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Session Objectives#4

MUST describe the differences between the main types of primary memory

SHOULD explain the role that primary memory plays in computer processing

COULD explain the function and purpose of the control unit, memory unit and ALU as individual parts of a computer

Create solutions to the Little Man Computer assignment

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Computer ProcessingSTARTER: GO FOR 5....

Try to list 5 factors which affect how a computer performs.

Ext: For each explain what affect it has and why.

1.Size of processor 2.Amount of Cache Memory3.Number of cores 4.Amount of RAM5.Transfer speed of data buses.BONUS:Amount of free Hard Disk space...If a computer is using all or it’s RAM it will use a section of hard disk as a supplement. This is called VIRTUAL MEMORY. However this is still slower than pure RAM.

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Primary Storage This is also known as Main Memory or Primary Storage.

INVESTIGATION (7 mins): Research what is known as the ‘bootstrap’ program of a computer. Take notes and prepare to explain where and how is stored in the computer and why it is so important.

This is the first instructions the CPU receives when a computer is turned on and is commonly called the BIOS (Basic Input Output System). It contains code which controls the basic hardware settings of a PC. It is mainly stored in ROM (Read Only Memory) which is NOT erased when power is turned off.

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MEMEMORY – Remember??To recap...There are 2 main categories of memory:

RAM – Random Access Memory This is volatile memory as it’s erasable (without power) but can be accessed quickly by the CPU.

ROM – Read Only MemoryThis is non volatile as the dataIs retained without power. ThereforeKnows how to start up (or boot) afterBeing turned off.

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4 Min Investigation

What type of memory is cache memory?

Are there any sub-divisions of memory? Create a table and note their characteristics.

HomeWork – Investigate SRAM and DRAM. What are their characteristics, differences and uses in terms of computer processing.

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The Fetch-Execute CycleThe CPU receives data and instructions in binary form. An instruction will have 2 parts – an instruction and possibly some data, a number or a memory location. The programs that the CPU needs to process are stored in main memory. The CPU simply fetches the next instruction it needs to process, decodes it and executes it before repeating the process.

The speed of this cycle is determined by an electronic Real Time Clock (RTC) chip. The computer synchronises all processes to this clock signal. The clock speed is measured in Hertz (Hz) or cycles per second. TASK: 500 Hz would be 500 cycles per second, how many could a 3GHz processor be capable of?

Fetch

DecodeExcecute

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Visit the following site and follow the simulations of the Fetch-Execute cycle using the Little Man Computer (LMC)http://www.cs.ru.nl/~erikpoll/III/dag4.html

This is an interpretation of how a processor handles machine code. TASK: Follow the instructions and make a note/diagram of where the Little Man goes to throughout the Fetch Execute Cycle. REMEMBER: Instructions are split into 2 parts, the instruction (+,-, x, store etc) and the data itself (or memory location/address of where the data to be used is stored)1) The Op Code (or Operation Code Field) is part of the binary code giving the instruction to be carried out i.e add or jump2) The Operand (Operand Field or address field) gives the address (memory location) where the data to be used in the operation is stored.

Machine Code with The Little Man Computer

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Little Man Code Library

CODE MEANING1ab Load2ab Store3ab Add4ab Subtract500 Input600 Output700 Stop800 Skip If Negative801 Skip If Zero802 If Skip Positive9AB Jump

Beware: the Little Man 0 is a positive number, so the instruction 802 is actually Skip if Non-negative.

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Little ManWhich parts of the processor does each LCM item belong to?

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System Block Diagram

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Little Man Machine Code TasksAssignments1. Create a simple that will add any 2 numbers and display the results.2. Create a simple programs that will calculate the perimeter of any rectangle.3. Create a program using the LMC to allow the input of 2 integer values and then order them to output the largest value first and then the smallestRGB conversion SW 4. Colors of a pixel on a color are often represented with three values (r, g, b) that the red, green and blue value display. Grayscale on a monochrome display are represented by only one gray value. Choose a program that adds three inputs and divide by three, and so rgb values to the grayscale.

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Flow Chart to LMC Assignment 1

Input A

Store A

Add BLoad A

Store B

Input B

Output Result

START

END

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Coded Solution to Assignment

00 500 01 299 02 50003 29804 19905 39806 600

INPUT A

STORE Value A at memory location (address 99)

INPUT B

LOAD A

ADD B

OUTPUT Result

STORE Value B at address 98

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Flow Chart Flow chart of solution to LMC Assignment 3