Computer Science Topics: Deadlock Detection and NFS

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What does the Domain Name System (DNS) provide?

Host-name-to-network address translations

What is the purpose of the Common Internet File System (CIFS)?

To create network logins with user authentication

What are the benefits of using a buffer cache?

It optimizes sequential access by storing frequently used blocks in a separate section of main memory.

What is the purpose of the file control block (FCB)?

It is a storage structure that contains information about a file. Signup and view all the answers

Explain the concept of "collisions" in file systems.

When two file names hash to the same location. Signup and view all the answers

What is the difference between a "shared lock" and an "exclusive lock"?

A shared lock allows multiple processes to read a file concurrently, while an exclusive lock only allows one process to write or modify the file. Signup and view all the answers

Define "positioning time" in the context of disk access.

It's the time required to move the disk arm to the desired cylinder (seek time) and for the desired sector to rotate under the disk head (rotational latency). Signup and view all the answers

Summarize the key components of the "virtual memory" concept.

It separates the user's logical memory from the physical memory of the system, providing a logical view of how a process is stored in memory. Signup and view all the answers

Which of the following is NOT a necessary condition for a deadlock?

Preemption Signup and view all the answers

What is the primary function of the "Banker's algorithm"?

It is used to prevent deadlocks in a system by allocating resources in a safe manner. Signup and view all the answers

What are the primary benefits of using RAID 1?

It provides high reliability by keeping a duplicate of each disk. Signup and view all the answers

What is the purpose of the "lazy swapper" technique in virtual memory management?

It only swaps a page into memory when it is actually needed by the process. Signup and view all the answers

Explain the mechanism of "copy-on-write" (COW).

It allows both parent and child processes to initially share the same pages in memory, and only creates separate copies of modified pages. Signup and view all the answers

Describe the concept of "global replacement" in the context of page replacement algorithms.

It allows any process to replace a frame from the set of all frames, even if it belongs to another process. Signup and view all the answers

Match the following file types with their usual extensions:

Executable = exe, com, bin Object = obj, o Source code = c, cc, java, pas, asm, a Batch = bat, sh Text = txt, doc Word processor = wp, tex, rtf, doc Library = lib, a , so, dll Print or view = ps, pdf, jpg Archive = arc, zip, tar Multimedia = mpeg, mov, rm, mp3, avi Signup and view all the answers

Study Notes

Material Covered

Lectures covered slides 8.32 (Deadlock Detection) to 15.13 (Client-Server Model).
Tutorials covered from 6 to 10 (inclusive) and supplemental material like Journaling File Systems.
Self-study assignments included assignments 4 through 6.

Key Concepts

NFS Mounting: A process of connecting a network file system to a local system.
Data/Metadata Journaling: A method of recording changes to data for recovery purposes.
Demand Paging: A memory management technique that loads pages into memory only when they are needed.
Deadlocks: A situation where two or more processes are blocked indefinitely, waiting for each other to release resources.
Detection Algorithm: An algorithm for identifying deadlock situations in a system.
Intel Architectures: Computer designs by Intel.
LRU Algorithm: Least Recently Used algorithm: A page replacement algorithm that evicts the page that has not been used for the longest time.
FIFO algorithm: First-In, First-Out algorithm: A page replacement algorithm that evicts the page that entered the system first.
Page and Frame replacement algorithm: Mechanisms that remove pages or frames to make room for new ones in memory.
RAID: Redundant Array of Inexpensive Disks. A technique to improve storage reliability and/or performance.
Storage Device Management: The software and hardware that manages the storage devices.
C-SCAN: A disk scheduling algorithm.
Disk Attachment: A method of connecting a disk device to a computer system.
Nonvolatile Memory Devices: Storage that retains data even when power is off.
Mass Storage Structure: A higher-level organization of storage devices.
Power Management: Energy consumption optimization for storage devices.
I/O Subsystems: The combination of hardware and software that manages input/output operations.
Graph Directories: Data structures that represent directory structures using graphs.
WAFL: A file system optimized for speed, in particular for Web applications.
Free Space Management: Algorithms used to manage disk space effectively.
Linked Allocation: A storage method in which data blocks are chained together by using links.
File Systems Layers: Hierarchical organization of software modules for file system management.

Definitions and Terms

Root Partition: The partition on a disk used to boot an operating system and usually contains the OS itself.
Domain Name System (DNS): Translates hostnames (e.g., www.example.com) to IP addresses.
Network Information Service (NIS): Provides network authentication/authorization services.
Common Internet File System (CIFS): A protocol for sharing files over a network using user authentication.
File Session: A series of file access operations, from opening to closing.
Sun Network File System (NFS): A protocol that allows accessing remote files.
Virtual File System (VFS): Abstraction layer to handle different file systems uniformly.
Journaling: A process of logging changes before updating the disk, allowing recovery from failures.
Journal write: Writing the effects of the transaction to the log.
Journal commit: Writing that the transaction has been committed to stable storage.
Checkpoint: Storing the state of an operation to a designated location allowing to return to it if something fails.
File control block (FCB): Stores information about a file such as its location and size.

Other Important Concepts

Device drivers: Software that manages I/O devices.
Mount table: Stores file system mappings (mount points).
System-wide open-file table: A system-wide directory of all currently open files.
Buffer cache: A memory area for frequently used blocks (to speed up reading from disk).
Page cache: Caches pages in memory rather than disk blocks.
File Attributes: Information about a file (name, identifier, type, size, etc.).
File Operations: Actions such as creating, reading, writing, and deleting files.
Collisions: Situations where two things hash to the same location.
Transfer Rate: Speed of data flow between computer and drive.
Positioning Time: Time to move disk arm to specified sector.
Head Crash: Disk head touches the disk surface.
Access Latency: Average access time.
RAM Drives: Devices that function like RAM, though not using the standard RAM chips.
Error-correction code (ECC): A method of detecting and correcting errors in data.
Mean time to repair (MTTR): Average time to repair a system after failure.
Mean time to data loss (MTTDL): Average time until data loss (often a factor of the MTTR).
RAID: Redundant Array of Independent Disks. A method of improving storage protection and/or performance.
Mirroring (RAID 1): Duplicates each disk to increase data redundancy.
Striped mirrors (RAID 1+0): Provides a balance between performance and redundancy.
Block interleaved parity (RAID 4, 5, 6): Uses redundancy checking to ensure data reliability.

Additional Concepts

Virtual memory: Technique to use secondary storage (e.g. hard disk) to extend main memory for processing.
Lazy swapper: Swaps pages to disk only when needed, not when predicted.
Copy-on-Write (COW): Method of copying page content to protect against shared data.
Least Frequently Used (LFU) Algorithm: Replaces least-used page.
Most Frequently Used (MFU) Algorithm: Replaces least-used page.
Global/Local replacement: Page replacement approaches that consider all or individual processes.
Page address extension (PAE): Memory addressing beyond 4GB.
Resource Type: Categories of resources.
Available Resources: Number of resources that can be used.
File Open Count: Number of current sessions to a file.
Shared/Exclusive Lock: Method for concurrent access to files with multi-user environments.

Study Assignments

The specifics of the assignments are outlined in the original document.

Deadlock

Four necessary conditions for deadlock: Mutual exclusion, no preemption, hold and wait, circular set.
Demand paging: A memory management technique used in virtual memory systems.
Banker's Algorithm: An algorithm used to prevent deadlocks in resource allocation systems.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers key concepts in computer science including deadlock detection algorithms, NFS mounting, and data journaling techniques. You will also explore demand paging, Intel architectures, and the LRU algorithm. Test your understanding of these fundamental topics in operating systems and network file systems.