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CompTIA A+ RAM

220-801/802

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Hardware


Like almost every chapter in the CompTIA A+ Cert Guide book, the RAM chapter is split into a hardware and software section. These are also commenly reffered to as 801 for hardware and 802 for software. This section will show you general knowledge that is coverd by the 801 objectives for the A+ certification test.

To begin understanding RAM, there are some general things to know. RAM stands for random access memory, and is used by the computer to store data temporarily when it is using it often. RAM is also volitile, which means that when the system powers down, all the data on the RAM is gone. There have been many types of RAM modules, and here is the list you should be comfortable with for the 801 test.

  • DRAM - Dynamic RAM. This type of RAM is constantly refreshing to update to the new temporary files that are being used. Pins for DRAM include 30, 72, and the rarely seen 168.
  • SRAM - Static RAM. This RAM doesn't need to be periodically refreshed like dynamic RAM does and is constantly found in CPU cache, buffer in hard drives, or in other small quantities. It is very fast and in return is fairly expesive. SRAM is typically soldered directly onto the part so it doesn't have pins.
  • SDRAM - Synchronous Dynamic RAM. This was the first type of RAM that ran at the same speed of the CPU bus. Pins for SDRAM include 168-pin DIMM. Bus speeds ranges from 66 MHz to 133 MHz.
  • DDR SDRAM - Double Data Rate SDRAM. This was the first type of RAM to perform two transfers per clock cycle. Pins for DDR SDRAM are mainly 184-pin DIMM. Bus speeds range from 200 MHz to 400 MHz.
  • DDR2 SDRAM - Double Double Data Rate SDRAM. This type of RAM runs its external data bus at twice te speed of DDR, enabling faster performance. Pins for DDR2 SDRAM are only 240-pin DIMM. Bus speeds range from 400 MHz to 800 MHz.
  • DDR3 SDRAM - Double Data Rate 3 SDRAM. This type of RAM runs at lower voltages than DDR2 and is twice as fast by increasing the bus speeds again. Pins for DDR SDRAM are only 240-pin DIMM, but the notch on the modules is different than DDR2 so they cannot be used interchangably. Bus speeds range from 1066 MHz to around 2800 MHz and even higher. DDR4 is a thing now but is not covered by Comptia A+ yet.



Another important factor when it comes to RAM is the actual shape and size of the memory modules. Heres the list you should now for the test.

  • SIMM - Single Inline Memory. Has a single row of 30 or 72 edge connectors on the bottom of the module. Single means that both sides of the module have the same pinout.
  • SIPP - Sinlge Inline Pin Package. A short-lived variation on the 30-pin SIMM, which had pins instead of edge connectors. SIPP has 30 pins.
  • DIMM - Available in 168-pin, 184-pin, and 240-pin, this is the most common version of RAM as it is seen in all versions of DDR. Dual refers to each side of the module having a different pinout.
  • SODIMM - This is a compact version of DIMM, and is available in various pins (pins for SODIMM are not on the test). SODIMM is commonly found in laptops, netbooks, and laser printers due to its size.
As far as hardware goes, the last thing to note about the RAM chapter is ECC and Parity checking. Parity and ECC are both ways your RAM tries to warn you of problems, and both involve having an additional chip or two on the RAM module. Parity checking goes adds the ones and zeros in a byte to see if it adds up to an odd number. Issues in the RAM will cause the total number from a byte to be even, so parity checking can tell you when there is a problem. ECC on the other hand not only checks the data but also fixes problems. RAM modules with ECC are more expensive and are often found on servers, where keeping the system running is crucial. ECC checks bit by bit, making it more thorough, and fixes the problems without the user having to get involved. This should cover most of the basics for the RAM chapter in the Comptia A+ Cert Guide.

Software


Something you are required to know for your 802 test is how to properly handle and install RAM. When handeling any component of a computer, the first thing you should do is make sure to get rid of any ESD as it can damage and ruin your parts. For this it is recommended that you have an antistatic wrist strap, but touching any uncolored part of a computer case will do. Next comes installing the RAM, which is a simple, three step process.

