Podcast
Questions and Answers
Which of the following is NOT a type of file attribute?
Which of the following is NOT a type of file attribute?
- Identifier
- Content Type (correct)
- Protection
- Location
The 'Size' attribute of a file indicates the type of file it is.
The 'Size' attribute of a file indicates the type of file it is.
False (B)
What operation is performed when you want to change the position within a file?
What operation is performed when you want to change the position within a file?
Reposition within file
A file that contains a ready-to-run machine-language program usually has the extension _____
A file that contains a ready-to-run machine-language program usually has the extension _____
Match the following file types with their functions:
Match the following file types with their functions:
Which access method allows reading and writing data in a specific format, skipping directly to the needed data?
Which access method allows reading and writing data in a specific format, skipping directly to the needed data?
A file is defined as a contiguous logical address space.
A file is defined as a contiguous logical address space.
List one of the operations that can be performed on a file.
List one of the operations that can be performed on a file.
Which command would you use to create a new subdirectory?
Which command would you use to create a new subdirectory?
Deleting a file named 'mail' will only remove the file itself and leave the rest of the directory structure intact.
Deleting a file named 'mail' will only remove the file itself and leave the rest of the directory structure intact.
What does the command 'chmod 761 game' achieve in terms of file access?
What does the command 'chmod 761 game' achieve in terms of file access?
The current directory can be navigated using the command 'cd __________'.
The current directory can be navigated using the command 'cd __________'.
Match the following access modes with their corresponding permissions:
Match the following access modes with their corresponding permissions:
What is the main function of a directory structure?
What is the main function of a directory structure?
A two-level directory allows users to have the same file name for different users.
A two-level directory allows users to have the same file name for different users.
What does RAID stand for in the context of disk structure?
What does RAID stand for in the context of disk structure?
In a _____ directory, all users share a single directory, leading to naming conflicts.
In a _____ directory, all users share a single directory, leading to naming conflicts.
Match the directory type with its characteristics:
Match the directory type with its characteristics:
Which of the following operations can be performed on a directory?
Which of the following operations can be performed on a directory?
A volume contains a file system and tracks its information in the volume table of contents.
A volume contains a file system and tracks its information in the volume table of contents.
Name one advantage of a tree-structured directory over a single-level directory.
Name one advantage of a tree-structured directory over a single-level directory.
What is the main advantage of contiguous allocation for files?
What is the main advantage of contiguous allocation for files?
Linked allocation allows for random access to file data.
Linked allocation allows for random access to file data.
What does the Boot Control Block contain?
What does the Boot Control Block contain?
In the UNIX directory listing, 'drwxrwxrwx' indicates that the file has _____ permissions.
In the UNIX directory listing, 'drwxrwxrwx' indicates that the file has _____ permissions.
Match the allocation methods with their characteristics:
Match the allocation methods with their characteristics:
Which of the following is a disadvantage of contiguous allocation?
Which of the following is a disadvantage of contiguous allocation?
The file control block (FCB) contains details about file permissions, file dates, and file owner.
The file control block (FCB) contains details about file permissions, file dates, and file owner.
What is the purpose of a volume control block?
What is the purpose of a volume control block?
Flashcards
File concept
File concept
A contiguous space in memory used to store data or programs.
File identifier
File identifier
A unique identifier used to locate a specific file within a file system.
File protection
File protection
Controls who can access and modify a file.
Sequential access file
Sequential access file
A file is accessed in a linear order, from start to finish.
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Direct access file
Direct access file
A file can be accessed directly at any location within the file, without going through the entire sequence.
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Directory structure
Directory structure
Provides a structured way to organize and manage files within a file system.
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Archiving
Archiving
The action of grouping related files into a single file for storage or distribution, sometimes involving compression.
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Compiling
Compiling
The process of creating a runnable program from source code.
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Disk Partitions
Disk Partitions
A disk can be subdivided into smaller sections called partitions.
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RAID Protection
RAID Protection
RAID protects against disk failures by mirroring or striping data across multiple disks.
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Raw vs. Formatted Disk
Raw vs. Formatted Disk
A disk or partition can be used without a file system (raw) or with a file system formatted to organize data.
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Volume and VTOC
Volume and VTOC
An entity containing a file system, also known as a volume, tracks information about the file system in a device directory or volume table of contents (VTOC).
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File System
File System
A file system is like an index for your computer, allowing you to easily find and organize your files. It helps you navigate and manage your information.
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General-Purpose File System
General-Purpose File System
A file system that is not designed for a specific purpose and can be used for a wide range of tasks, It's like a general-purpose tool that can be used for many different jobs.
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Special-Purpose File System
Special-Purpose File System
File systems designed for specific tasks, often within the same operating system or computer. It's like a specialized tool designed for a particular job.
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Current directory
Current directory
The current directory is the location where you are currently working. For instance, if you are in the 'spell' folder, you can access files and folders inside 'spell' directly.
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Absolute or relative path
Absolute or relative path
Absolute paths provide the full route from the root directory to the desired file or folder. Relative paths indicate the location based on your current directory.
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Access mode
Access mode
To access a file, you need permissions to 'read' its contents, 'write' to it, or 'execute' it (for programs).
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Access groups
Access groups
Different groups of users can have varying permissions on files or folders. The owner has the highest permissions, then the group, and lastly, the public.
