Flashcards - Computer Systems Week 10_ Operating Systems
What does the OS need memory for?
Instructions, Static data, Dynamic data (heap or stack)
What does the Memory Management subsystem handle?
Relocation, Allocation, Protection, Sharing, Logical organisation, Physical organisation
What are the three types of address binding?
Compile time, Load time, Run-time
What does the MMU do?
Maps logical memory addresses to physical memory addresses
What is fragmentation?
Occurs when the hole is not big enough for the program
What does paging allow for in memory management?
Clear separation between user and system view
What is a page fault?
Type of exception raised when a process can’t map to a memory page
What is the purpose of the Translation Lookaside Buffer (TLB)?
To speed up memory reference checking
What is Virtual Memory?
Memory that appears to exist in main memory but is partially held in secondary storage
What is the stack arrangement in memory management?
Last In First Out (LIFO)
What is a file in terms of non-volatile storage?
Basic unit containing meta-data to identify file type or format of data
What does a directory service do?
Handles file access and maps from names to file ID
What kind of data structures do file systems store on the disk?
Boot-control block, volume control block, File Control Block, Inodes
What is a Directory in computing?
A file that contains information about other files and their organisation
What is the requirement for directory namespace efficiency?
Must allow for quick access
What are the advantages of a hierarchical directory structure?
Helps solve grouping problems and prevents naming conflicts
What is the main disadvantage of single-level directory naming?
Naming problems due to different users using the same file name
What is dynamic partitioning in memory allocation?
OS determines the location in memory as process(es) arrive
What is the role of the File Control Block (FCB)?
Contains details about ownership, size, permissions, and dates
What does the stack in memory management represent?
An arrangement created by the OS handed to program for faster access
