How many computers did you use today?
You woke up with your phone. You took a bus with a card reader. You warmed food in a microwave. You opened a website.
The phone, the card reader, the microwave and the web server are all computers. You used four this morning, and only one of them looks like a computer.
Computers come in different types. Each type is built for a different job.
Key words
| Word | What it means | Example |
|---|---|---|
| Personal computer | A computer made for one person at a time, such as a laptop or a desktop. | A college laptop |
| Mobile device | A small computer you carry, with a battery and a touch screen. | A smartphone |
| Server | A computer that gives a service to other computers. | A web server |
| Embedded device | A small computer built inside another machine to do one job. | A microwave |
| Request | A question that one computer sends to another. | Please send me this web page |
| Battery | Stored power. It lets a device work away from a plug. | The battery in a phone |
The cells students fill in are left blank in this preview.
The four types side by side
| Type | Main job | Features | Example |
|---|---|---|---|
| Personal computer | Everyday work, study and games | Keyboard, mouse, big screen. A desktop is easy to upgrade. | Laptop |
| Mobile device | Calls, messages, maps, photos | Small, battery power, touch screen, always connected | Smartphone |
| Server | Gives a service to other computers | Very powerful, runs all day, many users at once, often has no screen | Web server |
| Embedded device | One fixed job inside a machine | Tiny, uses little power, no screen or a very small one, cheap | Microwave |
The cells students fill in are left blank in this preview.
Quick check
Have a go
Quick check
5 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Servers: computers that serve
A server waits for a request. A request is a question from another computer.
You type a web address. Your computer asks a web server for the page. The server sends it back. One server can answer thousands of people each minute. So it needs a strong processor (the part that does the work), a lot of memory and fast storage.
Embedded devices: computers you do not see
An embedded device is a small computer built into a machine. It has one job. A car holds dozens of them. One watches the brakes. One controls the windows.
The job is fixed, so the computer can be small and cheap, and it uses little power. Most embedded devices have no keyboard and no screen.
Try it: count your computers
my_computers = ["phone", "laptop", "bus card reader", "microwave", "games console"]
print("I used", len(my_computers), "computers today.")
for one in my_computers:
print(" -", one)
# Add two more computers you used today. Then press Run again.