Test
Operating System Analysis and Design 1
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Preguntas del test (45)
1What is an operating system?
A program that acts as an intermediary between a user of a computer and the computer hardware- AVerdadero
- BFalso
2Computer system can be divided into four components:
[blank_start]Hardware[blank_end] - provides basic computing resources
[blank_start]Operating system[blank_end] - controls and coordinates use of hardware among various applications and users
[blank_start]Application programs[blank_end] - define the ways in which the system resources are used to solve the computing problems of the user
[blank_start]Users[blank_end] - people, machines and other components- AHardware
- BOperating system
- CApplication programs
- DUsers
3OS is a [blank_start]resource allocator[blank_end]
- manages all resources
- decides between conflicting requests for efficient and fair resource use
OS is a [blank_start]control program[blank_end]
- controls execution of programs to prevent errors and improper use of the computer- Aresource allocator
- Bcontrol program
4The one program running at all times on the computer is the kernel
everything else is either
- system program
- application program- AVerdadero
- BFalso
5Bootstrap program is loaded at power-up
- Atypically stored in ROM or EPROM, generally known as firmware
initializes all aspects of system
loads operating system kernel and starts execution - Btypically stored in RAM or ERRAM, generally known as firmware
initializes all aspects of the motherboard
loads operating system programs and starts execution
- Atypically stored in ROM or EPROM, generally known as firmware
6Computer system operation:
- AOne or more CPUs, device controllers connect through common bus providing access to shared memory
- BConcurrent execution of CPUs and devices competing for memory cycles
- CI/O devices and CPU can execute concurrently
- DEach device controller is in charge of a particular device type
- EDevice controller informs CPU that it has finished its operation by causing an interrupt
- FRAM and ROM of the operating system ensure the CPU can properly manage its resources
7A trap or exception is a software-generated interrupt caused either by an error or a user request
An operating system is interrupt driven- AVerdadero
- BFalso
8Direct Memory Access Structure
- used for high-speed I/O devices able to transmit information at close to memory speeds
- device controller sends blocks of data directly to main memory without CPU intervention
- only one interrupt is generated per block, rather than the one interrupt per byte- AVerdadero
- BFalso
9Multiprogramming (batch system) needed for efficiency
- Asingle user cannot keep CPU and I/O devices busy at all times
- BMultiprogramming organizes jobs so CPU always has one to execute
- CA subset of total jobs in system is kept in memory
- DOne job is selected and run via job scheduling
- EWhen it has to wait, OS switches to another job
- FWhen the job is finished, the OS uses the scheduling to select the first job in the waiting list
10[blank_start]Timesharing[blank_end] is a logical extension in which CPI switches jobs so frequently that users can interact with each job while its running, creating [blank_start]interactive[blank_end] computing
- [blank_start]Response time[blank_end] should be < 1 second
- Each user has at least one program executing in memory -> [blank_start]process[blank_end]
- if several jobs ready to run at the same time -> [blank_start]CPU scheduling[blank_end]
- If processes don't fit in memory, [blank_start]swapping[blank_end] moves then in and out to run
- [blank_start]Virtual memory[blank_end] allows execution of processes not completely in memory- ATimesharing
- Binteractive
- CResponse time
- Dprocess
- ECPU scheduling
- Fswapping
- GVirtual memory
11[blank_start]Dual-mode[blank_end] operation allows OS to protect itself and other system components
- [blank_start]User mode[blank_end] and kernel mode
- [blank_start]Mode bit[blank_end] provided by hardware- ADual-mode
- BUser mode
- CMode bit
12A process is a program in execution
- AProgram is a passive entity
Process is an active entity - BProgram is an active entity
Process is a passive entity
- AProgram is a passive entity
13Process Management Activities
