BS2911 Week 1 1

Networking and the Internet (1)

Where the module fits in:» Mandatory module for IT and e-Commerce Pathways» Useful for any business that depends on technology

Goals of the Module» Build understanding of Computers and Networks» Prepare you to make decisions with IT implications

– e-Commerce, internal networking– Judgement is improved by understanding the issues

» Enable understanding of Computer press– So that you can stay current in fast-moving area

» Build practical skills with HTML and the Web

BS2911 Week 1 2

Hot Issues to be considered The Internet and Intranets

» Thin client computing» e-Commerce» “Web2”

Corporate networking» Inside and between enterprises

Operating system directions» Can Linux reduce dependency on Windows?» Does the mainframe still have a role?

Future of telephony» Convergence of voice and data; and cellular with WiFi» Voice over Internet Protocol (VoIP), Skype, etc.

BS2911 Week 1 3

Telling significant trends from hype

It’s not easy:» People once thought satellite was the way of the future…» ...and that the Network Computer would challenge Microsoft

(it didn’t, but the idea is being revived as Cloud computing)

Best approach is to learn the principles» Basic understanding of how computer works» Knowledge of Operating System fundamentals» Key elements of networking technology

If you look at the underlying problem, it’s easier to understand the solutions arrived at

BS2911 Week 1 4

Week 1 Agenda What do you know already?

Why does Networking matter?

Some thoughts about e-Business» Electronic Commerce» “dot.com” boom and bust in 2000 – and partial recovery

(now it’s just another channel to market for most firms)» The rest of e-Business

Hardware foundation – Computer architecture

Software» Operating Systems» File storage» Introduction to Networking

BS2911 Week 1 5

What is your current experience?

Know about» Creating web sites» ADSL» Indirect telephone services» Internals of computer» Local Area Networks (LAN)» Instant Messaging » Streaming audio and video» Voice over the Internet» B2C e-commerce» Internet banking» Data Encryption» Wireless technologies» Cellular technologies

Have already done/got/used» Web site creation » ADSL» VarTec, OneTel etc.» Computer upgrade» LAN Set up » MSN Messaging or equivalent» Internet radio or video» Conversation over Internet» Bought things on-line» Internet banking» Set up 128-bit encryption» WiFi or other wireless LAN» Data/photo over mobile phone

What else do we need to cover?

BS2911 Week 1 6

Why does Networking matter? Because business is about interactions between people:

» Stand-alone computers are only a small part of our world» Networking is prevalent within companies» Increasingly used in interactions between companies

Growth of high-capacity, long-distance networking» Distance ceasing to be important

(http://www.telecom-tariffs.co.uk )» Driving globalization of trade

Networking is an enormous business it its own right» Multi-billion mergers: Time-Warner/AOL, Skype/eBay» No sign that growth in traffic will decline…» …though the profits have largely evaporated

BS2911 Week 1 7

Business Implications

Investment: is it safe to invest in networking companies?» If you get it wrong, you’ll lose your shirt

or miss out on major growth opportunity

In your own enterprise, should you stick to vendors so big they are likely to survive?» Or prefer the more innovative and fleet of foot?» In any case, does big mean safe? Think of Enron, HBOS

Best approach is to:» Apply normal business principles» Use understanding of the underlying technology to decide

who to trust

BS2911 Week 1 8

e-Business

IBM’s term for a business making full use of IT Not just e-Commerce – includes any of:

» Electronic support for business processes, for example– Integrated manufacturing – Enterprise Resource Planning– Customer Relationship Management– Computer-aided telephony

» Communications for:– Internal activities such as e-mail and information sharing– Publicity and support– Supply-chain management– e-Commerce – B2B and B2C

BS2911 Week 1 9

Electronic Commerce Already a key part of industrial supply-chain

» Orders, bids, payment transferred between partner firms» Allows “Just in Time” logistics» Typically heavily coded information» Use of XML will enable growth of “open” B2B

