This directory should include computer -parts-, not peripherals.
Idea from http://www.bunkermentality.net/sg01.html

It was originally created to hold pictures of screws in 2004.

Sick details:

Second, some of these screws are, almost interchangeable.  The case screw
and the hard drive screw use the same thread pattern.  Specifically they
are both 6-32 (six gauge wire with 32 threads per inch) American National
Coarse Thread (UNC) machine screws and are both cut to accept a No. 2
Phillips driver.  The case screw has a 1/4-inch hex head with integral
washer and the hard drive screw is simply a "pan head" type.  Case screws
are typically 1/4-inch long but can be as long as 5/16-inch whereas hard
drive screws are pretty much always 3/16-inch long.  Trying to mount your
hard drive using a 5/16-inch case screw is probably not a good idea.
Mounting your power supply, case door, or expansion cards with hard
drive screws should work just fine.

Floppy drive and CD-Rom screws are M3x0.5 (3 millimeter wire with a
0.5 mm thread pitch) machine screws and are both cut to accept a No. 1
Phillips driver.  Both have integral washers but the floppy drive screw
has a "round head" compared to the CD-Rom screw's hex head.  As noted in
the quiz the CD-Rom screw and the case screw look confusingly similar.
I'm sure many of us have mangled the threads on a CD-Rom drive by trying
to force feed it a case screw.  Floppy drive screws are a diminutive 4
mm in length compared to the standard 5 mm long CD-Rom screws.

As you can tell, PC innards are pretty much a machinist's nightmare.
Case screws and hard drive screws are made according to English units
of measure (or more correctly United States Customary Units) whereas
CD-Rom and floppy drive mounting hardware are made to metric standards.
Whose brilliant idea was this?

The screws are all similar enough in size and load bearing requirements
that they could have probably been standardized to a single size.
The coarser UNC thread pattern is more durable and will stand up better
to repeated insertions and extractions, but the finer 0.5 mm thread pitch
(thread pitch is the measurement of the space between the same point
on adjacent threads) of the M3x0.5 metric screws is more resistant to
becoming loose through vibration and rough handling.  The most bizarre
thing of all is the size of the hex head on the CD-Rom screw.  As best
as I can tell, this metric-threaded screw has a 7/32-inch hex head!
It is definitely larger than 5 mm but smaller than 6mm.  Whose idea of
a sick joke was this?!?

I haven't said much about the lowly case fan screw.  I guess because there
is not much to say about them.  They are usually 10 mm long and are cut
to accept a No. 2 Phillips driver.  They are technically a flat-head,
"self tapping" screw.  Self tapping screws cut their own threads as they
are driven.  Flat head screws are meant to leave a smooth, flush-mounted
appearance.