Understand that the principal life-limiting factor was the accumulation of dust on the solar arrays. Since that hasn't happened at anywhere near the predicted rate (for a variety of reasons), the rovers have been able to continue operating far past their expected mission lifetime.
That does raise an interesting question though: given that the rovers were supposed to only last 90 sols or so, does the fact that they have lasted so much longer (once the prime life-limiting factor was eliminated) indicate that they were over-engineered? Could the mission have been done for a much lower cost? Hard to say, since there was such schedule pressure to get the mission done that the engineers probably tended to go with the most obvious solution (within the mass limit), rather than spending much time investigating cheaper alternatives.
Because in many cases the band would like to actually get their fans at the show.
Then perhaps they should set up a system like the one used by the Dave Matthews Band, where members of the DMB fan club get early access to concert tickets. Quoting from the website:
An allotment of each North American show's tickets will be offered directly to members instead of through a standard ticket distributor. Members of the Warehouse will have access to these direct sale tickets in advance of the general public.
Um, other than large, oil-rich countries like Iran actively writing them large checks, shipping them truckloads of explosives, and giving them enormous moral support in the form of "democracy is a failure" and other "wiping off the face of the planet" type rhetoric from the elected governments of those countries (hint: Iran).
The UK survivied for decades under the threat of IRA terrorists back by enormous amounts of money and resources from the US. But for some reason Tony Blair seems to have decided that the semi-mythical al Qaeda (which has not perpetrated a single attack in the UK - investigation has shown that the Underground bombings were carried out by local nut-jobs, not part of a larger organization) is somehow a bigger threat than the IRA (which perpetrated many successful attacks), and therefore warrants all sorts of new legislation. The same hysterical pattern has been followed in the US. It appears that there are a lot of politicians in both countries who are interested in keeping the public afraid, and accumulating power to themselves, rather than actually dealing with the problems at hand.
You're right that they're trash, but they're trash that are busy soliciting (and getting) major logistical and financial support from multiple sources, and busy cultivating shopping pipelines through east Asia to delightful places like North Korea.
Well, perhaps if the US hadn't stopped supporting them (it was, after all, the CIA that trained and funded bin Laden and his cronies), they wouldn't have turned on us...
Nope, and they don't have to be to blow themselves up on a train full of commuters in London or Madrid. Nothing special by your standards or mine - just mentally broken enough to think it's the right thing to do.
Again, the IRA (to use just one example) perpetrated many more attackes (albeit on a smaller scale in many cases) than "al Qaeda" (or those inspired by it) have managed. If existing laws were sufficient to deal with the likes of the IRA, why are they insufficient to deal with al Qaeda? For that matter, Timothy McVeigh and his buddies managed to make just as many successful terrorist attacks of large scale on US soil (i.e. one), but we didn't see the rampant retraction of civil-liberties in the aftermath of the bombing of the Murrah building that we've seen "post-9/11".
the CATO institute (not exacty a bastion of left-wing liberalism)
No, but they are an essentially libertarian institution, which will tend to make them oppose massive government intrusion in anything (not that I'm trying to claim they're in any way consistent about this).
I'm sure there will be some kind of exemption for party-political websites. Just as there were exemptions for politicial material in the recent anti-telemarketer and anti-spam legislation.
Not sure what rock you've been living under... I've known about the GCSB for years. So have most of my friends in New Zealand. As for Echelon, that's been common knowledge for years too - I remember a John Campbell story on "60 minutes" or "20/20" (I forget which one he was on back then) that was going on about Echelon and the Waihopai listening station a good 10-12 years ago. It just never seems to be much of an issue come election time. Everyone's more concerned with the petty squabbles between National and Labour.
There are various notations and formal methods for reasoning about real-time systems. Off the top of my head, these include: Duration Calculus, Timed CSP, TCOZ, and TLA+. However, reasoning about execution time directly remains a difficult problem, and an area of active research.
And really good unit testing is exactly that, exhaustive
That is blatantly false. Almost any non-trivial piece of software has far too many possible input and output values to perform truly exhaustive testing. What unit testing can do is test "representative" inputs. But, unless you've done some rigorous analysis of your code, there is still a leap of faith there that the "representative" inputs do actually represent input equivalence classes for the program in question.
You're right! It would be better to get a technology designed for multi-threaded programming. But then you go on to push Java? I'm confused.
Now, granted, Java does provide builtin support for concurrency. Although that support is an implementation of the 30-year old monitor concurrency primitive, which even one of its principal inventors (Tony Hoare) long ago abandoned in favor of better things. Not to mention that Java's implementation of monitors is known to be broken (or at least was - maybe they've fixed it now?).
