (09/03/90)

In article <1990Aug30.211334.2689@cs.uoregon.edu> mkelly@cs.uoregon.edu (Michael A. Kelly) writes:
>I seem to remember reading somewhere that System 7.0 will include a similar
>utility.  Is this true?  And if so, how does it compare to the aforementioned
>product?

True.  The two implementations are pretty similar, from what I've seen.
Both have cdev interfaces, etc.  With the version of Apple's virtual memory
cdev I saw, you could choose to put the virtual swap file on the root of 
your hard disk or in the system folder.  Connectix Virtual lets you put it
wherever you want.  That's about the only difference I've seen.
Oh, yes...Apple's version will [eventually] be free, while Connectix' costs
about $125.

>And, is Virtual _really_ as fast as the ad claims?

I use Virtual on a 2-meg SE/30 to run with 5 virtual megabytes.  I don't feel
that this machine is particularly doggy compared to the 5 [real] megabyte IIci
at work.

chaz

-- 
--
 Joan Rivers Slaughters Ninety-Five Chinese Physicists in drunken rampage.
                 			 -spew
clarson@ux.acs.umn.edu                                       AOL:Crowbone