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Comment: Re:Bogus algorithm (Score 1) 67

by QQBoss (#48687835) Attached to: The World of YouTube Bubble Sort Algorithm Dancing

I teach both C and Data Structures. Bubble sort is for my C class where I am trying to make sure the students fully comprehend arrays (most of my students come from a non-existent programming background, and the school isn't sold on my teaching them Python as a first language just yet as apparently I am the only instructor who can use it meaningfully), how indexes work (getting them to reverse an array or a string doesn't quite seem to do it for about half of them), and my better students will have implemented bubble sort on linked lists by the end of the semester, as well. Understanding that bubble sort works isn't a problem for them, but they are only starting to think beyond what a single loop can do algorithmically. I have tried jumping to insertion sort and as a whole there is poor integration of the knowledge to take forward. Good/better/best options just can't happen for most of these students at this point, and so it has to wait for Data Structures where the first sort they learn is Insertion Sort and I don't care which language they use. I guess if someone started using Mindfuck or Ada I might start to care. They add every sort to one big program where they can calculate how much work each sort does and how much system time it takes to operate for randomly generated lists.

As for concerning themselves with cache misses as one person suggested it, until students have a better understanding of systems, that can't be readily done with a class of 40+ frequently unmotivated students (it can with ~10 motivated students, the breakpoint occurring somewhere in the middle, of course), though I start introducing the penalties of register/cache/RAM/disk in this class so that by the time I am teaching embedded systems the students who chose that path usually have a good grasp of it, with the best ones looking even at divide instructions with disdain. With the semester system being what it is, though, teaching all of that as a simultaneous, cohesive chunk of information just isn't going to happen.

Comment: Re:Many DDR3 modules? (Score 1) 138

by QQBoss (#48666829) Attached to: Many DDR3 Modules Vulnerable To Bit Rot By a Simple Program

It can, but the chances of it staying perfectly readable is very small. And realize that removing RAM from a machine puts it under a very different condition than intentionally accessing the RAM in a pattern which causes faster than normal leakage, so the results aren't mutually exclusive.

Comment: Re:Study financed by (Score 1) 281

by QQBoss (#48650655) Attached to: Study: Red Light Cameras Don't Improve Safety

In this case, you an believe both, as the statements aren't contradictory, only your misunderstanding of what you read. The law the judge is referring to is Illinois Uniform Vehicle Code, not federal law (though it generally does follow Federal Highway Administration guidelines). But you are more than welcome to keep believing your misconceptions and misunderstandings. Every state has one, btw.

Comment: Re:Study financed by (Score 1) 281

by QQBoss (#48645033) Attached to: Study: Red Light Cameras Don't Improve Safety

The summary is shit (not shiat), though, because THERE IS NO FEDERALLY MANDATED MINIMUM TIME FOR AN AMBER SIGNAL LIGHT! Why do people think there is??? There are lots and lots of recommendations, and most states follow them, but local traffic laws aren't covered by federal law, and shouldn't be unless a traffic light gets used on an interstate.

As a general rule, what was taught to the Civvies I knew (I was comp sci, the civivies were on the floor below us) when I was in college was that amber lights should have a minimum duration of 3 seconds and go up by .5 second for every 5 MPH over 30 MPH. The Institute of Traffic Engineers currently suggests it be .5 second longer for each 5 MPH over 25 MPH. But there is no federal law or federally enforced standard. There are just municipalities who can't (or won't) comprehend physics when it works out in their financial favor.

+ - Municipal FTTH Feasibility

Submitted by honestOctave
honestOctave (3893945) writes "Local rural municipality is upset it didn't get Google's Fiber bid that went to Kansas City. They are heavily invested in a proposal that would *supposedly* bring Gigabit to each household via Fiber To The Home with smart metering. The market involves 3700 households, of which they are expect 40-60% to particpate. The price tag is $25 Million with principal and interest over 20 years. Am I the only one thinking the numbers aren't really adding up with contention ratios, backhaul costs, etc.? Current cable company offers 50-80 Mbps. DSL offers 1.5-20 Mbps. Anyone care to provide some holes in this arrangement from any experiences they might have in the industry or similar arrangements?"

