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When Spun Really Fast, CDs Explode
Anonymous Coward writes: "Ever wonder why cd-rom/cd-rw drives are not getting any faster? Wonder why they heat up? This page has a rather amusing experiment where they put various CD's into something that can spin up to 30,000RPM and found that most cd's explode at just around 28,000RPM. Oh and they seem to like using Corel CD-ROM discs for their experiment." Update: Yep, it's a dupe...
They should at least have chosen AOL CDs to destroy. Sheesh.
Al.
This story (with the same URL) was posted here. I know duplicate-URL checking wouldn't help everything, but it could at least catch stuff like this...
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I can see it now, the RIAA manufacturing discs that experience structural failure when you spin them faster than 1X to rip them....
:-)
oh boy.
Wonder what happens if you spin a floppy at 30,000 rpm?
I want to see more of this kind of story!
I want to see what else can explode in my box. I want to see what happens (with big color pictures) to to a hard drive at 20000 atmospheres of pressure. I want to see ASUS vs ABit mobo's head to head for resisting g-forces. I want to see what happens when you force 100,000 volts through a cat-5 cable.
Isn't this what the internet is all about, pictures of stuff exploding, videos of people endangering their lives for my tittlation while discovering what happens if you fill a case with gasoline and run it as a server. Get cracking people.
Oh great. Now CD players will be banned from planes.
Table-ized A.I.
The article talks about constant linear velocity (used in the original audio standard) and constant angular velocity drives. It comments how manufacturers like to have CAV drives to quote impressive speeds compared to the CD (audio) standard, but doesn't mention a much more important reason for using CAV: if you used CLV you'd need to wait for a long time (probably seconds) for the spin rate to change and stabalize whenever you seeked from one part of the disk to another.
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Actually, it's a little-known fact that all CD-ROMs do keep the CD stationary, and simply spin the rest of the universe around it. True fact. ;)
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will be one of two things I think:
1. The CD will be spun at 64x or so clockwise. Under that will be a second counter-rotating plane that will contain the laser. With the platters rotating in opposite directions you can break the 30K RPM physical limitations of the media. You can build the mechanism strong enough to do 300x normal CD speed I'd guess. 300 * 64 = 6,000x or ( 2.5GB/s). I wouldn't be surprised to start seeing such a mechanism in hard drives either. The disks i
2. What I think will truely be the big breakthrough will be to not spin the disk or reader mechanism at all. Instead, the drive will use a scanner like method to read the entire CD in to a 700MB buffer in a few seconds. The disk will then sit idle while all requests are served from the buffer. I see this used in a slot loading scheme, so as the disk is drawn in it is read.
The nifty thing about this would be that you could create a CD image in the buffer, change the bugger copy just like a normal disk drive, then eject the physical master and burn the buffer to a new CDR(/CDRW disk.
Article X: The powers not delegated... by the Constitution...are reserved...to the people
Actually, it's a little-known fact that all CD-ROMs do keep the CD stationary, and simply spin the rest of the universe around it. True fact. ;)
Yeah, right. Next you're gonna tell me that CDs are flat and if you read too far you'll fall off the edge.
Some people have a way with words, and some people, um, thingy.
IWARS.
People, in general, disappoint me. Politicians even more so.
A 64x CAV CD-ROM drive will spin at a maximum of 12,800 RPM, according to my math, but drives don't seem to exist at that speed just yet. More common 56x drives spin at 11,200 RPM.
If things are consistantly and violently exploding at a little over twice that speed, would it not make sense that there is a very real safety issue in making things faster than this?
One might theorize that off-balance discs, cracked/scored/otherwise-damaged media, and just plain bad luck might cause things to go dangerously amiss even at current speeds.
Current high-end SCSI hard drives spin at 15,000RPM, but do so using extremely well-balanced, carefully-produced, expensive solid aluminum platters and motors. And, besides, they're also encased in heavy metal boxes, and don't have a soft plastic face through which to fire shrapnel into the chest of the user.
Consider that a CD-ROM has a much larger diameter than a typical hard disk platter, and is thus exposed to far greater centrifugal force and linear velocity. Consider also that a CD-ROM drive only costs a few dollars to make, and that CDs are down to a couple of cents each in large volume.
Given this information and that contained in the article, I doubt it would take much effort to make a CD explode in a current 56x drive, thus presenting a very real bottleneck, indeed.
Kid-proof tablet..
A fun experiment is to put a polished, hardened steel rod through the spindle hole, then hit it with a jet of compressed air. If you get the bearing effect just right the CD will spin up to a 10-20krpm and will occasionally disintegrate on the spindle. Mostly though if you let it slip off the spindle it'll hit the ground, stand due to gyroscope effect while the edge melts against the ground enough to get traction, then take off across the room and explode on impact with the opposite wall.
You can also make an air bearing with an orange by cupping your hand just right and blowing compressed air between your hand and the orange. Oranges explode good.