Dan's Data letters #128
Publication date: 16 October 2004.Last modified 03-Dec-2011.
The forgotten nerds
I see regular "best-bang-for-the-buck" articles on choosing hardware for gaming machines, and sometimes for "business users", but can you give some advice to someone not particularly interested in games or overclocking but who needs more horsepower than is required for Word and Excel?
As a self-employed (rather elderly) programmer, I recently developed an enhancement to a J2EE/Oracle application that uses Apache FOP to produce a Gantt Chart in PDF format, and had to wait up to 15 minutes while my (admittedly overloaded) 1.6GHz 512Mb DDR i845E Pentium 4 machine worked away in the background to produce the PDF file. I suspect that I could take a gaming machine recommendation and just replace the recommended video card with an entry level card and that would be close enough, but (a) the motherboard is often chosen based on overclocking abilities and bundled games, (b) the cooling requirements would be less without the hot video card, and (c) perhaps the case/power supply would also not be optimum for my needs? Any tips would be appreciated.
Glen
Answer:
Exactly what needs to be upgraded to chop your processing time down depends on what's actually falling short.
If the tasks' pretty much just CPU limited, then a mainstream current model Pentium 4 or Athlon 64 system will give you around twice the speed for a non-stupid price. If you want to save money, a top-end Athlon XP won't be much slower, but of course won't give you a CPU upgrade path.
Perhaps, however, you're short of memory. If there's a lot of virtual memory disk flogging going on, another 512Mb of memory, or even more, could massively improve performance.
Or perhaps the task is more hard disk limited; disk flogging doesn't necessarily equal running out of memory. If the computer's ploughing through a far bigger data set than memory can hold, then you'd reap the best benefit from upgrading to a faster drive or, preferably, a few of them running from a proper ATA RAID controller (a 3Ware Escalade, say). Cheaper RAID solutions (bargain Promise and HighPoint controllers, software RAID) are likely to be better than nothing, but not really worth the effort.
Another possibility you just dodged, but which afflicts many owners of old P4s, is that their computers merely suck. There were some pretty woeful P4 systems sold early on in the processor's life. The early SDR-memory i845 chipset, for instance (not your i845E), was a great way to spend a bunch of money and get a 1.7GHz machine that was barely faster than a 1.13GHz P-III. Someone who's saddled with an SDR i845 box doing work that's partly CPU limited and partly RAM bandwidth limited, which is perfectly possible, may find that upgrading to a 3GHz P4 with 1Gb of DDR RAM (a pretty mainstream system these days) gives better than triple their current speed.
Also, snow on the TV is talking to us
We have recently moved into our first home, and an old touch lamp is a little worrying. The problem is the lamp used to have 4 settings - off, dim, brighter, brightest. However in this house the lamp doesn't turn off - it still works as before, except the off position is a very dull glow. Even turning the wall switch off has no effect, it still glows. The only way to turn it off is to unplug the lamp.
Have we discovered perpetual energy?
Bruce
Answer:
My first guess is that you've got the lamp plugged into a miswired socket, or one with a defective switch. I presume
you've already tried plugging it into a socket somewhere else in the house (another socket on the same wall plate,
or even in the same room, may be screwed up the same way), but if you haven't, you should.
A fault with the lamp by itself shouldn't be able to cause this symptom, but it's possible that you've got a combination of a lamp fault (old gear that's been moved to a new house often has a frayed wire bounced loose inside, or something) and questionable wiring. For instance, the lamp could be leaking current from the neutral side of the bulb to earth, and the wall socket could be switching neutral instead of active (a pretty common flaw in incompetently wired plugs), So when you turn it off, the earth leak lets current pass from active (which is still live, because the switch has interrupted the other conductor), through the bulb, to earth. This'd trip an earth leakage circuit breaker, by the way (ELCB, "safety switch"), but houses with old crappy wiring seldom have safety switches installed, for the simple reason that the numerous faults throughout the building will cause the thing to nuisance-trip all day, every day.
Bruce's e-mail address told me he's in Australia; this sort of problem is more common in the USA, where a lot of appliances use non-polarised plugs, so they don't have a designated "active" or "neutral" conductor inside. But it's far from unknown in Australia.
It worked for him too
There is a show in the US called MythBusters. Very much up your alley I'm sure. Anyhow, they tackled the myth of the magstripe being erased by an eelskin wallet a while back. Among their tenets is, even when the myth is busted, see what it would take to make the result occur. In this case they created an electromagnet and tried to wipe/corrupt the data on a magstripe card. They progressively increased the strength of the magnet (and measured the strength), and could not corrupt or erase the data. According to this site, they were able to crank the magnet to 1600 Gauss. Though this recounting says that they were able to eventually corrupt the card by waving it over a 1000 Gauss magnet; I'm not sure I remember that part.
I have, however, as you have, witnessed essentially the same occurrence of picking up a magnet with a card in my hand, then having the card unreadable. I was wondering if you could see a reason for the disparity?
Mike
Answer:
I think some network here in Australia's showing MythBusters by now, but I have of course
already seen most of the episodes.
Not that one, though.
