Hardware RAM testers exist, but are rare, and an A+ certified tech rarely would have access to one in the field. Software RAM testers are less reliable, but are often free and easy to include on a flash drive as part of a software toolkit. That makes them a go-to tool when the symptoms suggest bad RAM. False negatives are common—bad RAM will often be reported as A-OK after a scan. But if your RAM tester tells you your RAM is bad you have a smoking gun clearly implicating the culprit.

MemTest86 has long been the classic software tool for this job and it does the job well. A downside is that you must restart your computer, since MemTest86 can’t test your RAM while your operating system is using it. Thankfully, for those quick and dirty jobs, HCI Design has given us MemTest for Windows. It’s a Windows executable, so you just run the program and it starts testing away while Windows and maybe other apps are happily clicking away. If you think that MemTest for Windows can’t test RAM currently being used by other programs, you’re right. That may be a deal breaker for some, but MemTest for Windows will wait for currently used RAM to become available, and will test it when it does.

The end result is that the A+ certified tech can be confident that if they run MemTest for Windows for x hours, then one can be confident that the system is capable of running for x hours without any RAM related problems. Clever A+ certification candidates might realize that they could simply run a computer for x hours without any testing software, and prove that the system could run for x hours. But remember, the A+ certified technician is looking for that smoking gun that leads them to the culprit. If MemTest for Windows does throw an error, the A+ certified tech has closed the case with solid evidence.

CompTIA alerts A+ certification candidates that diagnosing RAM problems is covered in Domain 2.0: Troubleshooting, Repair & Maintenance on the A+ Essentials certification test, and Domain 1.0: Hardware on the A+ Practical Application certification test.

MemTest86 and MemTest for Windows are both freeware.

MemTest86

MemTest for Windows

CompTIA’s A+ test objectives include Domain 5.0: Security, which among other things, requires A+ certification candidates to know about “Data wiping / hard drive destruction / hard drive recycling”. If an A+ certification student is working in the industry it’s likely that their organization has some kind of hard drive disposal policy, usually involving the wiping of the hard drive. This can either take the form of software which electronically randomizes the bits, or a device which magnetically erases the information.

However, nothing beats the finality and satisfaction of physical destruction, but most A+ certification candidates have no direct experience with this method. Fortunately a company called SSI Shredding Systems has produced a series of videos demonstrating their products, which include a hard drive shredder. For fun I recommend their videos of other items being shredded, even if they have nothing to do with A+ certification. My favorite is the VW Hippie Bug.

Other companies have used YouTube to demonstrate their wares, and their commercials can be instructive and interesting.

On the flip side of the coin, a British program called The Gadget Show tested a couple of rugged storage systems by subjecting them to water, then explosives. The results were as entertaining as they were illustrative.

Though CompTIA updates their A+ objectives every few years sometimes the information you find in books and websites that are supposed to help with A+ certification is surprisingly out of date. Most A+ certification material I see, especially online, tends to perpetuate old stereotypes about inkjets and laser printers. This material is often carried forward from old A+ certification sources, and is only accurate for old CompTIA A+ certification tests.

Many A+ certification resources preach that laser printers have a lower cost per page, due to the high cost and low capacity of inkjet consumables. Tom’s Hardware has done a comparison study that puts the lie to old thinking about inkjets, laser printers and comparable costs. The truth, it seems, is more complicated than it used to be. The bottom line: if you shop carefully and don’t fall for the cheapest inkjet, you can approach and sometimes surpass the performance and economy of a laser printer with a good quality inkjet.

CompTIA requires A+ certification candidates to know about the pros and cons of inkjets and laser printers inA+ Domain 1.0: Hardware.

Inkjet Vs. Laser: An End To Stereotypes

One cool feature is that unlike standard RAID arrays, the drives don’t have to be equal in size. You can throw a newer, larger hard drive in right next to an older, smaller one and Drobo intelligently manages the data and parity information so that if either drive fails you don’t lose any data.

Cooler yet is that Drobo makes any old drive hot-swappable. While your system is running and accessing Drobo you can open it up, eject a hard drive by pressing a button, and insert a replacement. I wouldn’t have believed it had I not seen their video, which I recommend.

CompTIA doesn’t ask about Drobo on the A+ certification test, but RAID is covered in Domain1.0 Hardware, and NAS (network attached storage) is mentioned, though not directly asked about. Still, Drobo represents an interesting, if proprietary, step forward from the hardware basics CompTIA covers in the A+ certification exams. CompTIA prefers A+ certified technicians to have 500 hours of hands-on experience. That emphasis is reflected in the new CompTIA A+ Practical Application exam. Keeping abreast with new technologies like Drobo, and how they differ from the RAID arrays asked about on the A+ certification tests, helps frame CompTIA’s A+ certification exam objectives in a real world context.

Drobo

All A+ certification books describe the difference between regular cable and plenum cable in a fire, but would you like to see the difference? L-com sells cable and put together a series of videos so that customers can see what they’re paying for when they spend extra for plenum rated cable. Fortunately their videos are a great illustration for anyone pursuing CompTIA A+ certification, since this topic is covered in the Networking domain of the CompTIA A+ certification exam.

