David L. Farquhar on technology old and new, computer security, and more
If you’ve been around computers long enough, you know an IP address that starts with 169.254 usually means trouble. But what is a 169 IP address, what does it mean, and how do you fix it?
A 169.254 IP address is called an APIPA IP address. Your computer receives a 169 APIPA address when it can’t get an address from the DHCP server.
There’s no official rule regarding how many outlets can be on a 20 amp circuit. And there’s no official rule about how many outlets can be on a 15 amp circuit either. But there are guidelines you can and should follow to avoid unnecessary breaker trips. And there’s another rule that’s much more important than the number of outlets.
The National Electric Code has no rules regarding how many outlets you can daisy chain off a single breaker. But generally speaking, it’s best to keep the number below 13 because of average current draw.
Retro computer enthusiasts and computer technicians either love or hate Deoxit D5. There’s no middle ground with it. But I think the hate comes from people misusing it. Used sparingly, Deoxit D5 seems like a miracle cure. Here’s how to use Deoxit D5, and when.
It’s hard to strip the insulation off wire without cutting or nicking the copper beneath.It’s frustrating when you cut through the wire, but nicking the wire is bad too. The danger when you do that is you weaken the wire. And then the end may snap off someday, causing a bigger problem. So here’s how to remove wire insulation without cutting the wire.
If you consistently cut through the wire, check your tool. Some wire strippers work with all types of wire, and some work with just one. If you have the kind for one type of wire, get the other one too, and learn to recognize which is which.
It’s January 29, 2021 as I write this. Thirty five years after the Challenger disaster. I was in math class when I found out it happened. That was a little unusual.
When it comes to O gauge trains, I don’t know if there’s a more confusing topic than track dimensions. Standards, schmandards. Let’s see what I can do to de-mystify O gauge curved track dimensions.
O gauge track comes in some common dimensions, the most common being 31, 36, 42, 54, 72, and 96 inch diameters. The problem is not every track system has each diameter, and the measurements tend to be nominal, kind of like lumber.
My wife has a phone that has a nice screen and doesn’t lag. It’s an older model but it’s still a nice phone. Well, except when it’s cold. It turns out it’s not super unheard of when a phone turns off in cold weather. So if your phone dies in cold weather, or shuts off when cold, here’s how we fixed it. It makes sense, once you think about it.
I had a busy day at work today, writing for my current employer about something my previous employer discovered. Qualys discovered a buffer overflow condition in sudo that, well, basically makes all your users root. I joked with one of my coworkers that Qualys could have used this to solve all its permissions problems when scanning Linux and Unix instead of disclosing this, but they did the right thing.
Most any Linux distro released between 2011 and 2020 has this flaw. So, run yum update or apt-get update to clean up those old sudos. Because we all know giving all your users root isn’t a good idea.
The contour gauge may be the best kept secret in carpentry. When you need to cut a piece of flooring to fit around a piece of trim, or copy a piece of trim that you can’t buy anymore, a contour gauge lets you do it. Here’s how to use a contour gauge.
We usually only think about thermal paste during new system builds. But you may not know that thermal paste dries out over time and needs to be replaced. So how often should you replace thermal paste? And why do you need to?
How long thermal paste lasts depends on how hard you use your computer. It’s best to replace it every 3-5 years or so, if you keep your system that long, but there are other times it’s a good idea to replace it too.