Dan's Data letters #49Publication date: 14-June-2003.
Last modified 23-Aug-2012.
I read your review of the Samsung 17" LCD with great interest. I'm planning to purchase one of the 19 inch ones from Aus PC Market (due to good reviews and Samsung's 0-defect pixel policy). One point I'd like an opinion on is the difference between connecting to the PC with a standard monitor cable or using the DVI cable. I have a Hercules Prophet 9700 Pro with both outputs, and Aus PC Market have the Samsung 191N (no DVI) for $AU1375 and the 191T (with DVI) for $AU1500.40.
In your opinion, is the extra $125 worth paying for the DVI connection? Is the picture quality that much better ?
DVI makes monitor setup a complete piece of piss (that's a technical term), but it's pretty close to that even without DVI. Connect VGA cable, turn everything on, press the Auto button, tweak contrast and brightness to taste (you'll still have brightness adjustment when using DVI), and then maybe, maybe, adjust the pixel clock setting a tad, and you're done.
The image quality difference between DVI and VGA should approach zero, assuming you take a moment to set up the screen. Modern LCDs and video cards deal with the inelegant digital-to-analogue-to-digital dual-conversion process very well. People running dual identical LCDs from the two outputs of a regular VGA-plus-DVI video card can often tell the difference, but that's what it takes. It's not something worth getting excited about.
Lousy VGA cables and/or connectors can create lots of blur and ghosting at medium resolutions (1280 by 1024 at 85Hz, which is the most you'll be running here), but with a modern video card and the OK-quality cable that comes with the Samsung monitors, there shouldn't be a problem. If there is, then upgrading to a better VGA cable will probably cure it - but that cable may cost you most of the price difference between the two 191 models.
Monitors with two switchable inputs can be handy. They're not a replacement for a KVM (keyboard, video, mouse) switch, but it's still nice to be able to poke one button to see what your server box is doing.
The best option for people who only need one input would be a version of the 191 screen with DVI input only. All things being equal, it could sell for less than a VGA-only model. Since most PCs still don't have DVI outputs, though, Samsung probably aren't tripping over themselves to build a "191D".
I was reading up on Peltier devices, and they are very fascinating to me. Do you think it would be possible to put a heatsink on an automotive engine, with an array of Peltiers mounted on it? They would be cooled by the air coming in from the grill (the engine heatsink would be mounted towards the front). I think the temperature differences would be pretty extreme.
Would there be any way to generate enough electricity to replace the engine alternator? The voltage seems to be in the right range, but could you generate enough current? How many/how big of a Peltier would you need to accomplish this? And finally, would this be an expensive system to implement?
An advantage to this system would be smaller size (I think), no moving parts, DC power from the start, and no loss in engine power having to drive an alternator belt. It would also continue to charge the battery after the engine has stopped.
Such a system couldn't come close to replacing the alternator unless it was really enormous (which would make it ruinously expensive). It's a fun idea, though.
An unremarkable automotive alternator can deliver about 400 watts; you'd have a hard time getting one watt out of a single 40mm square Peltier device. Half a watt per device wouldn't surprise me, actually; these things can't survive very large temperature gradients, and only have about 20% efficiency.
If you covered virtually the whole engine with Peltiers, or a similar area somewhere else connected to the engine by coolant piping, or a lot of the exhaust system, then you might get somewhere. But protecting the Peltiers from vibration, water damage and overtemperature, and getting enough air flowing through the whole system to keep the cold side cool, would be non-trivial. And the system wouldn't produce any power while the engine was cold, which'd be a bit of a bummer if your battery was low or you did a lot of short trips. The system would, conversely, keep charging after the engine stopped, but the lack of air flow over the heat sink would rapidly reduce the temperature gradient.
Given that the alternator isn't even going to eat one kilowatt of the engine's power, it's really not much of a load.
Thermoelectric generators using Peltier devices are practical, for low-power applications; you can run a radio off them forever if you've got a temperature gradient going begging. In a boat, for instance, you can heat one side of the Peltier with sunlight and cool the other with water.
There's a relevant Usenet post here.
I'm wondering if there are any programs out there that can defragment a drive with a cluster size larger than 4 kilobytes. I made the mistake (?) of creating a bigass RAID using a 64K NTFS cluster size before I found out that neither Win2000's built-in defragmenter, nor Diskeeper (at least version 7.0.428), will even attempt to defrag it.
I think I'm going to have to recreate the RAID (eventually) with a 64Kb stripe and a 4Kb cluster size, but it'd be nice to keep the 64Kb cluster size for that extra performance boost.
So is there anything out there that will defrag it? Google hasn't helped, and some options would be great.
