1ISM 50 - Business Information SystemsLecture 17Instructor: John MusacchioUC Santa CruzNovember 23, 20102Student Presentation3mySQLWhat does mySQL make?How Successful is mySQL?Visibility: Fortune magazine, more mentions on wwwReaction from giantsRevenue growth 2001 700k, 2002 6.2m, 2003 10mGood performance reviewsRecent SAP allianceBut Market share tiny:$10 million out of $10 billion market!Why Success?Good TechnologyLarge DBMS bloated with features most dont needInnovative OSS model4mySQLHow does OSS work?Two Types of License:GPLFreeNo SupportAny software that uses MySQL as a module must itself be made GPLCommercial LicenseSupportCould be distributed with non-open source software Not Free: MySQL: Classic $250, Pro $495 (for ~ 50 users)Compare to:MSFT $3150 single proc for 50 usersIBM $33000 single proc for 50 usersOracle $40000 single proc for 50 users5Aside: DBs in different software stacksOperating SystemMiddlewareApplicationMS Windows or other OSOracleor MySQL, IBM, etcSAPOr Oracle, Axtapa, etc.ERPSoftwareStackLinux or other OSMySQL or other DBApache Web ServerWebApplicationSoftwareStackProprietary Business LogicBankingSoftwareStackIBM z/OSor other OS GeneralSoftwareStackOracleor other DB ProprietaryBanking App.Which companies are competitors?Which are complimenters?Which are both!?6mySQLWhich segments of market is mySQL strong in?Large Companies or Small Companies?Web applications or Critical Enterprise data?Why would a major enterprise want to pay so much more for an Oracle or IBM DB?7My SQL: marketSmall 20% Medium 30% Large 50%Enterprise wide data 90%Web Sites 10%MicrosoftOracle IBMMy SQLReliabilityScalabilitySupportLongevityCostFigure Adapted from Teaching Note for MySQL Open Source Database, 6/1/04, Stanford GSB.How should mySQL grow in order to meet its stated goal of getting to $100 million In revenue?8My SQL: Growth Strategy- Lack of Brand identity in this segement- MySQL lacks the organization to offer support- Large enterprises have high switching costsSmall 20% Medium 30% Large 50%Enterprise wide data 90%Web Sites 10%MicrosoftOracle IBMMy SQLReliabilityScalabilitySupportLongevityCostFigure Adapted from Teaching Note for MySQL Open Source Database, 6/1/04, Stanford GSB.9My SQL: Growth Strategy- Not a big enough market to reach stated $100 million goal.Small 20% Medium 30% Large 50%Enterprise wide data 90%Web Sites 10%MicrosoftOracle IBMMy SQLReliabilityScalabilitySupportLongevityCostFigure Adapted from Teaching Note for MySQL Open Source Database, 6/1/04, Stanford GSB.Stay Put?10My SQL: Growth Strategy+ Many of these customers already using MySQL with websites+ Less emphasis on global organization+ Leverage SAP alliance- Up against Microsoft.Small 20% Medium 30% Large 50%Enterprise wide data 90%Web Sites 10%MicrosoftOracle IBMMy SQLReliabilityScalabilitySupportLongevityCostFigure Adapted from Teaching Note for MySQL Open Source Database, 6/1/04, Stanford GSB.Maybe?11My SQL: Growth Strategy+ builds on existing brand and strengths- Market not so bigSmall 20% Medium 30% Large 50%Enterprise wide data 90%Web Sites 10%MicrosoftOracle IBMMy SQLReliabilityScalabilitySupportLongevityCostFigure Adapted from Teaching Note for MySQL Open Source Database, 6/1/04, Stanford GSB.Maybe?12Networks13Network ArchitectureNetwork architectures are layeredEach layer uses the services of the layers belowTo offer more advanced services to layer aboveAllows layers to be designed independently We will talk about 3 layers nextPhysicalLinkNetwork14What are some examples of communications networks?Public Telephone NetworkInternetLANs (Local Area Networks)15What does a network do?1) Transport data from one host to another.16Physical Layer: Convey bits over a wireBits: 010110...TimeVoltage0101 10SenderReceiverWireTimeVoltage11 1000Noise17Physical layerOther schemes for mapping a bit sequence to a physical sequence are possible.These are called modulation schemes18Link LayerMake a Frame link out of a bit linkInstead of endless sequence of 1s and 0s, we want distinct packages of data that are separate from each otherSay we want to send 2 Frames with data01010101010111010 and 101010101011010Concatenate them and send them as a sequence?How can the receiver tell where the new frame begins?Solution: insert a special sequence at the start of frame: for example: 0111111019Link Layer (contd)Also does error detection/correctionInsert extra information the helps the receiver to determine if the data has been corrupted.Example: parity bitSender adds a 1 or zero to end of data so number of ones is always odd10011 or 10000If receiver counts an even number of ones, than it knows the data was corrupted.20More Link Layer.. -- EthernetWant to allow multiple hosts to share a linkHow do they avoid talking at the same time?Dont transmit if you hear another host transmittingIf there is a collision, stop wait a random amount of time, and try againThis is a Medium Access Control (MAC) ProtocolHost AHost B Host C Host D21Ethernet ContinuedHow do the hosts on this Ethernet identify each other?Each host (actually each interface) has a globally unique MAC addressCannot be changedHost AHost B Host C Host D22Ethernet HubHub broadcasts packets on a link to all othersAs if all hosts connected to single linkWe say it is a Single collision domainOnly one host can talk at a timeHost AHost B Host CHost DHUB23Ethernet SwitchIf switch knows where the destination isSwitch forwards an incoming frame to destination only.Otherwise, it broadcasts it to everyone.Thus, parallel conversations possible.Host AHost B Host CHost DSwitch24Network LayerA wants to send some data to CSuppose A knows Cs addressA sends a packet towards CA marks his packet with Cs Address (an IP Address)Host AHost BHost CHost DLink 1Link 2Link