The operating system is responsible for the following activities in connection with process management:- ACreating and deleting both user and system processes
- BSuspending and resuming processes
- CProviding mechanisms for process synchronization
- DProviding mechanisms for process communication
- EProviding mechanisms for deadlock handling
- FProviding system security for process user checks
14Memory Management
To execute a program all of the instructions must be in memory
All of the data that is needed by the program must be in memory- AVerdadero
- BFalso
15Main memory - only large storage media that has the CPU can access directly
- [blank_start]random access[blank_end]
- [blank_start]volatile[blank_end]
secondary storage - provides large [blank_start]nonvolatile[blank_end] storage capacity
[blank_start]caching[blank_end] - copying information into faster storage system
[blank_start]device driver[blank_end] for each device controller to mange I/O- Arandom access
- Bvolatile
- Cnonvolatile
- Dcaching
- Edevice driver
16I/O subsystem is responsible for
- Amemory management of I/O operations
- Bgeneral device-driver interface
- Cdrivers for specific hardware devices
- Ddriver protection for memory I/O
17[blank_start]Protection[blank_end] - any mechanism for controlling access of processes or users to resources defined by the OS
[blank_start]Security[blank_end] - defense of the system against internal and external attacks- AProtection
- BSecurity
18Client-server computing
[blank_start]Servers[blank_end] that response requests which are generated by [blank_start]clients[blank_end]
- [blank_start]compute-server system[blank_end] provides an interface to client to request services
- [blank_start]file-server system[blank_end] provides interface for clients to store and retrieve files- AServers
- Bclients
- Ccompute-server system
- Dfile-server system
19Daily computing, storage, even apps as a service across a network
[blank_start]public[blank_end] cloud - available via internet to anyone willing to pay
[blank_start]private[blank_end] cloud - run by a company for the companies use
[blank_start]hybrid[blank_end] cloud - includes both public and private cloud components- Apublic
- Bprivate
- Chybrid
20Process
A program in execution
Terms job and process almost interchangeably- AVerdadero
- BFalso
21Program is passive entity stored on disk (executable file),
process is active- AVerdadero
- BFalso
22[blank_start]new[blank_end]
the process is being created- Anew
- Bready
- Crunning
- Dterminated
- Ewaiting
23[blank_start]ready[blank_end]
the process is waiting to be assigned to a processor- Aready
- Bnew
- Cwaiting
- Dterminated
- Erunning
24[blank_start]running[blank_end]
instructions are being executed- Arunning
- Bnew
- Cready
- Dwaiting
- Eterminated
25[blank_start]waiting[blank_end]
the process is waiting for some event to occur- Awaiting
- Bnew
- Cready
- Drunning
- Eterminated
26[blank_start]terminated[blank_end]
the process has finished execution- Aterminated
- Bnew
- Cready
- Drunning
- Ewaiting
27Drag proper to label
- Arunning, waiting, etc
- BLocation of instruction to next execute
- CContent of all process-centric registers
- Dmemory allocated to the process
28Parent process create children processes, which, in turn create other processes, forming a tree of processes
Generally, process identified and managed via a process identifier (pid)- AVerdadero
- BFalso
29Parent and children share [blank_start]all[blank_end] resources
Children share [blank_start]subset[blank_end] of parent’s resources
Parent and child share [blank_start]no[blank_end] resource- Aall
- Bsubset
- Cno
30Process Creation:
Execution options
Parent and children execute concurrently
Parent waits until children terminate- AVerdadero
- BFalso
31Process Creation:
Address space
Child duplicate of parent
Child has a program loaded into it- AVerdadero
- BFalso
32[blank_start]fork()[blank_end] system call for creating a new process
[blank_start]wait()[blank_end] allows the parent process to wait while the child executes
[blank_start]exec()[blank_end] system call used after a fork() to replace the process’ memory space with a new program
- Allow the child to run a different program
Process executes last statement and then asks the operating system to delete it using the [blank_start]exit()[blank_end] system call.
