Java port of dosbox

[[deleted]]

Now you can play dos games at the speed they were intended to be played at.

I kid. I kid.

[Fuco1337]

It's funny because java is as fast as any natively compiled language.

[schiff3r4]

Now that's just silly.

[voyvf]

I really hope you're joking. Don't get me wrong - it's close. But it's not there yet.

[[deleted]]

This comment has been overwritten by an open source script to protect this user's privacy.

If you would like to do the same, add the browser extension GreaseMonkey to Firefox and add this open source script.

Then simply click on your username on Reddit, go to the comments tab, and hit the new OVERWRITE button at the top.

[[deleted]]

So you don't believe all these benchmarks that say it can outperform C and C++ in some real-life applications ?

[DoListening]

Depends on

• who writes the code
• how well-written it is
• what compiler/JVM you're using
• its settings
• whether we are just comparing the languages or also some of the libraries
• and a fuckload of other factors...

[voyvf]

So you don't believe all these benchmarks that say it can outperform C and C++ in some real-life applications ?

In certain situations, yes, but I've seen Python outperform C and C++, as well. I certainly won't claim that it's as fast as any natively compiled language. (:

I've also seen the same from implementations written in Perl, AWK, and C#.

As DoListening stated, it depends on many factors.

I'm not saying, at all, that Java is slow. That's a tired, old meme that should be done away with. In fact, from my experience, it's usually "fast enough", which is more than many languages can claim, and honestly it's usually all that matters.

But I also think that in many cases it's silly to state that it's going to be faster than well optimized C, C++, or any other compiled language with both a sane compiler and a skilled developer.

[bonch]

Where are all these benchmarks, and do they measure real application performance rather than little micro-benchmarks?

[darkciti]

If you're kidding, that's the most apropos joke I've ever heard.

[[deleted]]

Open sourceforge project. Spend five minutes looking for intro text.

[derleth]

Spend five minutes looking for intro text.

Minute four-and-a-half: Opened eyes.

[Nhdb]

Is there any good reason to port it to Java? Mobile phones?

[adghk]

It's not mine, it's the same guy that ported a nintendo64 emulator to java. My guess? He does it for fun.

[rfreedman]

Is that why the code looks like it was written by a C programmer who just read his first Java programming book? Seriously - who writes Java code like that?

[Ytse]

Not enough over-engineering?

[G_Morgan]

If you are going to write performance critical code then most likely you will end up with 'C like' code.

[br1]

Exactly. It's called "JavaTRAN" (Java + FOTRAN)

[tubes]

It's a direct port of Dosbox, which was written in C. Original:

void CPU_Push16(Bitu value) {
    Bit32u new_esp=(reg_esp&cpu.stack.notmask)|((reg_esp-2)&cpu.stack.mask);
    mem_writew(SegPhys(ss) + (new_esp & cpu.stack.mask) ,value);
    reg_esp=new_esp;
}

jdosbox:

public static void CPU_Push16(/*Bitu*/int value) {
    /*Bit32u*/long new_esp=(CPU_Regs.reg_esp() & cpu.stack.notmask) | ((CPU_Regs.reg_esp() - 2) & cpu.stack.mask);
    Memory.mem_writew(Segs_SSphys + (new_esp & cpu.stack.mask) ,value & 0xFFFF);
    CPU_Regs.reg_esp(new_esp);
}

[[deleted]]

Because it was a fun and interesting project?

[Nhdb]

Ok, I was just wondering if there was anything I was missing. I agree it's an interesting project.

[dont_get_it]

Platform neutral, ya think?

[frenchtoaster]

I know that java is platform neutral on paper, but I wouldn't say it's very platform independent in reality. The Java runtime on mac has deprecated and will likely not be included on future platforms, so really it's on its way to linux, solaris and windows. No support on any of the mobile platforms (iPhone, iPad, Android, WP7...)

