The third-smallest hard drive

1.8-inch drive, interface adapters, and cat feet

(Don't worry - he's an anti-static cat.)

I had this little "20Gb" 1.8-inch hard drive, as seen in older iPods, just sitting around. It actually has a formatted capacity of only 18.6Gb, but that's still several gigabytes bigger than my "out" directory that contains pretty much everything I've ever written, including pics. So the little drive looked like a good place for me to make another backup of "out".

(I could also use a 16Gb flash drive, which would be a much tougher backup device, and not very expensive - just today, DealExtreme listed a 16Gb Kingston USB drive for less than $US35 delivered. But I already had the little Toshiba, and it's not going to be my only backup of this data.)

I attached the little drive to my computer via two adapters. The thing at the back with the cable plugged into it is the WiebeTech FireWire Super DriveDock that I reviewed back in 2003; the FireWire cable can provide more than enough power to spin up this little drive, so I didn't need to plug in the DriveDock's plugpack.

The circuit board between the DriveDock and the drive is a Toshiba-1.8-inch to parallel ATA adapter. Like other such doodads - CompactFlash-to-PATA adapters like the one I reviewed way back in 2000, for instance - these adapters are now dirt cheap from Hong Kong dealers. EBay's full of 'em, but I got this one for $US3.49 delivered from DealExtreme.

If you're thinking of doing this yourself, because you've got a junked MP3 player or some such with a perfectly good 1.8-inch drive in it, or because you just bought such a drive on eBay for $3, bear in mind that there is more than one kind of 1.8-inch drive. (This information is also important for people who want to replace the drive in their iPod or other small hard-drive MP3 player.)

Two-point-five-inch drives are the normal type used in laptops, and also in pocket-sized portable hard drives. 2.5-inch SATA is also the form factor that many Flash-RAM Solid State Drives use. 2.5-inch PATA and 2.5-inch SATA drives all have the same pinout, regardless of manufacturer, and differ only in height. So you can put pretty much any 2.5-inch device in pretty much any laptop, USB box or what have you, as long as

1: you don't try to mix PATA and SATA (you can get PATA-to-SATA adapters, but there won't be room for one in a laptop or USB-drive-box), and

2: you're not trying to fit one of the uncommon, unusually-thick kinds of 2.5-inch drive into a destination device that only has room for the common 9.5mm-thick kind.

1.8-inch drives come in SATA and PATA versions as well, but the PATA ones - which are the only ones you're likely to find cheap or free in 2009 - come in different flavours.

The two main types of PATA 1.8-incher are Hitachi (née IBM) and Toshiba. Toshibas have a female connector on the back of the drive, and Hitachis have a male. Apart from that I think they're very much the same, so you can probably get PATA adapters that come with two cables and can work with both types of drive. If you're buying a $3.49 adapter, though, make sure it's got the right connector for your drive.

You can also find 1.8-inch drives with one or another kind of zero-insertion-force (ZIF) ribbon-cable connector. Once again, Toshiba and Hitachi have implemented slightly different versions of the same thing. So, again, all you need to plug these into a standard ATA device is a pin adapter (in this case a "contact-pad-to-pin-adapter"), but you have to get the right one. (Here's an adapter to give you a Toshiba 1.8-inch pin-connector from either kind of ZIF 1.8-incher.)

You may also find 1.8-inch drives in disk packages made to slot into a laptop PCMCIA/PC Card slot. I think there'll probably be a standard Hitachi or Toshiba PATA drive in those which you could dig out with a bit of careful surgery, but if I were you I'd leave the drive in its little armoured package and access it via a laptop, or a PC with a PCMCIA-socket card.

(If you want to dig the drive out of a PCMCIA package because you need to bring a dead iPod back to life, and you don't need a zillion gigabytes of storage, I suggest you try a CompactFlash card in a CF-to-Toshiba-1.8-inch adapter instead. Once again, though, remember that newer iPods use the ZIF-connector type of 1.8-incher, which requires a different adapter.)

