Jan 072010
Laptop Memory
Posted by: LaptopsArena in Accesories, Peripherals & Components
Since we’ve started with the series about “things you should know about your laptop componentsâ€, today we are going to talk about laptop memory. When we referrer to this subject, we are thinking about 2 different types of memory. There is the RAM which is basically the laptop’s virtual memory and the disk space, which is your physical memory where you can actually store your files.
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RAM is short for Random Access Memory. If you need a short explanation of how this type of memory works, I can tell you that different bytes of it can be accessed without using any previous byte. That’s right, it’s all random. RAM is also divided into 2 different types of memory. First, we have the DRAM (short for Dynamic Random Access Memory) which is the common type of RAM found in most laptops and computers. It’s more common because it cheaper compared to SRAM. SRAM stands for Static Random Access Memory and it’s more expensive than DRAM because it’s faster. DRAM needs to be refreshed while using it (your laptop does this as an automatic process) while SRAM doesn’t and this is why we have a price difference between the 2.

Be careful not to mistake RAM for ROM. ROM is the Read Only Memory of your laptop or computer which is used for storing your programs that help boot your computer. RAM is the main memory of your laptop, the one that helps you run applications. The more RAM you have, the more simultaneous programs you can run in your laptop. RAM is a temporary type of memory because every time you shut down your computer, whatever programs were running, get lost. This is why when you restart your PC or laptop, the running applications are being shut down and they are no longer available when you log on to Windows (you have to start the application again).
Modern day laptops use DDR, DDR2 and DDR3 RAM. But do these letters and numbers mean? DDR means Double Data Rate so you can think of DDR2 and DD3 as upgrades to the regular DDR, a type of RAM that helps speed up the transfer rate. RAM is far more expensive than hard disk memory and this is why the numbers of these two are never equal. A good laptop will have between 2 and 4 GB of RAM because today we tend to run as many applications as we can on our notebook. Different programs use a certain amount of your random access memory and the more programs you run, the more RAM they occupy, therefore slowing down your computer.

The other main type of laptop memory is the hard disk. This component looks just like a box. On your hard disk you can store all your files, documents, pictures, music, games, applications and movies. Think of your hard disk like the drawer of a desk. You can put some files in there until the desk gets full. All hard drives basically have the same structure but it depends on the quality of the components used which determines the overall quality and performance of the hard drive. There are 5 basic components that are found in every hard drive: the platters, the spindle, the spindle motor, the read and write heads plus the head actuator. The platters are in fact disks that are used to store the magnetized data. In the past, these platters were made using aluminum alloy and other material but today they are made of glass and ceramic because these materials are more resistant to heat.  The number of platters is influenced by the quantity of memory the hard disk has. These platters are separated from each other by space. Between them you can find rotating spindle that turn them around. Think of these platters like a vinyl disk and they are rotated in a pickup. These spindles are powered by small motors that help perform their rotations (this is why every time you check a laptop’s specs, you will see that the hard drive has 7200 rotations per minute – this speed is determined by the spindle and the spindle motor).
The read and write heads simply reads and writes the data onto the platters. These heads stop whenever the platters also stop spinning and they rest on a so called landing zone. All of these heads are attached to head actuator. This “arm†helps move the heads. This head actuator is becoming a thing of the past because it seems to produce some alignment problem not to mention some serious heat. Instead, a voice coil actuator is used because it’s much more efficient. All these five components are found in the Head Disk Assembly (or HDA for short). In the exterior of this HDA we have a logic board. This logic board controls the movements of all the internal parts plus the movement of the data.

Since laptops are way more fragile than desktop computers, manufacturers are developing anti shock systems that protect the hard drive in case you accidentally drop your laptop. These systems are usually found in business laptops because they make the unit more expensive. What this system does is that it stops the disk heads in case the laptop suffers any shocks therefore preventing hard disk damage. There are 5 main manufacturers that produce hard drives: Toshiba, Samsung, Hitachi, Seagate and Western Digital. Hard drives are usually a part that is located inside your laptop or computer but if you feel that you reached a certain point where the storage capacity is not enough, you could buy an external hard drive that you can connect to your computer with the help of a cable and an USB port. One similarity between the disk space and the RAM is that the more you fill them up with applications, the slower your laptop will run. If you have an optical drive, such as a DVD burner, you can use it to free up some disk space by making backup copies of your stuff on DVDs and then erasing them from the laptop’s memory.



















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