File management Flashcards
Also called the File Management System and is the software responsible for creating, deleting, modifying, controlling access to files.
File manager
Provides support for libraries of programs to online users, for spooling operation, and for interactive computing.
File manager
- The building blocks of any operation system
- Permanent storage of information & data
Files
__ is not interested in what information is stored in file
__ maps files with physical devices.
OS
___ represent program and data.
File
The output of program is called ____.
executable file
______ mechanism refers to the manner in which the records of a file may be accessed
File access
There are several ways to access files (3)
• Sequential File Access
• Direct File Access
• Indexed File Access
Is a method of accessing data
sequentially/one record at a time
by starting from the beginning of the file to its end.
Sequential file access
This access method is the most
primitive and straightforward
method of accessing files.
Sequential file access
Direct file access is also known as ____
Random file access
Also known as Random file access
Direct file access
Allows users to access data directly from any location within the file without the need to read/write all the records that come before it.
Direct file access
Is a method that incorporates the benefits of both sequential and direct file access.
Indexed file access
Creating an index file that maps logical keys or data elements to their corresponding physical addresses within the file.
Indexed file access
refers to the ability of the operating system to distinguish different types of file such as text files, source files, and binary files etc.
File types
Operating system like MS-DOS and UNIX have the following types of files:
• Ordinary files
• Directory files
• Special files
• These are the files that contains user information.
• These may have text, databases or executable program.
• The user can apply various operations on such files like
- add, modify, delete or even remove the entire file.
Ordinary files
• Contains list of file and other related information to those files.
• Also known as “folders” in other operating systems.
• Folders that holds and organize multiple files.
Directory files
• These files are also known as device files.
• Represents physical devices like - disks, terminals, printers, networks, tape drive etc.
Special files
These files are of two types of special files
• Character special files
• Block special files
Data is handled character by character as in case of terminals or printers.
Character special files
Data is handled in blocks as in the case of disks and tapes.
Block special files
File operations (9)
• Create
• Delete
• Open
• Close
• Read
• Write
• Append
• Seek
• Rename
File ______ operation is performed just to read the data that are stored in the required file.
read
The file ____ operation is used to write the data to the file, again, generally at the current position.
write
The file ____ operation is same as the file write operation except that the file append operation only add the data at the end of the file.
append
For random access files, a method is needed just to specify from where to take the data. Therefore, the file ____ operation performs this task.
seek
The file ____ operation is used to change the name of the existing file.
rename
is a list of files that stores all the related information about the file it hold with the contents
Directory
______ is a list of files
Directory
Types of directories (3)
• Single-level directory structure
• Two-level directory structure
• Tree-structured directory structure
in a ______ directory system, all the files are placed in one directory
single-level
in the ____ directory system, the system maintains a master block that has one entry for each user.
two-level
in the _____ directory, the directory themselves are files. This files to the possibility of having sub-directories that can contain files and sub-subdirectories
tree-structured
File Management System Structure
Layered file system (6)
• Application program layer
• Logical file system layer
• File organization module layer
• Basic file system layer
• I/O control interface layer
• Physical hardware device layer
layer where user creates application program
Application program layer
The meta data information is managed at this layer
Logical file system layer
Layer that maintains information about file
File Organization Module Layer
Layer that:
- generates command for device driver
- also manage buffer memory and cache
Basic file system layer
- it consists of device driver & interrupt handler
- transfer data: between main memory to disk system.
I/O control interface layer
- it consists of device driver & interrupt handler
- transfer data: between main memory to disk system.
I/O control interface layer
contain actual hardware device
Physical hardware device layer
A reduction in the amount of bits required to represent data is known as ____.
data compression
______ can save storage capacity, speed up file transfer and decrease costs for storage hardware and network bandwidth.
Compressing data
When information is sent or received via the internet, larger files – either singly or with others as part of an archive file – may be transmitted in a __, __ or other compressed format.
ZIP, GZIP