  1. Line up the modules' connectors with the socket. DIMMs have connectors with different widths, preventing them from being inserted backwards.
  2. Verify that the locking tabs on the sockat are swiveled to the outside (open) position.
  3. After verifying that the module is lined up correctly with the socket, push the module straight down into the socket until the swivel locks on each end of the socket snap into place at the top corners of the module.



Other than installing RAM and handeling it properly, you must also learn how to troubleshoot RAM related problems. The first thing any good technician should do when they suspect the RAM is the problem is to verify compatibility. If the RAM in your copmuter isn't compatible then right off the bat there is no chance of the system working properly. To determine compatiblity refer to any documentation that came with the computer, or lookup the motherboard on the manufacture's site to gain more info.

Other things you should watch out for as a technician is misuse of RAM. One of the fastest ways to wear out a hardware component is to overclock it and RAM is no exception. If you are experiencing problems with RAM that is overclocked, return it to the base speed an voltages. Messing around with overclocking can give performance boost but it also increases temperatures and decreases the life span of the overclocked component. Another issue you may run into is have different kinds of RAM in a system. This can lead to problems with compatibility, but if the speeds are different it can lead to problems. Many motherboards have adapted to become more user friendly and will lower the speed of all the RAM modules to meet the lowest one, or some can even run each module at a different speed. Regardless it is recommended to have RAM modules that have the same speed. You can learn more about overclocking and how to do it safely at overclock.net.

Additional Resources


While the Comptia A+ Cert Guide book is definetly the right place to start studying, it's not the only thing that can help you on the road to becoming A+ certified. Having passed the test myself I can reliable say that there were quite a few outside sources that definitely helped me reach my goal. One of the greatest recources I encountered while studying was Professor Messer (Check him out here). This man has made over 100 videos that are all free for the public on both 801 and 802 information. He covers every objective in the book, in thorough detail, and I would suggest watching him when you feel like you have some free time or if you need a break from reading. Here is one of the two videos he did about RAM for the 801 test.



Another hidden gem a good colleague of mine showed me was Exam Cram. This series of books is very useful when studying for huge tests like this one, and it covers a lot of topics, and a lot of certifications. This book is amazing because it condenses the information as much as possible, provides lots of practice problems along the way, and has big review tests in the back. Additionally, the book was exam alerts and little notes telling you when something is crucial for the test or other important information that can help you narrow what you need to review. I used this book to help me cram and review anything I didn't know during the week before my test, and it sure helped considering I'm now certified. The Comptia A+ Cert Guide tends to cover some information that won't show up on the test (but it is useful information to know so I would recommend reading it if you have the time), so if you are pressed for time, Exam Cram is the right book for you.


An obvious resource that most don't take advantage of is simply the Comptia website. This website not only has all the information about testing, it has a full printable list of the objectives, which is a list of everything you are expected to know when going into the test. There are different objectives for 801 and 802, but a study method I used was printing out the list and checking off what I was sure I could do. It can help you narrow down the amount of information you need to review before the test. Use all of these resources plus the original book to help you study and prepare for the 801 and 802.

About Me


I'm Peter Zeqo, a student at Natick High School. I'm currently taking both A+ Certification and Advanced Web Design as electives at my school. This is my final project for web design, and I decided to mix two of my favorite classes. My goal is to leave high school with an A+ certification, which I got this year, a Dreamweacer certification, and a Mac+ certification. Next year I will be taking Advanced Web Design 2 with the aim of getting my second certification by the end of the course. Other classes I enjoy in school are math and physics. This year we are forced to take chemistry, which I didn't particularly like, but I do plan on taking AP Physics in my senior year. Other than science I also love math, and next year I will be taking BC Calculus.
Outside of school hours I am part of my high school's robotics team, RoboNatick. Sophmore year has been my first year on a robotics team and we managed to get to third in states this year. I found the new experience to be intresting, so I'm going to be around for the last two years years of my high school career. Recently I was voted to become a leader of one of the three teams which I think will be a challenge, but a great experience for high school. As for sports, I like playing soccer competetivly, but also just for fun. My favorite time of the year to play is the Winter because I find indoor soccer the most fun. Other than soccer I like working out at the gym and playing various sports with my friends. Additonally I like to bike, and since I can't drive yet, I tend to bike a lot to get around town.
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