File Systems

• •File is uninterrupted, unstructured collection of information 
• •File operations: delete, catalog, create, rename, open, close, read, write, find, … 
• •Access methods: Algorithms to implement operations along with internal file organization 
• •Examples: File of Customers, File of Students; Access method: implementation of a set of operations on a file of students or customers. 
• File Management System Problems : 
• •Data redundancy 
• •Data Access: New request-new program 
• •Data is not isolated from the access implementation 
• •Concurrent program execution on the same file 
• •Difficulties with security enforcement 
• •Integrity issues . ize/ � 0 t � � ght:115%;font-family:"Times New Roman","serif"; mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-ansi-language: EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA'>

What Is Data?

•Different view points:
–A sequence of characters stored in computer memory or storage
–Interpreted sequence of characters stored in computer memory or storage
–Interpreted set of objects 

– Database supports a concurrent access to the data