David L. Farquhar

Home » Archives for Dave Farquhar » Page 187

What is the purpose of a screen saver?

Dave Farquhar Retro Computing August 15, 2017December 16, 20201990s, atari, best buy, blank screen, malware, spyware

What is the purpose of a screen saver? Screen savers served both a technical and a marketing purpose. From a technical perspective, the purpose of a screen saver was to keep an image from permanently being engraved in a CRT-based monitor’s phosphors. But it wasn’t long before screen savers started serving a vanity or entertainment purpose.

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.

dfarq.homeip.net

Commodore computer models

Dave Farquhar Retro Computing August 14, 2017September 15, 2025

The Commodore 64 is by far the most famous and successful computer Commodore ever made. But there were numerous Commodore computer models over the years. Some were also successful. Some were complete flops. Overall Commodore had a good 18-year run, but it could have been so much longer and better.

Let’s take a walk through the Commodore computer models from the beginning in 1976 to the bitter end in 1994.

Dave Farquhar

dfarq.homeip.net

Expanded vs Extended memory, or EMS vs XMS

Dave Farquhar Retro Computing August 11, 2017October 5, 2019Bill Gates, intel, memory slots, XT

DOS veterans may remember messing with expanded and extended memory to get memory above 640K. Here’s what you need to know about expanded vs extended memory, or EMS vs XMS. They are two different approaches to solving the same problem.

Dave Farquhar

dfarq.homeip.net

Why do Lionel trains have three rails?

Dave Farquhar Toy trains August 10, 2017August 5, 20171950s, 1960s, american flyer, electric trains, lionel, Louis Marx, marx, o gauge, Quaker Oats, Standard Gauge

Why do Lionel trains have three rails? After all, real trains usually have two. This unrealistic feature is a legitimate drawback for Lionel and other makes of O gauge trains, but the decision made sense at the time.

Dave Farquhar

dfarq.homeip.net

Commodore 64 Z80 cartridge

Dave Farquhar Retro Computing August 9, 2017April 3, 20231541, 1980s, 6502, apple, apple ii, commodore, commodore 64, intel, MOS, spartan

One of the most popular add-ons for an Apple II added CP/M compatibility. So I guess it should be no surprise that Commodore tried the same thing. But the Commodore 64 CP/M operating system and the associate Commodore 64 Z80 cartridge was a flop. Why?

Dave Farquhar

dfarq.homeip.net

Reliable power supply brands

Dave Farquhar Hardware August 8, 2017September 29, 2019antec, corsair, seasonic, tin

If you’ve built a few PCs, or repaired a few PCs, you have some idea how important the power supply is. If you buy any old tin box that fits, you can probably expect to run into some problems. Here’s some advice on buying power supplies, including reliable power supply brands.

Dave Farquhar

dfarq.homeip.net

Most valuable baseball cards of the 1970s

Dave Farquhar Baseball August 7, 2017October 11, 20231950s, 1980s, 1990s, andre dawson, baseball cards, cardinals, Kansas City, Topps, Willie Mays

Although the 1970s may not have been quite the golden era for baseball that, say, the 1950s were, the decade produced a good number of stars. An important thing to consider, too, is that many players Generation X grew up watching came up in the 1970s. That, along with lower production numbers, makes it an important decade in today’s market. Let’s take a year by year walk through the most valuable baseball cards of the 1970s.

Dave Farquhar

dfarq.homeip.net

Vacancy switch vs occupancy switch

Dave Farquhar DIY August 4, 2017August 3, 2017kitchens, occupancy sensor

If you’re wondering about a vacancy switch vs occupancy switch, both types of switches have their uses. The basic difference comes down to whether you want the light to turn on when it senses motion and turn itself off after the last time it senses motion, or only turn itself off after the last time it senses motion.

Dave Farquhar

dfarq.homeip.net

Do AC adapters go bad?

Dave Farquhar Hardware August 3, 2017April 15, 2023

Do AC adapters go bad? The answer surprises many people, but the answer is yes. The question, then, is how to lengthen their life expectancy and what to do if they do eventually go bad.

Dave Farquhar

dfarq.homeip.net

Watering hole attack prevention

Dave Farquhar security August 2, 2017August 1, 2017Adobe Flash, antivirus, breach, malware, malwarebytes, Proxy server, Whitelist, Windows 10, windows 7, Windows XP

A watering hole attack is an indirect attack on a victim. Rather than directly attacking the victim’s network, the attacker attacks a web site that the victim’s employees are likely to visit. Then the attacker attacks the victim’s network, via its own workstations, from that web site. A former colleague asked me how you protect against watering hole attacks, and I thought this was a good exercise. So here are some strategies for watering hole attack prevention.

Dave Farquhar

dfarq.homeip.net

The Silicon Underground

Author: Dave Farquhar

What is the purpose of a screen saver?

Commodore computer models

Expanded vs Extended memory, or EMS vs XMS

Why do Lionel trains have three rails?

Commodore 64 Z80 cartridge

Reliable power supply brands

Most valuable baseball cards of the 1970s

Vacancy switch vs occupancy switch

Do AC adapters go bad?

Watering hole attack prevention