Doug Lea's util.concurrent package (now part of Java 1.5) certainly helps things on the Java front, but it's hardly a panacaea. Depending on the application, you may want to take a look at JCSP instead - it provides for an almost direct translation of ideas from Tony Hoare's CSP into Java. For languages with good concurrency support out of the box, you might try Erlang, Ada, Mozart/Oz, E, or Eiffel.
That story feels a little questionable to me. Not that I'm saying you're Dad is lying. But there're a lot of people out there that get off on dropping mention that they're ex-SEALs (or whatever) into the conversation, despite the fact that they probably never even went to BUDS (basic SEAL training). It wouldn't surprise me if the landlord in question was one of these folks, and was just trying to intimidate your Dad. The "reflexive response" just doesn't ring true to me, at least based on the (real, uniformed) SEALs that I have interacted with in the past.
Why on earth would it be a good thing to have a university (academia by definition) teach something other than academia? I'd rather see them stick to what they are good at, and leave the non-academic courses to technical colleges (who are good at those things).
Not to mention the fact that computer science is...well...science, and therefore somewhat academic. As another poster already pointed out, there are already SE and IT courses that cover the details of specific applications of computer science knowledge (albeit also from an academic perspective).
Lisp is the first language that I'm aware of to use it, but I bet someone else did it even earlier.
According to Wikipedia John McCarthy invented garbage collection sometime around 1959, specifically for implementing Lisp.
Re:the "pet rock" of programming languages
on
EiffelStudio Goes Open
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· Score: 2, Informative
Effiel was the first language with garbage collection if I remember correctly.
Er... you don't recall correctly. Lisp had garbage collection in the early 60's (in fact, John McCarthy invented garbage collection specifically for Lisp). Eiffel isn't even the first OO language with GC - that honour goes to Simula (also the first OO language ever).
The preamble simply states the intended goals of the constitution. That is, it states that there are certain ends that the framers wanted to achieve by creating the constitution (like domestic tranquility and general welfare). It does not confer powers on anyone. The remainder of the constitution explicitly enumerates the powers of the various branches of the federal government. The framers intended these powers to contribute to achieving the goals described in the preamble. From a strict constitutional standpoint, if you don't believe that existing enumerated powers are sufficient to fully promote "the general welfare", then you should amend the constitution (by, for example, explicitly making the building of highways a federal concern).
The constitution only enumerates the powers of the federal government. It says nothing at all about the powers of state governments. That is left to state constitutions and the like.
Actually, solar sails are pushed by photons. The force generated on a solar sail by the solar wind (all of the "crud") is about an order of magnitude lower than that generated by photon momentum transfer. OTOH, the proposed Mini-Magnetospheric Plasma Propulsion (M2P2) system does use a "magnetic sail" of sorts to obtain thrust from the solar wind.
So what he needs to do is develop a design that is robust in the face of errors. In other words, it needs to be fault tolerant. There are well-known design practices for doing this (checkpoints, watchdogs, rollbacks, etc.) as well as design patterns for robust distributed computation (see, for one example, Joe Armstrong's thesis on making reliable systems in the presence of software errors.
No, the situation the OP is in is not ideal. But it's also not impossible to work with, and there are techniques that can help him to get closer to achieving his goals within the constraints placed upon him.
Wow. An entire thread devoted to this question, and so far this is the only answer that actually addresses the problem. Every other suggestions seems to be "changes languages", or "here's how to avoid bugs".
Anyway, let's talk specifics here. For the theoretical end of software fault tolerance, you can get a quick overview here or here.
In terms of practicalities, I know of an older fault tolerance library for Unix that includes watchdog, checkpointing, and replication utilities, and was created by AT&T (details and downloads here). A newer version appears to be available for Windows under the name SwiFT. Disclaimer: I haven't actually used either of these, and they both seem a little old. But I don't know of anything newer that isn't a proprietary in-house solution.
Finally, in terms of general design patterns for fault-tolerant distributed systems, you can't go past Joe Armstrong's PhD thesis, "Making reliable systems in the presence of software errors". While it's mostly about Erlang, many of the ideas he presents are readily applicable to other languages too.
You might try mentioning your draft over at Lambda the Ultimate. They're very interested in programming language design over there, including things like type systems. A few stories on Ruby have popped up recently, and I'm sure they'll be interested in the work you're doing.
News flash! Not every tool is right for every job! In other news, newly released book discusses why afterburning turbofans make poor engines for commuter cars.
And no, the Batmobile doesn't count as a "commuter car".
one would interpolate to the left a trend similar to the others
Actually, if one was going to do anything, one would extrapolat. That is, interpolation involves puting more points between the existing points on a curve. Extrapolation involves extending a curve with additional points outside the range of the existing point.
