Memory and Storage

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Memory

Primary memory or temporary storage is called RAM.  RAM stands for Random Access Memory.  RAM is stored on the motherboard, in modules that are called DIMMs (Dual Inline Memory Module).  A DIMM is called a dual inline module because it has two independent rows of pins, one on each side.   A DIMM memory module has either 168, 184, 240, or 288 pins. The DIMM is installed on the motherboard in memory slots.  Any given motherboard can have varying numbers of memory slots.  The average motherboard will have between 2 and 4 memory slots.

In order for data or a program to run on a computer, it first needs to be loaded into RAM, so the data or program is first stored on the hard drive, and is then loaded from the hard drive into RAM.  Once it is loaded into RAM, the CPU can now access  the data or run the program.  When the amount of available memory is too low, it might not be able to hold all the data that the CPU needs. When this happens, some other data has to be kept on those slower hard drives, in order to compensate for the low memory.  So instead of a data going from RAM to the CPU, it has to do extra work by going back to the hard drive; when this happens, it effectively slows down the whole computer.  To solve this problem, all you need to do is increase the amount of RAM in the computer. By increasing the amount of memory available, more data can be loaded into the faster RAM, without the necessity of constantly accessing the slower hard drive.  The result: a computer that performs better.  This serves as an explanation as to why a computer with more RAM performs better than a computer with less RAM.

RAM requires constant electrical power to store data. If the power is turned off, the data is erased.

RAM also comes in different types:

  • DRAM – Dynamic RAM. DRAM is a kind of memory that contains capacitors,  which must be constantly refreshed with electricity.
  • SDRAM – Synchronous DRAM. It is used today in RAM DIMMs.  It operates synchronously with the system clock, and is faster than DRAM.

Storage

Storage refers to a medium of storage in which information remains whole until it is removed or overwritten.  Whether the computer has power or not is of no importance to the amount of storage available.

Types of storage device

  • Hard drive – a hard drive is a high capacity, self-contained storage device, containing a read-write mechanism, plus one or more hard disks hidden inside a sealed unit. This piece of equipment is also frequently referred to as a hard disk drive (DVV).  Standard hard drives spin at 7200 RPM (rotations per minute).  Slower hard drives spin at 5400 RPM, while the fastest drives currently available spin at 15,000 RPM.  The faster your drive can spin, the faster you can search through your folders and word documents, plus whatever you have stored at those locations.  However, the downfall of hard drives is that as you use them they wear out, and as such have a maximum lifespan beyond which they won’t be able to function.
  • Solid State Drive (SDD) – a non-volatile storage device that stores persistent data on solid state flash memory. SSD are faster than hard drives, as well as being more expensive.
  • 2 SSD – just like a regular SSD, but plugged directly to the motherboard. Again, this is very fast, and as a result of its speed is also expensive.
  • Hybrid drives – a combination of solid state drives and hard drives, best described as somewhere between the two.

Memory is not the same as storage.  Storage is where the majority of the information is kept and stored.  While it’s great to have a lot of information, it’s hard to actually use it and keep stored at the same time.  This is where memory comes into play.   While memory can’t keep a lot of information at one time, it is able to retrieve relevant information that can subsequently be used by the computer when needed.