Hard Disk Selection Simplified
The NickLock is meant to simplify the rather annoying process of changing the main hard drive. Usually, to change the hard drive you have to first open the case and change the IDE jumper settings and probably the cabling as well. The typical way around this inconvenience is to use a removable frame system, in which each hard drive that you plan to use is installed into its own frame. After shutting down the computer, the drives can be exchanged freely. However, this solution is not ideal if you have to do this frequently, since hard drives are sensitive to physical movement. In the worst-case scenario, you could cause a head crash if you remove the drive before the read/write heads have been securely parked. In a more harmless scenario, the bearings could get out of whack, resulting in a noisier drive in the idle state.
With the NickLock, you can avoid these kinds of hazards and inconveniences. The NickLock assumes that there are two IDE drives running as master and slave at one IDE port. After installing NickLock, you can access a key switch at the front of your PC, which lets you choose between the two drives or make both drives inaccessible to the system.
The NickLock at a Glance
The manual contains very clear illustrations on how to install the system. As you can see here, both IDE drives have to be running at a single IDE port. Each master jumper is replaced by the NickLock connector.
Choosing The Hard Drive
The key switch has three different positions: Left, right and middle. This picture shows the key at middle position, which causes neither of the drives to be accessible to the system, effectively creating a lock. If you switch the key to left position, it selects the drive on the left by having its cable close its master jumper.
Although it might have been useful to include a setting that lets you choose both drives, there is probably a good reason why NickLock only allows you to select between single drives or none. For one thing, only a few drives run as slave by default if no jumper mode is set. The majority of drives run in single or master mode by default, and if you use two of them, there is no way to assign the specific drives to master or slave, thus causing a conflict.
Compatible Hard Drives
According to the information on the NickLock homepage and the installation manual, the NickLock is supposed to work with all IDE hard drives. However, I can imagine that some drives could prevent your system from working properly, particularly if they don't have any mode jumper set. Because the NickLock selects drives by closing their master jumper pins, it could be a problem if a hard drive shall not be activated: The master jumper will remain open without the slave jumper being set. Particularly very old drives (< 540 MB) tend to make your system behave strangely if the mode jumpers are not set correctly. That's mainly due to low tolerance in case of jumper configuration mistakes. I tried both a Seagate ST320430A (Barracuda ATA) and IBM's DTLA307030 (DeskStar 75 GXP); both drives worked properly.
The NickLock could be a perfect and inexpensive solution for those who have to share a single computer: Dad can create a computer specifically for the kids by installing the NickLock along with a second hard drive. Leaving the key lock on the second position will ensure that the kids can use the computer without putting his important data at risk. At work, the NickLock could prove a valuable add-on if there is a large number of part-time employees who don't have overlapping work schedules - by sharing a computer, the company could save on hardware costs. Furthermore, when leaving the office at the end of the day, access to the data can be secured by locking the system. Although it definitely isn't meant to be a professional security system, it still provides a convenient way to switch between two hard drives.