File Systems: Concepts, Security, and Best Practices

What is a file system?

A file system is a part of the OS that manages and organizes data stored on various storage devices.

What types of storage devices do file systems manage?

File systems manage data on hard disk drives, SSDs, and network storage.

What structure does a file system provide for data organization?

A file system provides a hierarchical structure of files and directories.

What is the purpose of a file system?

The purpose of a file system is to enable users and applications to interact with data systematically.

What is abstraction in the context of file systems?

Abstraction allows applications to access files using logical paths rather than physical disk addresses.

How does file system abstraction simplify application development?

It simplifies application development by allowing developers to use logical paths instead of dealing with physical storage details.

What benefit does file system abstraction provide regarding hardware platforms?

It enhances portability across different hardware platforms.

What are directories (or folders) used for?

Directories (or folders) are containers used to organize files.

What type of structure do directories form?

Directories form a tree-like structure.

What is the purpose of metadata?

Metadata provides context and attributes about files and directories.

What is authentication?

The process of verifying the identity of users attempting to access files or perform file system operations.

What does authentication prevent?

Unauthorized access to sensitive data.

What do file permissions regulate?

Access to files and directories.

What actions can file permissions determine?

Read, write, execute, or delete files.

What do Access Control Lists (ACLs) provide?

Granular control over permissions.

What is the purpose of encryption in file systems?

To safeguard sensitive information stored on disk.

What does built-in encryption in file systems prevent?

Unauthorized access to sensitive information.

What happens if the physical disk is compromised?

Encryption helps to prevent unauthorized access to the data.

Secure Deletion

Ensures that sensitive data is permanently erased from the disk, making it unrecoverable by unauthorized users.

Auditing and Logging

Tracks file access and modifications, helping detect and investigate security breaches or unauthorized activities.

Integrity Checking

Ensures the integrity of stored data by detecting unauthorized modifications or tampering.

Secure authentication mechanisms

Methods used to verify the identity of users accessing the file system.

Strong file permissions and access controls

Rules that determine who can access or modify files and directories.

Encryption for sensitive data

The process of converting data into a coded format to prevent unauthorized access.

Auditing and logging

Tracking and recording file access and modifications for security purposes.

Regular updates and patches

Routine maintenance of file system software to fix vulnerabilities.

Network access limitations

Restricting access to file systems through firewalls, ACLs, and network segmentation.

User education on security awareness

Training users on best practices for security, including password hygiene and recognizing phishing attempts.

FCFS (First Come First Served)

An algorithm that processes requests in the order they arrive, which is fair but inefficient.

What does SSTF stand for?

Shortest Seek Time First

What is the main function of the SSTF algorithm?

It selects the request closest to the current head position.

What is a potential drawback of the SSTF algorithm?

It can lead to starvation.

What is the SCAN algorithm in disk scheduling?

An algorithm that moves the head in one direction servicing requests.

What happens at the end of the disk in the SCAN algorithm?

The algorithm reverses direction.

What does C-SCAN stand for?

Circular SCAN

How does C-SCAN differ from SCAN?

C-SCAN moves the head back to the start after reaching the end.

What is a benefit of using C-SCAN?

It provides more uniform wait times.

What is LOOK in disk scheduling?

A variant of SCAN where the head only goes as far as the last request before reversing.

What is C-LOOK in disk scheduling?

A variant of C-SCAN where the head only goes as far as the last request before reversing.

What do LOOK and C-LOOK aim to avoid?

Unnecessary movement of the disk head.

Registers

Fastest storage located within the CPU, used for immediate data processing.

Cache

Faster than RAM but limited in size (a few MB), storing frequently accessed data to speed up CPU operations.

What does RAM stand for?

Random Access Memory

What type of memory is RAM?

Volatile memory

What is the primary use of RAM?

Temporary storage of data and programs currently in use

What happens to data in RAM when power is off?

Data is lost

ROM storage

Non-volatile storage that retains data even when the power is off.

Hard disk drives

Storage devices that utilize discs and heads to read/write data.

What does SSD stand for?

Solid State Drive

What is a key feature of SSDs regarding data access speed?

Accessing data from anywhere on the SSD is at the same speed.

How do SSDs compare to HDDs in terms of cost?

SSDs are more expensive than HDDs.

CDs, DVDs, and cassette tapes

Media types that are excellent for archiving data.

ROM (Read-Only Memory)

Non-volatile memory used for firmware and boot processes. Data is retained even when power is off.

What technology do Hard Disk Drives (HDDs) use to access data?

Spinning disks and read/write heads

How do Hard Disk Drives (HDDs) compare to SSDs in terms of speed?

Slower than SSDs

Are Hard Disk Drives (HDDs) generally more or less expensive than SSDs?

Cheaper than SSDs

What is a key advantage of Hard Disk Drives (HDDs) regarding storage capacity?

They have larger capacities than SSDs

What are CDs and DVDs classified as?

Optical Storage

What is a key benefit of using optical storage for archiving?

Immutability

What is the cost characteristic of CDs and DVDs?

Low cost

What does WORM stand for in the context of CDs and DVDs?

Write-Once, Read-Many

Tape Storage

Slow but cheap and high-capacity, ideal for long-term archival storage.

Contiguous Allocation

Files occupy contiguous blocks of storage. Simple but leads to fragmentation.

What is Linked Allocation?

Files are stored in non-contiguous blocks, with each block pointing to the next.

What is a benefit of Linked Allocation?

It avoids fragmentation.

What is a drawback of Linked Allocation?

It can be inefficient for random access.

What is indexed allocation in file systems?

Uses an index block to store pointers to all blocks of a file.

What is one advantage of indexed allocation?

Provides fast access to file blocks.

What is a disadvantage of indexed allocation?

Requires additional space for the index block.

How does indexed allocation affect fragmentation?

Reduces fragmentation.

What is multi-level indexing?

A method that extends indexed allocation with multiple levels of index blocks.

What is the benefit of multi-level indexing?

It allows efficient storage and access of large files.

What does Virtual File Systems (VFS) provide?

A standard interface for accessing files.

What types of storage devices can VFS access?

Local disks, network drives, CDs.

What does Limiting Network Access actually do for file systems?

It Restricts network access to file systems using firewalls, ACLs, and network segmentation.

How can Educating Users help for file systems

Provide training on security best practices, including password hygiene and recognizing phishing attempts.

How do Regular Updates help for file systems?

Regularly update and patch file system software to protect against vulnerabilities.