Agenda Data Storage Database Management Systems Chapter 3 AOL Time-Warner Case
Data Storage Character Sets File Systems RAID File Storage Network File Systems Internet File Systems Storage Area Networks Network Attached Storage
Character Sets Representations of all text elements ASCII – Standard for PC’s, unix EBCDIC – The Mainframe alternative UNICODE – The web standard
File System Concepts and Issues File Allocation Table (FAT) / Volume Table of Contents (VTOC) Disk Sectors and Fragmentation Hierarchical File Systems Journaled vs raw file systems Disk Caching Mechanism Reason
Shared Storage Arrays Vendors: StorTek, IBM, EMC, … Goals: Management, flexibility Issues: Connectivity Virtual Storage
RAID (redundant array of independent disks) RAID 0 (Striping) –Consecutive blocks written to different disks –Performance gain only RAID 1 (Mirroring) –Writes all data to two separate drives –Reads from either for performance RAID 5 (Parity disk) –Any disk can fail without loss –Parity drive allows failed drive to be recreated
RAID 0 Diagram (Striping) Disk A Disk B Disk C Disk D Block 1 Block 2 Block 3 Block 4
RAID 1 Diagram (Mirroring) Disk A Disk B Block 1
RAID 5 Diagram (Even Parity) Disk A Storage Mechanism Disk B Disk C Disk D Parity Disk
Remote Data Network File Systems Internet File Systems Considerations: Performance Security “Roaming”
Storage Area Networks “Fabric” connectivity between servers and storage Access is still via “owning” server Used for structured data, data associated with specific application
“Fabric” Storage Area Network Server 1Server 2Server 3Server 4 SAN Side 1 SAN Side 2 Disk A Disk B Disk C Disk D Disk E
Network-Attached Storage File systems accessed via internet Appear as remote drives Used for unstructured data (e.g. documents), data used by many servers
NAS Diagram Network Server NAS
Database Management Systems Programs that manage databases Link different data structures logically Single version of all rules –Structures –Domains –Access Data reliability enhancements –Locking –Logging –Journaling Standard “API” –SQL: Structured Query Language Granular Access
Relational DBMS Concepts Value-based relations Joins Tables and Views Set Processing
Text Chapter 3: Themes Networking the Business –“Act big and small” –“Fast firms” Blueprint –Operating Processes –Managing and learning Value Networks –Virtual Integration –Cost/Risk Analysis –Market Relationships –Proprietary processes vs Virtual Integration
Text Chapter 3: Discussion What systems enable “company- smart” decisions When does “scope of control” effect growing firms
Case: AOL Time Warner Is the company successful? Explain stock drop vs other Internet “servicers” What (if any) “rules” were broken?