Computer Memory: How It Works, Facts, and Resources
What is Computer Memory?
Computer memory refers to the state of information in a computer. The term memory is used for the existence of information in physical systems which are able to be accessed quickly, for example, random information memory. This also includes the existence of information in physical systems which are slow to access, for example, information or data storage. Computer memory, as a definition, is usually meant to refer to a complex semiconductor technology that is used to store information in computers. The term memory does not refer to the amount of information that is stored on a computer, rather it refers to physical devices used to store information or programs (sequences of instructions) on a temporary or permanent basis. There are two categories of computer memory common to modern computers: volatile memory and non-volatile memory.
What is Volatile Memory?
Volatile memory involves physical systems that require power, for example, to turn on the computer to maintain stored information. Volatile memory technology is usually either stationary random access memory (RAM) or dynamic RAM. It is actually found on computer chips that are placed onto a computer’s motherboard. RAM is electronic, and not mechanical; it does not have parts that move, and, as a result, access to its data (DAT) is very fast.
Most of the computer’s operating systems are loaded into RAM when the computer is started up; this allows the computer to access a variety of functions, such as handling mouse clicks and keystrokes. Whenever a program is opened, the interface and functions characterized by that program are also loaded into RAM and accessible only during the time the computer is powered.
What is Non-volatile Memory?
Non-volatile memory retains stored information even when the computer is not powered. Prime examples of non-volatile memory are read-only memory (ROM), flash memory, and most types of non-RAM computer storage devices. This includes, but is not limited to, hard disks, floppy disks, and optical disks. These physical systems are located external to the motherboard; they are stored in the hard drive of the computer. The hard drive consists of a stack of round metal platters called disks encased in a metal air tight shell. The function of the hard drive is to store all the files and software that the computer uses. Any file or software program used by RAM most likely will come from the hard drive.
How is Computer Memory Measured?
Computer memory is measured predominantly in bytes. A byte is the standard unit of digital information used in computing or telecommunication systems. All information or programs are created by encoding the information using the binary value of zero or one; this numerical value of zero or one is referred to as a bit. A byte can be defined as the number of bits used to encode a single character of text in a computer. Historically, a byte could consist of as few as five bits or as many as 16 bits; today, a modern standard byte consists of eight bits. The majority of computer applications use the eight bit standard per byte and processor designers generally conform to this common format. The common acceptance of eight bits to a byte was accepted because it is the most convenient formula for converting to the power of two. Unlike the metric system, which uses the power of 10 as its conversion base, computer measurements use the power of two as the basic formula for conversion There are 1,048,576 bytes in a megabyte and 1,073,741,824 bytes in a gigabyte.
Modern personal computers have somewhere between 1 to 3 gigabytes of RAM or volatile memory capacity. On the other hand, most modern disk drives, or non-volatile memory capacity, have a memory capacity that ranges between 30 gigabytes and 600 gigabytes. This can be explained by the necessity of the disk drive to permanently store all of the files and programs that the computer uses.
What is Cache Memory?
In computer terminology, cache memory is a type of random access memory that a computer’s central processing unit (CPU) can access more quickly than its regular random access memory (RAM) or information stored on the hard drive. As cache is built on or next to the CPU itself, it does not need to use the motherboard bus system to transfer or access data, and thus, anything stored on the system cache can be accessed extremely quickly. As a general rule, a computer has multiple areas for cache storage, referred to as levels, which are differentiated by their proximity to the microprocessor itself. L1 cache, or Level 1 cache, for example, is generally built on the CPU itself, with L2 and L3 caches being located physically farther away or even on a separate, designated microchip.
Different levels and sizes of caches allow for a computer to better organize data according to the level of need and improved performance. The small (usually 32-128 KB) but lightening fast L1 holds data critical to the task that is most frequently used. Less frequently accessed data is subsequently stored hierarchically to other, increasingly larger but slower caches, L2 and then L3 for instance.
How much Cache Memory is Needed to Encode a Video?
Video encoding is a complex task. The process of video encoding involves the transfer of video, generally from outside sources such as digital and analog video recorders or cameras, onto a computer’s hard disk. As video captured and transferred to disk without compression would result in extremely large, almost unmanageable file sizes with a number of proprietary formats, the computer must then further compress the video data into a more manageable file that can be read across a number of computers, using one of many existing standards, such as Mpeg4 or WMV, for instance.