Reminds me of the first episode of the excellent Blackadder series:
Edmund: "They'll kill us all -- We have to get out of the castle! Run for the hills! Run for the hills!"
Baldrick: "M'lord, they're coming from the hills..."
Edmund: "Oh...er... Run away from the hills! Run away from the hills! If you see any hills, run the other way!"
That qualifies me to say: this guy doesn't know what he's talking about.
Uh, James Oberg worked in Mission Control at JSC from well before Challenger until well after. I'd say that qualifies him to "know what he's talking about", at least as much as you're qualified by your experiences.
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IIRC, "full mission success" included lasting the full 90 sols. The "minimum mission success" criteria were quite a bit lower.
Understand that the principal life-limiting factor was the accumulation of dust on the solar arrays. Since that hasn't happened at anywhere near the predicted rate (for a variety of reasons), the rovers have been able to continue operating far past their expected mission lifetime.
That does raise an interesting question though: given that the rovers were supposed to only last 90 sols or so, does the fact that they have lasted so much longer (once the prime life-limiting factor was eliminated) indicate that they were over-engineered? Could the mission have been done for a much lower cost? Hard to say, since there was such schedule pressure to get the mission done that the engineers probably tended to go with the most obvious solution (within the mass limit), rather than spending much time investigating cheaper alternatives.
Then perhaps they should set up a system like the one used by the Dave Matthews Band, where members of the DMB fan club get early access to concert tickets. Quoting from the website:
The UK survivied for decades under the threat of IRA terrorists back by enormous amounts of money and resources from the US. But for some reason Tony Blair seems to have decided that the semi-mythical al Qaeda (which has not perpetrated a single attack in the UK - investigation has shown that the Underground bombings were carried out by local nut-jobs, not part of a larger organization) is somehow a bigger threat than the IRA (which perpetrated many successful attacks), and therefore warrants all sorts of new legislation. The same hysterical pattern has been followed in the US. It appears that there are a lot of politicians in both countries who are interested in keeping the public afraid, and accumulating power to themselves, rather than actually dealing with the problems at hand.
Well, perhaps if the US hadn't stopped supporting them (it was, after all, the CIA that trained and funded bin Laden and his cronies), they wouldn't have turned on us...
Again, the IRA (to use just one example) perpetrated many more attackes (albeit on a smaller scale in many cases) than "al Qaeda" (or those inspired by it) have managed. If existing laws were sufficient to deal with the likes of the IRA, why are they insufficient to deal with al Qaeda? For that matter, Timothy McVeigh and his buddies managed to make just as many successful terrorist attacks of large scale on US soil (i.e. one), but we didn't see the rampant retraction of civil-liberties in the aftermath of the bombing of the Murrah building that we've seen "post-9/11".
No, but they are an essentially libertarian institution, which will tend to make them oppose massive government intrusion in anything (not that I'm trying to claim they're in any way consistent about this).
I'm sure there will be some kind of exemption for party-political websites. Just as there were exemptions for politicial material in the recent anti-telemarketer and anti-spam legislation.
Not sure what rock you've been living under... I've known about the GCSB for years. So have most of my friends in New Zealand. As for Echelon, that's been common knowledge for years too - I remember a John Campbell story on "60 minutes" or "20/20" (I forget which one he was on back then) that was going on about Echelon and the Waihopai listening station a good 10-12 years ago. It just never seems to be much of an issue come election time. Everyone's more concerned with the petty squabbles between National and Labour.
There are various notations and formal methods for reasoning about real-time systems. Off the top of my head, these include: Duration Calculus, Timed CSP, TCOZ, and TLA+. However, reasoning about execution time directly remains a difficult problem, and an area of active research.
That is blatantly false. Almost any non-trivial piece of software has far too many possible input and output values to perform truly exhaustive testing. What unit testing can do is test "representative" inputs. But, unless you've done some rigorous analysis of your code, there is still a leap of faith there that the "representative" inputs do actually represent input equivalence classes for the program in question.
You're right! It would be better to get a technology designed for multi-threaded programming. But then you go on to push Java? I'm confused.
Now, granted, Java does provide builtin support for concurrency. Although that support is an implementation of the 30-year old monitor concurrency primitive, which even one of its principal inventors (Tony Hoare) long ago abandoned in favor of better things. Not to mention that Java's implementation of monitors is known to be broken (or at least was - maybe they've fixed it now?).
