What is the primary function of the hard disk drive in operating systems?
To provide persistent data storage
The hard disk drive is essential for storing data permanently, unlike volatile memory.
What is the primary purpose of persistence in operating systems?
To ensure data is not lost after a system crash or shutdown
Persistence is crucial for maintaining data integrity across sessions.
What are the two components of positioning time?
- seek time
- rotational latency
These components are critical for determining how quickly data can be accessed on a disk.
The surface of a magnetic disk platter is divided into _______.
sectors
The platter is organized into tracks, and each track is further divided into sectors.
Which phase of a seek operation involves carefully positioning the disk head over the correct track?
Settling
This phase is crucial for accurate data retrieval.
Which of the following disk head scheduling algorithms does not take into account the current position of the disk head?
FCFS (First-Come, First-Served)
Other algorithms like C-SCAN and SCAN consider the disk head’s current position.
Which of the following is a disadvantage of the SSTF (Shortest Seek Time First) scheduling algorithm?
Starvation of far-away requests
SSTF can lead to inefficiencies for requests that are not near the current head position.
What is the main goal of using RAID?
Enhance storage capacity and redundancy
RAID configurations are designed to improve data reliability and performance.
Which RAID level uses mirroring to ensure data redundancy?
RAID 1
RAID 1 provides redundancy by duplicating data across multiple disks.
What is the primary disadvantage of RAID 0?
No data redundancy
RAID 0 offers performance benefits but lacks fault tolerance.
Which RAID level combines both striping and mirroring?
RAID 10
RAID 10 provides both performance and redundancy.
How does RAID 5 achieve redundancy?
By storing parity information distributed across all disks
This allows for data recovery in case of a single disk failure.
What is the purpose of the inode in a file system?
To store metadata about a file, such as its size, permissions, and location
Inodes are essential for file management in Unix-like systems.
What is a superblock in a file system?
A data structure that contains metadata about the file system itself
The superblock holds information necessary for managing the file system.
Which data structure is commonly used to keep track of free blocks in a file system?
Bitmap
Bitmaps efficiently represent the allocation status of blocks.
In an inode-based file system, how is the actual file data located?
By reading the directory entry and resolving file names to inodes
This process is crucial for accessing file contents.
What is the correct sequence for reading a file in an inode-based file system?
Search directory for file name → Retrieve inode → Read data blocks using inode pointers
This sequence ensures proper access to file data.
How does parity contribute to fault tolerance in RAID systems?
By storing a calculated value that can be used to reconstruct lost data
Parity allows for data recovery without full duplication.
What is the total usable file data space available in a file system with 27 data blocks of 512 bytes each?
13,824 bytes
This is calculated as 27 blocks * 512 bytes/block.
What is the purpose of the inode bitmap?
Tracks which inodes are in use (allocated) vs. free
This helps manage inode allocation efficiently.
What is the purpose of the data bitmap?
Tracks which data blocks are used vs. free
This is essential for managing storage space.
How many inodes can this filesystem support?
8 inodes
This is determined by the number of blocks and the size of each inode.
What is the file size for a file using 2 direct data blocks of 512 bytes each?
1024 bytes
Each block contributes 512 bytes to the total file size.
What blocks store file data?
Blocks 10, 11, 13, 14, and 15 store file data
These blocks include both direct and indirect references.
