David L. Farquhar

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What is RS-232?

Dave Farquhar Retro Computing, Servers and Networking November 2, 2020March 19, 2024

Many vintage computers have RS-232 ports, and some current equipment does too, especially network switches. But what is RS-232? And why did it only partly fall out of favor? And what about RS-232C? I’ll try to clear up the confusion.

Dave Farquhar

David Farquhar is a computer security professional, entrepreneur, and author. He has written professionally about computers since 1991, so he was writing about retro computers when they were still new. He has been working in IT professionally since 1994 and has specialized in vulnerability management since 2013. He holds Security+ and CISSP certifications. Today he blogs five times a week, mostly about retro computers and retro gaming covering the time period from 1975 to 2000.

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GFCI vs AFCI

Dave Farquhar DIY October 29, 2020October 11, 2020

GFCI and AFCI are both safety measures, but they are distinct and not interchangeable. Let’s compare and contract GFCI vs AFCI so you can be sure you’re getting the right thing.

If you don’t know, buying combination GFCI/AFCI outlets or breakers is an option, and it’s not a bad idea. But if you can’t afford the higher price for a combo unit, or want to maximize convenience, knowing GFCI vs AFCI is important so you get the right safety feature for your application.

Dave Farquhar

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How to mount a power strip

Dave Farquhar DIY October 28, 2020October 11, 2020

Power strips are a necessity when you don’t have enough outlets, but they can be unwieldy. One way to get them to stay where you want is to mount them to your wall, desk, workbench, or entertainment center to keep them out of the way. Here’s how to mount a power strip.

I used this trick to mount a power strip to my train table, my desk for my work computer, and to a monitor stand I made for one of my retro computers. It works well. This allows me to keep it where I want it, whether that means completely in reach in the case of a workbench, or out of sight but very easy to reach, in the case of my retro computer monitor stand.

Dave Farquhar

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Qualys severity vs CVSS

Dave Farquhar security October 27, 2020October 17, 2020

I’ve spent a little more time than I would like studying severity models in vulnerability scanners. One question that comes up occasionally is Qualys severity vs CVSS, or any of its competitors, for that matter. Let’s take a look at how Qualys severity compares against the industry standard.

Qualys’ severity score predates CVSS, which is now the industry standard. The two have similarities but there are various reasons for choosing one over the other.

Dave Farquhar

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DIY wood crate shelves

Dave Farquhar DIY October 26, 2020November 25, 2020

I needed some shelves for my office. Most of the ready made shelves I could find wouldn’t fit in the space I had. So I made some myself using cheap wooden crates. Here’s how I make DIY wood crate shelves that are attractive, functional, and reasonably durable.

You can buy three wooden crates for $36 and they will make a shelf that’s equivalent to a $40 particle board shelf in terms of storage space. But the crates give you more options in terms of versatility, both in the way they look and the way they work. And while I wouldn’t call them super strong, they’re at least as durable as particle board.

Dave Farquhar

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Why are some books so expensive on Amazon?

Dave Farquhar Saving money, scams October 22, 2020January 16, 2023

Books are expensive, but some books are a whole other universe of expensive. There are generally three reasons for that. I don’t think I’m giving away any deep, dark secrets, so I’ll explain why some books are so expensive on Amazon. Like, $800 expensive, sometimes. Better yet, I’ll also explain how to know if the book you’re looking at is overpriced, or if it typically does sell for those high prices.

Some books legitimately are extremely valuable and expensive. But sometimes low-demand books get caught up in price wars that drive prices up due to short supply.

Dave Farquhar

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What to look for in a surge protector

Dave Farquhar DIY October 21, 2020October 31, 2020

Surge protectors cost a lot less now than they did when I was a kid. That’s probably a good thing. But buying one today is no less confusing than it was in 1985. Here’s what to look for in a surge protector, so you’re getting the protection you think you are, and without sacrificing convenience.

A good surge protector offers an indicator light that tells you it’s working, enough plugs to be useful to you, and at least 1,000 joules of protection. Be sure to look for at least those three things.

Dave Farquhar

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Asymmetric attack examples

Dave Farquhar security October 20, 2020October 3, 2020

In security, we talk about asymmetric attacks all the time. If you don’t know what that means, here’s an easy definition and some examples from the real world. We have to be careful not to conduct asymmetric attacks on ourselves, because frequently we inadvertently do just that.

An asymmetric attack is an attack that’s substantially more expensive to protect against than to launch. This makes them a common challenge in security.

Dave Farquhar

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Can’t type in PyCharm? Try this first.

Dave Farquhar Software October 19, 2020September 12, 2023

PyCharm is a lifesaver for developing in Python, but it has a glitch. Sometimes, after you run a script, you lose the ability to type in the editor and make changes. Loads of web sites offer elaborate suggestions to fix the problem, when PyCharm doesn’t allow typing, but frequently, these complex solutions don’t work. Frequently they cause other problems. Try the easy solutions first.

The two easy solutions are to double-click on another file in your project, then double click on your script again. And if that doesn’t work, just exit PyCharm entirely and relaunch it.

Dave Farquhar

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