4 ms·

You can try to have fault-tolerance in the JVM, but not real-time fault-tolerance, and there is a difference. The goal is to have decent performance while bein

by okeuday 13y ago

You can try to have fault-tolerance in the JVM, but not real-time fault-tolerance, and there is a difference. The goal is to have decent performance while being fault-tolerant. The JVM garbage collection prevents real-time fault-tolerance when using an Actor model within the JVM.

RyanZAG 13y ago
Can you explain this concept in a bit more detail? There is nothing I can find to back this up anywhere, and the idea seems very strange to me as I've never heard of it before. A quick Google search on the topic seems to show a number of papers detailing real time fault tolerance on Java.[1] At any rate, as far as I can tell CloudI is mainly intended for network and web systems, which are not going to be real time when running on Linux/Windows in any event. (network buffers, etc) [1] http://dl.acm.org/citation.cfm?id=1404893 http://dl.acm.org/citation.cfm?id=1404893 https://weblogs.java.net/blog/editor/archive/2013/03/18/jonas-bon%C3%A9r-jfokus-2013-building-scalable-highly-concurrent-fault-tolerant-systems-lessons-learne https://weblogs.java.net/blog/editor/archive/2013/03/18/jona... http://books.google.co.za/books?id=BroUpHAZThwC&pg=PA470&lpg=PA470&dq=java+real+time+fault+tolerant+systems&source=bl&ots=tSzIVpUOo4&sig=OmguyZgN3lxwppMu9Kk7Qtm-iyg&hl=en&sa=X&ei=dIvEUduLHMnF7AbahYGACA&ved=0CDQQ6AEwADgK#v=onepage&q=java%20real%20time%20fault%20tolerant%20systems&f=false http://books.google.co.za/books?id=BroUpHAZThwC&pg=PA470&lpg...
- okeuday 13y ago
  CloudI and Erlang underneath are focused on soft real-time. For hard real-time (embedded) you need tighter integration with hardware. While it is true that people attempt to pursue (soft) real-time fault-tolerance on the JVM, the point in the CloudI article is that the pursuit does not achieve fault-tolerance which can be considered real-time, simply due to the JVM garbage collection which must interrupt real-time processing of an Actor model. This problem isn't often discussed, but is a simple way of showing the problems with fault-tolerance on the JVM. Without the JVM supporting fault-tolerance, the effort to have decent (real-time) fault-tolerance would be similar to creating a new VM. Since creating a VM is difficult to do properly, and testing is required after its completion, it makes much more sense to use the Erlang VM since it has native real-time fault-tolerance that is already used in commercial products.

by okeuday 13y ago

RyanZAG 13y ago

Can you explain this concept in a bit more detail? There is nothing I can find to back this up anywhere, and the idea seems very strange to me as I've never heard of it before. A quick Google search on the topic seems to show a number of papers detailing real time fault tolerance on Java.[1] At any rate, as far as I can tell CloudI is mainly intended for network and web systems, which are not going to be real time when running on Linux/Windows in any event. (network buffers, etc) [1] http://dl.acm.org/citation.cfm?id=1404893 http://dl.acm.org/citation.cfm?id=1404893 https://weblogs.java.net/blog/editor/archive/2013/03/18/jonas-bon%C3%A9r-jfokus-2013-building-scalable-highly-concurrent-fault-tolerant-systems-lessons-learne https://weblogs.java.net/blog/editor/archive/2013/03/18/jona... http://books.google.co.za/books?id=BroUpHAZThwC&pg=PA470&lpg=PA470&dq=java+real+time+fault+tolerant+systems&source=bl&ots=tSzIVpUOo4&sig=OmguyZgN3lxwppMu9Kk7Qtm-iyg&hl=en&sa=X&ei=dIvEUduLHMnF7AbahYGACA&ved=0CDQQ6AEwADgK#v=onepage&q=java%20real%20time%20fault%20tolerant%20systems&f=false http://books.google.co.za/books?id=BroUpHAZThwC&pg=PA470&lpg...

okeuday 13y ago
CloudI and Erlang underneath are focused on soft real-time. For hard real-time (embedded) you need tighter integration with hardware. While it is true that people attempt to pursue (soft) real-time fault-tolerance on the JVM, the point in the CloudI article is that the pursuit does not achieve fault-tolerance which can be considered real-time, simply due to the JVM garbage collection which must interrupt real-time processing of an Actor model. This problem isn't often discussed, but is a simple way of showing the problems with fault-tolerance on the JVM. Without the JVM supporting fault-tolerance, the effort to have decent (real-time) fault-tolerance would be similar to creating a new VM. Since creating a VM is difficult to do properly, and testing is required after its completion, it makes much more sense to use the Erlang VM since it has native real-time fault-tolerance that is already used in commercial products.