As if it wasn't hard enough to keep tools on hand for the following screws:
- Flat blade
- Hex (in metric and fractional inch sizes)
- Tamper-resistant Torx (with a post in the middle)
- Torx Plus (with wider holes)
- Tamper-resistant Torx Plus (hard to come by -- with wider holes, a post in the middle, and five points instead of six)
- TTAP (a six-point variation with a deep hole in the middle, also hard to come by)
- Tamper-resistant TTAP (which I've never seen)
- Several other unusual fastener heads, such as square, two-pin, etc.
I've found that certain hard drive screws use a five-pointed variant of the six-pointed Torx star shape, which corresponds to "none of the above" and which doesn't seem to be available, anywhere. I found this out the hard way after buying a very nice set of Torx bits. The screws in question are so small it is very hard for my 40-year-old eyes to distinguish the five-pointed star from the six. They are roughly the size of a Torx T3 or T4.
The only reason I can imagine that manufacturers would use a fastener like this is sheer perversity. It isn't to make the devices tamper-proof -- the screws can be turned with a flat-head screwdriver of just the right width, although this is not ideal for either fastener or tool. Or, I could always just drill them out, as I've done on more than one occasion with a very stripped or damaged screw.
To the best of my knowledge the correct tool is not available for purchase _anywhere_ for a nobody like me, although I think you can sometimes find tools for larger versions of the bits for sale on eBay.
Several of these fasteners are apparently actually patented, and several apparently can't be legally sold except to properly licensed OEMs or other authorized personnel. Wiha sells, but will not sell to me, tamper-resistant Torx Plus tools, for example. And even if they would, they don't seem to have any this small.
As far as I'm concerned, such restrictions should be illegal. I'm sure there is an analogy here to be made to software APIs. I'm reminded of a talk I saw by Stallman, in which he drew puzzle pieces representing APIs, and talked about the evils of proprietary APIs. I bought it, I ought to have the right to take it apart!
By the way, the device in question is an iPod hard drive, made for Apple by Toshiba. But I'm sure there are many other variants of the same thing going on.