LEARNING OBJECTIVES
Design a wix page template for Computer Science.
SUCCESS CRITERIA
Success Criteria:
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Define the purpose of the RAM and ROM and how they differ.
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Identify the difference between Primary and secondary storage.
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Define the term Virtual memory and why we used it.
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To be able to calculate the size of a file.
1.2 Memory
Learners should have studied the following:
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the difference between RAM and ROM
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the purpose of ROM in a computer system
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the purpose of RAM in a computer system
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the need for virtual memory
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flash memory.
EXAM TIP
People often interchange “memory” with “storage,” and vice-versa.
EXAM TIP
People often interchange “memory” with “storage,” and vice-versa.
did you know?
In 1947 Freddie Williams, working at Manchester University, devised a method for storing data as charged spots on the surface of a cathode-ray tube.
HOME LEARNING
MEMORY - LESSON 1
STARTER
KEYWORDS
Byte: eight bites; symbol B
Bit: binary digit 0 or 1;
symbol b.
Kilobyte: 1024 Bytes.
Volatile memory: loses data when there is no power.
Non-Volatile memory: retains data even when the power is turned off.
Post its
Choose RAM or ROM.
Write down at least 3 things you know about your chosen one.
Be ready to share your notes with the rest of the class in 5 min.
Computers require input hardware, processing hardware and output hardware. The hardware that defines a computer is the CPU and memory. Without these a computer could not function.
In the 1940’s when work on the computer started to take shape memory was very limited, often just a few Bytes and quite unreliable. Originally Data was stored using vacuum tube with each vacuum tube Able to store a single Bit (0 OR 1).
What is memory?
Data and programs needs to be stored in a computer system. The technology used called memory. Memory is divided into two types main memory and secondary storage .
Main memory is any memory that is access directly by the CPU. examples of the memory are
1.RAM (Random access memory)
2.Rom (read only memory)
Registers and internal cache are not considered as main memory as they reside to the CPU.
Hard disk and flash memory are considered as secondary storage. when CPU needs to use programs or data from the hard disk, they are first loaded into the main memory and then accessed from there.
Main memory can hold more than one program at the time, which makes it quicker for the CPU to swap between tasks.
Secondary storage is used for holding large amount of data and programs long -time but, but it only can be accessed relatively slowly.
INPUT
Read Only Memory (ROM)
ROM is a special kind of memory which stores the instructions which the computer uses when it 'boots up' - the BIOS (basic input output system). It allows it to check the type of hard disk installed, the amount of RAM installed the type of CPU being used etc.
ROM is a type of memory that retains its data even without power, so even when the computer is switched off, it will not lose the data which is saved onto it.
This kind of memory is needed because the computer must be able to obtain instructions from the moment it is switched on and it must know some basic things about the hardware that makes up the machine i.e. 'its configuration settings'.
Because the data is 'read only', it can be read but not changed by the user.
The ROM chip (although there may be more than one) is attached to the Motherboard.
The key thing to remember about ROM is that the data is not erased when the computer is switched off - the data is stored permanently. This type of memory is also called 'non volatile memory‘.
http://www.cambridgegcsecomputing.org/modules_lms/more
id_module=132628&id_course=134785&id_course_inquiry=&id_section=4039
Random Access Memory (RAM)
How many times have you worked for a whole lesson on something
which you were just about to save but then the computer crashed or
your mate 'accidentally' switched it off. When you rebooted and
logged back in, your work was gone forever.
This was because your work was stored in RAM, or 'temporary memory'. It was fairly safe there while the computer was working, but as soon as it was switched off, everything disappeared. This type of memory known as 'volatile memory'.
As well as storing the data you are working on, RAM also stores the modules that are needed to make your applications work. For example, when you open up your favourite word processing application, you may notice a short delay while the modules are loaded into RAM.
RAM is also needed so that you can have multiple windows open and so that you can switch between them.
However, if you have a lot of windows, documents and different applications running, you might find that your system starts to slow down. This is because your RAM is full up and it is having to decide what it needs to keep stored in memory at any given time and what it can release. If this happens to you a lot, you can improve the performance of your computer by installing extra RAM.
Most computers are typically sold with 1-4 GB of RAM installed.
Why do we need RAM?
Make notes
taSK 1
Match the correct functions for ROM and RAM.
TASK 2
Research the two types f RAM.
1.Dynamic RAM
2.Static RAM
TASK 4
Answer the following questions
1. State two functions of the BIOS.
2. Explain why the BIOS is stored in ROM instead of RAM.
TASK 3
Research the two types of RAM.
1.Dynamic RAM
2.Static RAM
TASK 2
Answer the following questions
1. Describe the difference between ROM and RAM?
2. When a computer is working, what is stored in RAM?
3. How does a computer use ROM?