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IT Groundwork ICS3UC - Unit 1 Hardware. Overview of Computer System.

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Presentation on theme: "IT Groundwork ICS3UC - Unit 1 Hardware. Overview of Computer System."— Presentation transcript:

1 IT Groundwork ICS3UC - Unit 1 Hardware

2 Overview of Computer System

3 Input/Output Devices (I/O) Examples of input devices: – keyboard – scanner – microphone Examples of output devices: – monitor – printer – speakers

4 Memory Computer memory consists of blocks of bits called words. Word sizes vary from computer to computer. Each word will hold either data or program instructions. RAM Random Access Memory - temporary ROM Read Only Memory – permanent, cannot be changed

5 Storage Hard Drive Floppy Drives CD-ROM DVD R-CD-ROM RW-CD-ROM Zip Drives

6 The CPU contains a Control Unit, Arithmetic Logic Unit (ALU) and a small number of memory locations called Registers. Different registers perform different tasks such: as manipulating data, keeping track of the results of decision making operations, and pointing to the next instruction to be executed Central Processing Unit

7 Central Processing Unit Memory RAM ROM Input Devices Output Devices Secondary Storage Devices Computer Hardware Functions

8 Bits & Bytes Bit - Binary Digit; represented by a 1 or a 0 – abbreviated as b Byte - a fixed-size collection of bits – technically, minimum number of bits required to represent a character – generally, 8 bits – usually, the smallest addressable unit of storage – abbreviated as B

9 Computer Units Quantity/size/capacity – Kilo byte -- KB one KB is 1024 bytes (2 10 ) – Mega byte -- MB one MB is 1024KB = 1024x1024 bytes (2 20 ) e.g., 4096KB = 4MB – Giga byte -- GB one GB is 1024MB = 1024x1024x1024 bytes (2 30 ) – Tera byte -- TB one TB is 1024GB = 1024x1024x1024x1024 (2 40 )

10 Some Standard Contexts Memory = MB, megabytes Disk storage = Gigabytes CPU clock speeds = MHz (now GHz) Memory access times, = nanoseconds billionth CPU cycle time CPU switching times = picoseconds trillionth Disk access times = milliseconds


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