Nice FAQ. Also going read your book.
Shouldn’t you have mentioned jME in the Scenegraph list though?
Yes I should have, good eyes 8)
Actually I’m still researching and gettign right the whole J2ME section there which will incldue both 184 as a scenegraph and the joglES JSR currently in comittee as the OpenGL binding.
As you say, “CDC Hotspot” IS CVCM, just with their JIT compiler finally in place. Since there is some confusion I will ad a “Wjhat is CDC Hotspot?” point.
I hadn’t realized they even had monty out the door. If it makes you feel better Ill mention it to but it is NOTwhat people are experiencing today and I do NOT want to confuse them.
[quote] In my opinion you should change CVM to CDC Hotspot since it is the name that pops up the most
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This week. I’m not going to drive the FAQ by marketing terms. If you look at java.sun.com you’ll actualyl see quite a mix of what terms are used (I’ve been looking since you brought this up).
But I went and scoured the specs and you are right that the most technically correct thing (even though soem of our own stuff on j.s.c gets this wrong) is that CVM and KVM are implementatiosn fo specs that dont have names beyoind “CDC VM spec” and “CLDC VM spec”. Ergo I’ve modified wording to reflect this 8)
My extensive talks with the CDC guys.
A fast turtle is still a turtle, my friend. Game programmer care about real speed compared to their real options-- which today is C like it or not.
Neither. “CDC Hotspot”, “CLDC Hotspot” and “J2SE Hotspot” are ALL totally sperate codebases.
CDC Hotspot is CVM plus its JIT.
CLDC Hotspot ts Monty, which was an independent research project.
J2SE Hotspot is the second generation VM from the J2SE team.
There is some simialrlities between J2SE Hotspot and Monty, but only because the Monty projectwe as strated by folks who came over from the J2SE Hotspot team.
No, see above.
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True but developers have to target the lions-share of the market. The target phones are still much smaller. This is why I talk about such phones as “next egenration.” They may be available now but they are not yet the target market. Furthermore, the primary audiance of my peice are people using their phones and seeing a slow Java. I am explaining to them why that is what they see and why it is not represetative of Java anywhere but on those phones.
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Well that depends on your market target I for instance am targeting JSR184 enabled phones and most phones with 3D capabilities have already pretty good memory capabilities
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And what percentage of the existing phone-in-hand comsumer market is that?
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Well i did not make that argument “with a good GPU VM performance doesn’t matter”, I only mention GPUs because it is one of the things that can make java games depend less on VM speed
But that was my point, VM == CPU. ANd mdoern games don’t depend less on CPU speed. They just shift other thinsg to the CPU.
Okay then we agree.
Got one that runs on my Samsung APH-A600? At least to the US developers, thats the target level you are talkign about and the level of their Jave experience.
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I think YOU do him a disservice now. Three years ago at Quake con (I was there) a prime point of his speach was “low level bit twiddlign is dead.” He made it very celar that he believed that, as the hardware took over more and more functionality, higher level tools were going to become the preferred norm.
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Probably so, but i am not a Carmack Fan,
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Neither am I but I do respect his abilities and intelligence. I only have 2 problems with him. (1) As I said he tends not to know what he doesnt know and (2) people pick up what he says and mindless rpeeat it without considering other options or poinst of view. The lst though isn’t entierly his fault (though I do think to some degree he encourages it.)
Okay,
A few minor changes made and two new points added to address “CDC Hotspot” and “CLDC Hotspot”.
Those are useful, thanks.
JK
Whoops! I’llfix!
By the way… is it prounced “Wurm” (like the english word for something that wriggles through the ground) or “Vurm”? (or the germanic “Vee-urm”? )
yes… but when Im hoenstly technically wrong its good for me to know that…
Just expect me to make you fight to prove me wrong, at least on major things 
And 32 MB is still tiny compared to mdoern consoles and desktops.
Plus with all this talk of memory the OTHER key factor of processor performance is being ignored. Unless you have some amazing battery technology over there I can;'t imagine its much better then we have here as battery life is the limiting factor on cell-phone processors.
So i don’t see where that conflicts with my points at all shrug.
Are you saying that the average eurpoean cell phone is delivering Java performance up to C performance levels? That I find hard to believe and would like to see proof of…
Well PSP has 32Mb of memory and most 3G phones already have processors that are comparable to that console (1-333MhZ) some are even more powerful so i would say that is enough to make games look good (of course you can’t really honestly compare a single purpose product like the PSP to a multi-purpose device like a 3G cell phone, just like you can’t compare a PC to a Playstation or any other single purpose Console), you already have phones from SonyEricsson with over 256Mb, 300Mb, 400Mb, i still see PCs for sale with 256Mb so and also support for memory cards that make them able to store up to 1-2Gb per mem card.