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Chmod command
Chmod command
The 'chmod' command changes the permissions of a file. The numbers 761 represent the permissions for owner, group, and public respectively. For example, 'chmod 761 game' grants full access to the owner, read/write to the group, and only execute permission to the public.
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Boot Control Block
Boot Control Block
The first block that contains essential information for the OS to boot from a specific volume.
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Volume Control Block
Volume Control Block
A block that holds details about the entire volume, like its size and format.
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File Control Block (FCB)
File Control Block (FCB)
A table of information about a specific file, including permissions, dates, owner, size, and location of data.
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Contiguous Allocation
Contiguous Allocation
A method where file data is stored in consecutive blocks on the disk.
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Linked Allocation
Linked Allocation
A method that links blocks using pointers, allowing for non-contiguous data storage.
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Indexed Allocation
Indexed Allocation
A method that uses an index to directly point to data blocks, enabling both speed and flexibility.
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Dynamic Storage Allocation Problem
Dynamic Storage Allocation Problem
A type of memory management issue that arises when a file grows, requiring more space than initially allocated.
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Indexed Allocation (Advantage)
Indexed Allocation (Advantage)
A space-efficient file allocation strategy.
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File Systems and Storage
- File systems manage how computer files are stored and accessed.
- Files are organized in a logical address space (contiguous).
- Data types include numeric, character, and binary.
- Programs also occupy this logical address space.
File Attributes
- Name - human-readable file identification.
- Identifier - unique tag identifying a file within the system.
- Type - helps differentiate types of files.
- Location - pointer indicating file position on the device.
- Size - current file size.
- Protection - controls user access levels (read, write, execute).
- Time, date, and user identification - data for security and usage tracking.
- Information about files is stored in a directory structure maintained on the disk.
File Operations
- File is an abstract data type.
- Operations include: create, write, read, reposition within file, delete.
File Types - Name, Extension
- File types are associated with different functionalities and formats.
- Examples: Executable (
.exe,.com,.bin), Object (.obj,.o), Batch (.bat,.sh), Text (.txt,.doc), Word Processor (.doc,.rtf,.tex), Library (.lib,.a,.so,.dll), Print or View (.ps,.pdf,.jpg), Archive (.arc,.zip,.tar), Multimedia (.mpeg,.mov,.rm,.mp3,.avi).
Access Methods
- Sequential Access: Reading/writing occurs sequentially, starting from the beginning.
- Direct Access: Reading/writing occurs directly to a specific block location via its relative block number.
Sequential-access File
- Conceptual representation of a file as a linear sequence of data blocks.
Example of Index and Relative Files
- An index file provides a lookup table to find the location (relative block number) in the relative file.
Directory Structure
- A directory is a collection of nodes.
- These nodes contain information about the files.
- Files and the directory structure reside on the disk.
Disk Structure
- Disks can be partitioned for fault tolerance.
- A disk partition can be used in a raw mode or formatted with a file system.
- Partitions are also known as minidisks or slices.
- An entity holding a file system is known as a volume.
- Volumes manage file system metadata (device directory/volume table).
- Special-purpose file systems often exist alongside general-purpose ones within the same OS or computer.
A Typical File-system Organization
- Partitions with directories and files.
Operations Performed on Directory
- Directory operations include search, create, delete, list, rename, and traversal.
Single-Level Directory
- A single directory for all users.
- Challenges include naming conflicts and lack of organization.
Two-Level Directory
- Dedicated directory for each user.
- Problem: same file name for different users
- Advantages: efficient searching, organization of files per user.
Tree-Structured Directories
- Hierarchical directory structure.
- Efficient searching, grouping files.
- Current directory/working directory
- Operations like
cd,type.
Tree-Structured Directories (Cont)
- Path names (absolute/relative) within a tree structure.
- Directory operations(create,delete,rename)
Access Lists and Groups
- Different access modes (read, write, execute).
- User, group, public permissions
- Groups and chmod
- Windows XP ACL Management (example of Access Control List)
A Sample UNIX Directory Listing
- Example showing different folder permissions and listings (
-rw-rw-r--, etc.).
File-System Implementation
- Boot control block (OS booting info).
- Volume control block details info about volume.
- Directory structure organizes files.
- Per-file File Control Block (FCB) for storage of file details.
A Typical File Control Block
- Summarization of components within the FCB (file permissions, dates, owner, group, ACL, size, data blocks).
Allocation Methods
- How disk blocks are assigned to files: contiguous, linked, and indexed allocation.
Contiguous Allocation
- File blocks are stored sequentially on the disk.
- Simple, efficient random access but inefficient regarding space.
Contiguous Allocation of Disk Space
- Example illustration of contiguous allocation with assigned blocks and counts.
Linked Allocation
- Blocks can be anywhere on the disk as they are linked in a chain of pointers.
- Handles file growth because file grows in contiguous blocks.
Linked Allocation
- Conceptual illustration of linked lists of disk blocks.
File-Allocation Table
- Table associating file names with start blocks, often used with linked allocation.
Indexed Allocation
- All pointers to blocks are collected in an index block.
- Efficient random access but index requires extra storage.
Example of Indexed Allocation
- Demonstrates how file blocks are tied to the index block using pointers.
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