L-com’s Plenum Cable Flammability Tests Videos

As good as some book illustrations are, they are almost always black-and-white, and of course non-interactive. That’s why I’m fond of pointing A+ certification students towards How Stuff Works’ Computer Channel. The full color illustrations are nice, but the real draw is the interactive Flash-based graphics that can show processes, not just hardware. Some of the nice ones I’ve found:

• Front-side buses
• DRAM
• Flip-flops (used in high-speed cache memory)
• Inkjet printers
• Routers

How Stuff Works Computer Channel

“That attack demonstrated a severe fault in American infrastructure: its centralization. The city of Morgan Hill and parts of three counties lost 911 service, cellular mobile telephone communications, land-line telephone, DSL internet and private networks, central station fire and burglar alarms, ATMs, credit card terminals, and monitoring of critical utilities. In addition, resources that should not have failed, like the local hospital’s internal computer network, proved to be dependent on external resources, leaving the hospital with a “paper system” for the day.”

Wouldn’t you think cell phone service would still work if you severed underground fiber? But cell phone service is basically a network, and even towers that use radio frequency transmissions rely on their wired connections to centralized servers. Wouldn’t you think a hospital’s internal network could carry on without a connection to the outside world? But it too was dependent on outside services.

Service was out for about a day for hundreds of thousands of people and businesses. That may not seem terrible until you think about what a day without 911 service would be like. What pulled the city through was the local cadre of ham radio operators. Respect and thanks are owed to these volunteers, and kudos to the local authorities for the foresight to have long standing relationships with the hams.

Why haven’t we heard more about this?

In the modern, consumer-driven, 24-hour news cycle, if it bleeds it leads. Since, strangely, there was no concurrent terrorist attack and no one was hurt, the event was a blip on the news radar screen which quickly vanished. It is left to the imagination how much we would have heard about it had the intent (which remains mysterious) been more malicious.

I can’t realistically fault the mainstream news media for not analyzing in depth a story in which not one person was injured. But I remain surprised at the lack of noise that has reached my ears from respected sources in the information security world. Neither SANS nor NIST have a whisper about the attack or its implications for those of us who work with computers, networks, and information security on their websites. Industry specific blogs, for example related to the internet or homeland security, have reported the event, but the computer industry has been remarkably silent about the important lessons illustrated by this event.

So what are the lessons for computer professionals?

First, the Morgan Hill attack should remind any computer professional of the primacy of physical security. If you can get your hands on it, it’s game over.

Second, I’ve always been a big fan of having low-tech backups for high-tech solutions. How many calls for emergency police and fire services would have gone unanswered if not for the ham radio enthusiasts of Morgan Hill?

Third, the drawbacks of centralization must be mitigated. Bob lives in San Martin. Someone cuts a fiber optic cable in Morgan Hill. Now Bob’s cell phone doesn’t work. It seems ludicrous, but it happened because the local cell phone network was optimized through central switching devices for speed and service, not reliability. We must examine our networks carefully for non-obvious single points of failure, and dependency on remote services.

Remember, if you’re going for CompTIA A+ certification, networking is 15% of the Essentials test and security is 8%. For the CompTIA A+ Practical Application test the percentages are 15% and 13%, respectively. The attack on Morgan Hill provides a vivid and blessedly bloodless (this time) example of the real world importance of these topics.

Fortunately Consumer Reports has put together a wonderful visual aid that I use in A+ certification classes when we talk about phishing. Their online security guide has a link at the bottom, “Go phish”. Follow and it will launch an interactive Flash quiz that presents real phishing emails mixed in with legitimate emails, and challenges the user to determine which are the fakes. A real boon is that the phishing emails are subsequently highlighted to display the little mistakes that give them away, making the tool not only a great introduction to the concept of phishing, but an education in real, practical tips for email safety.

Most of my students are pretty savvy, and have the experience to know a fake when they see one. But being able to show someone else how to spot a phishing attack is something else again. That’s why I’ve been recommending to my students who work in IT to use the tool as a means to educate the end users in their charge.

Consumer Reports Online Security Guide

CompTIA requires information like this in domain 4.0 Networking of the 220-701 A+ Essentials test, and domain 3.0 Networking of the 220-702 A+ Practical Application test. Specifically, A+ Essentials domain 4.2 requires you to “Compare and contrast the different network types”, and lists DSL, cable, fiber, dial-up, wireless (all 802.11 types, they specify) and more.

I consider the Network Speed Table a work in progress and I’ll be updating it in the future. Particularly, CompTIA mentions other network types such as satellite, cellular, and Bluetooth, which the table does not include. When I’ll update the table I’ll post a notification here on the front page. Additionally, the speeds listed include minimum, maximum, and typical speeds. For this information I drew from various sources, including A+ certification books, books for other CompTIA certifications including Network+ and Security+, and good old Wikipedia. As such there is certainly room for some, shall we say, discussion about the speeds. The speeds I list as typical are particularly open to interpretation and may conflict with your personal experience, but rest assured those numbers were not pulled out of a hat. They were pulled out of Wikipedia. I know that’s not an authoritative source, but that way I know if you and I have a disagreement over them, then other geeks have already had the same disagreement and the result you see on the table is the result the Wikipedia-editing geek community has come to rest on (for now). However some of the other numbers were drawn straight from CompTIA A+ certification books, and I’ve been around enough to know that those numbers aren’t always accurate, even though they ought to be. Heck, sometimes two different books don’t agree with each other, even though they have each gone though a supposedly authoritative vetting process. Therefore, if you find an inaccuracy in the table, or have any suggested addition or edit, leave it in the comments!