To home computers, digital clocks and VCRs, one second without power seems like the end of the world. When the power goes out, unless the system has some sort of back-up device, the unit will lose its memory resulting in the common problem of eternal mid-night or the blinking twelve. If the unit is a VCR or computer, programs and data can be lost. To prevent this problem, look for clocks and VCRs with built-in battery back-up. It won't keep the unit operating during a power outage, but it will preserve the memory and settings.
To prevent data loss with your home computer, consider purchasing a stand-by power supply or SPS. The SPS will provide at least a few minutes of back-up power to get you through the momentary power disturbance. Aftermarket battery back-up systems will often cost more than a new clock or VCR, therefore they aren't recommended for these applications. Remember, most internal or external battery back-up won't prevent your equipment from being damaged by surges. Surge protection calls for a surge protection system.