1. GCSE COMPUTER SCIENCE
Computers
1.2 Memory, Storage and Binary

2. Primary Memory RAM Random Access Memory ROM Read Only Memory
This is storage that the CPU (processor) can access directly. There are two types of primary memory:
RAM
Random Access Memory
ROM
Read Only Memory

3. Write out the following sentences about memory and fill in the blanks.
Activity 1
Fill in the blanks
Write out the following sentences about memory and fill in the blanks.
Primary memory is storage that the CPU can access __________. There are two main types of primary memory; __________ and __________ .

4. RAM
RAM is used to store the programs (applications) and data the computer is currently working on.
RAM is volatile, this means that it is wiped when the power is turned off.
The more RAM a computer has, the more programs and data it can run at the same time without it slowing down.

5. Activity 2
RAM is used to store the __________ and data the computer is currently working on. RAM is __________ , this means that it is wiped when the power is turned __________ . The more RAM a computer has, the more programs and data it can deal with at the same time without __________ down.

6. ROM
When a computer is turned on it needs to start fetching and executing instructions.
The problem is that RAM is blank when the computer is turned on.
The ROM contain the program that is used to start up the computer. This is known as the ‘boot’ program.
In many systems the boot program is known as the BIOS (Basic Input Output System).
The program inside the ROM is not easily changed or deleted.

7. Activity 3
ROM: When a computer is turned on it needs to start __________ and __________ instructions. The problem is the RAM is __________ when the computer is turned on. The ROM contains the program that is used to start-up the computer. This is called the __________ program. In many systems the boot program is known as the __________ (Basic Input Output System). The program inside the ROM is not easily __________
or deleted.

8. Secondary Storage
These devices allow data to be stored when not in use by the CPU.
They are non-volatile so the data is not lost when the computer is turned off.
They also allow users to transfer data from one computer to another.
When data in secondary storage needs to be used, it needs to be transferred to the primary memory.

9. Example: Hard disk drive.
Internal and Removable
Internal
Internal storage devices are built into the computer. They are used to store the operating system, programs and files.
Example: Hard disk drive.
Removable
Refers to storage that can be taken away from the computer and used on another computer.
Sometimes the device itself is not removed from the computer, only the medium on which the data is stored is removed not the drive.
Example: CDs and DVDs

10. Activity 4
Fill in the blanks
Write out the following sentences about secondary storage and fill in the blanks.
Secondary Storage: These devices allow __________ to be stored when not in use by the CPU. They are __________ so the data is not lost when the computer is turned off. They also allow users to __________ data from one computer to another. When data in secondary storage needs to be used, it needs to be transferred from the __________ __________ .

11. Activity 5
Fill in the blanks
Write out the following sentences about storage and fill in the blanks.
Internal & Removable Storage: Internal storage devices are built into the __________ . They are used to __________ the operating system, programs and files. Refers to storage that can be taken away from the computer and used on __________ computer. Sometimes the device itself is not __________ from the computer, only the medium on which the data is stored (e.g. a CD) is removed not the drive.

12. Magnetic Storage Hard Disk Drive Floppy Disks
Feature a spinning disc and a moving head that can either magnetise or demagnetise any part of the disk.
1s are represented by the magnetised parts of the disc.
0s are represented by the demagnetised parts of the disc.
Hard Disk Drive
Floppy Disks

13. The data is stored on a reflective disk.
Optical Storage
The data is stored on a reflective disk.
0s are represented by altering parts of the disc so they don’t reflect a laser beam
1s are represented by parts that haven’t been altered and still reflect a beam.
CDs
DVDs
Blu-Rays

14. Solid State Storage Internal Drives Memory Sticks Memory Cards
The term solid-state refers to all devices that use flash memory.
They are ‘solid-state’ because they have no moving parts.
This is useful for portable devices that need to be carried around. They are also faster and more reliable.
Internal Drives
Memory Sticks
Memory Cards

15. Activity 6
Fill in the blanks
Write out the following sentences about magnetic storage and fill in the blanks.
Magnetic Storage: Feature a spinning __________ and a moving head that can either __________ or __________ any part of the disk. 1s are represented by the __________ parts of the disc. 0s are represented by the __________ parts of the disc.

16. Activity 7
Fill in the blanks
Write out the following sentences about optical storage and fill in the blanks.
Optical Storage: The data is stored on a __________ disk. 0s are represented by altering parts of the disc so they don’t reflect a __________ __________ . 1s are represented by parts that haven’t been altered and still __________ a laser beam.

17. Activity 8
Fill in the blanks
Write out the following sentences about solid state storage and fill in the blanks.
Solid-State Storage: The term solid-state refers to all devices that use __________ memory. They are ‘solid-state’ because they have no __________ parts. This is useful for __________ devices that need to be carried around. They are also faster and more reliable.

18. Binary
What is binary?

19. Humans use it because we have 10 fingers.
Denary
The denary number system (also known as decimal) uses 10 symbols (0-9) to represent numbers. It is a base-10 number system.
Humans use it because we have 10 fingers.

20. Circuits
Computers don’t have fingers, they have circuits. These circuits can be in one of two states, on or off. So they use a base-2 number system.
On = 1
Off = 0

21. Transistors
Transistors are switches that are used in digital circuits, in their off state they represent a 0 and in their on state they represent a 1.
Computers use combinations of millions or even billions of transistors to carry out instructions.

22. We need 8 volunteers to stand at the front facing the class.
Counting in Binary Part 1
We need 8 volunteers to stand at the front facing the class.
Each place in a binary number has a value. These go up in multiples of 2.
128 64 32 16 8 4 2 1
Sitting = 0
Standing = 1

23. This is how we represent the number 1 in binary.
Counting in Binary Part 2
This is how we represent the number 1 in binary.
Who needs to stand up?
128 64 32 16 8 4 2 1

24. 0 0 0 0 0 0 1 0 Counting in Binary Part 3 128 64 32 16 8 4 2 1
This is how we represent the number 2 in binary.
Who needs to show a number one and who need to show zeros?
128 64 32 16 8 4 2 1

25. How do we represent these numbers in binary?
Counting in Binary Part 4
How do we represent these numbers in binary? 65 92 21
129
254
255 58 5 17 72 63 7
167
150
256
128 64 32 16 8 4 2 1

26. Start by writing out the place values:
Denary to Binary 65
Start by writing out the place values:
128 64 32 16 8 4 2 1
Then write 1s underneath the place values that add up to the denary number.
As a class convert these numbers from denary to binary: a. 3 b. 46 c. 76
ACTIVITY

27. Start by writing out the place values:
Binary to Denary
Start by writing out the place values:
128 64 32 16 8 4 2 1
64+8+2=74
As a class convert these numbers from binary to denary: a b c
ACTIVITY

28. The design should take up a whole page.
Activity 9
Binary Task
You are going to write a guide in your book on how to convert between binary and denary and vice versa.
The guide should be written for someone who has never learnt binary before. For example, year 7 students.
It could use text, images and diagrams and should take up half a page in your exercise book.
The design should take up a whole page.