Author: Dave Farquhar

What is recursion in Python? Here’s an example

Dave Farquhar Software
What is recursion in Python? Here’s an example

Recursion in computer science is a subroutine that calls itself. So what is recursion in Python? The same thing. A function that calls itself.

Recursion is a concept that first or second semester computer science classes frequently cover, but it can be confusing. I will admit that I generally tried to avoid using it, but it can be useful. I especially find recursion in Python useful when working with APIs, which is a common Python use case.

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Dept 56 Village Express Electric train set

Dave Farquhar model railroading
Dept 56 Village Express Electric train set

The Dept 56 Village Express electric train set was a train set made by Bachmann for Department 56. It was available from 1998 to 2006.

A train is a natural fit for Dept 56, which is meant to evoke a romanticized past. Today’s megastores have displaced those downtown shops that Dept 56 represent, and the automobile has displaced the passenger train has a favored means of travel. A passenger train and a few recognizable cars are a good way to firmly set the time period for your Dept 56 village.

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IBM 5170 battery

Dave Farquhar Retro Computing
IBM 5170 battery

Long ago, if you needed an IBM 5170 battery, you could drive 5 minutes to Radio Shack and they would have one. It might cost $10, but the time you saved was probably worth it. But those batteries disappeared sometime around Y2K, and of course Radio Shack has been gone nearly a decade now too. Here’s how I cobbled together a suitable IBM 5170 battery for around $6.

This battery was something of a standard, so a lot of motherboards, even into the 486 era, had a connector for this type of battery. So it’s useful for more than just an IBM 5170. If you have a 4-pin battery connector on your board, chances are this solution will work on it too.

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Mouse moves with arrow keys? The fix

Dave Farquhar Windows
Mouse moves with arrow keys? The fix

My Windows mouse cursor was moving on its own on my work laptop and driving me up the wall. Here’s how I traced the problem and how I fixed it. It turned out the mouse cursor was moving when I pushed the arrow keys. I’ve seen this happen in both Windows 10 and Windows 11. The obscure problem where keyboard arrows move the mouse is easy enough to fix, fortunately.

Two things can cause the Windows mouse cursor moving with arrow keys. Those are an obscure feature called Mouse Keys, or the venerable Microsoft Paint app.

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Brains 25 cents: The story behind the meme

Dave Farquhar St. Louis
Brains 25 cents: The story behind the meme

There is a popular photograph of a rundown urban building with a painted sign that says “Brains 25 Cents” with an arrow and words “drive in” pointing toward the back of the building. What’s the story behind the sign?

The “Brains 25 Cents drive in” painted sign was on the second story of Harvey’s Sandwich System, a diner at the corner of Chouteau and Carr Lane Avenue in St. Louis. The restaurant closed in 1976, the sign was demolished in 1983 or 1984, and the building was demolished in 1993.

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How big is an N scale train?

Dave Farquhar model railroading
How big is an N scale train?

N scale is the second most popular scale for model railroading, because it’s small enough that you can fit a big layout in a reasonable space without it taking over your basement, or build a small layout in a very small space, as small as a coffee table. But how big is N scale? How big is an N scale train?

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Why does my wifi say not secure?

Dave Farquhar security
Why does my wifi say not secure?

Sometimes, if you get a new device, or if you connect to a network you’ve never connected to, you can receive a message that says your Wi-Fi is not secure. Why does my wifi say not secure? Here’s why, and also why you shouldn’t ignore that message.

That message got your attention, didn’t it? It’s designed to get your attention. And it’s really easy to dismiss it as being alarmist. People have a tendency to either greatly overestimate or underestimate how much interest someone might have in attacking them. Especially if I tell you that the security that you’re getting a warning about has much more to do with privacy than it does with viruses. That message does not mean that this network is any more or less likely to infect you with a viruses.

But you need to do something about it when you see this message. First let me tell you why, then I will tell you what you need to do.

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Install Windows 11 on an unsupported CPU

Dave Farquhar Windows
Install Windows 11 on an unsupported CPU

Ever since Microsoft announced Windows 11 would have much stricter hardware requirements than its predecessors, people who don’t want to go and replace all of their computers have been looking for work arounds. Here is the easiest way to install Windows 11 on an unsupported CPU, including virtual environments like VMware or Virtualbox. No need to edit files, mess with an ISO file or disk image or Rufus or the registry editor.

The easiest way to install Windows 11 on an unsupported CPU is to delete one file, appraiserres.dll, from your installation media. This trick will hopefully keep some usable computers out of landfills a little while longer.

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Scroll lock on laptop

Dave Farquhar Hardware
Scroll lock on laptop

Scroll lock is an obscure key that has mostly outlived its usefulness. Size-constrained laptops often omit the key, layering it with some other key combination that you generate by pressing the FN key plus a second key that varies. Here’s how to get scroll lock on a laptop when your keyboard doesn’t have the key.

Usually to get scroll lock to toggle, use the FN key and a combination of a second key, often C, K, S, or even F12. You can also use the Windows on screen keyboard.

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Don’t use vape fluid in your Marx smoke unit

Dave Farquhar Toy trains
Don’t use vape fluid in your Marx smoke unit

Someone sent me a YouTube video talking about using vape fluid in Marx smoke units as an alternative to using mineral oil. Here’s why vape fluid in your smoke unit is a terrible idea in any train, whether Marx, Lionel, or modern.

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