Dear all, I was going through the explaination for taskRestart() call in the vxworks reference manual.I believe such a feature is available for most of the RTOS in the market.This dicussion talks about vxworks,But it applies in general for any rtos which offers a restarting facility.I am looking for replys from a architecture perspective rather then os specific discussion. Vxworks reference manual for taskRestart() states the following: "This routine "restarts" a task. The task is first terminated, and then reinitialized with the same ID, priority, options, original entry point, stack size, and parameters it had when it was terminated. Self-restarting of a calling task is performed by the exception task. The shell utilizes this routine to restart itself when aborted. " I have never got a chance to use this call in my application,but curious to learn how it works.Heres my doubt: After restarting will the task start executing from the starting point or will execute from where it left?(that means continue executing,from the point where its terminated before restarting?). Incase it starts executing from scratch from the place where its spawned,will it not cause problems to my application?For eg,I am in middle of some biomedical application and some task goes for a toss and I restart it using this call,the task will start performing everything from scratch which may not be suitable to the current status of application(In terms of micro heart surgery,typically lets say the task performing the cutting of tissues goes for a toss after some time,and I restart,if it again starts cutting the tissues which is not required for me,because I have already removed it!). If its otherway around,for eg it starts executing from the point where it got terminated,how does the task ensure it gets all the resources like I/O device,semaphores or some other resource,which is required to execute from the point where it was terminated?Because the time before it restarts,may be there can be another high priority task which may own the resources required by the current task and I feel this should not be possible because it will cause problem to the entire application. In precise can someone clarify me how this taskRestart() call work?Under what situations its preferred to use this call?What are the pros and cons of using this call in our application? Looking farward for your replys and advanced thanks for the same, Regards, s.subbarayan
Self restarting property of RTOS-How it works?
Started by ●February 7, 2005
Reply by ●February 7, 20052005-02-07
You wil find an explanation and advices here: http://www.bluedonkey.org/cgi-bin/twiki/bin/view/Books/VxWorksCookbookTheKernel#Restarting_a_Task Look for restarting a task
Reply by ●February 7, 20052005-02-07
s_subbarayan@rediffmail.com wrote: snip> After restarting will the task start executing from the starting point > or will execute from where it left?(that means continue executing,from > the point where its terminated before restarting?). > > > Incase it starts executing from scratch from the place where its > spawned,will it not cause problems to my application?For eg,I am in > middle of some biomedical application and some task goes for a tosssnip>Are you saying that it's acceptable in any way, shape or form for a task in a biomedical application to "go for a toss"? -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Reply by ●February 7, 20052005-02-07
> After restarting will the task start executing from the starting point > or will execute from where it left?(that means continue executing,from > the point where its terminated before restarting?).Surely "restart" is self-explanatory?> For eg,I am in > middle of some biomedical application and some task goes for a tossDamn. Fell for the troll :-( *plonk* Al.
Reply by ●February 8, 20052005-02-08
Al wrote:> > After restarting will the task start executing from the startingpoint> > or will execute from where it left?(that means continueexecuting,from> > the point where its terminated before restarting?). > > Surely "restart" is self-explanatory?If this is the case, your question mark is redundant.> > > For eg,I am in > > middle of some biomedical application and some task goes for a toss > > Damn. Fell for the troll :-( >Whenever someone asks a newbie question there are always would be gurus who feel obliged to be insulting even if the question was politely expressed. I think there is a pattern here.> Al.Right
Reply by ●February 8, 20052005-02-08
"Tim Wescott" <tim@wescottnospamdesign.com> wrote in message news:110f5dul9b2grdc@corp.supernews.com...> s_subbarayan@rediffmail.com wrote: > > snip > > > After restarting will the task start executing from the starting point > > or will execute from where it left?(that means continue executing,from > > the point where its terminated before restarting?). > > > > > > Incase it starts executing from scratch from the place where its > > spawned,will it not cause problems to my application?For eg,I am in > > middle of some biomedical application and some task goes for a toss > > snip > > > > Are you saying that it's acceptable in any way, shape or form for a task > in a biomedical application to "go for a toss"? >Oh, is that not acceptable? I hadn't fully divined your attitude toward the patients... Rufus
Reply by ●February 9, 20052005-02-09
Hi, While I appreciate your sincerity in replying,I would be happy if you avoid circausism in your reply.When I say task goes for a toss-this does not mean that always it goes to it,I was refering to the exceptional condition,such exceptional conditions do happen in biomedical world,if you could remember or read about THERMAC radioactive machines which failed due to some problem.While people take exceptional care for biomedical,some times human error do happen. I believe you are also human being to accept errors and no ones GOD here remember. Regards, s.subbarayan Tim Wescott <tim@wescottnospamdesign.com> wrote in message news:<110f5dul9b2grdc@corp.supernews.com>...> s_subbarayan@rediffmail.com wrote: > > snip > > > After restarting will the task start executing from the starting point > > or will execute from where it left?(that means continue executing,from > > the point where its terminated before restarting?). > > > > > > Incase it starts executing from scratch from the place where its > > spawned,will it not cause problems to my application?For eg,I am in > > middle of some biomedical application and some task goes for a toss > > snip > > > > Are you saying that it's acceptable in any way, shape or form for a task > in a biomedical application to "go for a toss"?
