Data Centers

A+ exam prep: Fill those knowledge gaps!

As an experienced computer technician, Faithe Wempen walked into her A+ exam feeling cocky. The experience humbled her. Read this Daily Drill Down to let her experience be your guide to acing the test.


We all have them—areas of computer technology where we haven’t had much practical experience or don’t feel as confident. In real life work as computer technicians, we can usually sidestep these areas with help from co-workers or a bit of studying with a reference manual, but on the A+ exam, you can’t fall back on these resources. It’s easy to start floundering if you hit a series of questions about a subject that’s in one of your blind spots, especially since the test became adaptive as of July 1, 2000.

I passed the A+ exam on my first try, but I didn’t score anywhere near the top of the scale. This lower score was primarily due to a few knowledge gaps I had neglected to fill in during my preparation. In this Daily Drill Down, I’ll tell you about the subject areas that gave me trouble, and what you might need to study to avoid the same fate.

One item, many names
One thing that can really trip you up if you aren’t ready for it (as I wasn’t): The A+ exam often refers to things by a name other than the common ones to which you’ve grown accustom. Ports are a prime example. Instead of calling it a serial port, for example, a question might refer you to the RS-232 port.

Here are some of the technical names used for common PC elements:
  • BNC—A type of network cable connection for 10Base2 networks that looks like a cable TV cable connector
  • DB-25—A 25-pin D-shaped connector, with pins (in the PC) it’s a serial connector but with holes it’s a parallel connector
  • DB-9—Any nine-pin D-shaped connector (most commonly a serial port)
  • DIP (dual inline package)—A type of chip with “legs” on either side that fit down into holes in a circuit board
  • Local bus—A generic term that can refer to VLB, PCI, or AGP on the motherboard
  • PGA (pin grid array)—Any chip that plugs into a socket with lots of little pins; examples include socket 7 and socket 8
  • PLLC (plastic leadless chip carrier)—A low-profile CPU packaging—mainly found in laptops—with legs that curve under and around the edge
  • RJ-11—A telephone plug
  • RJ-45—A 10Base-T networking plug or ISDN plug (looks like a wide telephone plug)
  • RS-232-C—A serial communications standard (can be either a DB-9 or a DB-25 connector)
  • Slot 1—A slot for a Single Edge Contact Cartridge (SECC) such as the Pentium II processor
  • Slot A—An SECC slot for the Athlon processor
  • Slot M—An SECC slot for the Itanium processor
  • Socket 370—Alternative packaging for early Celeron processors that lacked an L2 cache
  • Socket 7—The socket for the original Pentium-class CPUs with 321 pins in five staggered rows
  • Socket 8—The Pentium Pro microprocessor socket, with 387 pins in five dual-pattern pin rows

Know your resource assignments
Quick—on a sheet of paper, write down the numbers 0 through 15 in a column. Then, next to each number, jot down to which device the IRQ commonly corresponds. Some of them are easy—like LPT1 on IRQ7. But what about LPT2? Few systems have a second parallel port, so not many technicians encounter this in daily life—the answer is IRQ5. Here’s a quick list of IRQs and their associated devices to help jog your memory:
  • 0—System timer (internal)
  • 1—Keyboard controller (internal)
  • 2—Second IRQ controller cascade (internal)
  • 3—COM2 and COM4
  • 4—COM1 and COM3
  • 5—LPT2 or sound card
  • 6—Floppy disk controller
  • 7—LPT1
  • 8—Real-time clock (internal)
  • 9—Available (as IRQ2)
  • 10—Available
  • 11—Available
  • 12—Motherboard mouse port (usually PS/2)
  • 13—Math coprocessor (internal)
  • 14—Primary IDE
  • 15—Secondary IDE (if used; otherwise Available)

Know how to do circuit testing
I’ve always been of the throw-it-away school of thought when working on PCs. I figure that a new $20 power supply is a lot cheaper for the customers than having them pay me $35 an hour to troubleshoot their old one. However, this propensity of mine to replace components rather than attempt to repair them means I don’t do much electrical testing.

The A+ test requires you to know your way around a multimeter, no question about it. The best way to become familiar with electrical testing is to get a multimeter and use it. A multimeter gets its name from the fact it can check multiple electrical settings: resistance, DC voltage, or AC voltage. (In contrast, a voltmeter can test only voltage.) You’ll find both analog and digital models in stores, but digital is much better for computer use because it uses less voltage to check resistance. (It’s therefore less likely to harm sensitive components.) Regardless of the type, a multimeter has a pair of probes—which are little wands—you use to take readings.

