Please enable JavaScript.
Coggle requires JavaScript to display documents.
File Management, Terminology - Coggle Diagram
File Management
Responsibilities
File storage tracking
keep track where each file is stored
Policy implementation
purpose
determine where and how files are stored
efficiently use available storage space
provide efficient file access
Determine:
File storage location
how user and system can access the file
Access to material
factor 1
Flexibility of access to information
share file
provide distributed access
allow users to browse public directories
factor 2
Subsequent protection
prevent system malfunction
security checks
file allocation
activate secondary storage device
load file into memory
update records
file deallocation
update file tables
rewrite file
notify waiting processes of file availability
Interacting with File Manager
Device independent if information about physical location, medium and network knowledge already available in device driver
physical location
cylinder, surface, sector
device medium
tape, magnetic disk, optical disc, flash storage
network knowledge
Logical commands
broken into lower-level signals
example: READ
move read/write head to record cylinder
wait for rotational delay (sector containing record passes under read/write head)
activate appropriate read/write head and read record
transfer record to main memory
send flag indicating free device for another request
Introduction
Efficiency affected by
how the files organised
how the files stored
how the files structured
how user access to all files protected
Terminology
File
group of related records
information used by specific application programs
flat file - no connections to other files; no dimensionality
Field
group of related bytes
identified by user (name, type, size)
Database
group of related files
interconnected at various level
give users availability of access to store data
Record
group of related fields
Program files
contain instructions
Data files
contain data
Directories (folders)
listing of filenames and their attributes