Norton SpeedDisk (part of SystemWorks) used to be able to do it; pretty much every other WinNT/2000 defragger used Microsoft's own defrag APIs, which don't support larger cluster sizes. Now SpeedDisk apparently uses the MS APIs as well, though, so it's no good any more. I'm told that Raxco's PerfectDisk will work.
Microsoft's APIs for Windows XP, however, do support larger clusters. So the built-in defragger in WinXP, assuming you upgrade, ought to be able to defrag your RAID.
In your article here you mention that you use "naphtha lighter fluid" to clean up any residue left behind from application of various thermal goops. However, I failed Sleuthing 101 and I've got absolutely no idea where you're supposed to buy this stuff. Should I be visiting a tobacconist?
Yes, a tobacconist will stock it. You want Zippo fluid, or any other brand that comes in the same sort of flip-spout steel bottle (which is quite good for dispensing small amounts). Although many wick lighters, definitely including Zippos, will run on pretty much any flammable liquid, there are only two normal kinds of "lighter fuel" - naphtha and butane.
If I have a device that wants a 9VDCwallwart at 300mA, I can plug in a 9VDC wall wart with '1000mA' written on it, right? It's current capacity, not current output? I don't want to fry my vibrator^H^H^H^H guitar pedal.
P.S. Just kidding about the vibrator. Those things run on batteries.
Yes, this is fine, provided you're not connecting an unregulated AC adapter to something that expects regulated input. Unregulated adapters deliver more than their rated voltage when they're not fully loaded, which a 1000mA-rated adapter certainly won't be, if it's running something that'll work from a 300mA adapter. Your guitar pedal probably expects a regulated adapter.
The maximum voltage of an unregulated DC adapter, which is probably just a transformer, bridge rectifier and capacitor, is root-two times its rated voltage. So an unloaded "9V" adapter can supply up to 12.7 volts.
If an adapter doesn't have "regulated" printed on its label, you can't be sure about it without testing it. Testing's really easy, though; get yourself a $15 multimeter, set it to an appropriate DC-volts range, plug the adapter in, and apply the probes to the plug terminals. That'll give you the unloaded voltage. If it's significantly higher than the rating, you've got an unregulated plugpack.
I have a Dell Inspiron 2650 with only a VGA out. I am wondering if I can connect that to a normal television without any expensive stuff; expensive meaning more than 20 US bucks. I saw this cable on eBay - one of those very simple cables that go from VGA to either composite out or S-Video out. I'm wondering if those cables really work, considering there are $50 VGA to TV converters out there?
Basic VGA-to-TV boxes with very ordinary video quality can be had pretty darn cheap, and might even come in under your $US20 limit. The base price for a decent converter, though, is more like $US75; see here for the kind of thing I'm talking about (note - that's an Australian site, so the prices are in Aussie dollars).
The cheap adapter cables only work if your video adapter has a TV out function that works through the D-sub VGA connector. Most PC video cards with TV out have an S-Video (Y/C) connector, with a couple of extra pin-holes that carry a composite signal. You can plug an S-Video lead straight into them, or use an adapter that converts the extra pins to an RCA socket for a standard composite video lead.
Some other adapters, like for instance Matrox's DualHead G400 and newer Parhelia cards, can send Y/C and/or composite signals to pins on the VGA connector. Then, you just need one of those cheap adapter leads to get connectors for your standard video cables.
Some laptops work the same way; it reduces the number of connectors the machine has to have, which is handy on the cramped back panel of a portable computer.
Normal PC video adapters, though, can't send TV output to the VGA connector pins. One of those cables might or might not cause mayhem if you tried to use it on a normal video adapter, but it certainly wouldn't work. Since your laptop doesn't have any kind of TV output, I'm afraid you're out of luck.
I have a problem with my PSU voltage. I think. It's a Q-Tec 400W gold PSU. Under Windows there's no problem. My Win2000 setup is dead steady, and does what I want. Except burning DVD's.
Well, that's not consistent either. It burns some DVD's, but usually it gives me a "Power Calibration Error" whenever I try. Thankfully, this happens before it actually writes something on the DVD.
My burner is a NEC DVD+RW 1100A, and I use Nero to burn. I've tried a lot of different media, and some other DVD burning progs as well - they all give out the same (or equivalent) error. It doesn't matter if I burn at 2.4X or 4X - it will fail either way.
Now, most people on different boards I've searched think it's a fault with media or burner. I'm not so sure. So I checked the voltage. The "usual" voltages looks good from within Windows (Asus Probe gives me OK readings on +/-12v and +5v), but the probe in the BIOS gave me something else. It says The -5v is actually at -5.70/-5.75. The other voltages differ as well, but not by this much (they're well within the "off by 10 per cent" mark).
Both burner and PSU are fairly new, so returning either or both should not be a problem. My question here is, which one should I exchange for a new unit? Can there be something else causing this?
