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Comment: Re:Nope. (Score 5, Insightful) 268

by Sprite_tm (#40971161) Attached to: Ask Slashdot: Personal Tape Drive NAS?

For playing a movie - maybe. For actually burning a torrent - fair enough... if that is the _only_ thing that happens.

The point is that multiple accesses is going to delay the drive by a huge amount. If you want to, say, copy that Linux iso to your NAS at the same time as someone is playing a movie, the tape drive is going to have to move between the locations of the two files, which is going to wreck the access times, as I stated. Torrents are worse: you're downloading from / uploading to a bunch of other computers, all wanting to read from or write to a different location in the file. Again, this means moving between locations and the resulting huge access times.

You may be able to alleviate the process by putting a SSD or HD as cache in between, but I'm not sure if there's off-the-shelf software to do that, and I'm not even sure if that's going to work comfortably. Besides, if you're going to put a SSD or HD in between, why not just use that?

Comment: Nope. (Score 5, Informative) 268

by Sprite_tm (#40971043) Attached to: Ask Slashdot: Personal Tape Drive NAS?

The big disadvantage of tapes is that it has long seek times. Not 'long' as in a few times that of a hard disk, but 'long' as in: can take a full minute to do. Access of multiple files on a normal HD is done by reading a meg of the first file, then seeking to the second file and reading a meg, going back to the first file and reading a meg etc. On a tape drive, even when the seek time is only, say, 10 seconds, you'd get a total throughput of 100K/sec that way. And I'm not even talking about the havoc that using it for storage of torrent files wreaks on it: that's a random-access process if I ever saw one, and the seek times on tape would kill your bandwidth very quickly, and probably your tapes too (because of wear&tear).

Comment: Actually not a touch_screen_ as such... (Score 5, Informative) 96

by Sprite_tm (#39957281) Attached to: Disney Research Can Turn Nearly Any Surface Into a Touch Screen

The device can detect the _way_ tou touch it (one finger, complete hand, ...) but not _where_ you touch it, so it's not a touchscreen per se, more of a more-intelligent touch switch. I admire the way they made it from fairly simple components: I built my own prototype working in the same fashion in about one evening after reading their docs: http://spritesmods.com/?art=engarde

Comment: Re:Khan (Score 1) 162

by Sprite_tm (#38802785) Attached to: Professor Resigns From Stanford To Launch Online Education Project

I think Andrew Ng had an easier job: machine learning is a course with a curriculum that's better defined than the almost all-encompassing AI class. That's why I had the idea the AI course sometimes jumped from subject to subject, while the ML class was more building up to something. I agree the ML class was easier to follow, I don't think it's because of the teacher, though: swap Andrew and Sebastian/Peter and I think you'd gotten the same result. Aside from that, I immensely enjoyed both courses (enough to enroll in one of Udacities courses as soon as it was announced), so they both did an excellent job.


Jumentum Introduces a Single-Chip Linux System 76

Posted by timothy
from the ok-but-can-you-make-one-with-fewer-chips dept.
An anonymous reader writes "The Jumentum open source project has announced a single-chip programming system based on the NXP LPC1768 (the same as in the mbed) that can generate PAL/NTSC video and use a PS/2 keyboard, so it may operate as a standalone BASIC programmable computer, similar to many old BASIC computers (e.g. Apple ][ or C64) of yore. Projects such as the Raspberry Pi provide a multichip Linux solution, and the Humane PC uses three AVR microcontrollers, but the Jumentum system can provide a true one-chip solution. Video is generated by software, and only a few external resistors are required to interface to a composite video input. With the Jumentum system, you can take your tiny one-chip computer on-the-go, or use it as part of your own electronics projects (using for example, the mbed) to give it a convenient interface (along with Jumentum's Ethernet web and USB interfaces)."

In German Trials, Airport Body Scanners Easily Confused 91

Posted by timothy
from the bitte-to-be-straightening-dein-pleats-maedchen dept.
OverTheGeicoE writes "The German government just finished a 10-month test of millimeter-wave body scanners made by L3 Communications. It appears they are not happy with the results. The devices raise false alarms 7 times out of 10, and are confused by layered clothing, boots, zippers, pleats, and even incorrect posture. Australia recently started a trial, and the second person in at the Sydney airport set off the alarm repeatedly due to sweaty armpits."

Magnetic Nanoparticles Fry Tumors 111

Posted by Soulskill
from the fried-tumors-are-a-delicacy-in-the-south dept.
sciencehabit writes "In a new study, a team found that injecting mice with tiny magnets and cranking up the heat eliminated tumors from the animals' bodies with no apparent side effects. The nanoparticles heat up when a magnetic field is applied, and because they are only injected into tumors, only cancerous cells get fried. Researchers hope the technique, known as magnetic hyperthermia, could be used in cancer patients, obviating the need for chemotherapy and radiation."