Reply by ●February 9, 20052005-02-09
Well said!Some people are more interested in fishing for the errors in the query ,leaving the crux of the main query.... "Lanarcam" <lanarcam1@yahoo.fr> wrote in message news:<1107855611.010433.245820@c13g2000cwb.googlegroups.com>...> Al wrote: > > > After restarting will the task start executing from the starting > point > > > or will execute from where it left?(that means continue > executing,from > > > the point where its terminated before restarting?). > > > > Surely "restart" is self-explanatory? > > If this is the case, your question mark is redundant. > > > > > > For eg,I am in > > > middle of some biomedical application and some task goes for a toss > > > > Damn. Fell for the troll :-( > > > > Whenever someone asks a newbie question there are always would be gurus > who feel obliged to be insulting even if the question was politely > expressed. I think there is a pattern here. > > > Al. > > Right
Reply by ●February 9, 20052005-02-09
"s.subbarayan" <s_subbarayan@rediffmail.com> wrote in message news:c396173e.0502082037.54b8b7e@posting.google.com...> Hi, > While I appreciate your sincerity in replying,I would be happy if you > avoid circausism in your reply.When I say task goes for a toss-this > does not mean that always it goes to it,I was refering to the > exceptional condition,such exceptional conditions do happen in > biomedical world,if you could remember or read about THERMACTherac-25. Not a computer problem per se, but often used as an example of system failures due to design error.> radioactive machines which failed due to some problem.While people > take exceptional care for biomedical,some times human error do happen. > I believe you are also human being to accept errors and no ones GOD > here remember. > Regards, > s.subbarayan > > > > Tim Wescott <tim@wescottnospamdesign.com> wrote in message > news:<110f5dul9b2grdc@corp.supernews.com>... >> s_subbarayan@rediffmail.com wrote: >> >> snip >> >> > After restarting will the task start executing from the starting point >> > or will execute from where it left?(that means continue executing,from >> > the point where its terminated before restarting?). >> > >> > >> > Incase it starts executing from scratch from the place where its >> > spawned,will it not cause problems to my application?For eg,I am in >> > middle of some biomedical application and some task goes for a toss >> >> snip >> >> > >> Are you saying that it's acceptable in any way, shape or form for a task >> in a biomedical application to "go for a toss"?
Reply by ●February 9, 20052005-02-09
Top-posting fixed. s.subbarayan wrote:> > Tim Wescott <tim@wescottnospamdesign.com> wrote in message news:<110f5dul9b2grdc@corp.supernews.com>... > >>s_subbarayan@rediffmail.com wrote: >> >>snip >> >> >>>After restarting will the task start executing from the starting point >>>or will execute from where it left?(that means continue executing,from >>>the point where its terminated before restarting?). >>> >>> >>>Incase it starts executing from scratch from the place where its >>>spawned,will it not cause problems to my application?For eg,I am in >>>middle of some biomedical application and some task goes for a toss >> >>snip >> >> >>Are you saying that it's acceptable in any way, shape or form for a task >>in a biomedical application to "go for a toss"?> > Hi, > While I appreciate your sincerity in replying,I would be happy if you > avoid circausism in your reply.When I say task goes for a toss-this > does not mean that always it goes to it,I was refering to the > exceptional condition,such exceptional conditions do happen in > biomedical world,if you could remember or read about THERMAC > radioactive machines which failed due to some problem.While people > take exceptional care for biomedical,some times human error do happen. > I believe you are also human being to accept errors and no ones GOD > here remember. > Regards, > s.subbarayan > > The Therac 25 killed because of piss-poor design in a piss-poor environment that allowed piss-poor software quality -- probably because people had the attitude that mistakes happen and errors that may kill me or you are acceptable as long as money is being made. For details on the Therac 25 accidents see http://www.embedded.com/showArticle.jhtml?articleID=55300689 and http://sunnyday.mit.edu/papers/therac.pdf. When those tasks "went for a toss" it was because several somebodies weren't paying a hell of a lot of attention. The _only_ excuse that can be granted is that the Therac 25 was one of the first systems where the software had the power to kill people. It's been 20 years, we should know better now. These days going to exceptional lengths to insure software quality in life-critical applications is no more playing god than changing your tires when they go bald, it's simply doing what should be done. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
