Interesting - how easy would it be for a commercial company to change the license of an OpenSource product like OOo to something more restrictive?
Or is it as easy as releasing a "new version" with a new version number and including an "updated license"?
you are entitled to your opinions sir,
I don't believe that RISC (or CISC) are THE future - parallelism begs for solutions more akin to a Cell architecture. Both RISC and CISC will be around for a while longer. Our hardware architecture lecturer (former chief architect of AMDAHL) always maintained that
(a) registers are an optimization/hack
(b) RISC is an optimization, CISC can be opmtized to match RISC - it is only a matter of cost.
"The advantages of RISC are well known — simplifying the CPU core by reducing the complexity of the instruction set allows faster speeds, more registers, and pipelining to provide the appearance of single-cycle execution."
I know this has been argued to death already - but it just isn't completely true that a RISC has advantages over a CISC. The gain in speed is usually negated by the lack of expressiveness and the number of registers would help a CISC just as much as a RISC. Why is this being dragged up again?
Why am I not getting this? I studied a little bit of physics; I'm not pretending to understand this all
and was fascinated by the article, so I re-ran the numbers;
lets see:
Suppose we build a spaceship of 100 tonnes (a big one) - this is 100,000,000 grams - right?
Then suppose we want to travel at 0.1C (as stated in the article) - so to get to that speed and assuming there is no friction in space (or at least this friction is more or less negligible) we have:
E = 1/2 * M * V^2 - plug in values:
E = 1/2 * 100,000,000 gms * (0.1 * 299,792,458 m/s) ^ 2
E = 44937758936840882000000 J
Ok - so assuming that we get fusion to work or use some fissile material and convert it to 100% energy - we get Einsteins mass-energy equivalent equation E = M C^2
We already have E, we know C^2, so we get the mass needed = 44937758936840882000000 / (299,792,458) ^ 2 = 500,000 gms
i.e. M = 500 Kgs
Thats not too difficult to do. What am I missing? We only need to accelerate to 0.1C and then
coast till we get close enough to start decelerating (so M = 1000 KGs for both accel and deccel?)
It'll still take a long time - but it doesn't seem impossible.
Slashdot Mirror
Interesting - how easy would it be for a commercial company to change the license of an OpenSource product like OOo to something more restrictive? Or is it as easy as releasing a "new version" with a new version number and including an "updated license"?
you are entitled to your opinions sir, I don't believe that RISC (or CISC) are THE future - parallelism begs for solutions more akin to a Cell architecture. Both RISC and CISC will be around for a while longer. Our hardware architecture lecturer (former chief architect of AMDAHL) always maintained that (a) registers are an optimization/hack (b) RISC is an optimization, CISC can be opmtized to match RISC - it is only a matter of cost.
"The advantages of RISC are well known — simplifying the CPU core by reducing the complexity of the instruction set allows faster speeds, more registers, and pipelining to provide the appearance of single-cycle execution." I know this has been argued to death already - but it just isn't completely true that a RISC has advantages over a CISC. The gain in speed is usually negated by the lack of expressiveness and the number of registers would help a CISC just as much as a RISC. Why is this being dragged up again?
Totally agree with your reasoning - there is no way this process can be 100% efficient.
0 6/the_high_frontier_redux.html)
Its just that the referenced article from this article made claims that it was totally impossible
even if the process were 100% efficient. (see http://www.antipope.org/charlie/blog-static/2007/
Like yourself I didn't see this limitation - it just takes a bit of fuel (compared to the mass of the ship)
The author of the original article seemed to think that a fuel tank the size of a Volvo was not acceptable.
Why am I not getting this? I studied a little bit of physics; I'm not pretending to understand this all and was fascinated by the article, so I re-ran the numbers; lets see: Suppose we build a spaceship of 100 tonnes (a big one) - this is 100,000,000 grams - right? Then suppose we want to travel at 0.1C (as stated in the article) - so to get to that speed and assuming there is no friction in space (or at least this friction is more or less negligible) we have: E = 1/2 * M * V^2 - plug in values: E = 1/2 * 100,000,000 gms * (0.1 * 299,792,458 m/s) ^ 2 E = 44937758936840882000000 J Ok - so assuming that we get fusion to work or use some fissile material and convert it to 100% energy - we get Einsteins mass-energy equivalent equation E = M C^2 We already have E, we know C^2, so we get the mass needed = 44937758936840882000000 / (299,792,458) ^ 2 = 500,000 gms i.e. M = 500 Kgs Thats not too difficult to do. What am I missing? We only need to accelerate to 0.1C and then coast till we get close enough to start decelerating (so M = 1000 KGs for both accel and deccel?) It'll still take a long time - but it doesn't seem impossible.