Dan's Data letters #105
Publication date: 20 May 2004.Last modified 03-Dec-2011.
NATO acronyms ahoy
Now that most new motherboards come with on-board network adapters, there is often mention of "PHY" used in association with the description of the performance of the embedded NICs. Just what is "PHY" exactly?
Mal
Answer:
PHY is, confusingly, short for "Physical Layer Device". It's the hardware at layer 1 of the
OSI networking model that handles the actual electrical
(or optical) signaling, encoding, clocking; all that basic stuff that actually moves the higher level data from place
to place. Those joke documents about implementing TCP/IP over Army
tanks or carrier pigeons or whatever are proposing new, and
impractical, PHYs.
Spyware economics
Just one thing that I don't recall you mentioning in your letters after the PC PowerScan letter: interesting to see that the Google Ads on that search page for n.a.n-a.s was a bunch of products designed to (apparently) remove the spyware that PC PowerScan installs in the background. I see marketing people are as enthusiastic as ever about sneaking whatever they can into your system.
My big question with this is: just how much money does spyware make its owners/writers? There must be some non-trivial amounts in it for these people to pay their programmers or whatever - so who's paying? And how useful is the information? (I mean, knowing that X many males between the ages of 8 and 70 surf for porn at least once every month isn't that revolutionary...)
Paul
Answer:
Powerscan is a different piece
of software from PC PowerScan; I mention this difference in my reply to that letter.
PC PowerScan, whatever its faults, isn't spyware, foistware, or any other kind of pseudo-malware.
I don't know how much money there is in spyware. It's difficult enough to dig up good numbers on the value of "clean" Web advertising; the shadowy world of crapware is more obscure still.
There's obvious value in tracking people's browsing habits (the fact that they're browsing in the first place probably indicates some disposable income...) and letting marketers point apparently appropriate ads at those people. How much value there really is, I don't know, though some people clearly aren't too impressed, and I'm not about to become part of the industry myself to see.
I think this is probably another one of those industries like spamming, where a few outfits make a lot of money, and a lot of schmucks lose money, often propping up the few profitable businesses in the process. In spamming, the profitable businesses leeching off the doomed members of the industry are the outfits that sell expensive spamming software and address lists; in spyware, at least some of the profitable businesses are the ones who don't actually have any valuable customer-finding service to sell, but who manage to persuade marketers that they do. Maybe there are spyware pushers who manage to make great, valuable marketing data as well; who knows?
The natural course of a spamming business is to go bankrupt (Rule #4), so it's not a stretch to imagine this sort of arrangement for the spyware industry too; only a few talented scammers who float from bankruptcy to bankruptcy, funding their lavish lifestyle and hiding assets on the way, seem likely to do well out of scummy quasi-legal enterprises like this. The spyware business has fewer basic "products" and a lot more hapless affiliates ("Distribute our crummy spyware for a month, then wait to be paid! And wait! And wait!") than spam, but I bet it's the same sort of mutated pyramid scheme, overall.
Publicity hunter
After seeing what you said about PC PowerScan, I thought you might want to take a look at PC Pinpoint, the product made by the company I work for. If you'd like to review our product, I'm pretty sure I could set you up with an account.
Nick
Answer:
PC Pinpoint seems, according to independent
reviews of exactly the kind that nobody can find
for PC PowerScan, to actually be what PC PowerScan claims to be. You would appear to recognise the fact that
Windows diagnostic and tweaking programs are, by themselves, of little value (and good ones are available
for free, anyway); users need to be
able to phone someone to sort out even many trivial
problems, let alone major screw-ups.
I'm not itching to review PC Pinpoint, though. Partly because I don't generally do software reviews, and partly because I'm not very keen to call the USA to try out your phone support.
Volts and amps to horsepower
I have long thought an "electric supercharger" would be a great invention for cars. The existing solutions to pressurize incoming air (as I understand them) are below. The REASON to add air is that if you add more air you can add more fuel, which gives a bigger explosion and more horsepower.
1. Ram Air - uses a hood scoop, etc. to channel more air into the engine at speed.
2. Turbo Charger - uses exhaust pressure to spin a turbine which sucks more air into the engine.
3. "Traditional" Supercharger - belt driven by engine to spin an impeller which sucks more air into the engine.
All of these require various complicated things such as intricate plumbing - exhaust header, mounting kits, intercoolers, etc. Also known as "LOTS OF MONEY". A turbo kit for my car can run $US5,000 and more.
Why can't we just stick an electric motor inline with the air intake and call it a day? I remember reading that when cars go to a higher voltage base (than 12 volts) this will be possible. Why not today?
Well, that's what eSuperchargers.com say they can teach you to do!
Michael
Answer:
The electric supercharger is not actually a very exciting invention.