Because of the complexity of the task, video encoding requires the CPU to process and transfer large amounts of information, and thus it is said to be a highly processor-intensive task. This means that video encoding puts a great strain on a CPU’s ability to process information and execute commands quickly, and consequently the CPU frequently utilizes the systems cache to improve performance. Due to the fact that the L1 cache is typically quite small, in most discussions related to the amount of memory used in video encoding, the size of the L2 cache is considered to be of critical importance.
When dealing with cache, the general rule is “the more, the better.” Experts recommend ensuring that the computer has a minimum of two megabytes of L2 cache. L2 memory cache will help to reduce the time and storage requirements of video encoding because the L2 cache does not require the CPU to continuously access the hard drive or RAM, instead the information will always be “on hand.”
However, it must be noted that not all video encoding applications themselves make equal use of a computer’s cache. Some programs, such as DivX, XVid, Cinema Craft Encoder, and Canopus ProCoder, are sensitive to a computer’s cache, meaning they generally perform better the more L2 cache the computer has. On the other hand, other programs can be more or less indifferent to L2 cache, meaning that they benefit more from the CPU’s ability to support hyper-threading, which is the ability for a core processor to process and execute two or more streams of instructions at once.
Thus, while the amount of cache will still be important, as video encoding is always cache intensive, certain programs may show significant improvement in speed by upgrading to a CPU that supports hyper-threading rather than simply one with more L2 cache.
What is Virtual Memory?
Virtual memory has become very common to central operating systems in many desktop and laptop computers. This is because it provides a huge benefit for users at a cost effective price. Most of today’s computers have approximately 256 megabytes of random access memory, or RAM available for use by the central operating system of microprocessor.
RAM is the volatile memory system that is located on the computer’s motherboard and the volatile memory system is mainly used to temporarily run all of the computer’s programs and systems that a user accesses during one computer session, while the programs and systems are stored permanently in the computer’s disk drive. Most of the data that is stored on RAM is lost once the power is shut off; therefore, RAM memory must be sufficient to run all of the programs the user will use simultaneously during one computer session. The amount of RAM is not enough to access all of the computer programs that most users expect to be able to access throughout a single session on the computer. For example, if a user uploads an e-mail program, a web browser program, such as Google Chrome, Firefox, or Internet Explorer, one of more social networks, such as Facebook or Twitter, the Windows operating system and Windows Office into their RAM simultaneously, 256 megabytes is not enough to hold it all efficiently.
What is the Difference Between Virtual and Volatile Memory?
Virtual memory is not a physical storage system like volatile memory, located in the motherboard nor is it, in and of itself a non volatile memory device. It does not operate as a mode of information storage, such as the disk drives, hard disks, floppy disks, flash disks, and so on. It is a memory management system developed to handle user multi-tasking that requires a computer to operate a vast array of information and programs simultaneously.
Virtual memory does, however, require hardware support, meaning that users have to go and buy actual memory to be installed onto their computer. It is considered a form of memory management that must be built into the central processing unit (CPU) of a computer. It is recommended that a computer professional be the one to install the memory management unit in to the CPU. This management system “virtualizes” the design of the computer and allows a computer program to be designed as if there is only one hardware memory device in the computer. Virtual memory performs like RAM, but operates in the hard drive. Before accessing hardware support, first, an individual has to figure out how much RAM is already on the computer by clicking the “My Computer” option located on the desktop. The next step is to go to “Properties” and then click on the section entitled “Computer.” An individual should then get in touch with the manufacturer of the computer to determine what kind of RAM is needed for the computer, the speed of RAM, the number of pins, and the number of RAM slots available.
How do I increase virtual memory on my computer?
Most of the newer operating systems have system specific ways of expanding the virtual memory of a computer within the operating system. Each operating system has a very clear protocol for expanding virtual memory that can be readily found on the Internet. One general way is to steer clear of having virtual RAM function on the identical drive as the computer system’s files. One can prefer to optimize one’s computer’s memory usage instead. If an individual uses their computer predominantly as a workstation, as opposed to using the computer as a server, they are able to have more memory devoted to relevant programs. The programs will work quicker and the system cache size will be the default dimension that was with the operating system. Divide space between numerous drives to optimize virtual memory and remove it from sluggish drives or drives that are heavily accessed. In short, divide your virtual memory space among multiple physical hard drives.
Resources about Computer Memory
How the computer works The CPU and Memory. Visual overview of the internal components of a computer
Andrew Boyd explores COMPUTER MEMORY on Engines of Our Ingenuity.
PDF from Stanford.edu about computer memory
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