Comment: Re:There's a lot more going on... (Score 1) 161

by QQBoss (#47781417) Attached to: Research Shows RISC vs. CISC Doesn't Matter

That is more or less accurate. The goals of the original RISC were stated to be making a Reduced Instruction Set Computer, but what was in fact produced was a Reduced Instruction Set Complexity CPU. By restricting the touching of memory to only loads and stores, all other instructions that were able to be executed in one clock COULD be executed in one clock always. Whereas some CISC instructions involving arrays could kick off 10+ memory touches as a side effect, RISC instructions could never do that (sans via exceptions). So when all 10 of those memory touches weren't required, the RISC architecture could optimize away the unnecessary ones (which was a bitch in 1990, but common place by 2000 and exceedingly trivial by 2010, to put it roughly).

I taught CISC architectures (68K mostly) and was a minor architect for PowerPC (I helped work on the early EABI- embedded application binary interface- architecture)

But this leads to a problem: Cache. That CISC operation that made 10 memory touches took roughly 10-18 bytes of instruction storage (68K example), and 10 data cache accesses that would either hit or miss. But a 16 bit RISC would take 22 bytes (and didn't double the number of useful registers available) and a 32 bit RISC would take 44 bytes (but generally doubled the number of useful registers, reducing the need for so many loads and stores). Thank goodness you took fewer transistors to implement the instruction pipeline, because you need them all back to make the Icache bigger! The hope being that those 10 memory touches were rarely needed if you had more registers, so you could cut back on other loads somewhere (but we didn't get really good at doing that automatically until the late '90s, by which time we could show that the RISC penalty was effectively negated, specific numbers remain the property of my name-changed employer but were down to single digit percentage differences). Dcache would have the same hits and misses, unless you were also able to allocate saved transistors to some Dcache which might affect hit rates by some low single percentage points.

But with complicated instructions come pipeline clocking challenges. Implementing the entire x86 pipeline in 5 stages would result in having a sub-200 MHz pipeline today- the P4 push to 4 GHz required up to 19 stages (and who knows how many designers) worst case, IIRC! Meanwhile, most RISC architectures zoom along happily with 5-7 stages and only manufacturing nodes or target design decisions keep them from clocking up to x86 frequencies.

Hands down, it was never any 'benefits' of CISC (or, specifically, the x86 architecture) that allowed Intel to take the field, it was market forces and manufacturing might. A win is a win.

BTW, to the AC GP, just because an instruction appears complex (most SIMD operations, MADDs, FPSQRTRES, etc...), they still count as RISC if they can be either executed in one clock or at least pipelined with nominally one result per clock if they don't impact the pipeline for all the other commonly executed instructions. After all, we can made a divide instruction execute in 1 clock, too, as long as you don't mind your add instructions taking 16x longer (though still one clock), but that is cheating.

Comment: Re:One of the most frustrating first-world problem (Score 1) 191

by QQBoss (#47660641) Attached to: Reversible Type-C USB Connector Ready For Production

At some point in your life you're going to have to go all Zen about it and not care so much.

Only then can you throw those old SCSI cables out.

Hah, I scrapped 4 cubic yards of collected computer detritus, including at least a dozen different SCSI cables (with some ultraSCSIs) today. Been needing to do that for years. I did shed a bit of a tear over the Amiga stuff, though.

Yes, I donated to anyone and everyone all that I could before I scrapped. But 4 working PCs couldn't even be given away to an orphanage!

Comment: Re:A robot can only make 30,000 devices and...? (Score 1) 530

by QQBoss (#47406459) Attached to: Foxconn Replacing Workers With Robots

The robots can build 30,000 devices PER YEAR.

Which would be a perfectly reasonable reading and what I expected to find, as well, though without knowing what units are being produced you have no idea if 30,000 is an impressive number at all.

And, yet, across neither of the two articles I posted previously, nor any of these have any information suggesting that any one robot can make 30,000 units in any specific time, in fact one of them explicitly says that the robots are incapable of building a single iPhone from start to finish as they don't have the necessary functionality However, the new machine can perform only a few basic tasks, such as lifting and placing components. In other words, they do not have the precision needed for the assembly of the iPhone... which suggest they are capable of making 0 units per year, and not 30,000.

However, each and every one of them say that Foxconn plans to have 30,000 robots installed by the end of the year. Wanna play Occam's Razor?

Comment: A robot can only make 30,000 devices and...? (Score 4, Informative) 530

by QQBoss (#47405217) Attached to: Foxconn Replacing Workers With Robots

"Foxconn said its new "Foxbots" will cost roughly $20,000 to $25,000 to make, but individually be able to build an average of 30,000 devices."

