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Definition: memory
(1) In general usage, memory may refer to any stored data. However, because the basic operation of a computer is the interaction between storage drives and RAM (random access memory), one has to be clear when discussing or writing about the mechanics of computer processing. Definition #2 below is the precise definition of memory, a key component in every computing device.
(2) Random access memory (RAM) is the temporary workspace in every computing device (desktop, laptop, smartphone, etc.). The interplay between memory, storage and the CPU is how work gets done. Memory capacity typically ranges from 4GB to 64GB (4-64 gigabytes) for the average computer. Large-scale computers can have hundreds of gigabytes, even several terabytes. When the device is turned off, the content in memory is lost. See dynamic RAM, memory card and storage vs. memory.
All the Real Work Takes Place in Memory
All program execution and data processing takes place in memory. Often called "main memory," a program's instructions are copied into memory from storage or the network, and from memory they are extracted into the CPU for analysis and execution. Instructions direct the device to input data into memory, process the data in memory and output the results from memory.
Processing Means Calculate, Compare and Copy
All data are processed (calculated, compared and copied) in memory (see 3 C's). As programs and data are written into memory, the previous contents of that space are lost. After processing, the new data are typically output (copied) from memory to the screen and back into storage.
An Electronic Checkerboard
Memory Doesn't Remember
Memory loses its content when the power is off, so why call it memory? Because the first memory "did remember," but today's memory chips do not. However, for certain unchangeable functions, there are memory chips that do retain their content and remember (see ROM, UEFI and non-volatile memory). See storage vs. memory.
Memory Can Be Clobbered!
Memory is allocated by both the operating system and the applications but released when no longer needed. However, errant programs can fail to release memory, reducing the amount for other programs. Bugs in software can alter the wrong memory bytes creating erroneous values that can only be reset by powering the unit off and on to reboot, which clears memory. For example, rebooting from a cable box to a washing machine does the same thing: it clears memory to reset everything.
(2) Random access memory (RAM) is the temporary workspace in every computing device (desktop, laptop, smartphone, etc.). The interplay between memory, storage and the CPU is how work gets done. Memory capacity typically ranges from 4GB to 64GB (4-64 gigabytes) for the average computer. Large-scale computers can have hundreds of gigabytes, even several terabytes. When the device is turned off, the content in memory is lost. See dynamic RAM, memory card and storage vs. memory.
All the Real Work Takes Place in Memory
All program execution and data processing takes place in memory. Often called "main memory," a program's instructions are copied into memory from storage or the network, and from memory they are extracted into the CPU for analysis and execution. Instructions direct the device to input data into memory, process the data in memory and output the results from memory.
Processing Means Calculate, Compare and Copy
All data are processed (calculated, compared and copied) in memory (see 3 C's). As programs and data are written into memory, the previous contents of that space are lost. After processing, the new data are typically output (copied) from memory to the screen and back into storage.
In storage, data reside in blocks of several thousand bytes, but after the block is written into memory, any number of contiguous memory bytes can be calculated, compared and copied with any others. See byte addressable, early memory and RAM.
Memory loses its content when the power is off, so why call it memory? Because the first memory "did remember," but today's memory chips do not. However, for certain unchangeable functions, there are memory chips that do retain their content and remember (see ROM, UEFI and non-volatile memory). See storage vs. memory.
Memory Can Be Clobbered!
Memory is allocated by both the operating system and the applications but released when no longer needed. However, errant programs can fail to release memory, reducing the amount for other programs. Bugs in software can alter the wrong memory bytes creating erroneous values that can only be reset by powering the unit off and on to reboot, which clears memory. For example, rebooting from a cable box to a washing machine does the same thing: it clears memory to reset everything.