There's a simple explanation for hard-to-erase magstripes; they're the newer "high coercivity" type.
Old-style low coercivity magstripes are essentially the same material as is used for cheap ferrite cassette tape; they have a coercivity of only about 300 Oersteds. That means a 300 Gauss field is enough to wipe them. You can easily get that from a plain ferrite magnet, or an electromagnet you can make in ten minutes with some wire and a nail and a lantern battery.
Floppy disks score 720 Oersteds, higher coercivity tapes (DAT, 8mm video tape...) can score as much as 1400-odd Oersteds, and high coercivity magstripes are as tough as hard drive platters, in the few-thousand-Oersted range. Some high coercivity stripes apparently manage as much as 4000 Oersteds, though I think ISO Standard 7811 only specifies 3000. Magstripes are, of course, easier to wipe than a drive platter with the same coercivity, because you can lay a magnet right down on top of a magstripe; they don't have an aluminium casing around them like a hard drive.
My giant rare earth truncated pyramid fridge magnet has a real live 7000 Gauss field strength at its small end, which is way more than is needed to wipe any magstripe ever made. The part I grabbed is the big end, but that's quite likely to still manage better than 4000 Gauss.
You snooze, you lose
Having left it a little too late to decide that the Arc-AAA was the torch for me, I'd be interested to know:
What would you go out and buy tomorrow if you lost your Arc-AAA?
[yet another] Dan
Answer:
Nothin', 'cos I've still got a lovely mint Limited Edition version sitting on my shelf
over there!
Assuming that wasn't there, though, and that I couldn't find a reasonably priced Arc-AAA on eBay (they're out there, but bidders seem to really want them...), there are some other options.
If you must have something with basically the same very small size as the Arc-AAA, then the CMG Sonic seems to be an OK product (CMG have been eaten by Gerber, who are in turn a Fiskars brand; there are now a bunch of Gerber-branded LED lights including the old CMG products). The only real problem with the Sonic is that its weird pinched in nose gives it a considerably narrower beam than the Arc-AAA.
I don't know of any Arc-AAA-shaped single AAA cell lights, though there's probably a decent one or two out there somewhere. Usually, affordable AAA and AA lights are made by people who insist on making them "look like a flashlight", with a flared end that they don't really need. If you can stand the massive bulk of a single AA cell, though, then the CMG Infinity Ultra is a fine Arc-AAA replacement, and cheap, with better battery life.
TNC are a boutique manufacturer whose "Key-Lux" light is in the same size category as the AA lights, but packs a one watt Luxeon LED powered by a rechargeable battery, so gives far more light per cubic centimetre. It's expensive, though, and they can't make enough to meet demand (I haven't even bothered trying to scam review lights from them).
A reader's now pointed out Peak LED Solutions to me, as well. They've got a wide range of well-priced little lights, including N-cell models that are even smaller than an Arc-AAA yet offer one or three LEDs. They could be just what frustrated Arc buyers are looking for.
The mourning continues
I was hoping that you could help me out on some LED torch advice. Now that Arc appear to be defunct, I was looking for a supplier in the UK that provides the CMG Infinity Ultra, when I came across the Inova X1. Appalling name, but is it any good?
Matt
Answer:
It's apparently OK, but only if you want
a pretty narrow beam light.
Good price, excellent build quality for the money (well, if it's anything like the old X5 I reviewed), but not much use as a seeing-where-your-feet-are-going sort of light.
Well, are ya, punk?
Dan: Are you ready?
Jan
Answer:
No, I don't think I am.
Things like this press my hoax button, but maybe this outfit's real, despite their blatant use of stock photography, as seen in other cutting edge ventures.
Assuming they're serious, I wasn't aware that neatly trimmed fingernails and sunglasses that aren't held together with tape were essential for a rich, full life, but I guess you learn something every day.
Some of the other questions are entertaining, too. Remember: Even if your parents kept you chained up in the cellar for 17 years, you should still have told them you love them in the last three months!
Also, make sure to not suffer. Apparently you shouldn't be using illegal drugs or misusing prescribed medication (hey, no problem), but that busted up body of yours still shouldn't be causing you any suffering. Nor should the fact that you're a penniless peasant stuck in the middle of Darfur be a problem, because if you don't live in the geographical location of your choice, you should just move, silly! Remember - You Can Do It!
Furthermore: Be aware of your wants and needs, and get them taken care of. And remember, the less usual your wants and needs are, the more important it is that you spend time with people who don't try to change you.
From our Magic Roundabout correspondent
I just read about your experiences on this page.
You are very fortunate - you've been able to see truths that not many get a chance to actually see before the appointed time.
Realize they are (for the very most part) real.
I can't go into it all but am sure you have the resources to do the research on your own. You can find all the testimonial evidence (from all types of people) you need online. One person I read after quite a bit is Dr. Maurice Rawlings, a cardiologist who stumbled into the whole thing on his own - like you but through a different door.
I implore you to value your experiences for what they really are and make the most of them - learn all you can. They will be invaluable to you and everyone you know.
Take it all,
bday.....
Answer:
See, now this is why I stuck with the happy gas and left the
shrooms for other people.
