Managing the Testing Process: Practical Tools and Techniques for Managing Hardware and Software Testing

A.5. Mechanical Life

Any part of the system that can move, flex, rotate, bend, latch and unlatch, plug and unplug, toggle, switch, open and close, click, press and depress, or is in any way subject to opposing forces will be subject to strains and wear. Prime examples of this are hinges and latches, keyboards, touchpads, touchscreens, mice, trackballs, power switches, removable drives, CD-ROM/DVD-ROM/CD-RW players, floppy drives, and so forth. These items can have multiple moving parts. For example, a CD-ROM drive has the spindle, the laser and read head, the soft eject button (that works when the system is on), the hard eject button (that works when the system is off), and the platter. The floppy drive has many of these components and often a hinged cover. Any connector (e.g., telephone for a modem, network for a LAN) or a regularly touched surface such as a keyboard or trackpad or touchscreen is subject to the wear associated with regular use.

For any of these moving parts, the hardware test experts must make some reasonable assumption about how many motion events the part will experience over the course of its life. For keyboards, for example, test cases are often based on an assumption that each key will be pressed between 1 to 10 million times. Range of motion is another consideration, especially for latches, hinges, and the like. The test cases should also take force of motion into account. Often, frustrated computer users will bang on or sharply actuate computer keys or ...