COMP3370-01-introduction-systems-and-abstractions.pptx

The UK’s European university COMPUTERS AND THE CLOUD/ LECTURE 1 COMP3370/COMP5810 Module Overview, Systems, and Abstractions  Agenda Lecture 1 Overview of COMP3370/COMP5810 What are you going to learn? 2  Computers and the Cloud A...

The UK’s European university COMPUTERS AND THE CLOUD/ LECTURE 1 COMP3370/COMP5810 Module Overview, Systems, and Abstractions  Agenda Lecture 1 Overview of COMP3370/COMP5810 What are you going to learn? 2  Computers and the Cloud An introduction to Computer Systems – As COMP3370 and COMP5810 You’ll be able to – Describe architecture of a distributed application – Install and configure such applications – Explain the underlying infrastructure – Assess economic, security, and ethical tradeoffs 3 Computers and the Cloud Teaching Team Matteo Migliavacca David Castro-Perez m.migliavacca@kent. d.castro-perez@kent. ac.uk ac.uk Office: Kennedy 207 4  Module Map Practical Foundational Algorithms Aspects Technology Challenges of Overview Distribution Distributed Distributed Systems Algorithms Operating Systems Distributed A Cloud Data Structures Application Network Protocols Computing Distributed File and Society Systems Virtualization Building on Network Docker Technology Parallelization Cloud Computing and Software Map Reduce Development 5  Module Map Practical Foundational Algorithms Aspects Technology Challenges of Distribution Overview Distributed Distributed Systems Algorithms Operating Systems Distributed A Cloud Data Structures Application Network Protocols Computing Distributed File and Society Systems Virtualization Building on Network Docker Technology Parallelization Cloud Computing and Software Map Reduce Development 6  Lectures Thursdays 15:00 and Fridays 10:00 o Woolf Lecture Theatre o Links on Moodle A marked Moodle quiz every week o All quizzes together: 10% of your mark! o Deadline: each Wednesday 23:55 (UK time) 7  Moodle: Finding the Lecture Material Moodle – Slides – Lecture recordings – Quizzes – Assessments – Reading list https://moodle.kent.ac.uk/2023/course/view.php?id= 253​ 8 Assessments Overview (COMP3370 and COMP5810) Assignment 1: 20% Assignment 2: 20% Quiz 1: 5% – Quizzes 1st half of term Quiz 2: 5% – Quizzes 2nd half of term Exam: 50% 9  Study Effort Lectures 22 hours Private Study 128 hours Assignment 1 20 hours Assignment 2 20 hours Quiz 1 5 hours Quiz 2 5 hours Revising, Reading, Exam prep ±78 hours COMP5810 has cl a s s e s w i t h additional m a t er i a l 10  What is a System? 11  A System (definition) A set of things working together as parts of a mechanism or an interconnecting network; a complex whole. 12 Examples for Systems National Health Service a rather complex system, with a large number of parts 13 Examples for Systems t h e s y s t e m i s Note: complex, Railway System in England e t a i l y d us where wes w e m a y mangetting many elements, hopefully 14 Abstraction and Systems “abstracting” from concrete details m p u t e r S c i e n c e , In Co e’ll often be Systems can be very complex, w we want to focus on the essence, or t h e “eco n om i c a l w i t h relevant bits 15 Use of Abstraction Thinking in Applicati Layers on Focus on task at hand Operati Rely on layer ng System directly below Hide details of HardwaLargelower Sy s t e ms ar e layers re System built solving one p rob l e m a t a t i m e 16  Let’s talk about a Cloud System A practical system you may know: WhatsApp 17 How does a message get from one user to another? 18 Sending a Message A WhatsApp server, in the Cloud, i.e., on the Internet 19  How many computers are involved? 3 7 10s 100 1000 s s20 How does a message get to WhatsApp? JISC WiFi Network Network Network Server Interchan Provider ge m i c a l w i t h t h e Being “econo truth”: a r e a t l e a s t 2 0 There 21  How do all these Computers communicate? 22  They use Protocols What’s a Protocol? (let’s check the dictionary) 23  Protocols 1. The official procedure or system of rules governing affairs of state or diplomatic occasions. 