OK then. Here's a modified version of your original Func2:
void *Func2(char *a)
{ long i; for (i = 1; i < 100; i++) { a[((a[i-1]+1)**2) % 100] = a[i-1]+a[i+1]+3; } return a; }
How would you turn that into a parallel algorithm? You can't simply run n threads in parallel, because now the results of each stage of computation depend on previous results. If you did simply run n-threads, you'd get different results.
This is the basic problem with non-trivial algorithms - the results of a later part of the algorithm depend on results of a earlier part of the algorithm. So you can't run the later part until the earlier part has completed.
This is what people are talking about when they talk about FFTs or n-body simulation. In both those cases, although there may be parts of the algorithm that can be performed in parallel, the overhead of communicating the results to the other nodes may outweigh that, and the actual work of the algorithm involves repeating the same step over and over again, where the next step cannot be started until the previous step has been completed. That's why parallel computers do not always offer the speed benefits that one might think they do.
Not true, well at least, not according to IBM. According to the datasheet on their microdrive, the drive can withstand (with no hard error), 150G half sine wave shock pulse for 2ms, or 10G for 11ms during operation.
Non operating shock ratings are 120G for 11ms or 1000G for 1ms. This is from the same datasheet that warns that the drive must be shipped only in approved containers, otherwise the packaging might not protect the drive against shock levels induced when the box is dropped:o) .
I think all this proves is you have to take shock figures with a pinch of salt.
This seems like a step backwards (or at least in the wrong direction) to me. The reasons I like the idea of a solid state MP3 player are:
extremely good shock resistance
low power consumption
small size
Memory capacities will continue to grow, and the prices will (hopefully) continue to fall, at least for the next few years, so before long we'll be able to make players that can store, say, 5 hours of music easily.
I'd also be interested to know how well those hard drives can stand up to the sort of abuse they might get in a small handheld device.
Obviously there aren't many BeOS users reading Slashdot! I run BeOS (on a laptop) and it runs just fine. The benefits are:
A journalled file system means that the machine always boots quickly without having to check its discs.
Consistent user interface; almost all applications look and behave the same way - makes it easier to find your way around different applications.
Efficient OS runs well even on modest hardware.
The disadvantages (in this case):
Laptops are not supported by Be. You can get BeOS to run on them, but you'll get no help from Be Tech Support.
Limited hardware compatibility - check before you buy! There is a list on the Be web site (http://www.be.com/) of supported hardware.
In summary - I think it would be an ideal platform for someone who wants to surf (use Opera http://www.opera.com/, or the supplied browser, NetPositive), do a little writing (http://www.gobe.com), and reading eBooks - don't know of any applications for this off the top of my head; there's probably something out there that'll serve (http://www.be.com/beware/). I'd rate it as being about as stable as Linux (with the advantage that if it ever does crash you don't have to fsck). It runs _so_ much better than Windows 98 does.
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How would you turn that into a parallel algorithm? You can't simply run n threads in parallel, because now the results of each stage of computation depend on previous results. If you did simply run n-threads, you'd get different results.
This is the basic problem with non-trivial algorithms - the results of a later part of the algorithm depend on results of a earlier part of the algorithm. So you can't run the later part until the earlier part has completed.
This is what people are talking about when they talk about FFTs or n-body simulation. In both those cases, although there may be parts of the algorithm that can be performed in parallel, the overhead of communicating the results to the other nodes may outweigh that, and the actual work of the algorithm involves repeating the same step over and over again, where the next step cannot be started until the previous step has been completed. That's why parallel computers do not always offer the speed benefits that one might think they do.
Will
Non operating shock ratings are 120G for 11ms or 1000G for 1ms. This is from the same datasheet that warns that the drive must be shipped only in approved containers, otherwise the packaging might not protect the drive against shock levels induced when the box is dropped :o) .
I think all this proves is you have to take shock figures with a pinch of salt.
URL for IBM's datasheet is:
http://www.storage.ibm.com/hardsoft/diskdrdl/micro /datasheet.htm
It probably does cost a bomb.
extremely good shock resistance
low power consumption
small size
Memory capacities will continue to grow, and the prices will (hopefully) continue to fall, at least for the next few years, so before long we'll be able to make players that can store, say, 5 hours of music easily.
I'd also be interested to know how well those hard drives can stand up to the sort of abuse they might get in a small handheld device.
A journalled file system means that the machine always boots quickly without having to check its discs.
Consistent user interface; almost all applications look and behave the same way - makes it easier to find your way around different applications.
Efficient OS runs well even on modest hardware.
The disadvantages (in this case):
Laptops are not supported by Be. You can get BeOS to run on them, but you'll get no help from Be Tech Support.
Limited hardware compatibility - check before you buy! There is a list on the Be web site (http://www.be.com/) of supported hardware.
In summary - I think it would be an ideal platform for someone who wants to surf (use Opera http://www.opera.com/, or the supplied browser, NetPositive), do a little writing (http://www.gobe.com), and reading eBooks - don't know of any applications for this off the top of my head; there's probably something out there that'll serve (http://www.be.com/beware/). I'd rate it as being about as stable as Linux (with the advantage that if it ever does crash you don't have to fsck). It runs _so_ much better than Windows 98 does.
Odd, I've found the Blackdown port of 1.1.7 to be rock solid, but 1.2 is very fragile (possibly due to AWT problems?).