Burning CDs works just fine, by the way.
It probably is the burner, you know. Since you've tried different media and software (not that this problem is at all likely to be related to software or drivers), it's down to the burner itself; a new one will probably solve the problem.
Your out-of-range -5V rail is slightly odd, but the burner doesn't take -5V input (ain't no wire for that on its power cable), so that isn't it.
Note that the BIOS voltage display may be perfectly accurate, but the PSU is lightly loaded when you're looking at the BIOS screen; it may be out of range then, but A-OK when Windows is running.
"Let's say we hang a ten kilo weight off a permanent magnet butted to a steel roofing beam, and that the only thing holding the permanent magnet to the steel beam is the magnetism. Now let's do the same thing, but this time with an electro-magnet which requires a constant electrical input to maintain its magnetic qualities.
"Let's say we leave them both there for ten years...
"They will both perform the same task, that of holding the ten kilos off the floor. The electro-magnet, however, has needed to be fuelled by electricity provided by a generator of some kind - it could be hydro, nuclear, wind, solar, coal or oil - and has cost a large amount in terms of energy. Much work (in the scientific sense) has been done to provide the constant electric current necessary to maintain its magnetic hold on the steel girder."
So I thought...
I can do the same thing with string... or Blu-Tack... or superglue... or a coffee table... or Velcro.... or duct tape.... or a model goat built entirely from rice bubbles and mashed potato.
All these items can hold a weight off the floor. Are they all capable of producing unlimited energy?
Or maybe these guys are just making stuff up.
The truth is, maintaining a static magnetic field in an electromagnet/inductor doesn't require any energy at all. Energy goes into creating the field, that energy comes back when it collapses. But in its steady state with a DC supply, the only power lost in the coils of the electromagnet is from the resistance of the wire itself. Of course, that's a lot of power, since your inductor/electromagnetic is pretty close to a short at this stage... but it's going as heat, not into holding the weight up.
So, my question is... who really believes this tripe? And do you know of any resources for creating energy from Velcro? It seems the most promising option, as it was originally alien technology.
Apparently, all the things you list really do get work from nowhere! Patent your model goat over-unity perpetual motion levitation machine at once, before it goes mouldy!
To be fair, the Lutec people aren't really explicitly saying that they think permanent magnets and other static things do work-in-the-physics-sense, only that work must be done to provide the power that would allow a powered thing, like an electromagnet, to perform the same function. But lack of comprehension of the concept of "work", as it's used in physics, is nonetheless the source of a lot of defective ideas. Yes, a bird tying to hover while carrying a coconut will have to do a lot of work to stay in the air, but no work in the narrower physics sense is being done; the bird is doing the job of a bookcase, as far as keeping the coconut in the air goes. Similarly, a hot-air balloon hanging in the air with the same coconut sitting in its basket isn't doing any work.
Work equals force times distance; the magnitude of the force times the distance traveled equals the work, and only the component of the force that's parallel to the displacement does work. If there's no displacement (pushing on a brick wall), or no force (a balloon floating along with the breeze), no work is being done.
If the bird's flying along horizontally holding the coconut, the effort it's expending just to stay at the same altitude is not doing any work, in the physics sense.
Who believes this stuff? Why, many of the same people who believe the sun goes around the earth, I presume. If every one of them were to give you a penny, I would not be surprised if you ended up a very wealthy man.
With regard to your Which Video Card piece, here's something else you might want to mention.
The Radeon 9500 non-Pro 128Mb shares the 9700 and 9700 Pro's PCB, L-shaped RAM and all. (The black ones don't, but that's why people don't buy the black ones for this.) Since the 9500 really is just a crude hack from the 9700, it is in fact possible to make a 9500 non-Pro into a 9700 non-Pro with a little software modding (copy-and-paste-and-pray), 256-bit memory interface and all. The 8 rendering pipelines seem to be software-disabled, though of course a few 9500s out there are going to have defective rendering pipelines (it's not like they're checking to see if all eight work, and besides, some of 'em are binned 9700s). This means that a user with a little time and a little luck (this isn't 100%!) can make a shiny Radeon 9700 for considerably less.
The guy who discovered this has useful files at this location.
However, this ONLY works with 9500s with L-shaped PCBs. If the 9500 in question has the memory-in-a-row layout, modding it will only get you a 9500 Pro, and if it's a 64MB 9500, it only becomes a 9500 Pro. But it's still an interesting idea, and certainly worth it looking at the prices.
The way to tell if the rendering pipelines are OK seems to be to watch for artifacts (checkerboarded textures mostly). If you get them, the pipeline is not happy being in operation and may cause the card to quit functioning. If you don't, well, you have a Radeon 9700. It certainly works for at least a significant amount of the population; sure does for me!