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Re: Re: DOS all platforms
From: Valdis.Kletnieks () vt edu
Date: Sat, 24 Jan 2004 13:12:50 -0500
On Sat, 24 Jan 2004 11:56:17 EST, "Jonathan A. Zdziarski" said:
I heard of a bet going between a student and IBM many many years ago to write a virus to cause physical damage. Apparently the student was able to use harmonic resonance and the hard disk drive to physically shake the PC off the desk.
This story (and variants) dates back to the IBM2314 disk drive, if not further. The problem with using "harmonic resonance" is that you have to first find a resonant frequency. Having done that, you need to be able to supply more energy each cycle than is being damped out of the system. So ask yourself - is any desk you use bouncy enough so that if something approximately the weight of a pencil (yes, that's how light the heads on a drive that will fit on a desk are) was dropped on it, the desk bounced enough to matter? Add in the fact that the machine is probably sitting on little rubber feet precisely to damp the vibration, and the difficulty in having things bounce that much and not crash the heads.... Shake the desk enough to make a pencil roll off - probably doable. Enough to make a 30 pound computer walk off the edge? Doubtful. I'd be more inclined to believe the 2314 variant - it was a disk drive from the mid 60s, 10 platters, 14" no less, a data capacity of 29 megabytes. Oh, and it only did like 3600 RPM and min seek times were in the 50-75ms range (and full-stroke seeks took a lot longer). As a result, you had a lot more mass in the arm assembly, and the full inside-to-outside cycle was down nearer to 100hz where it might conceivably do something useful.
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Current thread:
- Re: DOS all platforms, (continued)
- Re: DOS all platforms Matt Burnett (Jan 23)
- Re: DOS all platforms Chris Brown (Jan 21)
- January 04 MDAC patch Geo. (Jan 23)
- RE: DOS all platforms James Lay (Jan 21)
- RE: DOS all platforms James . Cupps (Jan 23)
- Re: DOS all platforms Valdis . Kletnieks (Jan 23)
- Re: DOS all platforms Matt Burnett (Jan 23)
- Re: DOS all platforms Frank Knobbe (Jan 23)
- Re: DOS all platforms Valdis . Kletnieks (Jan 23)
- Re: DOS all platforms Tamas Feher (Jan 24)
- Re: Re: DOS all platforms Jonathan A. Zdziarski (Jan 24)
- Re: Re: DOS all platforms Valdis . Kletnieks (Jan 24)
- Re: Re: DOS all platforms Jeff Kell (Jan 24)
- Re: Re: DOS all platforms Jeremiah Cornelius (Jan 24)
- Re: Re: DOS all platforms Patrick J Okui (Jan 25)
- Re: Re: DOS all platforms Erik van Straten (Jan 25)
- Re: Re: DOS all platforms Michael Cecil (Jan 25)
- Re: Re: DOS all platforms ldreamer (Jan 26)
- Re: Re: DOS all platforms Jonathan A. Zdziarski (Jan 24)
- Re: FW: DOS all platforms Jan Lühr (Jan 27)