Session 3 Flashcards
Operating System Services
Set of operating-system services provides functions that are helpful to the user:
_______ _______ - Almost all operating systems have a user interface (UI)
Varies between Command-Line (CLI), Graphics User Interface (GUI), Batch
_______ _______ - The system must be able to load a program into memory and to run that program, end execution, either normally or abnormally (indicating error)
_______ _______ - A running program may require I/O, which may involve a file or an I/O device.
_____-_____ _______ - Programs need to read and write files and directories, create and delete them, search them, list file Information, permission management
Operating System Services
Set of operating-system services provides functions that are helpful to the user:
User interface - Almost all operating systems have a user interface (UI)
Varies between Command-Line (CLI), Graphics User Interface (GUI), Batch
Program execution - The system must be able to load a program into memory and to run that program, end execution, either normally or abnormally (indicating error)
I/O operations - A running program may require I/O, which may involve a file or an I/O device.
File-system manipulation - Programs need to read and write files and directories, create and delete them, search them, list file Information, permission management
_______ – Processes may exchange information, on the same computer or between computers over a network
Communications may be via shared memory or through message passing (packets moved by the OS)
_______ _______ – OS needs to be constantly aware of possible errors
May occur in the CPU and memory hardware, in I/O devices, in user program
For each type of error, OS should take the appropriate action to ensure correct and consistent computing
Debugging facilities can greatly enhance the user’s and programmer’s abilities to efficiently use the system
Communications – Processes may exchange information, on the same computer or between computers over a network
Communications may be via shared memory or through message passing (packets moved by the OS)
Error detection – OS needs to be constantly aware of possible errors
May occur in the CPU and memory hardware, in I/O devices, in user program
For each type of error, OS should take the appropriate action to ensure correct and consistent computing
Debugging facilities can greatly enhance the user’s and programmer’s abilities to efficiently use the system
_______ _______ - Almost all operating systems have a user interface (UI)
Varies between Command-Line (CLI), Graphics User Interface (GUI), Batch
User interface - Almost all operating systems have a user interface (UI)
Varies between Command-Line (CLI), Graphics User Interface (GUI), Batch
_______ _______ - The system must be able to load a program into memory and to run that program, end execution, either normally or abnormally (indicating error)
Program execution - The system must be able to load a program into memory and to run that program, end execution, either normally or abnormally (indicating error)
_______ _______ - A running program may require I/O, which may involve a file or an I/O device.
I/O operations - A running program may require I/O, which may involve a file or an I/O device.
_____-_____ _______ - Programs need to read and write files and directories, create and delete them, search them, list file Information, permission management
File-system manipulation - Programs need to read and write files and directories, create and delete them, search them, list file Information, permission management
_______ – Processes may exchange information, on the same computer or between computers over a network
Communications – Processes may exchange information, on the same computer or between computers over a network
_______ _______ – OS needs to be constantly aware of possible errors
May occur in the CPU and memory hardware, in I/O devices, in user program
For each type of error, OS should take the appropriate action to ensure correct and consistent computing
Debugging facilities can greatly enhance the user’s and programmer’s abilities to efficiently use the system
Error detection – OS needs to be constantly aware of possible errors
May occur in the CPU and memory hardware, in I/O devices, in user program
For each type of error, OS should take the appropriate action to ensure correct and consistent computing
Debugging facilities can greatly enhance the user’s and programmer’s abilities to efficiently use the system
Set of operating system functions exists not for helping the user but rather for ensuring the efficient operation of the system itself.
_______ _______ - When multiple users or multiple jobs running concurrently, resources must be allocated to each of them
Many types of resources - Some (such as CPU cycles, main memory, and file storage) may have special allocation code, others (such as I/O devices) may have general request and release code.
Set of operating system functions exists not for helping the user but rather for ensuring the efficient operation of the system itself.
Resource allocation - When multiple users or multiple jobs running concurrently, resources must be allocated to each of them
Many types of resources - Some (such as CPU cycles, main memory, and file storage) may have special allocation code, others (such as I/O devices) may have general request and release code.