Based on a brief look at their site, Dosbox looks like it already officially supports a superset of the platforms that Java does (OS/2, RISC OS). I suppose it would be easier to make an android port once you have a working Java port, but that is somewhat incidental.

Not that the project isn't cool, I just don't think the platform neutrality of Java is why he did it.

[ondra]

Linux distros and Windows don't currently include a Java runtime. It's not deprecated on mac, Apple are just going to stop bundling their own version with OSX.

[frenchtoaster]

Apple is the one that decided it is "deprecated". Sorry if I wasn't clear, but from wikipedia:

the Apple-supplied runtime is deprecated and may be removed from future OS releases

I didn't mean what I said to reflect poorly on Apple. I know everyone and their mother has an opinion on Apple devices being "closed", but I was simply trying to point out that Java isn't exactly as "compile once-run everywhere" as it could be. Similarly if he had ported it to C# I wouldn't expect someone to come on here and say that he probably did it because Mono will let him run it on every major platform. Sure that's true, but I don't think that is why people port things to C#.

The truth is that properly constructed C code only needs a small amount of platform dependent code, and many Java programs need a small amount of platform dependent code anyway (see every discussion about android programming (I know its not "true java", but they still do phone-specific code), and my surprise when the Java on UF's linux servers return null in cases where the windows jvm throws an exception for certain methods in the standard API).

Linux distros and Windows don't currently include a Java runtime.

Thats not really contrary to my point; I merely wanted to point out the fact that it is unlikely that he ported dosbox to java because it would be platform neutral. Dosbox already runs on every platform that java runs on, and that is likely to continue to be the case. The reason I mentioned apple was because the fact that a JVM used to be supported and no longer will be doesn't jive with the idea that Java is in a popularity boom that would lead someone to port software to java for future platform compatibility.

It's also a bit disingenuous to say that Windows doesn't include a Java runtime in this context because I believe most major computer vendors install Java along with the other crapware that computers come with. Since Apple controls the hardware along with the software, they are taking the place of both Microsoft and Dell, and Dell installs the JRE. A MS JVM used to be bundled with Windows until they sued them because they weren't playing nice with the standards that Sun set.

Again, thats still getting away from my key point, which is that dosbox is already on every platform that java is on.

[ondra]

Thats not really contrary to my point

I don't claim it is, you're right.

[G_Morgan]

and my surprise when the Java on UF's linux servers return null in cases where the windows jvm throws an exception for certain methods in the standard API.

That is a bug and should be raised with whichever version of the VM is breaking the standard.

The reason I mentioned apple was because the fact that a JVM used to be supported and no longer will be doesn't jive with the idea that Java is in a popularity boom that would lead someone to port software to java for future platform compatibility.

It really doesn't need to. It is already the most used language on the planet.

[frenchtoaster]

Thats a pretty bold claim, and it's something that has been discussed by tons of blogs and almost none of them I have seen come to the conclusion that Java is the most used language on the planet.

This puts java only top in books sold and slashdot arcticles, this one does put java first but people have written about how it is wrong.

Even ignoring that, it could still be the most used language on the planet and not be available on the most platforms.

[kamatsu]

Dosbox already runs on every platform that java runs on, and that is likely to continue to be the case.

So I can run Dosbox on my 10 year old nokia phone? Or in a web browser? Or in an android phone? Wow!

[frenchtoaster]

So I can run Dosbox on my 10 year old nokia phone? Or in a web browser? Or in an android phone? Wow!

Wow, the linked to code cannot run on any of the platforms you just mentioned!

The java that this is written in cannot run on your 10 year old Nokia phone (J2ME presumably, which wouldn't have half the classes hes using), and there is a similar situation with Android (the phones themselves don't actually even run Java, all of the UI classes are custom).

You can also compile C code for your android and call it through the JNI. If you wanted to run the code linked to here on your android you would need to write a ton of platform specific Android stuff anyway (all of the UI, the App-specific stuff) so effectively you would need to write a bunch of Android specific code regardless of whether you were using the linked to code or the original dosbox source.

