Are there any PRAM simulators?
I want to test some simple pararell algorithms.
There a language/compiler called Fork that claims to have a simulator in the distro called pramsim that's been recently ported to linux.
http://www.ida.liu.se/~chrke/fork95.html
Disclaimer: I've no hands-on experience with it.
Please have a look at PRAM Machine Simulator by Adam Stański (the source code is also available).
PRAM is not a very realistic model, ignoring the two factors that make parallel computation so difficult: synchronization and communication. You might have more results looking at Bulk Synchronous Processing (BSP) for example. If you are looking for a practical library, you could look into a Fork/Join style library such as IntelTBB or Java util.concurrency.
edit: To actually answer the question: Sorry, I do not know of any PRAM simulator. I have only seen it used in modified form for complexity-analysis.
Related
Here is my question:
Is tere any service or technology to run parallel algorythms on more computer without knowing them?
For example: I write a parallel algorythm. My friends install a simple client app, and if they have internet connection, they can help my calculation with their free processor capacity. I would like to see them like an additional core in my CPU.
If there is no technology like that, is there any unsolvable problems with developing one? (I know there must be a lot problems with code trasfering, operation systems, and compatibility)
I believe that you can use BOINC to set up your own volunteer computing project. But I have no experience of this to report.
Is there some sort of thing like a layout/plan of the windows api? A clear overview of which api depends on another? Or a website where they are linked in a hierarchical way (starting with the most dependable, ending with the core function)
e.g Kerenel32.dll!CreateFile() -> ntdll.dll!ntCreateFIle() -> ntoskrnl32.exe!zwCreateFile()
I can link them all by hand with a dependency walker but it takes much time. So I was just wondering if something like this already existed.
I don't have the answer to your question, but I think an even more interesting road would be to read what Geoff Chappell has found out regarding the Windows Kernel and the Win32 API. I have not read those sections, but so far everything I've read on that website has filled me with wonder and awe at how thoroughly things can be analysed given a disciplined and talented investigator.
You can always take a look at ReactOS:
ReactOS® is a free, modern operating system based on the design of Windows® XP/2003. Written completely from scratch, it aims to follow the Windows-NT® architecture designed by Microsoft from the hardware level right through to the application level.
Simply search for whatever function in the documentation and look at its source. 99% of the time you can just pretend to be looking at the actual Windows source :) Very helpful when playing around with a debugger too.
i am studying for a test on operating systems , and i would love it if i can take a look at
free source projects regarding memory management and memory paging.
Thanks very much for your help:)
Nataly
There's plenty of OS kernels with source available, but I have a feeling trying to pick through them is going to be very difficult. A production kernel is a complex piece of work, so it's hard to understand the theory behind it by looking at the code.
What you probably want is an OS simulator that focuses on teaching the theory. We wrote our own in my OS classes. Just a quick google search came up with this list of a number of them:
http://vip.cs.utsa.edu/simulators/
I’m looking into multithreading, and GCD seems like a much better option than manually writing a solution using pthread.h and pthreads-win32. However, although it looks like libdispatch is either working on, or soon going to be working on, most newer POSIX-compatible systems… I have to ask, what about Windows? What are the chances of libdispatch being ported to Windows? What are the barriers preventing that from happening?
If it came down to it, what would I need to do to preform that portage?
Edit: Some things I already know, to get the discussion started:
We need a blocks-compatible compiler that will compile on Windows, no? Will PLBlocks handle that?
Can we use the LLVM blocks runtime?
Can’t we replace all the pthread.h dependencies in userspace libdispatch with APR calls, for portability? Or, alternatively, use pthreads-win32 I suppose…
Edit 1: I am hearing that this is completely and totally impossible, ever, because libdispatch depends (somehow) on kqueue, which can’t be made available on Windows… does anybody know if this is true?
Take a look at : http://opensource.mlba-team.de/xdispatch/
This project (and other third-party libs) brings libdispatch into platforms(windows, linux) other than macosx
https://github.com/DrPizza/libdispatch
The Windows equivalent of libdispatch, from my basic understanding of it, is the Concurrency Runtime for unmanaged code and a collection of technologies collectively known as Parallel Extensions for managed code. It appears to me that GCD maps pretty well to both of these, since they both abstract work units (or "tasks") in a similar way.
From a bit of research, it appears that there's already a fair bit of interest in a port, but that port would be a fairly drastic undertaking and might end up being basically just another implementation of the API and not actually sharing significant code with the original libdispatch. I did see some proposals to porting libdispatch to being based on the Apache Portable Runtime instead of POSIX which'd make it easier to make it cross-platform to Windows, but even this would not be an easy change.
Likely, this would be by no means a small undertaking.
I think that rather than libdispatch-on-pthreads and pthreads-on-Win32, or libdispatch-on-APR and APR-on-Win32, it might be better to implement libdispatch directly on the Win32 Thread Pool API. The good news is that the two APIs are similar enough that you could probably do the port yourself. The bad news is that there would probably be lots of corner cases where there are small semantic mismatches that make exact behavior hard to achieve.
I did a numeric method as my diploma thesis and coded it in java. It needs a lot of computational time when adequately executed. So I looked for an alternative and found BOINC. Unfortunately I didn't have time for doing my method in BOINC, because I'm an Aerospace student and not a programmer and I decided to keep my priority on my java program. Now it's finished an I still would like to port this to BOINC environment.
Unfortunately I'm learning in re-doing examples and I couldn't find any, neither on the official site http://boinc.berkeley.edu nor in the internet.
So do you know a good and easy example or do you have any experience in BOINC and would like to start a new platform for such a boinc project?
I'm realistic about my method, that it wouldn't run 24/7, because there aren't as many work units as for seti or folding projects. So I would like to have a platform for more than just my project so that another platform project can be worked on, when one part of the project does not have any work units at that moment.
But to start this, I would keep it simple and just want to know how to code it and use it in the client and server system. It doesn't matter what the example projects will work on, as long as it is simple enough, that I can understand it and extending it for my method.
Thank you in advance, Andreas! :)
PS: I know that BOINC supports JAVA as a programming language, and my method is coded in JAVA.
As far as I know, JavaApps is just an idea; I don't know if anyone actually tried it in a real BOINC project. And it's Windows-only. And it seems to be a bit of a pain to redistribute the entire JRE as part of the BOINC application (both technically and legally).
Also, I generally dislike using that kind of “wrapper” where the science app (using the BOINC API) starts another process that then does the real computation. It's usually unreliable. There are lots of things that could go wrong with the wrapper, especially related to controlling the child process (eg. if something kills the wrapper, the child process has to quit too).
However, I just found something pretty interesting that may let me do a better Java wrapper for BOINC... Stay tuned! (but don't hold your breath either; it's the holidays!)
Meanwhile, I suggest you start by reading BOINC wiki and setting up a server with a “hello world” application; and if you have any trouble, ask a specific question about your trouble either here or in the boinc_projects mailing list.
(Of course, payin’ me to install the server for you is also an option ;) but I can't guarantee anything; not even my mere availability at this time of the year)