Lesson Objectives To understand the difference between RAM and ROM To be able to explain the need for ROM To be able to explain the purpose of RAM

Memory Recap 1 bit = ???? 1 byte = ??? bits 1 kb = ??? bytes 1 gb = ??? Kb 1mb = ???gb

Main Memory. Memory has increased hugely in the last 20 years. 1980 - 32kb of memory standard 2010 - 2gb of memory standard “640kb of memory is the limit - more than anyone will EVER need!” bill gates, 1981

R O M ead nly emory What does “Read Only” mean? When have you seen the term before? nly emory

How does a computer start? When the computer is first switched on ROM stores the instructions which it needs in order to “boot up”. ROM is a type of memory that is NON-VOLATILE. This means that any data which is saved to it is not lost when the computer is switched off.

ROM Because the data is “read only” it means that it can be read but cannot be changed by the user. The information on the ROM chip is often programmed by the manufacturer. It contains the Boot Program which Performs some basic checks Finds the operating system Hands over control to the operating system

How much ROM is needed? ROM does not need to contain very much data and is typically just 1 or 2MB in size Many devices, including music players, mobile phones and cameras need ROM to boot them up.

R A M andom ccess emory

What is RAM? Have you ever worked for an entire ICT lesson only for your computer to crash or be “accidentally” switched off, and you’ve lost all the work you were working on? That’s because it was stored in the RAM, and as soon as the computer is switched off it is emptied. It is VOLATILE

What is RAM? RAM stores the programs and data that the computer is currently working on The operating system will also be loaded into RAM in order to run.

Task 1 You are listening to some music while you are researching on the internet for information that you will copy and paste into a word processed document. Make a list of all of the things that might be stored in the RAM memory while you are doing this task The operating system for the computer Music player software The music file you are listening to The web browser software The website you are looking at The word processor software The word-processed file Anti-virus software Etc

Computers need a lot of RAM to deal with the large amounts of data they need to make available at any one time for the CPU. Adding more RAM to a computer will improve the performance of that computer by making more memory available for direct access from the CPU. A typical laptop will have 4 GB of RAM or more available.

Large Hadron Collider Approximately 600 million times per second, particles collide within the Large Hadron Collider. This produces more than 15 petabytes of data a year! At the main processing site in Switzerland they have 30 petabytes of RAM and 65, 000 cores These super computers have 30 millions times the memory than a normal PC

RAM and computer performance What happens when you try to run lots of programs, music, video or games at the same time? The computer crashes This is because there is not enough RAM to complete all of those tasks. The more RAM you have, the more tasks you can complete at one time.

Task 2: Complete the table below. RAM ROM Contents Volatile? Size Can contents be changed?

Task 2: Complete the table below. RAM ROM Contents Operating system, programs and data in use by the CPU The boot program used to start and set up the computer Volatile? Yes No Size Typically quite large, e.g. 8GB. More RAM enables the computer to work on more things at once Usually quite small just to store the boot program, 1 or 2 MB Can contents be changed? Yes, contents change all the time while the computer is running Not normally but can be changed by a special ‘flashing’ operation

Task 3: In your exam you will need to be able to explain how RAM can effect performance, and suggest solutions. Complete the exam style question

Question 1 Give a suitable reason why Pardeep’s computer might be running slowly “Pardeep’s computer might be running slowly because it doesn’t have sufficient RAM (1 mark) to deal with all of the applications and data that he has open at the same time (1 mark).”

Question 2: Suggest a related solution to help Pardeep improve the performance of his computer (2 marks) “The best solution to overcoming this problem is to add extra RAM chips (1 mark). This will allow Pardeep to increase the number of programs or amount of data that he is able to use at the same time (1 mark)” Or “Pardeep could try running less programs at one time, closing programs that he is not using. (1 mark). This will mean there is less pressure on the RAM and his computer will run quicker (1 mark)”