Amazingly enough, there are two hard-drive form factors that're even smaller than the 1.8.

The only really "standard", widely available type that's smaller than a 1.8 is the jewel-like CompactFlash "Microdrive" (360-degree Quicktime view here). Microdrives are called "1-inch" drives by IBM/Hitachi, I think because that's the approximate diameter of their platters, but Samsung call them "1.3-inch". They're the same size as a standard Type II (thick) CompactFlash memory card, 42.8 by 36.4 by 5mm (about 1.7 by 1.4 by 0.2 inches).

Microdrives were pretty hot stuff back in the day, but even though you can buy an 8Gb Microdrive these days, they've still been made obsolete by bigger and bigger, and cheaper and cheaper, Flash RAM.

The very smallest hard drives ever made even littler, though. They're made by Toshiba, and are 32mm by 24mm by 5mm (about 1.3 by 0.9 by 0.2 inches) and officially called "0.85 inch" devices. Toshiba have managed to pack "4Gb" into one (real formatted capacity about 3.7 "real" gigabytes), as I write this.

The 0.85 drives actually have the exact same height and width as an SD memory card, as used by most digital cameras, though they're more than twice as thick. They're apparently supposed to be for bulk data storage in mobile phones and other small devices, but I don't think they've actually been used for much; Flash RAM has streaked past them, too.

6 Responses to “The third-smallest hard drive”

  1. TimeDoctor Says:

    Wiebetech? I hear there is a Dan's Data kill-screen coming up in a few minutes.

  2. Red October Says:

    Those prices come as a relief, my tired old Thinkpad X20's Hard Disk seems to sometimes make disturbing noises, and the last time I checked, at least, the prices for a new 2.5" disk were outrageous.

  3. iworm Says:

    I'll have a dozen of those 0.85 inchers in a RAID0 array please!

    PS When I leave a comment, despite adding a "URI", my "Comment by iworm" string does not have a link to my blog. Not exactly important, but I was curious what I was doing wrong. :-/

  4. iworm Says:

    Well, since I wanted to test if my blog link now works (thanks Dan for the suggestion!) I'll also post something vaguely pertinent:

    I've wondered before how hard disks manage to put up with so much abuse (sudden movement, etc.) despite the awseomely small tolerances inside them - head hovering on a nano-wotsit of air and all that. My amazement is even greater in the case of those Microdrives - which in something like a camera get subject to the most violent forces, yet still work. How on earth do they manage to make the physical side of it work? 'Mazing.

  5. Popup Says:

    It's partly an effect of the scaling!

    It's a bit non-intuitive how forces and strengths scale with size, but it's quite illustrative to look at the extremes in the animal kingdom. Drop an ant from an aeroplane and it will probably walk off. Push an elephant down a flight of stairs, and it will end up as elephant stew.

    There is also a non-trivial amount of engineering involved in the design!

  6. Changes Says:

    (If you want to dig the drive out of a PCMCIA package because you need to bring a dead iPod back to life, and you don’t need a zillion gigabytes of storage, I suggest you try a CompactFlash card in a CF-to-Toshiba-1.8-inch adapter instead. Once again, remember that newer iPods use the ZIF-connector type of 1.8-incher, which requires a different adapter.)

    Note that not all CF cards will work. Most are incompatible with the hard-drive communication that players use, and will be unable to restore your player to life.
    There are some brands that are rumored to have fully compatible CF cards (including Transcend), but the most compatible ones (and the only ones I can attest to) are of brand A-Data, model "Speedy". I bought a 16GB one when I wanted to flash a rockboxed iPod Mini, and it worked. But there was no feeling with the iPod, so I took it out and tested it in a few other players. It worked in all of them.
    In the end it ended up with a CF-to-1.8"-IDE-adapter inside my Rio Karma, where it resides today.
    The Karma is the best music-only player in history, but it has a known problem with weak hard drives (well, the few still in existence do, anyway). Subtract the hard drive, add flash memory, and the result is pure awesomeness.

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