Doug Lea's util.concurrent package (now part of Java 1.5) certainly helps things on the Java front, but it's hardly a panacaea. Depending on the application, you may want to take a look at JCSP instead - it provides for an almost direct translation of ideas from Tony Hoare's CSP into Java. For languages with good concurrency support out of the box, you might try Erlang, Ada, Mozart/Oz, E, or Eiffel.
That story feels a little questionable to me. Not that I'm saying you're Dad is lying. But there're a lot of people out there that get off on dropping mention that they're ex-SEALs (or whatever) into the conversation, despite the fact that they probably never even went to BUDS (basic SEAL training). It wouldn't surprise me if the landlord in question was one of these folks, and was just trying to intimidate your Dad. The "reflexive response" just doesn't ring true to me, at least based on the (real, uniformed) SEALs that I have interacted with in the past.
Why on earth would it be a good thing to have a university (academia by definition) teach something other than academia? I'd rather see them stick to what they are good at, and leave the non-academic courses to technical colleges (who are good at those things).
Not to mention the fact that computer science is...well...science, and therefore somewhat academic. As another poster already pointed out, there are already SE and IT courses that cover the details of specific applications of computer science knowledge (albeit also from an academic perspective).
They're neither. Apple is a system company.
According to Wikipedia John McCarthy invented garbage collection sometime around 1959, specifically for implementing Lisp.
Er... you don't recall correctly. Lisp had garbage collection in the early 60's (in fact, John McCarthy invented garbage collection specifically for Lisp). Eiffel isn't even the first OO language with GC - that honour goes to Simula (also the first OO language ever).
The preamble simply states the intended goals of the constitution. That is, it states that there are certain ends that the framers wanted to achieve by creating the constitution (like domestic tranquility and general welfare). It does not confer powers on anyone. The remainder of the constitution explicitly enumerates the powers of the various branches of the federal government. The framers intended these powers to contribute to achieving the goals described in the preamble. From a strict constitutional standpoint, if you don't believe that existing enumerated powers are sufficient to fully promote "the general welfare", then you should amend the constitution (by, for example, explicitly making the building of highways a federal concern).
The constitution only enumerates the powers of the federal government. It says nothing at all about the powers of state governments. That is left to state constitutions and the like.
Actually, solar sails are pushed by photons. The force generated on a solar sail by the solar wind (all of the "crud") is about an order of magnitude lower than that generated by photon momentum transfer. OTOH, the proposed Mini-Magnetospheric Plasma Propulsion (M2P2) system does use a "magnetic sail" of sorts to obtain thrust from the solar wind.
So what he needs to do is develop a design that is robust in the face of errors. In other words, it needs to be fault tolerant. There are well-known design practices for doing this (checkpoints, watchdogs, rollbacks, etc.) as well as design patterns for robust distributed computation (see, for one example, Joe Armstrong's thesis on making reliable systems in the presence of software errors.
No, the situation the OP is in is not ideal. But it's also not impossible to work with, and there are techniques that can help him to get closer to achieving his goals within the constraints placed upon him.
Wow. An entire thread devoted to this question, and so far this is the only answer that actually addresses the problem. Every other suggestions seems to be "changes languages", or "here's how to avoid bugs".
Anyway, let's talk specifics here. For the theoretical end of software fault tolerance, you can get a quick overview here or here.
In terms of practicalities, I know of an older fault tolerance library for Unix that includes watchdog, checkpointing, and replication utilities, and was created by AT&T (details and downloads here). A newer version appears to be available for Windows under the name SwiFT. Disclaimer: I haven't actually used either of these, and they both seem a little old. But I don't know of anything newer that isn't a proprietary in-house solution.
Finally, in terms of general design patterns for fault-tolerant distributed systems, you can't go past Joe Armstrong's PhD thesis, "Making reliable systems in the presence of software errors". While it's mostly about Erlang, many of the ideas he presents are readily applicable to other languages too.
You might try mentioning your draft over at Lambda the Ultimate. They're very interested in programming language design over there, including things like type systems. A few stories on Ruby have popped up recently, and I'm sure they'll be interested in the work you're doing.
And no, the Batmobile doesn't count as a "commuter car".
Actually, if one was going to do anything, one would extrapolat. That is, interpolation involves puting more points between the existing points on a curve. Extrapolation involves extending a curve with additional points outside the range of the existing point.
Edmund: "They'll kill us all -- We have to get out of the castle! Run for the hills! Run for the hills!"
Baldrick: "M'lord, they're coming from the hills..."
Edmund: "Oh...er... Run away from the hills! Run away from the hills! If you see any hills, run the other way!"
Uh, James Oberg worked in Mission Control at JSC from well before Challenger until well after. I'd say that qualifies him to "know what he's talking about", at least as much as you're qualified by your experiences.