Article originally appeared as SMART Tools: Preventing Drive Failures (Linux Lab by Charles McColm, Full Circle Magazine issue 82 , Feb 2014) At our local computer refurbishing project, the top sources of hardware failure that we see are power supplies, CMOS batteries, RAM, and hard drives. The first three failures can cause systems not to POST (Power On Self-Test) correctly. Hard drive failures are a bit more tricky. A really bad hard drive can cause a system to hang while displaying POST messages, or cause a system to randomly reboot (we see more of this on Windows systems), or slow a system down to a crawl, or it might not appear to do anything at all. Knowing a drive has issues before the drive fails can save a lot of work.