There's no laws-of-physics reason why a forced induction device has to be spun by exhaust gas pressure or a belt from the engine. An electric blower certainly can do the same job as a turbo or belt-drive pump.
The problem is getting enough pressure. The people selling cheap electric superchargers - and there are plenty of them - like to talk about the amazing air flow statistics of their ferocious blowers, but they fail to note that the static pressure capability of those blowers is not nearly as impressive. Let the blower fly around on the end of its cable, or just use it to ventilate your house, and it will indeed shift enough air that you'd think it'd have a fighting chance of doing the job of a supercharger. Actually connect it to an engine, and its flow will plummet. Merely hooking up a fan-based blower that can shift 600 cubic feet per minute (when hanging in space) to an engine that natively inhales, say, 300cfm of air, will definitely not give you one atmosphere of boost.
Forced induction for engines is, by definition, not happening at atmospheric pressure; you want boost, more air being crammed in there than you could get just from a big tube leading to the outside world. Electric blowers don't come anywhere near delivering enough compression power to make a difference to the operation of normal engines, unless the electric motor involved is so inspiringly humungous that it's got similar power performance to a real supercharger or turbocharger - and, then, it can be argued that you might as well have a real supercharger, running directly from the engine via a belt, rather than an electric motor running from the alternator which in turn is running from the engine. There's no way for that electromechanical train to be more efficient than a humble belt.
Most cheap "electric turbos" or "electric superchargers" are actually bilge ventilating fans for boats (they're meant to be preventing dangerous fuel vapour buildup belowdecks), possibly with impressive jet-engine-ish decorations, generally sold at a monstrous markup. The suspiciously cheap eSuperchargers.com proposition is different; they're charging people $US14.95 for the privilege of being told to buy a bilge fan.
The most popular electric supercharger is the eRam. It seems to actually be good for a few per cent more power on many cars (like this one). But the eRam costs $US300, plus installation time. There are lots of other tweaks you can get for that kind of money. The difference from the eRam is small enough that your engine computer ought not to need any tweaking to deal with it - which is good, but which also indicates firmly that there's not much actually going on. Un-modified ECUs don't work right when you add a proper forced induction device to an engine, because they don't expect to see air coming in at higher than atmospheric pressure.
A more impressive system is Thomas Knight's ESC Electric Supercharger. It's got three big-ass motors driving a conventional Roots blower, and the claims made for it seem plausible enough, though I've little idea how well it really works.
The contraindications for the ESC are considerable, and such that the manufacturer doesn't recommend you buy one if you can get a regular somethingcharger kit for your car. The ESC costs thousands of dollars (around the same price as a regular turbo or even supercharger kit; it's just easier to install), it requires the installation of some extra batteries (which aren't included in the price; you may also need a high-output alternator to recharge them), and it makes a very loud noise (which you may or may not view as a drawback).
You also can't use the ESC all the time, because it drains its batteries much faster than any alternator can charge them. It's more like electric nitrous (or a switchable "Mad Max" supercharger) than like a conventional always-on supercharger. And, unlike regular whatever-chargers, the ESC doesn't run faster when the engine does; its speed is fixed, so it delivers respectable boost at low RPM but fades as you rev higher, because the engine then needs more air per second for the same boost, but is getting the same amount from the ESC.
The new 42 volt automotive electrical standard will indeed make it easier to make an electric supercharger work, because the multi-kilowatt motors required will no longer need to draw (such) horrendous currents through (such) giant cables. 12 kilowatts (an unremarkable small mechanical supercharger power consumption rating) at 12 volts is a thousand amps; you need a cable an inch thick to pass that continuously, though you can get away with mere third-inch 0 or 1 AWG cable for low duty cycle applications. A 42 volt supply would drop the current draw to a mere 286 amps. But the motors will still be big and beefy, and the other electro-charger problems will still apply.
Note that the Thomas Knight systems already run from at least 24 volts.
Energy equivalence
The lamps in my study all have labels that say, "To reduce the risk of fire, use 60 watt or lesser bulb". So, I sit in darkness. Or at least dimness.
Then I had a brain wave: compact fluorescents! They advertise "100 watt replacement" and use only 23 watts. This sounds way too good to be true. They advertise 1600 lumens, too, whatever that means.
Is it dangerous for me to use these big "100 Watt Replacements" in my "60 watt or lesser or suffer a horrible death" sockets? If it's safe, why doesn't everyone switch to these things? They even look cool. And they save the world and stuff.
Also, is the light given off by these puppies significantly different? Will my brain explode from the vibrating filaments? Will photos taken under this light be wacky in some indiscernible way? (Your photo tutorial said something about this, but left me wondering about the bottom line.)
