On Thu, Jan 8, 2009 at 4:01 PM, Ian Rogers <[email protected]> wrote: > 2009/1/8 Xiao-Feng Li <[email protected]> > >> On Thu, Jan 8, 2009 at 12:52 AM, Rui Chu <[email protected]> wrote: >> > Ignoring the native APIs, can we take the heap, stack, byte codes, TLS >> and other mgmt metadata in a JVM as an status information? Can we store the >> status in a disk file, and restore them later to perform an approximate >> "hibernate"? Maybe it is rather simple and coarse, while it would be >> attractive even when it only works for a few simple applications. >> > After all, JVM is also a simple machine model rather than a full layered >> OS and system hardware... >> >> I actually had made this work with another simpler JVM implementation. >> It should be not difficult to achieve with Harmony. >> >> Thanks, >> xiaofeng > > > There is a similar project using Jikes RVM: > > http://www.agentgroup.unimore.it/didattica/curriculum/raffaele/mobility_work.html > > As I understand it they are using a pre version 3 Jikes RVM and so don't yet > have the option of using the Harmony class library.
I guess it is more straightforward to implement such feature with a JVM written in Java like JikesRVM, because its boot-image has already part of the functionality. To add running application support is only an extension? Thanks, xiaofeng > Regards, > Ian > >> ------------------ >> > Rui Chu >> > 2009-01-08 >> > >> > ------------------------------------------------------------- >> > 发件人：Jack Cai >> > 发送日期：2009-01-07 17:27:07 >> > 收件人：dev >> > 抄送： >> > 主题：Re: Re: [general] features >> > >> > So to quickly answer your questions - >> > >> > #2: No, neither SUN JVM nor Harmony JVM support such "hibernate" >> operation. >> > JVM does not have an abstract Hardware level, even though it does manage >> the >> > memory and threads for a running process. So it is not a "real" operating >> > system. It accesses resources by calling the hosting OS's native APIs >> > directly. As a result, it's not as easy to hibernate a JVM as we do with >> > Windows, VMWare, etc. >> > >> > #3: Yes, sandbox is the built-in Java security model. You can achieve >> what >> > you described through a customized SecurityManager. You can search google >> to >> > find enough to read. >> > >> > - Jack >> > >> > 2009/1/7 Rui Chu <[email protected]> >> > >> >> Thank you, Xiaofeng. >> >> >> >> About Java Isolation, I am not sure whether SUN JVM implements it. If >> not, >> >> maybe the benefit of Isolation is still trivial to motivate the guys in >> SUN, >> >> although it looks nice in the proposal. >> >> >> >> About the second question, as you know, VMWare, as well as other >> >> system-level virtual machines, can suspend the guest operating system >> when >> >> you press the 'suspend' button. You can also resume it later, or even >> resume >> >> it in another host system. This feature really looks charming in my >> mind. I >> >> think JVM can also support it more easily because JVM has a relative >> simpler >> >> architecture then the system-level VMs (although it is still complex). I >> >> wonder if current Harmony or SUN JVM could do that. >> >> >> >> The sandbox in my third question does not only mean Applet. In my >> vision, >> >> it should support general java applications. The execution of the >> >> application is monitored and restricted, especially the operations >> through >> >> JNI. For example, the java application cannot access the native file >> system >> >> with the same privilege of JVM, and it can only accesses a virtualized >> file >> >> system instead. Is there any project or plan in Harnony or SUN JVM to do >> >> that? >> >> >> >> Thanks again, Xiaofeng. I have read some documents and source codes. But >> >> the souce codes can only prove what has been done in Harmony, while >> cannot >> >> tell me what is still not implemented. :) If possible, I want to >> continue >> >> to discuss this topic with you. Waiting for you kind response. Anybody >> else >> >> want to join the topic are also appreciated. >> >> >> >> ------------------ >> >> Rui Chu >> >> 2009-01-07 >> >> >> >> ------------------------------------------------------------- >> >> 发件人：Xiao-Feng Li >> >> 发送日期：2009-01-07 08:35:56 >> >> 收件人：dev >> >> 抄送： >> >> 主题：Re: [general] features >> >> >> >> Rui, thanks for your interests in Harmony. My personal opinions are >> >> inlined below. >> >> >> >> On Wed, Jan 7, 2009 at 12:39 AM, Rui Chu <[email protected]> wrote: >> >> > Hi, >> >> > I am a new comer of JVM and Harmony. Since I have just learnt Harmony >> for >> >> a few time, I wonder whether Harmony(especially the VM) has implemented >> or >> >> has been interested in the features as follows. >> >> > 1. SUN has proposed Java Isolation for a long while, and related >> >> specifications have also been released. Unfortunately I cannot find any >> >> support for it in SUN JVM till now. Has Harmony implemented or planned >> to do >> >> that? Or maybe SUN has implemented but I do not know it yet. >> >> >> >> [XF] I personally don't really see the needs to implement Isolation in >> >> Harmony. But it is welcomed if anybody wants to have a try and I'd >> >> like to help. I had some experience in it. >> >> >> >> > 2. Does SUN JVM or Harmony support to suspend, serialize and resume >> the >> >> JVM? In other words, a JVM can suspend the execution of itself and >> >> bytecodes, transfer the execution status into an image file and resume >> it >> >> later. Assuming the external environments such as file system or network >> >> connection still keeps. >> >> >> >> [XF] If I understand you correctly, the feature you described is the >> >> fundamental feature of a JVM for garbage collection and exception >> >> throwing. So all serious JVMs have it. >> >> >> >> > 3. Does the sandbox support appear as an independent project, or has >> been >> >> integrated in Harmony? Where can I find more documents about the sandbox >> in >> >> Harmony? >> >> >> >> [XF] I am not sure what you mean with sandbox. If you mean Applet >> >> support, yes, Harmony has it (almost done). >> >> >> >> > In general, I want to know whether Harmony planned to be another (open >> >> source) implementation of SUN JVM, or has its special features beyond >> the >> >> latter? I am not familiar with both SUN JVM and Harmony, so my question >> may >> >> be naive :) Your kind and patient answers are appreciated. >> >> >> >> [XF] Please read some documents on Apache Harmony in its website. That >> >> will help you to have a basic understanding. Harmony is an open source >> >> Java SE implementation under Apache license. I personally think >> >> Harmony wants to be compatible at first, and might have some special >> >> features. >> >> >> >> Thanks, >> >> xiaofeng >> >> >> >> > Thanks a lot! >> >> > >> >> > >> >> > >> >> > >> >> > Rui Chu >> >> > >> >> > >> >> > >> >> >> >> >> >> >> >> -- >> >> Managed Runtime Technology Center, Intel >> >> >> >> >> > >> >> >> >> -- >> Managed Runtime Technology Center, Intel >> > -- Managed Runtime Technology Center, Intel
