ddr3-ddr2-ram-evo.jpg

RAM, or Random-Access Memory, is the most commonly known and used form of computer memory and the photo above shows an example of two types of RAM. If you are anything like me you may have thought that the RAM is referred to as "random" because it would only make sense to confuse people like me further BUT according to "How Stuff Works" the "random" refers to the ability for a computer-user to access memory from the RAM randomly if the column and row is known. The RAM is opposite from the SAM (Serial Access Memory), which stores memory in an organized fashion allowing for a sequential memory retrieval. The design of a RAM chip is similar to that of the microprocessory because of the IC (Integrated Circuit) "made up of millions of transistors and capacitors." (Tyson, Coustan, 1998-2011).

Definition: Dictionary.com defines RAM as "random-access memory; computer memory available to the user for creating, loading, or running programs and for the temporary storage and manipulation of data, in which time of access to each item is independent of the storage sequence. As a storage medium, RAM is volatile, so its contents are lost when the power fails or is turned off." (Dictionary.com, 2002).

Standard Specifications: The different types of RAM models are listed below with a corresponding picture of the RAM type below the description.


  • FPM (Fast Page Mode) RAMs are known as part of the DRAM (Dynamic RAM) family. The FPM RAM holds the ability to access and retrieve data and information that is on the same page. FPM Memory was mainly used in 486 and Pentium based systems from 1995 and even earlier than that. FPM-RAM.gif




(Whitty, 2006).

  • EDO (Extended Data Out) RAMs were introduced in 1995 to replace the older model of memory for Penitum based systems. The name of this RAM refers to the process of keeping the data output drivers, located on the memory module, switched on when the column address is removed and the next cycle begins. EDO-RAM.gif





(Whitty, 2006).

  • SDRAM (Synchronous DRAM) is also a member of the DRAM family and has gained the name of "synchronous" because of the synchronization between this device and the memory bus. SDRAM became a popular choice for Intel based chipsets in 2001 and since 1996 the majority of Pentium and Celeron based systems have the SDRAM. In order to release and sell this model of RAM as better than those prior to it, this model had to offer something more, which was presented as being three times as fast as the FPM RAM and twice as fast as the EDO RAM. The SDRAM is able run at 133MHz.


SD-RAM.gif




(Whitty, 2006).

  • DDR (Double Data Rate) RAMs is in the SDRAM family and was released in 2001 and soon after its release the mainstream motherboards began supporting this RAM. "The difference between SDRAM and DDR RAM is that instead of doubling the clock rate, [the DDR] transfers data twice per clock cycle" (Whitty, 2006) and this process is more efficient and effective in doubling the data rate. This RAM model has become the 'King of all RAMs' and has set the standard for models to follow.

DDR-RAM.gif(Whitty, 2006).

  • DDR2 RAMs is simply a newer version of the DDR Model and it was released in 2003 marketed as being twice the speed of its older model family member. The majority of the components between the DDR and DDR2 are the same with one exception, the modified signaling. The signaling for the DDR2 creates higher speeds.

DDR2-RAM.gif(Whitty, 2006).

  • RAMMBUS (RIMM) RAMs were introduced to the market in 1999 and its architecture is completely different from any of the RAMs listed above. "The RAMBUS design gives smarter access to the ram, meaning that units can prefetch data and free some CPU work. The idea behind RAMBUS RAM is to get small packets of data from RAM, but at very high clock speeds." (Whitty, 2006). Unfortunately,the smarter design did not last long in the Intel market because of the number of complications that this RAM model presented.


RD-RAM.gif(Whitty, 2006).




Function: As stated above the RAM device is utilized for memory storage and retrieval. Regarding DRAM (Dynamic RAM) the capacitors and transistors are paired together, creating a memory cell, which is also known as one bit of data. The transistor holds a switch-like function, which when activated allows the contol circuitry on that particular memory chip "read" or change the capacitor. "A capacitor is like a small bucket that is able to store electrons. To store a 1 in the memory cell, the bucket is filled with electrons. To store a 0, it is emptied." (Tyson, Coustan, 1998-2011). Unfortunately, this "bucket" has a leak that creates a constant flow of electrons entering and exiting, and because of this the "bucket" empties every few milliseconds. In order to avoid the problem of continuously discharged capacitors, the CPU or memory controller must constantly and quickly recharge the capacitors that are holding a charge of 1 before the inevitable discharge. The CPU or memory controller must read and re-write the memory to achieve the recharge necessary to avoid constant discharge. (Tyson, Coustan, 1998-2011).

The following video, although slightly outdated, explains the general functions of a RAM:



How Does It Affect the End User: Because the RAM Memory device controls the access and retrieval of memory within the computer, those who intend on buying and using a computer should educate themselves on the inner and outer workings of the RAM and this includes me. I've owned a computer for the past 4 years and this is the first time I have researched and understood the functions of the RAM and now that I know I am going to ask more questions when buying my next computer. Simply knowing that the less advanced a RAM is, the slower the memory retrieval and upload or the more advanced a RAM is, the faster the memory retrieval and upload, is more information than I knew before this wikipage research.



Fun Fact!: The first computer, the Whirlwind, with RAM was introduced by MIT on March 8th, 1955. This computer was the first to contain the magnetic core RAM and real-time graphics. (Computer Hope, 2011).


Resources Utilized for this Page:
evolym. (2008). ddr3-ddr2-ram-evo [image]. Retrieved from http://www.evolym.com/2008/12/01/hardware-random-access-memory-ram/
Tyson, J., Coustan, D. (1998-2011). How RAM Works. Retrieved from http://www.howstuffworks.com/ram.htm
Dictionary.com. (2002). RAM. Retrieved from http://dictionary.reference.com/browse/RAM
khushangbhanushali. (2009, December 6). How RAM works.mp4 [image]. Retrieved from http://www.youtube.com/watch?v=_zmrDFV0QlU&feature=related
Whitty, B. (2006). Types of RAM: How to Identify and their Specifications. Retrieved from http://www.technibble.com/types-of-ram-how-to-identify-and-their-specifications/
Whitty, B. (2006). FPM RAM[image].Retrieved from http://www.technibble.com/types-of-ram-how-to-identify-and-their-specifications/
Whitty, B. (2006). EDO RAM[image]. http://www.technibble.com/types-of-ram-how-to-identify-and-their-specifications/
Whitty, B. (2006). SDRAM[image]. http://www.technibble.com/types-of-ram-how-to-identify-and-their-specifications/
Whitty, B. (2006). DDR RAM[image]. http://www.technibble.com/types-of-ram-how-to-identify-and-their-specifications/
Whitty, B. (2006). DDR2 RAM[image]. http://www.technibble.com/types-of-ram-how-to-identify-and-their-specifications/2/
Whitty, B. (2006). RD RAM[image]. http://www.technibble.com/types-of-ram-how-to-identify-and-their-specifications/2/
Computer Hope. (2011). When was the first computer invented? Retrieved from http://www.computerhope.com/issues/ch000984.htm