Not long ago I was surprised to hear a tech (my son, actually) tell me about a system he worked on that turned out to have a bad stick of memory. I haven't had any such problems in a long, long time and thought that they were a thing of the past.

Not so, apparently, and the symptoms can be very confusing. He had looked at the hard drive and a few other likely suspects before finally tracking it down.

When programs get copied into bad memory, they don't work right. When stuff is written from bad memory to hard drive, it's corrupted so that even if it gets copied into good memory the next time, it's still bad.

Yuck, yuck, yuck. And do run different patterns, the more variety, complexity, and length of time, the more likely you'll find the rotten apples.

-- Ed