Parent may terminate the execution of children processes using the [blank_start]abort()[blank_end] system call.- Afork()
- Bwait()
- Cexec()
- Dexit()
- Eabort()
33Multi-thread server benefits
- AResponsiveness
- BEconomy
- CScalability
- DResource Sharing
- EModulation
- FProcessing Speed
34[blank_start]Responsiveness[blank_end] - May allow continued execution if part of process is blocked
[blank_start]Economy[blank_end] - Cheaper than process creation, Thread switching lower overhead than context switching
[blank_start]Scalability[blank_end] - Process can take advantage of multiprocessor architectures
[blank_start]Resource Sharing[blank_end] - Threads share resources of process, easier than shared memory or message passing- AResponsiveness
- BEconomy
- CScalability
- DResource Sharing
35Multicore programming
- AParallelism - System can perform more than one task simultaneously
Concurrency - Supports more than one task making progress - BConcurrency - System can perform more than one task simultaneously
Parallelism - Supports more than one task making progress
- AParallelism - System can perform more than one task simultaneously
36Thread Management
[blank_start]Asynchronous[blank_end] - Parent and child threads are independent and execute concurrently
[blank_start]Synchronous[blank_end] - Parent creates and waits for the children to terminate to resume its service- AAsynchronous
- BSynchronous
37Reasons for cooperating processes:
[blank_start]Information Sharing[blank_end] - There may be several processes which need access to the same file
[blank_start]Computation speedup[blank_end] - A solution to a problem can be solved faster if the problem can be broken down into sub-tasks to be solved simultaneously
[blank_start]Modularity[blank_end] - Break a system down into cooperating modules. ( E.g. databases with a client-server architecture. )
[blank_start]Convenience[blank_end] - Multi-tasking, such as editing, compiling, printing, and running the same code in different windows.- AInformation Sharing
- BComputation speedup
- CModularity
- DConvenience
38Two models of IPC:
[blank_start]Shared Memory[blank_end] - Faster once it is set up, more complicated to set up, problem in dealing with multiple computers.
[blank_start]Message Passing[blank_end] - Requires system calls for every message transfer, slower, simpler to set up and works well across multiple computers.- AShared Memory
- BMessage Passing
39Paradigm for cooperating processes:
Producer process produces information that is consumed by a consumer process
Producer and consumer share a fixed-size buffer (bounded-buffer) used as a queue.- AVerdadero
- BFalso
40Operation
Producer puts information in the buffer while consumer removes it from the buffer.- AVerdadero
- BFalso
41There is need for synchronization when many processes share a resource
- AVerdadero
- BFalso
42Message passing:
IPC facility provides two operations:
send()
receive()
If processes P and Q wish to communicate, they need to:
Establish a communication link-channel between them
Exchange messages via send/receive- AVerdadero
- BFalso
43Message Passing
Naming:
[blank_start]Direct communication[blank_end] - more than one process may send messages to the receiver, to receive from a specific sender it requires searching entire buffer
[blank_start]Indirect communication[blank_end] - Messages are directed and received from mailboxes, Each mailbox has a unique id, Operations: create a new mailbox, send/receive through mailbox, and destroy a mailbox- ADirect communication
- BIndirect communication
44Message Passing - Synchronization
Blocking is considered [blank_start]synchronous[blank_end]
Blocking send -- the sender is blocked until the message is received
Blocking receive -- the receiver is blocked until a message is available
Non-blocking is considered [blank_start]asynchronous[blank_end]
Non-blocking send -- the sender sends the message and continue
Non-blocking receive -- the receiver receives: A valid message, or Null message- Asynchronous
- Basynchronous
45Pipe features:
Communication between parent and child
Implements the standard producer-consumer style
Producer writes to the write-end of the pipe
Consumer reads from the other the read-end of the pipe- AVerdadero
- BFalso
Información
- Descripción
- Computer Science Test sobre Operating System Analysis and Design 1, creado por Duncan Levings el 05/09/2019.
- Autor
- Duncan Levings
- Idioma
- English
- Visitas
- 0
- Historial
- Creado el 5 sep 2019 · actualizado el 26 sep 2019
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