9.2 Access Methods

 

Sequential Access

read next

write next

reset

no read after last write

(rewrite)

Direct Access

read n

write n

position to n

read next

write next

rewrite n

n = relative block number

 

Sequential-access File

 

      

 

Simulation of Sequential Access on a Direct-access File

 

       

 

Example of Index and Relative Files

 

 

         

 

 

A Typical File-system Organization

 

 

          

 

 

 

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