standard grade computing low level machine chapter 21

Standard Grade Computing

LOW LEVEL MACHINE

CHAPTER 21


Input Process Output

Task Input Process OutputMaking

toastBread &

electricityHeat from

grilltoast

Foundation




toastBread &


grilltoast

Boiling a kettle

Water & electricity

Heat Boiling water

Foundation




toastBread &


grilltoast

Boiling a kettle

Water & electricity

Heat Boiling water

Washing clothes

Clothes, soap, water

Washing Clean clothes

Foundation




toastBread &


grilltoast

Boiling a kettle

Water & electricity

Heat Boiling water

Washing clothes

Clothes, soap, water

Washing Clean clothes

Doing homewor

k

Questions & text book

Reading & thinking

Answers

Foundation


DATA STORAGE UNITS

Bit: Binary Digit i.e. 0 or 1Byte: 8 bits e.g. 0110 1100Kilobyte (Kb): 1024 bytesMegabyte (Mb): 1024Kb (= 1024 x 1024 = 1

048 576 bytes)Gigabyte (Gb): 1024Mb (= 1024 x 1024 x

1024 = 1 073 741 824 bytes)Terabyte (Tb): 1024Gb (= 1 099 511 627

776 bytes)

Foundation

The main memory size of a computer is measured in megabytes or gigabytes. Extra memory can be bought and added to allow greater data storage.


Data RepresentationMachine Code: is understood by computers and uses binary 0 or 1.

NUMBERS are represented using binary (>0)

General

128

64 32 16 8 4 2 1

24 0 0 0 1 1 0 0 0


Data Representation

128

64 32 16 8 4 2 1

24 0 0 0 1 1 0 0 0

59 0 0 1 1 1 0 1 1

General


Data Representation

128

64 32 16 8 4 2 1

24 0 0 0 1 1 0 0 0

59 0 0 1 1 1 0 1 1

94 0 1 0 1 1 1 1 0

General


Data Representation

128

64 32 16 8 4 2 1

24 0 0 0 1 1 0 0 0

59 0 0 1 1 1 0 1 1

94 0 1 0 1 1 1 1 0

157

1 0 0 1 1 1 0 1

General


Data Representation

TEXT (ASCII)American Standard Code for Information Interchange Each keyboard character is represented by a unique binary codeAn 8 bit code is used e.g. A = 65 = 0100 0001Understood by different text applications.Allows different computer systems to communicate successfully.

General


Data Representation

Bit Mapped Graphics (B&W)

• Screen contains pixels• Pixel either ON or OFF• Coded using binary• The example uses 8

bytes of storage i.e. 8 x 8 bits

• Increasing the resolution means more pixels

1 0 0 0 0 0 0 10 1 0 0 0 0 1 00 0 1 0 0 1 0 00 0 0 1 1 0 0 00 0 0 1 1 0 0 00 0 1 0 0 1 0 00 1 0 0 0 0 1 01 0 0 0 0 0 0 1

General


Storage Requirements

Bit Mapped CalculationPixels = 2500 x 1000 = 2 500 000

pixels1 pixel uses 1 bit of storage.

= 2 500 000 bits /8 = 312500 bytes /1024 = 305 Kb

Credit

2500 pixels

1000 pixels


Processor Structure

The processor is made up of 3 parts •Control Unit: carries out program instructions in order•ALU: does calculations & logical operations (decisions)

•Registers: temporary memory locations

Credit

INPUT DEVICES

BACKING STORAGE DEVICES

OUTPUT DEVICES

MAIN MEMORY

PROCESSOR

COMPUTER SYSTEM


And finally

WORD: Number of bits sent to the processor during each fetch operation

ADDRESSABILITY: All data is placed in storage locations. Each location has a unique address

Credit


The End

Remember to view this slide OFTEN for good learning!

standard grade computing low level machine chapter 21

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