modules on CD

[Craig Latta]

Hi Jecel--

 > > > [need to ship modules on a CD]
 > >
 > > You could populate the CD-ROMs with object memory snapshots that,
 > > when resumed, start servers on 'localhost'. Message-based
 > > negotiation still happens, it's just that the clients and servers
 > > are all on the same machine. The CD-ROM object memories could have
 > > all the modules you want to convey in them.
 >
 > I guess there are two ways this could be done:
 >
 > 1) for each module we would have a memory snapshot containing the
 > module itself, any modules it depends on including the very basic
 > stuff
 >
 > 2) a single memory snapshot containing all the modules we want to
 > ship, any modules they depend on including the very basic stuff
 >
 > Option 1 wastes some of the CD-ROM, just like in Unix before dynamic
 > linking each executable file had a copy of the basic libraries.

	This doesn't seem significant to me, given that an object memory with 
the usual "basic libraries" is from 90k to 200k on disk. Also note that 
a module doesn't have to have all its prerequisites in the same object 
memory, so I don't think we'd be duplicating modules much (just the ones 
needed to start the minimal snapshot).

 > Option 2, however, does take up quite a bit of (virtual) memory... if
 > less than 650MB can be considered quite a bit in this era of 1GB RAMs.

	Surely one could make snapshots which are somewhere in beween 90k and 
650MB. :)  I think that's Option 3: a combination of large and small 
snapshots. We have the flexibility of grouping modules according to 
considerations other than size. It might be moot anyway; once you get a 
group of object memories started, they can form a single distributed 
object memory.

 > This system is certainly usable and has many advantages, but takes up
 > more RAM and disk than alternatives which allow images to be split
 > into chunks which can then be lumped together again.

	To summarize, I don't think either the additional RAM (~200k per object 
memory currently) or additional disk (~90k per snapshot currently) is 
significant. More importantly, this system is *accurate*, by virtue of 
the live negotation that takes place, whereas the non-message-based ones 
are not.


	thanks,

-C

-- 
Craig Latta
improvisational musical informaticist
craig@{netjam.org, weather-dimensions.com, appliedminds.com}
www.netjam.org
Smalltalkers do: [:it | All with: Class, (And love: it)]