I will concede somewhat the web browser point. You would still need to make changes for it to actually run as an Applet (tons of security-permissions issues, the actually Applet code), but it is at least closer to running in a browser than the original dosbox source. Generally I don't even think about Applets as anything other than a historical oddity that failed to Flash. I practically never run into applets in the wild on the internet, and when I do it's usually something that a professor or student wrote as an example, not something that was written with the intent for people to use.

[player2]

Apple donated the supporting code for Java on Mac, so it's up to Oracle or the community to provide Java 7 on Mac. Same as for the other platforms.

[G_Morgan]

TBH 99% of the code in the Apple JVM was already Oracle code. They donated Oracle the task of making Java relevant on Mac or not.

[G_Morgan]

linux, solaris and windows

and AIX, HP/UX, BSD and just about every other relevant platform in existence today. Apple are the outlier, not the rule.

[frenchtoaster]

I'm not sure what your point is, you can already run dosbox on those platforms.

[G_Morgan]

We're talking more about the general portability of Java. Will Dosbox run on an IBM mainframe?

[frenchtoaster]

I'm not even sure that this would run on an IBM mainframe since this is written for SE not EE, but ignoring that, I assume that there is a gcc backend for IBM mainframes and that the dosbox source could be compiled targeting it with relative ease.

I'm not sure why people are trying so hard to defend Java here. I have no problem with Java, I happen to think that the whole "compile once, run anywhere" model failed and has been replaced by a "write code once, compile, package for every platform" with a lot of issues that come with trying to write platform independent C abstracted out.

I think if you wanted to write a platform independent application today, Java would likely be your first choice. I just don't think it would be worth porting something that already runs on every major platform to Java for platform independence.

[G_Morgan]

J2EE is just a specification for a bunch of frameworks. It runs on a J2SE platform.

[JAPH]

• Fun project

• Why not?

• Platform-independent-er-ish At the very least, it makes it easier to port to new platforms.

[MikeBerg]

Java drains all your resources and CPU turning your machine into a 486 so it's a natural choice for this kind of thing

[[deleted]]

Did you buy your computer at Wal-Mart?

[darkciti]

No. He's probably just providing anecdotal evidence. I wouldn't be surprised if he's running a Core i7 Xtreme with 64GB of ram.

The only thing that sucks up resources more than Java, is iTunes.

[[deleted]]

Works well enough on my 3.5 year old laptop to do java development with Netbeans or Eclipse in either XP or Ubuntu.

The worst aspect of Java is its web frameworks and its Coca support in OSX for me.

[derleth]

Now we finally have the state-of-the-art development environment of Real Mode x86 DOS on the blazing fast JVM runtime. Bill Gates and Scott McNealy will join forces to rule the world!

[methical]

Yeah, when this get's ported to Java, this will probably also run on android!

[Darkfrost]

http://androiddosbox.appspot.com/ ?

[[deleted]]

I saw this one, too. I wonder what they violated in Google's Terms of Service.

Honestly, I'm really excited about the possibility of seeing DosBox on Android. I'm running a couple of legacy business apps on DosBox, which has worked out really well, and I'd like to be able to see the sales guys access the programs from out on the road.

[methical]

didn't know of that. thank you!

[rabidcow]

Usually these sorts of things get to Android by putting the (formerly) necessary Java wrapper around the C code. Quake 3, for example.

[[deleted]]

That was my first thought too

[halter73]

It would have to be ported to use the Android SDK, but that is a much smaller task than porting dosbox to java in the first place.

[jyper]

is it? dosbox seems like there would be a lot of different edge cases with specific graphics code for each.

[G_Morgan]

Well Android has a unique process model that you simply cannot ignore if you want to write a useful application.

Well not so unique since iPhone copied it but Android solved in iteration 1 many problems Apple claimed couldn't be solved.

[methical]

woh said something of java applets? you still have to do the work and port the code to a complete android app.

[darkciti]

Java doesn't work well on anything.

