How Do Computers Store Data?

How Do Computers Store Data?

Memory & Function

Computers are able to
store data digitally in
two ways, determined by
ram (random access
memory) and rom
(read-only memory).

Let’s explore how
different components
contribute to caching and
retrieval of digital
memory.

Computer Memory and Function

So, what is computer memory,
and why is it so important?

Computer memory is
technically any type of
electronic storage. Without
it and without access to it,
a computer is just a useless
box. From startup to
shutdown, and all processes
in between, a computer
relies on several types of
memory in order to function.

Multiple Choice

Without memory and without access to memory, a computer is just a useless box.

• True

• False

Memory's Place in a Computer

At the core of the computer is the
central processing unit or CPU, the
source of control that runs all
programs and instructions.

In order to function, computers use
two types of memory: primary and
secondary.

The main storage is the primary
memory, and data and programs are
stored in secondary memory.

However, memory is not stored in the
CPU, but the CPU would only be a
mess of wires without it!

This diagram displays all inputs/outputs
and processing pieces of a computer.

Multiple Choice

The main storage is the_____

• primary memory

• secondary memory

Multiple Choice

Data and programs are stored in _________

• primary memory

• secondary memory

Memory

If you had the memory of a
computer, you would have a large
capacity for forgetting information!

That is because most computers
make use of what is called random
access memory (RAM).

This memory is used only when the
computer is completing a task.

Memory and Storage

While the terms 'memory' and 'RAM' are used interchangeably, the most
common term used is random access memory or RAM, which is the data that
contains instructions for processing computer operations: the memory is
used only for as long as the program needing it is running.

Some of the reasons that a computer only needs the memory for
processing include:

●The computer needs to be powered on for most programs to run; once
the power is off, the memory storage is wiped out.

●No single program can use all the memory. Programs running
simultaneously need to share memory, meaning it is split among
those programs.

●The memory storage may not be big enough to hold the processing
data, so it is released when it's done.

Multiple Choice

Programs running simultaneously do not need to share memory

• True

• False

Multiple Choice

The memory storage may not be big enough to hold the processing data, so it is released when it's done.

• True

• False

How a Computer Uses Memory

Once the computer is turned on, the
computer accesses read-only memory (ROM)
and makes a quick test of the pieces of
memory to ensure there are no errors. Next,
the computer starts the basic input/output
(BIOS) from the ROM.

The operating system is started after the
BIOS makes it through the startup routine;
the operating system is loaded into RAM.
This gives the CPU quick access to the
operating system, improving performance and
functionality. The CPU accesses this in a
continuous cycle--and it happens millions
of times per second!

RAM may be the most common reference to computer memory; however, computers will use
all types in a basic hierarchy.

How a computer uses memory

The Unified Extensible Firmware Interface (UEFI), however, is a more
contemporary version of BIOS. It boots up faster, has more graphics, and
includes additional security features.

When a user runs an application, such as Microsoft Word, it is loaded into
RAM; once it is running, any files (from internal or external storage) are
also loaded into RAM for the program's use.

Once the file is saved and closed, the information is written to storage, and
then wiped out from RAM.

Caching and Virtual Memory
—-----------------------------

We have discussed primary and
secondary memory, or ROM and RAM.

However, there are two additional
components that make up memory
usage in computers: Memory cache
and virtual memory.

Cache

CPUs are incredibly fast: They process much
faster than it takes the data to get from
memory. Therefore, caching is used: The data
is then made instantly available, creating
small pieces of memory called Level 1 cache.
It is usually a very small amount of memory.

Level 2 cache connects directly to the CPU
(it sits on the memory card) and has a large
size. About 95% of the time, the CPU is
using this cache, which reduces the wait
time for data from main memory.

Virtual memory basically tells the computer to
think that it has more memory than it really
does. It helps the computer run huge programs
that won't fit into RAM. The computer is then
able to support multitasking: without this, we
could not use a spreadsheet, Twitter, a
document editor, and the calculator
simultaneously.

Computers are able to create virtual memory and
swap it out across programs (in fact the memory
files are called swap files, and the pieces of
memory being swapped are called pages.)

However, if the virtual memory amount is set
too high, the disk has to work harder to swap
memory, which can drastically slow down
performance.

Virtual memory

Multiple Choice

When the data is made instantly available, creating small pieces of memory is called ______

• Level 1 cache

• Level 2 cache

Multiple Choice

_________ connects directly to the CPU

• Level 1 cache

• Level 2 cache

Multiple Choice

Memory files are called _____

• swap files

• pages

Multiple Choice

The pieces of memory being swapped are called ____

• swap files

• pages

Lesson Summary

In this lesson, we covered computer memory and function, describing
how a computer uses and accesses memory:

From power on to power off, a computer is using cached memory,
virtual memory, and random access memory.

Without memory, a computer is only a box of wires, since memory is a
core component to all of its functions.

Open Ended

Name one thing discussed in this lesson.