Where Are Magnetic Screwdrivers??

http://www.wikihow.com/Magnetize-a-Screwdriver

Your local hardware store may have bit sets with a magnetic head. The head goes into a handle or a [cordless] drill, and then your desired bit is magnetically gripped by it. Enough magnetism passes through to pick up screws.
You don't want to place these anywhere near a hard drive or other magnetic media, but in the last 25 years I have only ruined one 3.5" floppy. Just be careful.

You will need a serious magnet to damage a modern hard drive- one strong enough to pick up a car should do- so no worries about the Gauss effect of a magnetic phillips screwdriver damaging your hard drive.

If you open up a disk drive you will find very powerful rare earth magnets that are part of the voice coil actuator that moves the arm for the head. Associated with the permanent magnets is a magnetic coil with a varying magnetic field that is used to move the arm back an forth. If you take out the rare earth magnets and stick them to your refrigerator, they are so strong that you almost need a screwdriver to pry them off. You also have magnets and magnetic coils in the motor that spins the platters. All of these magnets are positioned within a quarter inch of the disks yet do no harm. It is not likely that a weak magnetic screwdriver outside of the case would have any effect.

Frequency???, are you sure you understand how magnets work? Unless you are spinning the screwdriver around there will be a "frequency" of zero.
If you pass the magnet (which is what the tip of the screwdriver has been turned into in manufacturing) near the hard drive you do run the risk of corrupting the data on that drive.

I built lots of rigs, all with magnetic screwdrivers. Any hadware store will have magnetic screwdrivers.

Every hard drive has a pretty powerful magnet INSIDE it which drives the voice coil head actuator. That magnet doesn't affect the data at all. It's likely that the Mythbusters test caused the head actuator to mistrack, and if it was writing data at the time that would certainly cause problems.

But magnets have no effect at all on hard drives that aren't running. You'd have to open the drive up and rub the magnet on the surface of the platter in order to cause any damage, and contamination from ambient dust particles would probably condemn the drive before you get get the magnet anywhere near the platter.

I have been building computers for about 25 yrs now and have always used magnetic screw drivers and not a one has had any problems. It is very easy to magnetize a screw driver as the link in the one post states. I wouldn't worry at all about a magnetic screw driver. I haven't even used grounding straps in building computers. You just have to touch the case so you have the same voltage in you as in the computer so no sparks.