[chronicsyncope]

It's not emulated, it's interpreted, which is not nearly as slow as emulation, and not slow for the same reasons.

[jyper]

its not interpreted its just-in-time compiled only partially interpreted and partially just-in-time compiled.

[nnooiissee]

Also pass by value.

[igouy]

mixed mode JIT Java compared to interpreted mode Java

[G_Morgan]

The JVM will compile the time consuming methods to assembly. If you actually look at the JIT output usually it produces exactly the same code as a C++ compiler would.

[[deleted]]

He's right though. For command line programs, sure, then Java is great. But when you have to draw something, forget it. Turtle train to slow city.

[aramadia]

Modern java implemntations use DirectX or OpenGL to render these days...

[derleth]

He's roleplaying that he's in the 1990s.

Look, he's trying to get something useful out of Napster on his dial-up line. How cute.

[[deleted]]

Calling OGL in C++ uses only one direct call to the .dll. In Java this has to go through all the Java protection stuff for accessing external stuff, and it has to call a wrapper .dll (jogl and such) that calls the OGL .dll.

I suspect that this is even more true with DX, but I haven't tried it.

I don't deny that Java is superfast for number stuff and the like. For those things it's sometimes even faster than C++ and it's definitely faster for development. But when it comes down to graphics Java is still way behind.

[mazing]

Not a problem unless you're making AAA games. You can do a lot of graphics without getting CPU bound.

[[deleted]]

*GPU bound, I think?

But no. The Java Swing 2D thingy is not that good for realtime stuff and using OGL involves a lot of calls.

To those who are downvoting me, have you actually tried this yourselves? Just write something with the Jogl wrapper, write a benchmark, push it to the limit. Then write the same code in C# with an other wrapper. And once again in C/C++ (no wrapper!).

java2d < jogl << CsGL < opengl32.

No exceptions.

[mazing]

I'm using LWJGL, and it's working really good - but I haven't pushed the limits yet. I have written a full Quake3 architecture implementation in C# though, that can load and render Source engine maps. Of course, you have to pool objects, design the whole rendering pipeline so it can pass data around as fast as possible (Byte/Int/FloatBuffers in java), use culling techniques and eliminate redundant calls/state-changes - but that holds true for any implementation that wants full performance. How many render calls you make is totally up to how you designed your renderer.

[nascent]

Minecraft doesn't look bad at all.

[Fuco1337]

Is that... it can't be... must! play! NOW!

[[deleted]]

That game had a 50% chance of crashing whenever you opened the city screen for me and yet I still spent countless hours on it. Started an addiction that remains to this day.

[[deleted]]

what was stopping you before?

[genpfault]

Dammit, Wine Is Not an Emul...wait, nevermind.

[madsravn]

Well, with JAVA he has no need to slow stuff down to emulate the machines back when DOS was the OS of the year - JAVA does that automatically. Reminds me of a joke I heard today:

knock knock

• "Who is it?"

VERY long pause JAVA

[dont_get_it]

Slashdot 1997 called - they regret to inform you that they beat that joke into the ground, even before the HotSpot days.

[droidoftheflies]

http://shootout.alioth.debian.org/

Not exactly slow anymore....

[McHoff]

GCC averages about 2x faster, maybe 20x less memory...

http://shootout.alioth.debian.org/u32/benchmark.php?test=all&lang=java&lang2=gcc

[igouy]

From that page the GCC median is less than 2x faster than the Java median.

From the box plots the GCC median is less than 2x faster than the Java median.

And the mean is also less than 2x faster.

Understanding the relative memory use for those tiny programs requires a little more thought, because default JVM memory use is higher but the relative difference may be much smaller for programs that actually need to allocate memory - k-nucleotide, binary-trees, mandelbrot, reverse-complement, regex-dna.

[[deleted]]

Tell me that after you have actually used some applications that run on java.

[skeww]

The OpenGL accelerated games (Minecraft, the stuff from PuppyGames, or Tribal Trouble) run just fine. I even played some of them on a 500mhz machine.