“Samsung APH-A600” does i have JSR184? I am not familiar with that phone, but since it is a 2003 model it is probably outdated, also Samsung does not have the best performance.
Not the average European but many (especially the gamer segment that plays 3D games on phones have pretty able machines already) and even more so in the Asian Market (South Korea, Japan, etc…).
Well actually it could have similar performance to C if phone makers started using ARM Jazelle ;), but since that is not going to happen any time soon, the top performance is always going to balance to C side (but that also happens on the J2SE sector so there you go).
Hey thanks for the info on the differences about CDC Hotspot and CLDC Hotspot base code, that is something i did not know, thank you for the info I learned something from YOU today, so Thanks ;D
Also i am glad you decided to use current terminology, i will keep an eye up for any inaccuracies or mistakes, and send you feedback.
All the Best,
-Dan
PS: You need a new phone, i recommend the SonyErcisson phones (they look great are feature packed and performe well in most models) the K750i is pretty good, but the upcomming W900 is what you really should aim at if you want cutting edge ( i know ill probably get one ;D ).
Hmm. Maybe. PSP is half-VGA resolution which is part of how theyw ere able to egt away with cutting RAM from the PS2 amounts.
I’d like to take a close look at those phone proessor specs. PSP doesnt get all that much continous use on a single charge (4-6 hours is the estimate.) A phone has to runa lot longer. If they are really getting PSP level processing out of a cell phone that woudl be pretty amazing power consumption.
Where? not in the us, certainly…
Not the same thing. Thats secondary storage.
Hardly. It has no 3D at all.
Its typical of the US market today I am afraid.
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Are you saying that the average European cell phone is delivering Java performance up to C performance levels? That I find hard to believe and would like to see proof of…
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Well actually it could have similar performance to C if phone makers started using ARM Jazelle ;),
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Or more so AJile’s Java processor, but thats clearly back in fantasy-future land, as you say.
Nope. Not any more. In general J2SE Java eprformance speed-wise is eqvuivaklent to C and has been for a couple generations of J2SE now. I can show you specific test cases in which, for one reaosn or another, Java actually beats the pants off C. (For some reason anyone I knwo who has done a FFT C v. Java face off finds the Java wins by quite a margin and I’ve seen it happen a few times now. Thsi has been true since about JDK1.3, but its IS a special case. Not quite sure why, I just know that it is.)
In general, on any significantly complex program, well written J2SE performs almost identically to well written C.
Thanks, its always good to be as accurate as possible. Im just not off on this stuff terribly often so you need to really get in my face to prove to me when i am. In that, maybe I’m a bit like Mr. Carmack
Honesltly all I do with my phone is make calls.
For games and media, i use a games and media device (currently PSP.)
Until you cna hand me a phone with as good a screen (and in general form factor) as the PSP, I don’t really want to use it for that. Now if one of our partners wanted to GIVE me a top end phone to prove to me what they coudl do, id gladly take it. But its not worth spending my money on to me.
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I pronounce it “vurm”. Mostly because it sounds cooler than “wurm”, but also because there’s really no ‘w’ sound in spoken swedish, so it’s easier to say “vurm” in the middle of an otherwise swedish sentence.
The name comes from the half-sandworms-half-dragons frequent in a lot of modern fantasy, such as Magic: The Gathering; http://www.abugames.com/i/content/version/63/PlatedWurm.jpg
You can take a look on the ARM site http://www.arm.com/products/CPUs/index.html, most 3G phones use ARM processors (many use ARM9) ARM already has processors for mobile devices with cores that range from 1MHz-1GHz, with all sorts of power saving technologies. Usual HighEnd 3G phones run at 200MHz and more.
Most phones also have smaller Screens than HVGA, with all sort of standby modes, etc… that’s why the bat. last longer on Phones than on devices like PSP (that only are useful wend ON, playing something game/video/music).
But battery is a big issue, if you would go on a head to head challenge in battery life with a similar game in a 3G phone VS PSP the phone would most probably die on you sooner, (hum someone somewhere must have made that comparision i have to see if i can find an article about that :-\ ).