Comment: Re:Well done (Score 4, Interesting) 95

by Sprite_tm (#36300124) Attached to: Bringing Old Arcade Machines Into the Internet Age

Sixpack for the win :) Nope, I didn't see the pacman machine, though I have heard about it. When I obtained an Atari from somewhere, I was inspired by the story and put it in the hallway with a copy of Xenon 2 permanently plugged in. Good times were had, until the machine broke. A bit later we got a PC next to the living room TV to watch all the creative-commons-licensed movies shared around the campus on (*cough*) and we played Puzzle Bobble completely to death. So yeah, the game , if anything, was an inspiration for more gaming :)

The PC connected to the TV still runs a menu on top of X that's written by me. I also automated the beer-list to a LCD+touchscreen thing, and while it's made out of bad soldering joints and gaffer tape, somehow that contraption still manages to survive.

Comment: Not sure if that'd work... (Score 4, Interesting) 145

by Sprite_tm (#33905828) Attached to: Unspoofable Device Identity Using Flash Memory

From what I know of flash, the 'bad bits' aren't repeatedly bad. The bad-sector-swap-out-routine in most flash drives and USB sticks will actually swap out a sector after a single read that can't be ECC-corrected, but that doesn't mean all the bits in the sector can't be written correctly ever again.

For example, in this article (IEEExplore, so paywalled for you, sorry) a generic NAND flash chip has been tested for bit-error-rates. In the 5K write cycles after an average bit has failed, it only failed to be written correctly 4 times more. That would mean that a single erase-rewrite cycle would write the complete sector without any bit errors 99% of the time: to find 'most' of the bad bits, the sector would have to be rewritten 1000s of times every time the software would want to check the fingerprint.

Not only would that take a fair amount of time, it would also introduce new failed bits. That would mean the ID of the flash chip can only be checked so many times beffore the complete sector goes bad.

Comment: Re:score tables (Score 2, Interesting) 153

by Sprite_tm (#28578325) Attached to: Source Code of Several Atari 7800 Games Released

It indeed is packed BCD. Some processors of that time have special instructions for that kind of notation, which makes calculating with them not much more difficult than normal binary. (Dunno if the 6502c has these kinds of opcodes, though; the Z80 for example does.) The advantage is that it makes blitting to screen really easy: instead of constantly dividing by 10, which is a processor-intensive task, you could just bitshift the number, which is much easier.

Comment: Some fun stuff... (Score 5, Interesting) 153

by Sprite_tm (#28576011) Attached to: Source Code of Several Atari 7800 Games Released
* From the devkit readmes:

2600/7800 DEVELOPMENT KIT<br>
Feel free to telephone John Feagans at Atari (U.S.) at area  code
(408)  745-xxxx  any  time you have a question  about  using  the
software.   He  wrote the download program and the  transfer  rom
code.   He's the one who did not write any support  documentation
to go with his software.

* From the base sw:
CPX     #1               ;HACK: WE STOP AT 1
INX                     ;BIGGER HACK: PUSH X INTO RANGE.

* Ofcourse, we have explicit words:
CMP     #$FF                   ;SEE IF ANY INPUT
JMP     GOTOSEL                ;GO TO SELECT MODE

LDA     #0                     ;ENOUGH TIME HAS ELAPSED TO ALLOW CAPS
LDA     #$14                   ;IO HARDWARE


* Citizen Kane anyone?
                                         ;THE FINAL VERSION
AND     INPT1,Y                ;REMEMBER
BMI     FUCKBAR                ;REMEMBER,. . ., ROSEBUD

* In Galaga, at 'a boss hit':

* Liek wtf?
*         0       regular dome           logram
*         1       regular pyramid        barra
*         2       detector dome          zolbak (and your mama, too)

*And finally, an original comment which couldn't be more to the point in 2009:

It looks like Hattrick is written mostly in Forth btw. I personally didn't know they wrote games in that language!

Mobile Wi-Fi Hot Spot 202

Posted by kdawson
from the boy-in-a-bubble dept.
bsharma writes to let us know about a little goodie that we will be able to buy starting May 17: a battery-powered, rechargeable, cellular, Wi-Fi hot spot that you can put in your pocket. "What if you had a personal Wi-Fi bubble, a private hot spot, that followed you everywhere you go? Incredibly, there is such a thing. It's the Novatel MiFi 2200, available from Verizon starting in mid-May ($100 with two-year contract, after rebate). It's a little wisp of a thing, like a triple-thick credit card. It has one power button, one status light and a swappable battery that looks like the one in a cellphone. When you turn on your MiFi and wait 30 seconds, it provides a personal, portable, powerful, password-protected wireless hot spot. ... If you just want to do e-mail and the Web, you pay $40 a month for the service (250 megabytes of data transfer, 10 cents a megabyte above that). If you watch videos and shuttle a lot of big files, opt for the $60 plan (5 gigabytes). And if you don't travel incessantly, the best deal may be the one-day pass: $15 for 24 hours, only when you need it. In that case, the MiFi itself costs $270." The device has its Wi-Fi password printed on the bottom, so you can invite someone to join your network simply by showing it to them.

Kill Ugly Processor Architectures - Karl Lehenbauer