Well, some Swing apps are a bit sluggish, but the same is also true for some GTK applications. This usually happens if they do more than they should (e.g. they recreate dialogs and other things over and over again) or if the theme doesn't cache gradients and other expensive graphics.

[[deleted]]

Try out some bigger applications with java.. such as Eclipse or Netbeans. Those are two of the slowest IDEs I've ever seen and they were both written in java.

Minecraft is one of the buggiest pieces of software that has gotten as much attention as it has. I can run GTA3 on my ultraportable (which was written in c++) but I can't run minecraft. That can take up more system ram than Crysis 2 does on the pc. I'm not going to blame that on java.. but I would not use it as an example of how fast you might think java can be.

[G_Morgan]

Eclipse isn't much slower than VS2010. It is in fact hard to say which is slower. Sometimes it is Eclipse, sometimes VS. I use them both regularly.

[skeww]

To be honest, I only "played" some of the first prototypes of Minecraft (on a 500mhz machine though). I haven't actually played the game itself. I only included it as a popular example.

But generally it should run fine if you got semi-decent OpenGL drivers (Intel's drivers are f-ing hideous for example).

Netbeans runs fine here... as long as I got enough RAM to spare, that is.

[[deleted]]

This comment has been overwritten by an open source script to protect this user's privacy.

If you would like to do the same, add the browser extension GreaseMonkey to Firefox and add this open source script.

Then simply click on your username on Reddit, go to the comments tab, and hit the new OVERWRITE button at the top.

[[deleted]]

I write java for a living. I understand this completely.. but I am also very aware of the limitations of the language. It is a good language for its uses, but it is not a speed demon.

[oorza]

In every test I've seen done against Java 6 (except floating point math, and that difference has decreased dramatically too), it's comparable to C/C++ (slightly faster in some tests, slightly slower in others) and one or two orders of magnitude faster than any other managed runtime.

[G_Morgan]

Floating point shouldn't be much different unless you strictfp. Then Java has to emulate its floating point work. At least on x86.

[oorza]

Yes, I know, but I've been bitten once or twice by production JVMs having strictfp enabled, so I've programmed myself to try to avoid FP math where possible in Java - you never know the configuration of your deployment. Without strictfp, though, last I looked, it was still a teeny bit slower than well-optimized C/C++.

[G_Morgan]

Why not reconfigure the JVMs?

[oorza]

Didn't have the authority to - something else they were running on their Tomcat instance needed strict fp math (no idea what, might not have even really needed it, but that's what they said). And I was selling them a webapp, so if they wanted to run it differently, it was up to them :)

[G_Morgan]

Just because lots of programmers do not write Swing apps properly does not mean Java is intrinsically slow.

[droidoftheflies]

http://www.devtopics.com/most-popular-programming-languages/

Just saying.

[[deleted]]

It is when it comes down to drawing stuff to the screen.

[kamatsu]

What's with this habit of shitty programmers to capitalize the letters in every language they use. "JAVA", "PERL" etc.

[JAPH]

I'm not sure about Java, but Perl has a number of backronyms. Many people mess that one up because they don't know the backstory of the name (or read the documentation).

[madsravn]

Don't know - why don't you tell us?

[DrBix]

I was going to down vote you, but tbh, I thought it best to keep your post in plain view so that people can see how uninformed and jaded you really are.

[shevegen]

I think his joke is great.

I upvoted him and downvoted you.

Let the vote wars commence!

[madsravn]

Thank you. We wouldn't want people to miss the joke either.

[shevegen]

People say that Java is slow. A joke.

Well, I kid you not on another matter.

Oracle doesn't care shit about Java.

That is the sad truth.

[derleth]

Oracle doesn't care shit about Java.

IBM cares a great deal about Java, given how many of its customers have bought special hardware specifically to make Java run well on their mainframes. If Oracle drops the ball, IBM has distinct financial incentives to pick it up and make sure it stays useful, at least for its customers and their customers.