Douglas
Answer:
The warnings on many lamps about bulb power are there because high powered incandescent bulbs will make the lamp too
hot. CFLs, like regular straight fluorescent tubes, have much higher efficiency than incandescent bulbs; they draw
only as much power as the label indicates, and make less heat than an incandescent bulb of that power rating, but
do indeed emit about as much light as an incandescent with their "replacement" power rating. Or something close to
it, anyway; the "equivalence" ratings are often a bit optimistic.
This also means, by the way, that you can hang ludicrous quantities of CFLs off a single socket with an appropriate adapter, without overloading the wiring or the switch.
Why doesn't everyone switch to CFLs? Because incandescent bulbs are really cheap, and so is electricity (in many countries, at least), and many CFLs don't fit properly in some lamps (because the folded tube is too long - coiled CFLs typically don't have this problem), and the light from most CFLs isn't necessarily as nice as the light from an incandescent.
CFLs are fluorescent tubes, so their "white" light is, as normal for fluoros, the product of the output from a mix of different coloured phosphors. Their output frequency distribution can, therefore, show spikes at particular colours, and not much output elsewhere. This gives lousy colour rendering, even if the actual light looks nicely white (as opposed to the greenish white of really high efficiency fluoros).
You can now buy good quality, high Colour Rendering Index (CRI) CFLs (and straight fluoro tubes) that get near as dammit to properly imitating the output of an incandescent globe. They're not as efficient as the nastier-output fluoros, but they still beat incandescent by a mile, and you'd have to be very picky to dislike their light.
People who remember not being able to tell their orange jelly beans from their pink ones under CFL illumination, however, (see this phenomenon in my old review here) may still be avoiding CFLs because they assume they haven't improved.
Audiophilia, continued
If loonies are prepared to pay epic money for cable, why don't they stay digital and attach independent digital decoders and power amps to each speaker? Surely that would be less expensive than running excessively large amounts of "platinum" wire around the room, and it means that the cheapest solid bell wire would be sufficient for long interconnects.
Surely there must be an "all digital" solution somewhere with independent digital speakers? You could probably build a set cheaper than $US3500, but I don't know how good the DACs will be. I would imagine rewiring your house to have a better earth (and removing washing machine, dishwasher, hoover, neighbours, lightning etc) would be more beneficial than any $US3500 power cable.
Mark
Answer:
Why don't lunatic-fringe audiophiles swap out their exotic analogue cables for dirt cheap digital ones? Because they'd
feel obliged to pay epic money for the digital cables, too!
And there are plenty of people who'll help them do it.
OK, the above-linked products only top out at $US2200 for 2.5 metres of special double-blessed (Pope and voodoo priest) digital interlink wire, but that's still pretty impressive for something whose purpose is the transport of highly incorruptible bits which, as you say, will flow quite happily down light duty zip cord, yours for $AU10 for a hundred metres, full retail.
And yes, it is possible to buy power cords specially optimised for analogue or digital equipment.
Only a fool would buy the wrong type.
(Back in the world of sanity, a reader's pointed out to me that digital-input active speakers exist too. These, for instance.)
I have an idea. I will bottle and market special audiophile air. Anybody who doesn't flush out his or her (but c'mon, it's always his) listening room with one of my $10,000 tanks of specially demagnetised, cryogenically treated, mountain-fresh oxy-nitrogen mixture (only the most thoroughly polished molecules make it through our exhaustive quality assurance process; no isotopes, guaranteed!) is subjecting his or her unprotected ears to sound that's been muddied, defiled - let's face it, basically defecated upon - by the ordinary, filthy, proletarian atmosphere.
How can I lose?
WTF department
I came across this photo...
...today on the Web. I have no idea what possible function this huge device would have, being suspended as it is over the barrel of this artillery piece. I figured that you might have some idea, due to your apparent encyclopedic knowledge of all things tank. If you have any idea I would love to know what the hell it is.
Jon
Answer:
I couldn't help but think that Freud might have had a clue, but I didn't know what it was. My guess turned
out to be pretty good, though, according to the readers who swiftly filled this hiatus in my knowledge.
I didn't think it looked like something meant to actually be used in combat, since there's no way to traverse or elevate it without the assistance of a team of engineers. I figured that it might be a flash or smoke suppressor (or conceivably even a silencer) of some kind, but as it's a semi-permanent construction then it'd only be useful in battle if the enemy had the decency to not move.
Accordingly, I figured it was some kind of test equipment, with sensors to measure projectile speed, gas volume and temperature, and so on. Usually this sort of thing's done with an open framework, I think.
As my helpful correspondents pointed out, it is indeed a piece of test equipment, used by the German Army's Wehrtechnische Dienststelle (military engineering department). As it turns out, it is a silencer, to reduce the earth shattering kabooms that'd otherwise drive the good people of Meppen, near the test range, nuts.
Here the thing is with an explanatory caption; "Schalldämpfer" means "muffler".
Another explanation worthy of an Honourable Mention: Ground-based Homotron 5000.
