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Scrubbing Old Hard Drives

The shelf that collects old hard drives filled up, so I’ve been wiping the data before recycling them. This takes a while, but we know what happens when your hardware falls into unexpected hands. The routine goes a little something like this…

Set the drive’s jumper to Master, plug the drive into the USB adapter, plug the adapter directly into a USB port on the PC (because outboard hubs tend to be flaky), make sure there’s no valuable data, unmount.

time sudo dd if=/dev/urandom of=/dev/sdc bs=4096
[sudo] password for ed: 
dd: error writing ‘/dev/sdc’: No space left on device
73259047+0 records in
73259046+0 records out
300069052416 bytes (300 GB) copied, 22276.7 s, 13.5 MB/s

real	371m19.003s
user	0m22.884s
sys		370m34.906s 

Good old dd works for me; the only trick is not obliterating the system’s main hard drive with a simple finger fumble. Numbers from /dev/urandom suffice for this purpose; that’s where most of the packaged programs get their data, too. I do hardcore style, just because.

Ordinary desktop drives, at least those from long ago, can write at a bit over 12 MB/s → 40 GB/h on the average, with the higher peak rates that generally appear in the drive descriptions remaining an occasional sight. They won’t go much faster, even when plugged directly into the system board, but it’s not as if I sit there waiting until it’s done. USB 2.0 “high speed” transfers can hit 60 MB/s, including all the overhead, so that’s not the limiting factor; I’d expect the adapter’s firmware to throttle the data long before the bus strangles.

Use gparted to write a fresh partition table with a single NTFS (because the next user will probably run Windows) partition labeled Scrubbed spanning the entire drive.

Then stack the drive neatly on the outbound heap:

Scrubbed hard drives

Scrubbed hard drives

That cardboard box isn’t quite as full of unscrubbed drives as it was a few weeks ago.

The stack in the back contains all those worthless 30 to 80 GB 5400 RPM drives from old Dells, plus a few 1.5 and 2.0 (!) GB drives from who knows where. I have a plan for those platters…

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  1. #1 by Red County Pete on 2015-10-23 - 10:05

    I’ve had drives bad enough to need deplatterizing. The 1998 5GB drive got disassembled and the platters broken, as did a 400MB drive from a 1993 Linux box. It was SCSI, as was a 1GB Jaz removable media drive used as swap space. I had to plug the Jaz drive into another computer for power, so it would disgorge the platter. The remnants went back in the 486, and it went to the recycling center. I use a 100MB Zip disc as a coaster, will do much the same with the old Jaz media…

    One of these days, I need to decommission my Y2K vintage laptop. 5 or 10GB drive, but it’ll need a wipe. Must bookmark this page.

  2. #2 by madbodger on 2015-10-23 - 10:17

    I used to wipe drives for commercial customers who were worried about their data. I followed some spec I’d found of something like seven passes of alternating all-ones and all-zeros, followed by a write of random data. It took a while, but these were SCSI drives, so I’d put them on end, and hook ’em up, seven at a time, with a big ribbon cable and a power supply octopus and let them run. We were getting paid for this, so it was all good. They were curious what we did with their dead drives. While I didn’t break up the platters like Pete did, I did disassemble the drives and remove the platters’ magnetic coating with a sandblaster. One customer insisted on watching the process, and was well and truly satisfied that I had thus made the data unrecoverable.

    • #3 by Ed on 2015-10-23 - 10:45

      remove the platters’ magnetic coating with a sandblaster

      Now that is doin’ it hardcore…

      Gives you a nice assortment of teeny nonmagnetic metric Torx screws, too.

  3. #4 by Frans on 2015-10-24 - 15:54

    I think the smallest drive I’ve got laying around in my stack of old drives is 120 GB. I recently decommissioned my oldest HDD still in operation, a 320 GB drive from early ’07 (manufactured, it says, in 2007.02, which would be mere days or weeks before I bought it). I replaced it with something like an ’09/’10-ish old 500 GB drive which hasn’t ran for even a fraction as many hours.

    I vaguely wish I’d kept that 40 MB HDD from the old IBM PS/2… although it’s not like it’d do anything but take up space anyway.

    • #5 by Ed on 2015-10-25 - 07:21

      The stack of never-to-be-powered again SCSI drives yielded a 340 MB Connor (labeled “dead” by somebody else) and the pair of 512 MB Fujitsu full-height drives (dated 1993) from my excruciatingly expensive 80386 box.

      IIRC, a 20 MB IDE drive stayed in the Original IBM PC when it went to the next plane of existence…

  4. #6 by Simon on 2015-10-24 - 17:36

    In the late 80s I worked for a company making solid state drives emulating HDDs – and we replaced everything from 50MB, 10 platter drives to my very favourite – a 5MB unit I think with 4 x 1/8″ brass disks, about 1M in diameter, revolving on a horizontal axle – known as the bacon slicer. But with a single head per track for the 300 or so tracks the head switch was near instantaneous. The drive was installed in a 5′ cube with a second one containing air supply (to supply air to the head assembly I think), cooling and power supplies. I think each cube weighed about a quarter of a ton.
    The ones I replaced were built in 1966…final switch over involved rebuilding the computer from the main backup – dozens of paper tapes which we spent a morning installing – probably about 2MB of data from the tapes using ASR33 TTYs. Interesting times.

    • #7 by Ed on 2015-10-25 - 07:10

      Making SSDs before the age of cheap Flash memory: that’s definitely targeting the upper 1% of the market!

      • #8 by Simon davies on 2015-10-25 - 09:17

        Well we used 16 and 64k bit DRAMs with battery backup and tape dump if the batteries ran out of juice. All controlled from basic logic with 74 series TTL and small PAL devices – not a micro or programmed device in sight!
        Replaced many 5 and 10MB drives in 19″ racks driven by PDP8s and that entire generation of minis

  5. #9 by jim oslislo on 2015-10-25 - 08:14

    I find drilling a 1/2″ hole clear through the drive is good enough for my needs. Anyone who can retrieve data after that is welcome to it.

    • #10 by Ed on 2015-10-25 - 09:13

      Some folks insist on 0.45 inch holes… [evil grin]

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