John V. Hinshaw

Delayed Failures

About a year ago, I had set up an extra computer to handle file storage and backups, among other tasks. I had enlisted an older computer, vintage 2002, for this purpose. This system had been chugging along for months before the surge event, serving up files and writing daily backups of itself plus our other computers to a 750-gigabyte (GB, 10⁹ bytes) external hard drive. The evening after the surge occurred I ran a thorough check on the external backup hard drive: no problems were detected. I also scheduled a check of the main hard drive to take place when it next rebooted — the check required that the main drive be "offline" for the extensive checkout process. It was too late that night, so I waited until the next evening to restart the system. I gave the command, the PC shut itself down and restarted, but then it asked me to "insert a bootable disk." A sinking feeling began to make itself known. This request was not good because it meant that the main hard drive was not being detected as containing an operating system.

The delayed failure was another eye-opener for me. I understood right away that, again, I had been lucky. If the power surge had taken out the external hard drive, which also was plugged into a surge protection device (SPD), I would have lost all the backed up files and been faced with the prospect of paying and waiting for a data retrieval service to recover them, if that was even possible. I had made plans to start archiving the files onto removable media but had not yet imposed the discipline on myself to do so. In the worst-case scenario, the original copies on our desktop computers would have been lost as well, leaving us with only partial digital records of the past ten years or so, whatever I could salvage from the collection of data CDs and older backup tapes I had accumulated during previous attempts at conserving data.

What about the other PCs that were running during the surge? Both of them are more recent, built in 2005 and 2007, and they both had power supplies that clamp the output voltages to safe levels in the event of a voltage spike, unlike the failed PC that did not have a clamping feature in its power supply. Thus, I have to conclude that the newer systems survived because they were connected to an SPD that limited the input voltage to around 330 V, and the effects of this spike were limited in turn by the PC's power supplies, which kept the voltages output to the computer components within safe limits.

Rebuild and Restore

Now, I faced the prospect of rebuilding the PC and restoring the data from the backed up files on the external drive. Due to the electrical stress so recently imposed upon them, I elected to replace all of the computer hardware components, especially the power supply, rather than take the chance that other parts might fail at any time. I decided to use my desktop PC temporarily in the role of the destroyed system until the replacement PC was ready.