問題一覧
1
resources cannot be forcibly taken a process
no-preemption
2
Associating a file or device directly with a portion of memory, allowing programs to interact with memory as if it were a file
memory mapping
3
Free memory is split into small, non-contiguous blocks
external fragmentation
4
The range of memory addresses that a process can use, typically isolated for protection and efficiency
address space
5
When the CPU scheduler selects the process for execution, it moves from ______-_____
ready-running
6
Allocating fixed blocks of memory for processes.
contiguous allocation
7
Faster memory that stores frequently accessed data to speed up processing,
cache
8
Moving processes between main memory and disk to optimize space and enable multitasking
swapping
9
is a process that has completed execution but still has an entry in the process table because its parent hasn't yet read its exit status. It is a defunct process that doesn't use resources, but it is still listed in the process table
zombie process
10
refers to an instance of a program that is being executed. A process contains the program code and its current activity, including the program counter, registers, and variables. Processes are fundamental to multitasking operating systems, as they allow multiple programs to run simultaneously
process
11
After being created, the process is admitted into the ready queue
new-ready
12
database system method that resolves deadlocks by reverting transactions to a previous state
rollback
13
Loads pages into memory only when required, reducing initial load time and optimizing memory usage.
demand paging
14
A parent process creates one or more child processes. The child processes can execute independently, but the parent can control or monitor them.
parent and child processes
15
Sometimes a process may be __________ from memory to free up space for other processes. The process is still ready or waiting, but it has been moved to secondary storage (like a hard drive). It remains inactive until it's swapped back into main memory.
suspended (swapped out)
16
When a process finishes its execution, it transitions to the terminated state.
running-terminated
17
Allocates variable-sized partitions based on process requirements, reducing internal fragmentation but possibly causing external fragmentation
dynamic partitioning
18
If a process is preempted (interrupted to give another process CPU time), it returns to the ready state.
running-ready
19
Allocates memory blocks that are powers of two, splitting larger blocks imo "buddies" when necessary.
buddy system
20
interact directly with the user, like applications that are currently being used
foreground processes
21
real time system method that shifts process priorities to avoid deadlocks
priority inversion
22
run without user interaction, often performing system maintenance or other tasks (e.g., a virus scan or system update)
background processes
23
A process goes through various states during its execution. These states represent different stages of execution, ranging from being idle to actively using the CPU. Here are the common
process states
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Entire process swapped out
full swapping
25
occurs when two or more processes are stuck, each waiting for the other to release resources, resultibg in a cycle of dependency and none of the processes being able to proceed
deadlock
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2 types of deadlock detection
resource allocation graph (rag), wait-for graph (wfg)
27
Optimizes memory by moving processes in and out of memory, facilitating multitasking
swapping
28
A hardware component that translates virtual addresses to physical addresses and enforces memory protection.
memory management unit (mmu)
29
Once the process has finished executing, it enters the ________ state. All resources used by the process (memory, files, etc.) are released, and the process is removed from the system's
terminated (exit)
30
Methods in preventing deadlocks
eliminate mutual exclusion, avoid hold and wait, allow preemption, prevent circular wait
31
impose a total ordering on resource request to avoid circular dependencies between processes
prevent circular wait
32
process holding resources are waiting for others
hold and wait
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Enables programs to read from and write to memory as if interacting with files, streamiining file operations
memory mapping
34
complex method used to solved deadlock by identifying and selecting resource involved in deadlock, then suspending the process
resource preemption
35
A technique that allows processes to use more memory than is physically available by utilizing disk space as an extension of RAM.
virtual memory
36
A process is in the _____ state when it is being created. The operating system allocates resources (e.g., memory) for the process during this stage
new
37
Divides memory into fixed-size partitions for process allocation, leading to potential internal fragmentation
fixed partitioning
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Allocating variable-sized memory blocks based on process needs.
dynamic allocation
39
permit the system to forcibly take resources from process when needed
allow preemption
40
The process is loaded into main memory and is ready to run, but it is waiting for the CPU to become available. Processes in the ready state are waiting for scheduling to get CPU time
ready
41
what are the 4 causes of deadlock
mutual exclusion, hold and wait, no-preemption, circular wait
42
identifying and terminationg processes involved freeing up resources
process termination
43
Prevents one process from accessing another process's memory space, ensuring stability and security.
memory protection
44
The process of handling a computer's memory resources effectively, involving allocation, tracking, and deallocation of memory space to optimize performance and system stability.
memory management
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4 Types of Deadlock Recovery
process termination, resource preemption, priority inversion, rollback
46
Only parts of a process swapped out
partial swapping
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Allocated memory blocks may be larger than necessary
internal fragmentation
48
uses graph to represents dependecies between process and waiting resources
wait-for graph (wfg)
49
Automatically identifies and reclaims memory occupied by unreferenced objects, preventing leaks and managing memory efficiently
garbage collection
50
Volatile memory for active programs and data
main memory (ram)
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only one process can cause a resource at a time
mutual exclusion
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Fragmentation (2)
external fragmentation, internal fragmentation
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a cycle processes exist where each is waiting for a resource held by another in a cycle
circular wait
54
Combines paging, and segmentation to allow larger processes to run systems with limited physical memory
virtual memory
55
Techniques aimed at managing the degree of multiprogramming and optimizing page usage to prevent excessive swapping that degrades performance
thrashing prevention
56
2 types of allocation
contiguous allocation, dynamic allocation
57
Small, fast storage locations in the CPU for temporary data.
registers
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it represents the current allocation state of the resource and processes
resource allocation graph (rag)
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Divides memory into fixed-size pages, allowing non-contiguous allocation and eliminating external fragmentation.
paging
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Non-volatile storage (eg, HDD, SSD) for long-term data.
secondary storage
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Once the event the process was waiting for occurs (e.g., I/O completes), the process moves back to the ready state
blocked-ready
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An automatic memory management technique that identifies and reclaims memory from objects no longer in use, preventing memory leaks.
garbage collection
63
require processes to request all necessary resources at once or release held resources before requiring new ones
avoid hold and wait
64
A technique to store frequently accessed data in a small, fast memory area to improve access speed.
caching
65
A process moves to the _________ state if it cannot proceed until some event occurs, such as waiting for input/output (I/O) operations to complete. For example, if a process is waiting for user input, it becomes blocked until that input is provided.
blocked (waiting)
66
Once a process is given the CPU, it moves to the _______ state. In this state, the process is actively executing instructions
running
67
allow resources to be shared by multiple processes
eliminate mutual exclusion