You can get phones with large memory from sonyErcisson just check out the specs: http://developer.sonyericsson.com/site/global/products/phones/phonegallery/p_phonegallery.jsp
About Memory I wonder how much performance difference there really is beetween Main Memory and Secondary Memory in phones, because usually the RAM chips used in mobile phones are not the fastest (helps save bat.), BUS speed is also slow (but this differs allot from model to model).
You guys need to get up to speed even my 56y old uncle has a SonyEricsson K750i (32Mb, JSR184, 2.0Mpxl cam, etc…) ;D
It is on a case per case situation, but…
I much prefer to use Java and all the tools, great refactoring, etc… than trying to squeeze a marginal performance improvement with tweaks in C or assembly. Java at least to me is not only the language, it is allot more than that and that is why i prefer to use it in J2SE (Desktop enviornments) to any other language (but i must say i am tempted to try using C#3.0 aka LINQ, it looks like a very flexible way to query and present data), but heck i still havent had the time to try all the stuff in 1.5 Tiger I will do that first, latelly all i do is J2ME 8)
Phones have good screens, just not the ones you use, CALLS what’s that? ;D VideoCalls, Pictures, MMS, Games (thats what i do most with my phone) i get sad wend i have a voice only call, or get a simple SMS 
It looks like you (and the USA) are still stuck in PC time (you guys have crappy operators) but i must admit that it really sucks to have all these hardware diffs in phones there are no form factors, it is changing (Nokia for instance is begining to share screen sizes in Series40, 60, etc… N60, N70, etc… SonyEricsson also has many model with equal screen sizes) but it still is a pain.
[quote] i get sad wend i have a voice only call, or get a simple SMS
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It seems as if you’ve forgot what mobile phones were originally build for…
So why then do we call those things still mobile phones, why not “all-around-tool, with wich you can make phone calls”, if phoning has gotten so unimportant nowadays?
EDIT: It seems it’s not only the US - I’m from Germany (just wanted to mention that)
It seems as if you’ve forgot what mobile phones were originally build for…
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To communicate i believe, the only diffs is that now we communicate with pictures, video, audio, not just voice, but other media, not just real-time but also in other time modes, not only with humans in a p2p way, but also with other systems (like in mobile photo blogs), etc…
To me it is a tool to communicate.
Why do we call PCs still PCs? Since their first introduction they can do allot more than what was original thought, you can also make phone calls from PCs, What’s in a Name? I don’t get your point :-\
I did not say that “phoning has gotten so unimportant nowadays”, phoning to me has no meaning i think in a more abstract (communicate) way and mobile phones are the tool that permit me to think in that way BTW i do most of my voice calls using my PC (unless i am outside).
Wend waiting in traffic or lines, i always like to play a little with my phone, play a game, check the traffic videocams, do all sorts of stuff that would be unpractical with a notebook (having to boot the notebook, get network access, access the site) and all this having the notebook on your passenger seat, making you look away from the road, people buzzing, etc…) with a mobile phone it is much simpler, allot of stuff you would try to do with a notebook and is unpractical, turn out to be practical with a mobile phone.
Europe is a big place and the network operators differ allot, if you say that 3G is still not at full hype in Germany all i can say is a feel sorry for you guys, maybe you have the wrong operator but allot of countries in Europe are already in full 3G mode.
Here are the main operator in Portugal (where i am right now) and my home country, they all have 3G in high gear for quite some time:
Optimus (my operator): http://64.207.158.28/optimus3g/
TMN (the biggest operator ~50% market share): http://www.tmn.pt/3g/
and Vodafone: http://www.vodafone.pt/main/Live/O+que+e+/default
All sites are in Portuguese (but you can look at the pretty pictures) some have English versions.
All operators in portugal have UMTS (3G).
The country had in June 2005 10,721,000 subscribers in total, or a 102.30% penetration rate.
more about in on: http://en.wikipedia.org/wiki/List_of_mobile_network_operators
There are also discount brands Uzo, Rede4 (virtual operators) from the same operators (for traditional servicies), and subbrands targeted at urban young people Yorn (some plans have 3G services).
But not all is wonderful, we have crappy ISPs that charge allot (monopoly situation), and that hurts high-speed internet in my country, we have traffic limits 
and high speed is not that high even though we have 2Mb, 4Mb, 8Mb, 16Mb* (ADSL) starting at 35€ (with 2G international traffic limit) and going up up up in price.
*One operator offers 16Mb but in a very limited area, and i do mean very limited.
Well, I’ve just ordered me a Sony Ericson K800w walkman thingy, which reckons it’s got MIDP2.0 APIs in it but I’ve no idea what sort of VM it has in there. Might be fun to try writing a game for it.
Cas 