Retail uses widespread; slightly limited by interfaces:» Great for commodities, where buying determined by price» Lack of “look and feel” limits range of goods » Attempts to provide more attractive images can lead to

intolerable response times, a killer on dial-up» Key issue is mapping customers’ paradigms to web-site» Must merge business data with web content to have

any chance of meeting user expectations

BS2911 Week 1 10

Forms of e-Commerce

B2C – Business to Consumer» Business operates computer, Customer is human user» Significant use for business customers – it’s still B2C» After 10 years growth, user population now extends to many

people in developed world

B2B – Business to Business» Heavy use in well-developed niches, usually proprietary

– EDI between companies with permanent relationship, Previously on private networks, now mainly over Internet

– BACS and other banking systems, including EFT» Open B2B, without need for proprietary network or software

– Relatively small coverage so far – most so-called B2B actually has a human user at the customer end

BS2911 Week 1 11

Growth Implications

B2C» Most G7 households now able to purchase on-line» Actual purchases low relative to customers’ total spending» Think of the concurrent users you’d get if they all piled on!

B2B» Open B2B development is very patchy» Transaction rate is not constrained by human think time» Only constraints are speed of partner computer and Internet

connections

Server reliability & scalability is going to be a key factor» Tilting balance from Windows to Solaris and z/OS

BS2911 Week 1 12

“Legacy” Applications

Most of world’s money transactions go via CICS/390» 30B transactions/day from 30M users – $300B/week» 5000 packages from 2000 vendors, plus bespoke

applications developed over 30 years» 950K programmers earn living from CICS

Most CICS applications are 3270 terminal based – how do they play on the Internet?

z/OS and CICS contain Web-server functionality» Easy to web-enable old and new applications » Underlying code remains unchanged (often COBOL)

z-Series scales from desk-side processor to parallel sysplex able to handle >250,000 concurrent users

2000figures

BS2911 Week 1 13

Other e-Business considerations

Not just a matter of electronic sales and purchases How do you milk the data you get?

» Enterprise Resource Planning – Integration of production and inputs with sales

» Customer relationship management (see BS3917)» Marketing information and exploiting it

Effect on economic balance of power» Large companies will need huge database processing» Can then get strong control on suppliers, and

understanding of existing customer base» Smaller enterprises can still “join” relatively cheaply to

exploit new markets missed by big boys» But cost of entry to e-commerce has been growing– why?

BS2911 Week 1 14

Any Computers Here?

When this hard-disk recorder downloads

new software, its user interface can

change

DVD recorder makes and

plays DVDs, with a fixed

user interface

DVD player with fixed user interface

BS2911 Week 1 15

What is a Computer? Full of electronics?

» But that’s true of a radio or television or video recorder Does complex things?

» Like a C17 musical clock or an automaton Does calculations?

» But a pocket calculator does that» And the WW2 code-cracking machines at Bletchley Park did

whole streams of calculations using electronics

All those devices do exactly what they were built to do:» Their capabilities are wired in, so if you want to do

something different, you need to tell them to (calculator) » or rebuild the device to do a different sequence of things

(Bletchley Park code machines)

BS2911 Week 1 16

Key features of a Computer

Computers are programmable» They contain memory into which you can load instructions

which they execute one after another» Change the contents of memory, you change what they do

Program can interact with the world, and take different actions depending on what happens» For example, cell-phone measures strength of signal, and

hunts for a new cell when it gets weak» Windows reacts to mouse-clicks and keyboard actions» We call its interactions “inputs” and “outputs”

Computer invented in 1935; nobody built one until 1948» That’s when the first memory technology arrived

BS2911 Week 1 17

Modern Computers

Contain microprocessors – chips containing circuits for calculations and for handling data» Now several million transistors etched on the chip» Some of them function as a clock to organize operations

Contain electronic memory to hold programs and data» These chips are much more repetitive than microprocessors

Have some mechanism for saving data from memory and getting it back (such as disk drives, SIM cards)

