The question is quite simple: Could running the program on a dual
(or quad) machine expose problems that weren't transparent under a
single processing machine, or does the JVM see these mutliple
processors as a single entity and control the threads accordingly?
THE MORE I THINK ABOUT THIS ISSUE, THE MORE IT FRIGHTENS ME!!!
Threading is scary, but worth learning. The new concurrency tools in
Java 5 and Java 6 are quite keen, and insulate you from the worst
problems, as long as you use them well.
If you have tested on a dual core, you have tested on a dual
processor. From the point of view of threading, they are the same.
That said, if you want to make sure your product runs on a PPC multi
processor, you should probably get one. They are somewhat different,
in that they generate different machine code, and thus things will
happen at different times. It is thus a good idea to try on both
fast and slow multiprocessors, and ones with different
architectures. Nothing replaces testing on every system you intend
to run on, but that is too expensive for most developers. Testing on
every major class - PPC, Intel, multiprocessor, single processor -
will catch the more egregious bugs.
Do remember, of course, that testing on a dual processor is not the
same as testing on a quad processor. On a quad, it can do four
things at once, which may bring up different deadlock problems.
Properly written code should not have any problems anywhere, but
verifying that your code is, in fact, properly written, is why we
test. Is it worth getting a quad? Not to me, not until quad intels
show up, but your mileage will vary.
This, of course, begs the question, is buying a PPC machine,
regardless of it's price, dual processor or not, even worth doing?
Depends. I do not have customers to support anymore, as I am
changing jobs. I thus need the best Java platform for my own
development, and to make sure my code works on Linux. Thus, a dual
boot MacBook Pro is good enough for me. When I was doing consulting,
I needed the same hardware my clients had, so I had a G5, a G4
laptop, and an Intel laptop. All depends on where your code needs to
function.
We do know that Leopard is going to work on PPC, and so you will be
safe until perhaps the start of 2008, and maybe even longer. It
takes some months for people to completely upgrade. (Also, since
applecare is a three year warranty, I am expecting whatever OS Apple
ships three years after the last ship date of a PPC machine to be
universal.)
That said, a slow PPC will have less life than a fast Intel machine,
so you have to decide how much that is worth. If the machine is
cheap enough, then it is probably a good thing to have. After all,
$800 is not far from what a loaded Mac Mini will run you, and a lot
of developers I know used that for their initial intel testing.
I have to assume that PPC dual processor machines will be replaced
by Intel based equivalents. Is there a timeline for this anywhere?
Yep. No timeline announced, save that the transition will be
complete by the end of this year. That said, Intel has talked about
the CPUs they are announcing and shipping, and the desktop
replacement chip is out there. One has to expect Apple hardware that
will use it pretty soon.
Scott
-------
email@hidden. http://www.iceweasel.com/~scott/
"You die, she dies, EVERYbody dies" - Heavy Metal
"When a great many people are unable to find work, unemployment
results" - Calvin Coolidge, attrib. by Stanley Walker, City Editor,
p. 131 (1934)
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Java-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/java-dev/email@hidden