Where you place the probes to take the reading depends on what you’re testing. To test a resistor, place a probe on either side of it. To test a power supply, you would unplug the power connectors from the motherboard and check the Power Good pin (P8-1 on an AT, pin 8 on an ATX) for +3 to +6v of power. When taking the A+ test, make sure you know where the probes go for various parts of the PC.

It’s also important that you correctly set the range when testing. DC voltage, for example, can be set to 200mv, 2v, 20v, 200v, and 1,000v maximum. Because computers use anywhere from +3v to +12v for various parts, you would normally use the 20v range for most computer testing. However, if you’re ever unsure about the range for a component you’re testing, start at the highest range and work your way down until you get a meaningful reading.

Familiarize yourself with system bus standards
If you routinely work with only a few types of PCs, it’s easy to fall into thinking that the kind you see every day is the only kind out there. But as you’ll find out on the test, that’s not the case. For example, I primarily work on systems that are all-IDE, no SCSI devices. Therefore, I’ve never been very proficient when configuring SCSI devices. So I had to study up on termination, SCSI IDs, the various SCSI standards, the advantages of SCSI, and so on.

Everyone should know the IDE interface backwards and forwards—how to configure masters and slaves, how to set up a hard disk in the BIOS manually if it doesn’t autodetect, and all the rest of the practical skills you probably use every day. But you should also make a point of memorizing all the variants of IDE and what makes one different from another: EIDE, ATA-2, ATA-66, and so on.

Remember there are other buses besides those used for hard disks. Know your video buses: VLB, PCI, and AGP, as well as what differentiates one from another. (Remember VLB? It stands for VESA Local Bus, and it was the precursor to the PCI local bus technology that’s the staple of motherboard architecture today.) Make sure you know your 8-bit and 16-bit ISA slots and the limitations that led to their demise.

Know your memory types
Any technician should be familiar with the types of RAM encountered in PCs of various ages, but if you work with only a few types of PCs, you might forget some of the older and more arcane types. Here’s a quick overview:
  • DDR SDRAM (double data rate SDRAM)—A newer type of DRAM that maximizes output by using both the leading and the following edge of the clock tick to perform operations
  • DIMM (dual inline memory module)—The modern type of PC memory that comes in 168-pin boards
  • ECC memory (error-correction coding memory)—A more expensive type of memory that self-corrects errors
  • EDO RAM (extended data out)—An improvement over FPM, but also older technology that comes in SIMMs
  • FPM RAM (Fast Page Mode)—This is an older, non-EDO memory that comes in SIMMs
  • Parity Memory—An earlier version of ECC memory
  • RDRAM (Rambus DRAM)—A more expensive, more efficient version of SDRAM, found in high-performance PCs
  • Registered RAM—RAM with an onboard register array
  • SDRAM (Synchronous DRAM)—A modern type of dynamic RAM, typically available in DIMMs with a speed between 66 MHz and 133 MHz, depending on the type
  • SIMM (single inline memory module)—An older type of memory that is found in 30-pin and 72-pin varieties
  • SLDRAM (Synchronous Link DRAM)—A protocol-based memory technology, rather than a physical type of RAM that functions with the CPU as the client and the SLDRAM bus as a server, for very fast I/O speeds of 1.6 Gbps
  • Unbuffered RAM—A type of SDRAM DIMM that relies on a controller to function predictably as it has no onboard register array

Know how a PC uses RAM
Besides knowing about the various RAM types, you should also know how the PC actually uses memory. Those of us who work with Windows 9x and NT every day tend to forget about the lowly beginnings of memory management back in MS-DOS. Knowing those fundamentals, however, can help you to both pass the test and understand the way the newer protected-mode operating systems like Win9x and NT/2000 operate.

The RAM you physically install in the PC is counted up when the PC starts, beginning with bank 0, then bank 1. No matter how much RAM a system has, the first megabyte is always treated the same way (in real mode, anyway). The first megabyte (1,024 KB) of a system’s memory consists of 640 KB of conventional memory and 384 KB of upper memory. Conventional memory is where MS-DOS runs programs. Upper memory is reserved for system use (such as BIOS functionality and the video system). Those of you who were DOS 5.x and 6.x gurus will remember the arduous task of optimizing the use of the upper memory area by loading drivers “high” in Config.sys and Autoexec.bat so they were placed in upper memory blocks (UMBs) instead of taking up space in conventional memory. (This only worked on 386 PCs and higher, even though even old XTs had upper memory.)

