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How many times could i run something like

dd if=/dev/urandom/ of=/dev/sda 

before the hdd starts to suffer? I thought in a modern hard drive the head doesn't touch the platter, but i am still not sure. Could this be run like a million times. I mean, is there some upper limit? Thanks.

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i know that wiping once or twice is considered unrecoverable but this is more of a theoretical question, hence the 'million times' thing. I won't run it a million times. – Daniel Gratz Jun 29 '11 at 16:10
When I was in my first job, my boss once tried to convince me that you could destroy a disk's MBR permanently by zeroing it too many times. – Tom O'Connor Jun 29 '11 at 16:12
Someone on a forum wrote: Some viruses read and write to the boot sector repeatedly, until the disk is damaged. A damaged boot second renders the disk useless to normal uses. – Daniel Gratz Jun 29 '11 at 16:18
are you doing this to wipe a disk? – Scott Keck-Warren Jun 29 '11 at 16:33
Scott yea but i won't that many passes, 1000 is fine. – Daniel Gratz Jun 29 '11 at 16:56
up vote 1 down vote accepted

Could this be run like a million times

Yep, you can write to the same sector billions of times on modern magnetic disks, more so on enterprise-class disks than on consumer ones but yeah, SO many times that you'd get bored waiting for it to fail. This cannot be said for SSDs however, even on the newest and most expensive ones.

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You're opening yourself up with "magnetic discs" there. After all, the source of much of the distorted information on this subject is in part the characteristics of floppy magnetic disc media. M. O'Connor will be edified to hear that I've worn out track 0 of the odd floppy disc in my time. (-: – JdeBP Jun 29 '11 at 16:51
@JdeBP I don't think "modern magnetic disks" fits the description of a floppy very well. – vcsjones Jun 29 '11 at 17:04

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