Interact with the world through input and output devices (sometimes called peripherals)

Also contain interrupt hardware to handle asynchronous events from outside (or inside)

BS2911 Week 1 18

Foundation for Networking

You have an understanding of basic computer architecture and networking from last year

We need to build on this in several ways:» pursue the idea of “encapsulation” of function into operating

systems» Plus how to do things concurrently» understand the factors that determine performance

First let’s revise basic hardware design» Some of this should be familiar from 14 months ago

BS2911 Week 1 19

Computer Architecture

ProcessorProcessorMemoryMemory

Disk StorageDisk StorageOther

long-term Storage

Other long-term Storage

Processor executes instructions from memory, and works on data in memory Other data flows through the bus

1234567890-=QWERTYUIOP[]#ASDFGHJKL;’ZXCVBNM,./

Input (Data)

Output (Information)Bus

BS2911 Week 1 21

Storage Hierarchy Cache on processor chip

» Very fast indeed, very expensive, rarely over 2MB» Allows actions to take place entirely on the chip» http://www.extremetech.com/article2/0,1697,1155325,00.asp

2nd-level cache» Very fast, less expensive, typically 2MB

Main memory» Fast: quoted speed <30nsec » Price down from £25/MB in 1996 to under 2p now

Magnetic Disk: non-volatile (unlike main memory)» Slower: 10msec access, longer if heads must move» Large and cheap; e.g. 750GB disk now under £50

sec msec µsec nsec

BS2911 Week 1 23

Operating Systems Though the processor is simple and serial, we want to

do more complex things, often several at once An operating system is a program that provides the

building blocks of complex systems» Some simply encapsulate function to save every application

from having to include a copy» Others handle specific hardware, presenting a generic

interface that hides behaviour unique to that hardware» Sometimes the interface is so generic that it has little to do

with the hardware – file structures are the best example Modern operating systems make it look as if the

computer is doing several things at the same time» Our operating system is Windows XP –

how many of you are now on Vista (bad luck) or W7?

BS2911 Week 1 25

Concurrent Operations

To give the appearance of doing several things at once:» OS must stay ready to accept work:

– keystrokes, mouse clicks, signals from modem, printer ready to receive another buffer of data

– These can interrupt a computation already being run» It then does a bit of the required work,» then goes back to an interrupted task, and so on.

We say the machine is doing things “concurrently” – they’re not simultaneous, but they look it!

The key is switching the CPU between logical processes» In theory, you could go round “polling” – high overhead» In practice, concurrency depends on hardware interrupts

BS2911 Week 1 26

Typical File Storage

PC disks are organized into “allocation units”» Identical blocks, addressed by number

Some of these are used to hold the actual data The others contain pointers to the data, and names so

you can refer to it – these are directories to the files A “folder” is a piece of data consisting of a directory,

so you can build a hierarchy in the file system Most modern computer systems work in this way,

including: DOS, Windows XP, NT, OS/2, Unix, VMS, VM DOS file identifier are made up of two pieces:

» a name of up to 8 characters, such as fred0516» a type (or extension) of up to 3 characters, such as doc

BS2911 Week 1 27

Files in Windows

Windows uses the file type to give short cuts to processing the file» In Windows 3.x, done by an “association” in WIN.INI» In Windows 9x, NT, 2000 & later, by Registry entries

For any file type, you can define “methods” (operations)» Most have an Open method (usual default for double-click,

though not for Word templates)» Other methods accessible by right-clicking the file ID

Files can now have “long names” – longer than 8+3» Stored in a separate place in the directory» 8+3 name generated to go in the “old” file ID position» You may sometimes see the 8+3 name on a diskette

BS2911 Week 1 28

This yearc:\mylets\2010\

Archives

c:\mylets\oldies\

My letters

c:\mylets\

My programs

c:\myprogs\

System files

c:\windows\system\

Windows

c:\windows\

Root Directory

C:\

Directory structure on Windows