Then, there’s the rest of the memory. The first 64 KB after the first megabyte is the high memory area, or HMA. Back in the MS-DOS days, you could use the DOS=HIGH command to place the DOS kernel into the HMA, further freeing up conventional memory. On 386 systems, all the rest is extended memory. Extended memory can be used by protected-mode programs, such as Windows 9x and NT/2000. Most programs can’t use extended memory directly; however, they want it in XMS format. XMS is a memory specification developed by Microsoft, Intel, and Lotus back in 1987. Himem.sys grabs up all the extended memory and provides it in XMS format to the programs.

EMS (Expanded Memory Specification) memory is not extended memory but rather an older kind of memory called expanded that was used in the original 286 systems. Another acronym for it is LIM (which stands for Lotus/Intel/Microsoft). You will seldom run across a program that wants expanded memory, but if you do, on an MS-DOS system you can use Emm386.exe in the Autoexec.bat file to make some of your extended memory emulate the expanded memory with the /RAM switch.

Understand laser printer technology
Since I’ve been primarily a home and small office technician, I haven’t worked on many laser printers. This was unfortunate at test time, because I had no idea about the process by which the data becomes a printed page in one of these devices.

The most important things you need to know about a laser printer are its location, its purpose, and the electrical charge of its various interior corona wires. Really, though, you ought to know the entire process that a page goes through from entry to exit. Here’s a summary:
  1. The primary corona applies a –600v charge to the drum.
  2. The printer receives data from the computer and uses a laser to hit certain spots on the drum. This partially neutralizes the charge in those spots, to –100v. Now, your page data is on the drum as an electrical pattern.
  3. The developer (roller) picks up some toner and negatively charges it. The toner then magnetically sticks to the developer.
  4. When the developer passes by the drum, some of the toner jumps off onto the parts with the –100v charge.
  5. The paper enters the printer. Beneath the paper is the transfer corona, which charges the paper to +600v.
  6. The drum moves past the paper, and the toner jumps off onto the paper.
  7. The paper passes by a static charge eliminator that neutralizes its positive charge.
  8. Then, the paper passes through the fuser, which is very hot (180 degrees F or so) and melts the plastic part of the toner so it sticks to the paper.

Don’t be overconfident
I have to admit, when I walked into that A+ test, I felt pretty cocky. After all, I was the author of a book on computer hardware upgrades (Tune Up Your PC in a Weekend) and an experienced PC consultant. The test is supposed to measure competence as a technician, and I felt like I was more than qualified. That confidence was soon deflated. By the last question, I was actually worried that I wouldn’t pass. As I don’t serve a large number of customers with very diverse hardware types, I found I had a few large knowledge gaps of which I wasn’t previously aware.

If you’re a technician working on a smaller scale, like me, don’t let this happen to you. Take plenty of practice exams before you sit for the real thing. The Transcender practice tests are widely considered the best; they are also among the most expensive. Check out other alternatives if cost is an issue. Take advantage of the free test questions sent out every day by Cramsession (which is also a great site to use for study resources.) Computer-based training modules are also available—Keystone and LearnKey are the best-known brands. A friend of mine was able to take a three-day intensive exam preparation course at a local Holiday Inn for under $1,000, which she reports helped tremendously.

The bottom line: Don’t assume that because you’re an ace PC technician with years of experience, you’re automatically ready for the test. The test favors those who have a firm grasp of the terminology and theory, not just the practice, and those who have experience with a wide variety of hardware and software. If that’s not you, give yourself a month or so to prepare rather than wasting your exam fee on a first try you’re not ready for.

Faithe Wempen owns and operates Your Computer Friend, a computer training and troubleshooting business in Indianapolis. She is the author of over 50 books on computer hardware and software, including the best-selling Tune Up Your PC in a Weekend (Prima Publishing), and was a major contributing author for the 2000 edition of The Complete Upgrade & Maintenance Guide by Mark Minasi (Sybex). She writes and teaches online courses for Barnes and Noble University Online (Powered.com) and is the Webmaster for Broadway United Methodist Church in Indianapolis.

The authors and editors have taken care in preparation of the content contained herein but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for any damages. Always have a verified backup before making any changes.

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