So approximately $1.2-$1.5 of the cost of an iPhone will be eaten up by a robot that can only make 30,000 devices before having to be replaced? For some reason, I think Foxconn is probably even better at the financial math than that, and the quote seems so wrong in both a factual error and a grammatical error sense I actually had to RTFA (I hate you, redletterdave) and sure enough the quote is direct from the Businessweek article (I hate you even more, Dave Smith of Businessweek). However, reading 5 other variations of the same announcement, not one of them uses the same phraseology, which makes me wonder where the quote actually came from. Dailytech, for example, says that Foxconn will have 30,000 Foxbots installed by the end of the year and makes no mention of the speed at which they can build anything (which makes sense, since the robots are so simple- basically pick and place- that no one robot could build an entire device). Another website, Regator, gives the same clue, saying they already have 10K Foxbots, and plan to install another 20K by the end of the year.

Comment: As a diver, all props to Gran Pere (Score 1) 30

Seriously, without Jacques Yves Cousteau (and military divers), there probably wouldn't have been nearly the early development of scuba diving that brought in the talent and creativity required to make it safer than riding a bike on the street (something else I do with great regularity at night, thank you, Cree LED lights). Scuba diving today has a fatality estimate of about 5 per 100K divers.

But other than show the effects of 31 days of 2.8 bar, what else did he do of significance that couldn't be more easily, cheaply, and probably better done using a 360 degree video camera set up with lights on an underwater drone dropped off the back of a research ship for 31 days?

Comment: Re:Let gay men donate (Score 3, Informative) 172

by QQBoss (#47220061) Attached to: Human Blood Substitute Could Help Meet Donor Blood Shortfall

Donating for a specific person, in particular for yourself, is a special situation where things are done differently. For example, many of the conditions that would make you ineligible to donate to another person are waived if you are donating for personal use (and the blood is tossed if you wind up not needing it). Though it also depends on what you mean 'my blood was tested...' If you mean that you were tested for blood type and anemia, things that can be done with only the blood from a finger prick, 100% of people receive those tests in any modern medical environment (and even most not so modern ones). If you mean they did a full screening for HIV and other BBPs before you were allowed to give more than a finger prick's worth, then that is a specific situation not covered by general donation rules. For general situations, the written/oral prescreening is a much less expensive solution to having to run a myriad of tests (some cheap, some not so cheap) on a lot of blood that never should have been donated in the first place.

Comment: Re:Let gay men donate (Score 5, Interesting) 172

by QQBoss (#47219457) Attached to: Human Blood Substitute Could Help Meet Donor Blood Shortfall

All donors ARE tested for HIV (at least in USA, Canada, and China), but the test is post-donation and not pre-donation. Donated blood is tested for far more than just HIV, as well, and failing that post-donation test can result in a temporary or permanent ban from future donations. Prescreening of donors reduces the cost of testing relative to acceptable donations, which is a useful tool for keeping the cost of the existing donor supply lower than it would be otherwise. The American Red Cross revisits this policy about every 5 years, IIRC, and goes through the math of where the percentage breakpoints are for breakeven results- when any population crosses that line the wrong way, a new question goes on the prescreening survey. Homosexually active men are no more discriminated against than people who got tattoos or ear piercings within a certain time period, or who lived in certain countries (don't be from Cameroon or Nigeria, for example). Want to change that? Try changing the incidence of disease in the indentifiable community below that break point, because manipulating only the math doesn't turn out well in any scenario.

Giving a blood test for all the possible BBPs (blood borne pathogens) and other issues prior to donating is not cheap if the number of donors goes up by any significant amount of people who wouldn't qualify, so a prescreening survey is going to remain the most cost effective way of dealing with these issues and keeping the number of people who would dilute the quality of the blood supply low.

If you don't qualify to pass the written prescreening test, and you still want to donate blood, at least in the USA you can do that. There is a box you can check to indicate that you want your blood disposed of after donation. This is most commonly used by drug users and homosexuals who are donating in the presence of family, co-workers, or friends who the donor feels are not aware of their situation. It wastes staff time and some property (collection bags, etc...), but allows an individual to maintain their privacy for a lower cost than a prescreening blood test would cost.

I am more bored than you could ever possibly be. Go back to work.