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2. Physical
s
File
system
By
Priya.G

3. FILE SYSTEM
• resides on secondary storage (disks) Provide efficient and convenient
access to disk by allowing data to be :
WRITE
CREATE OPEN CLOSE DELETE
READ

4. STRUCTURE OF A FILE
PHYSICAL FILE SYSTEM
LOGICAL FILE SYSTEM
FILE ORGANIZATION MODULE
BASIC FILE SYSTEM
I/0 CONTROL
DEVICES

5. TYPES OF PHYSICAL FILE SYSTEM
PILE DIRECT FILE
SEQUENCIAL FILE INDEXED FILE

6. THE PILE
• Datas are collected in the order they arrive.
• Records may have different fields.
• Record access is by exhaustible search.
• Purpose is to accumulate the mass of data and
save it.
• Least complicated form of file
organization

7. SEQUENCIAL FILE SYSTEM
• Records are stored and retrieved serially one after
the other.
• The files are searched from its begging until the
requested record is found.
• If the record not matched on search then record not found is sent to
the user.
• File name and length are attributes of the file.

8. INDEXED FILE SYSTEM
• Exhaustive index contain one entry for every record in the
main file
• Partial index contain entries to record
where the field of interest exists
• Records are accessed only
through their indexes
• Variable length record can
be employed.

9. Thanks
for your
presence
and
patience