Lecture 9: System Fundamentals Intro to IT COSC1078 Introduction to Information Technology Lecture 9 System Fundamentals James Harland

Lecture 9: Computer FundamentalsIntro to IT Introduction to IT 1-4 Introduction, Images, Audio, Video 5 Computer Fundamentals Assignment 1, WebLearn Test 1 Tuesday March 30 th, Wednesday March 31 st (no classes Thursday 1 st April, Tuesday 6 th April, Wednesday 7 th April) 6 Computer Fundamentals Tuesday April 13 th, Wednesday April 14th 7 Computer Fundamentals /Review/Catch Up 8 Operating Systems WebLearn Test 1 9 Operating Systems Assignment 2 10 Internet 11 Internet Security WebLearn Test 3 12 Future of ITAssignment 3, Peer and Self Assessment

Lecture 9: Computer FundamentalsIntro to IT Overview  Questions?  WebLearn Test 1  Assignment 1  Computer Fundamentals  Questions?

Lecture 9: Computer FundamentalsIntro to IT Web Test 1  Now Week 5 (this week)  Some quizzes (practice tests) available now  Rest & test available later this week  Content will be on weeks 2-4 Images Audio Video

Lecture 9: Computer FundamentalsIntro to IT Assignment 1  Due date is 9.00am on Monday 12 th April (1 st day of Week 6)  Can submit now if you wish …  Do submit something soon  Only PDFs for report

Lecture 9: Computer FundamentalsIntro to IT Introduction

Lecture 9: Computer FundamentalsIntro to IT Overview …

Lecture 2: Computer FundamentalsIntro to IT What do computers do?  Compute!  Input/Output  Processing  Memory

Lecture 2: Computer FundamentalsIntro to IT History ……  Babbage’s Difference Engine (1849)  Babbage’s Analytical Engine ( , never built)  Turing’s Universal Machine (1936, mathematical model)  Turing digital Boolean-logic multiplier (1937)  Colossus (1943, destroyed 1945)  ENIAC (1946)  Von Neumann architecture (c. 1945)  EDVAC (1949)

Lecture 1: IntroductionIntro to IT Overview “Thomas the Tank Engine”

Lecture 1: IntroductionIntro to IT Overview Video Audio Text Thumbnails

Lecture 9: Computer FundamentalsIntro to IT Memory via `Flip flops’ or and not

Lecture 9: Computer FundamentalsIntro to IT Memory via `Flip flops’ or and not

Lecture 9: Computer FundamentalsIntro to IT Memory via `Flip flops’  Can design other versions of flip-flops  Shows how circuits can be designed using AND, OR, NOT (NAND, NOR, XOR, …) in combinations (gates)  Hierarchy and abstraction  Shows how electric circuits can store values

Lecture 9: Computer FundamentalsIntro to IT Computer Memory Cells of 8 bits each (one byte) Most significant bit Least significant bit … … address

Lecture 9: Computer FundamentalsIntro to IT Random Access Memory (RAM) Random access means any cell can be accessed at any time (and in any order) Volatile – contents cleared when machine is switched off Very fast compared to other forms of memory DRAM: dynamic RAM (replenishes charges constantly) SDRAM: synchronous DRAM – faster still Often have small very fast caches and registers

Lecture 9: Computer FundamentalsIntro to IT Magnetic Disk  Thin spinning metal disk with magnetic coating  Each disk contains a number of circular tracks  Often several disks stacked on top of each other  Cylinders made up of tracks made up of sectors  Can have very large storage this way  Slow access time!

Lecture 9: Computer FundamentalsIntro to IT Magnetic Disk (Hard Disk) Seek time: move heads from one track to another Latency time: half time for complete disk rotation Access time: seek time + latency time Transfer rate: rate data can be read from disk `Typical’ Hard disk Seek time: 2ms to 15ms Latency time: 8ms to 20ms Transfer rate: 0.5 GB per second Sounds fast, but is actually quite slow …

Lecture 9: Computer FundamentalsIntro to IT Optical Disks (CDs, DVDs) Laser readers rather than magnetic ones Disks more error-tolerant than magnetic ones TypeFeaturesDateStorage CD“compact disk” MB DVDMultiple layers199515GB Blu-ray`blue laser’ (405 vs 650 nm) GB

Lecture 9: Computer FundamentalsIntro to IT Flash Drives Disks of all sorts are slow compared to other circuits Flash drives ‘write’ small electronic circuits Eventually decay after many changes of data Suitable for slow-changing data, not main memory Portable and much more resilient than disks

Lecture 9: Computer FundamentalsIntro to IT Older Storage Types Magnetic tape `Floppy’ disk (5.25’’ disk) 3.5’’ disk

Lecture 9: Computer FundamentalsIntro to IT Assignment 1  Use GIMP (or a similar tool) to perform some manipulations on an image  Address two issues in relation to this  Lab classes 2 and 3 based around GIMP  Main emphasis is on process, not result!  Is in the Learning Hub  SUBMIT VIA WEBLEARN SUBMIT IT! NOW!!

Lecture 9: Computer FundamentalsIntro to IT Conclusion  Web Test this week (week 5)  Do online quizzes later this week  Keep reading! (book particularly)