2. A set of rules governing the exchange or transmission of data between devices. 24  An Example of Social Protocol: How to write an email? Chose a subject meaningful to recipient. Give Name the sufficient recipient. context Always! Sign with your Keep the name, so main bit g e n e r a l l recipient knows e s fo r Ru how to address concise. o h e l p you. u c t u r e , t st r a t i on n i c ommu 25  Technical Protocols Abstractions make Problems Solvable XMPP Applicatio HTTP ns TCP Data Transport IP 802.11 Hardware MAC / 802.11 Physics a,b,g,n Each Layer has a specific responsibility and solves a problem. 26  XMPP: Extensible Messaging and Presence Protocol XMPP Defines how to exchange messages between client and server A text-based nthe L e v e l : Hey, can I get thelilink p c a t i o to article? Ap f u s e r s , s s i n g o ad dr e s e r v e r s t e a d o f i ns 27  IP: Internet Protocol Defines how to exchange data packets between internet addresses Bit 0 31 Version Length Version 4 182 byte Source Address 192.0.0.4 Destination Address 157.240.1.53 d d r e s s i n a l i fi meptwork Lee v e l : Hey, could I've a link to the SiN article? u d i n g a n l d ! v e r s , i n c of s e r a n d a i n g l i n e ” “open l i n e” 28 How does a message get to WhatsApp? JISC WiFi Network Network Network Server Interchan Provider Version 4 182ge byte 192.0.0.4 This is the 157.240.1.53 packet of bits e k s Hey, could I've a link to the article? In C om i n g W e 29  Hundreds of computers are involved in exchanging a message Can we make them “visible”? 3 7 10s 100 1000 s s 30  How to know the computers involved to send a message? Can we identify open network n the n ’t b e i connections? a n d s w o n c c o m m i fi c t o a S p e c i fi re s p e c h e y a e x a m , a s t r a Yes! t i n g s y s t e m. a s m ay ope h - le v e l i d e t s & h i g c o n c e p n e d. Th e e e xam i b Command Line/Terminal: to execute commands (programs), an interactive way of “programming” 31 Concept Command s Line vs. Graphical User Interface Graphical User Interfaces – Made for specific purpose – Often fixed, limited adaptability/combinability Command Line – Many special-purpose tools – More complicated, but easier to adapt and combine 32  First step: Open Connections of WhatsApp Using lsof –i we get a list of internet connections lsof is the command -i is a parameter to show connections lsof -h shows a help 33  First step: Open Connections of WhatsApp Using lsof –i we get a list of internet Applicat connections ion Protoc ol Sender & Receiver Address 34  First step: Open Connections of WhatsApp WhatsApp … TCP 192.168.1.65:59351->whatsapp- cdn-shv-01-lhr8.fbcdn.net:https (ESTABLISHED) WhatsApp is using the highlighted server to send messages to. 35  Second step: Find computers in- between Using the traceroute command traceroute shows the path of network packets to destination 36  Second step: Find computers in- between Using the traceroute command Sometimes, there are multiple routes 15 hops to the receiver server 37  Hundreds of computers are involved in exchanging a message 3 7 10s se 100 r e a l c om1000 p u t e r s ? A r e t ho And how d so w e m asn a g e ose? 38 The Cloud Software Stack Applicati Applicati Applicati Applicat on on on ion Containers Containers Operating Operating System System Virtual Machine Virtual Machine Hardware System 39  The Cloud Software Stack Built from Virtualization Layers Applicati Provides some desired on functionality, usually to a user Contain Isolate applications, their ers libraries, and dependencies Operati Manage hardware, and ng provide common services: System drivers, file systems, scheduling, … Virtual Share computing/storage Machin e between multiple tenants Hardwa Provides computing re and storage capacities System i l s : i n a b ou t 4 Deta 40 LECTURE WRAP UP 41  Wrap Up Important Terms and Concepts Systems Abstraction Application Operating System Hardware System Protocols Layers 42 THE UK’S EUROPEAN UNIVERSITY www.kent.ac.uk