This document provides an overview of how computers work. It explains that the CPU is like the computer's brain, receiving and carrying out instructions. Data is processed as binary digits (bits) that are grouped into bytes. Computers store data in RAM, ROM, and separate storage devices like hard drives. RAM is used for active programs and data, while information is saved to storage devices like hard drives for long-term storage when the computer is powered off. The document defines common units of digital storage like kilobytes, megabytes, gigabytes, and terabytes.

1. Week 1: Computer
Basics
Lesson 7: How Does My Computer
Work?

2. • When you shoot a basketball, your eyes, brain, and muscles
send many signals back and forth. When you use a
computer, you send signals to the computers CPU (Central
Processing Unit)., which is like the computer’s brain. A CPU,
or microprocessor, is a small chip that performs
calculations and carries out all the instructions you give to
your computer. Every time you press a key on the keyboard
or click the mouse, you give instructions to the CPU.

3. A faster CPU generally means that a computer can process more
data in less time. The process of receiving and carrying out
instructions is called a cycle. The speed of a CPU is measured in:
 Megahertz (MHz) –millions of cycles per second
 Gigahertz (GHz) – billions of cycles per second

4. Bits, Bytes, and Binary Numbers
• Computers can process only two numbers: 1 and 0. All data
a computer processes is turned into a string of 1s and 0s
called binary numbers.
• A bit is the smallest unit of information, always either a 1 or
a 0. Each letter, number, and symbol that we use in English is
represented by eight bits. Eight bits make a byte, the building
block for all information that flows through a computer. A
computer file can contain thousands, millions, or even billions
of bytes. A five-page research paper may use 40,000 bytes (or
40KB). A movie on a DVD holds around five billion bytes (or 5
GB).

5. Computer Memory and Storage
Basics
Computers process a lot of data, but what do they do with it?
They store it. Computers store data in three main places:
 Random-access memory (RAM)
 Read-only memory (ROM)
 On a separate storage device

6. Types of Computer Memory

7. When do I use RAM and ROM?
• Both RAM and ROM work together to keep your computer
running smoothly.
• When you turn the computer on and off, that is when ROM
is working. ROM tells your computer how to start up and tells
the operating system to start up.
• When you start and use software, you are using RAM. Once
the computer starts, RAM takes over. When the operating
system starts and you can see the desktop, you are using RAM.
The computer will access information stored in the RAM when
you start a software program like Microsoft Word.

8. How is information stored?
• We have all experienced that dreaded moment when we
forgot to save our work and we shut down the computer. Our
work is lost. This is because when you are working on
something, like typing a paper in Word, the data is stored in
RAM. And of course, when we shut down the computer,
everything in RAM is erased.
• Therefore, it is very important to save your work, and save
often. When you save a file, you move it from RAM to a
storage device, such as a hard drive, a server, or a disk. A
storage device is like your long-term memory, where you store
important information, like your home address or memories
of important events.

9. Types of Storage Devices

10. How big is a Terabyte?
• 1 Kilobyte (KB) = 1,000 bytes
• 1 Megabyte (MB) = 1,000 KB
• 1 Gigabyte (GB) = 1,000 MB
• 1 Terabyte (TB) = 1,000 GB