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. 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 >
