memmory

Central Processing Unit - CPU

This can be considering as the main part of a computer system and also known
as the brain of the computer as well as it functions according to the given
commands.
It consists of 3 main components.
1. Arithmetic and Logical Unit (ALU) - Perform all mathematical and logical
functions.
2. Control Unit (CU) - Controls all devices of a computer system.
3. Memory Registers - Positioned in the Central Processing Unit.
Temporarily stores data needed for the function of ALU.
Computer Speed
The unit used to measure clock speed of a computer is Hertz (Hz) and the units
used to measure computer speed are Megahertz (MHz) and Gigahertz (GHz).
Computer memory
Computer memory is any physical device capable of storing information
temporarily or permanently. We can classify computer memory as below.
Diagram
Primary storage, also known as main storage or memory, is the area in a
computer in which data is stored for quick access by the computer's processor.
RAM (random access memory)
This is the place in a computing device where the operating system (OS),
application programs and data in current use are kept so they can be quickly
reached by the device's processor. RAM is much faster to read from and write to
than other kinds of storage in a computer, such as a hard disk drive (HDD), solidstate drive (SSD) or optical drive. Data remains in RAM as long as the computer is
running. When the computer is turned off, RAM loses its data. Therefore this is
also called volatile memory. When the computer is turned on again, the OS and
other files are once again loaded into RAM, usually from an HDD.
Read-only memory (ROM) is a type of non-volatile memory used in computers
and other electronic devices.
ROM is "built-in" computer memory containing data that normally can only be
read, not written to. ROM contains the programming that allows your computer to
be "booted up" or regenerated each time you turn it on. Unlike a computer's
random access memory (RAM), the data in ROM is not lost when the computer
power is turned off. The ROM is sustained by a small long-life battery in
computer.
Cache memory, also called CPU memory, that a computer microprocessor can
access more quickly than it can access regular RAM. This memory is typically
integrated directly with the CPU chip or placed on a separate chip interconnect
with the CPU.
Secondary memory is where programs and data are kept on a long-term basis.
Common secondary storage devices are the hard disk and optical disks. The hard
disk has large storage capacity compared to main memory. The hard disk is
usually contained inside the case of a computer.
Magnetic Media Devices
Data is stored here by using magnetic field.
Hard disk
A hard disk is part of a unit, often called a "disk drive," "hard drive," or "hard disk
drive," that stores and provides relatively quick access to large amounts of data
on an electromagnetically charged surface or set of surfaces.
Magnetic tape
Magnetic tape is a type of physical storage media for different kinds of data. It is
considered an analog solution, in contrast to more recent types of storage media,
such as solid state disk (SSD) drives. Magnetic tape has been a major vehicle for
audio and binary data storage for several decades, and is still part of data storage
for some systems.
Used mostly in sever computers for back up due to its larger storage capasity.
But tape is not used in day today life as it is slow in reading and writing
Optical media
Since data stored digitally on a disk is read and written by laser beam, it is called
optical media. Optical media is commonly used to carry data and information and
there are several types.
Diagram
Solid State Devices Since these devices contain solid parts and does not contain
moving parts they are called Solid State Devices. They are used to read and write
data and information.
Flash drive
This has become a very popular secondary storage device due to its easy
portability and the ability to read and write data fast.
Secure Digital (SD) is a non-volatile memory card format developed by the SD
Card Association (SDA) for use in portable devices.
the method of connecting this to the computer is different and it is smaller in
physical size. This is used in digital cameras, mobile phones and computer
gaming devices.
01.What are the diffrences between primary and secondary memory.