ISM 50 Business Information Systems Lecture 10 Instructor John Musacchio UC Santa Cruz October 25 2010 Representation needs to be standardized Information Information If the representation is not standardized the information is garbled Data Communicate data to another user or organization Data Slide adapted from slides for Understanding Networked Applications By David G Messerschmitt Copyright 2000 See copyright notice Regeneration Make a precise copy of the data copy bit by bit If you know the representation this is equivalent to making a precise copy of the information Each such precise copy is called a generation process is called regeneration Slide adapted from slides for Understanding Networked Applications By David G Messerschmitt Copyright 2000 See copyright notice Replication of information 0101011010111 1010110110100 1011000000110 1010111101110 1010101110101 0101011010111 1010110110100 1011000000110 1010112101110 1010101110101 0101011010111 1010110110100 1011000000110 1010111101110 1010101110101 0101011010111 1010110110100 0101011010111 1011000000110 1010110110100 1010112101110 1011000000110 1010101110101 1010111101110 1010101110101 0101011010111 1010110110100 1011000000110 0101011010111 1010112101110 1010110110100 1010101110101 1011000000110 1010111101110 1010101110101 0101011010111 1010110110100 1011000000110 1010112101110 1010101110101 Anything that can be regenerated can be replicated any number of times This is a blessing and a curse Analog information cannot be regenerated Analog information can be copied but not regenerated We will never know exactly what the original of this Rembrandt looked like Discrete information can be regenerated Regeneration can preserve data but not its original physical form Regeneration is possible for information represented digitally which is tolerant of physical deterioration 0 noise 0 1 noise 1 Replication of information requires knowledge of representation Information Information Replication of information also presumes knowledge of its representation Replication Data Data Replication preserves the integrity of the data but that is not sufficient Slide adapted from slides for Understanding Networked Applications By David G Messerschmitt Copyright 2000 See copyright notice Implications Digitally represented information can be preserved over time or distance digital library digital telephony Replication of data is easy and cheap Implications con t Replication requires knowledge of the structure and interpretation Standardization or some other means Extreme supply economies of scale You can give away or sell and still retain Piracy relatively easy Architecture by David G Messerschmitt Copyright notice Copyright David G Messerschmitt 2000 This material may be used copied and distributed freely for educational purposes as long as this copyright notice remains attached It cannot be used for any commercial purpose without the written permission of the author Slide adapted from slides for Understanding Networked Applications By David G Messerschmitt Copyright 2000 See copyright notice What is Architecture How do you architect a solution Architecture A system is decomposed into interacting subsystems Each subsystem may have a similar internal decomposition Slide adapted from slides for Understanding Networked Applications By David G Messerschmitt Copyright 2000 See copyright notice Three elements of architecture Decomposition Organization Functionality Responsibility Interaction Cooperation Slide adapted from slides for Understanding Networked Applications By David G Messerschmitt Copyright 2000 See copyright notice System examples Let s quickly look at some system decomposition examples Quick tour of information technology systems Time sharing Point to point wire no network ASCII terminal no graphics Mainframe database and application server Two tier client server Local area network Server Mainframe Three tier client server Application server Client Enterprise data server System integration Architecture subsystem implementation system integration Bring together subsystems and make them cooperate properly Rrequires testing May require modifications to architecture and or subsystem implementation Emergence Emergence capabilities that arise purely from that interaction desired or not e g airplane flies but subsystems can t Why system decomposition Divide and conquer approach to containing complexity Reuse Consonant with industry structure unless system is to be supplied by one company Others Networked computing infrastructure by David G Messerschmitt Layering Elaboration or specialization Services Existing layers Example of Layering networking Application Messages Transport Packets Network Frames Link Bits Physical Signals Software Layering Application Middleware Operating System Operating system functions Graphical user interface client only Hide details of equipment from the application Multitasking Resource management Processing memory storage etc etc Middleware Functions Capabilities that can be shared by many applications but that is not part of OS Hide details of OS from application Example Database Management System DBMS Java Virtual Machine More purposes we ll talk about later What s a database Database File with specified structure Example relational table A Database Year 2002 2002 2002 2002 2002 2002 2002 2002 2002 2003 2003 2003 2003 2003 2003 2003 2003 2003 City Oakley Oakley Oakland Oakland Berkeley Berkeley Berkeley Albany Albany Oakley Oakley Oakland Oakland Berkeley Berkeley Berkeley Albany Albany Accommodation Bed Breakfast Resort Bed Breakfast Resort Camping Bed Breakfast Resort Camping Bed Breakfast Bed Breakfast Resort Bed Breakfast Resort Camping Bed Breakfast Resort Camping Bed Breakfast Tourists 14 190 340 230 120000 3450 390800 8790 3240 55 320 280 210 115800 4560 419000 7650 6750 Storage Middleware example DBMS Database Management System DBMS Manage Multiple databases Allow multiple applications to access common databases Implement standard data lookup query functions The Internet by David G Messerschmitt Intranet Private internet intranet Often connected to Internet Global Internet Firewall creates a protected enclave Router Firewall What is the Internet An internet is a network of networks Interconnect standard for LAN s MAN s and WAN s Internet the major global internet A private internet is called an intranet Client Server Computing Client Server Example Client Server I want to see www google com html head meta