_______ - To keep track of which users use how much and what kinds of computer resources
Accounting - To keep track of which users use how much and what kinds of computer resources
Accounting
To keep track of which users use how much and what kinds of computer resources
_______ ___ _______ - The owners of information stored in a multiuser or networked computer system may want to control use of that information, concurrent processes should not interfere with each other
Protection and security - The owners of information stored in a multiuser or networked computer system may want to control use of that information, concurrent processes should not interfere with each other
Protection and security -
Protection and security - The owners of information stored in a multiuser or networked computer system may want to control use of that information, concurrent processes should not interfere with each other
_______ involves ensuring that all access to system resources is controlled
Protection involves ensuring that all access to system resources is controlled
_______ of the system from outsiders requires user authentication, extends to defending external I/O devices from invalid access attempts
Security of the system from outsiders requires user authentication, extends to defending external I/O devices from invalid access attempts
User Operating System Interface - CLI
CLI allows direct _______ entry
Sometimes implemented in _______, sometimes by systems program
Sometimes multiple flavors implemented – _______
Primarily fetches a _______ from _______ and executes it
User Operating System Interface - CLI
CLI allows direct command entry
Sometimes implemented in kernel, sometimes by systems program
Sometimes multiple flavors implemented – shells
Primarily fetches a command from user and executes it
System Calls
Programming _______ to the services provided by the OS.
Typically written in a high-level language (C or C++)
Mostly accessed by programs via a high-level Application Program Interface (API) rather than direct system call use
Three most common APIs are Win32 API for Windows, POSIX API for POSIX-based systems (including virtually all versions of UNIX, Linux, and Mac OS X), and Java API for the Java virtual machine (JVM)
System Calls
Programming interface to the services provided by the OS.
Typically written in a high-level language (C or C++)
Mostly accessed by programs via a high-level Application Program Interface (API) rather than direct system call use
Three most common APIs are Win32 API for Windows, POSIX API for POSIX-based systems (including virtually all versions of UNIX, Linux, and Mac OS X), and Java API for the Java virtual machine (JVM)
System Call Parameter Passing
Three general methods used to pass parameters to the OS
_______: pass the parameters in registers
In some cases, may be more parameters than registers
Parameters stored in a _______, or table, in memory, and address of _______ passed as a parameter in a _______
This approach taken by Linux and Solaris
Parameters placed, or _______, onto the _______ by the program and _______ off the _______by the operating system
Block and stack _______ do not limit the number or length of parameters being passed
System Call Parameter Passing
Three general methods used to pass parameters to the OS
Simplest: pass the parameters in registers
In some cases, may be more parameters than registers
Parameters stored in a block, or table, in memory, and address of block passed as a parameter in a register
This approach taken by Linux and Solaris
Parameters placed, or pushed, onto the stack by the program and popped off the stack by the operating system
Block and stack methods do not limit the number or length of parameters being passed
Types of System Calls
Process _______
File _______
Device _______
Information maintenance
_______
Types of System Calls
Process control File management Device management Information maintenance Communications
System Programs
AKA System Utility
Provide a convenient environment for program _______ and _______
Some of them are simply user interfaces to system calls; others are considerably more complex
Categories:
_______ _______ - Create, delete, copy, rename, print, dump, list, and generally manipulate files and directories
Status information
Some ask the system for info - date, time, amount of available memory, disk space, number of users
Others provide detailed performance, logging, and debugging information
Typically, these programs format and print the output to the terminal or other output devices
Some systems implement a registry - used to store and retrieve configuration information
System Programs
AKA System Utility
Provide a convenient environment for program development and execution
Some of them are simply user interfaces to system calls; others are considerably more complex
Categories:
File management - Create, delete, copy, rename, print, dump, list, and generally manipulate files and directories
Status information
Some ask the system for info - date, time, amount of available memory, disk space, number of users
Others provide detailed performance, logging, and debugging information
Typically, these programs format and print the output to the terminal or other output devices
Some systems implement a registry - used to store and retrieve configuration information
_______ _______
Text editors to create and modify files
Special commands to search contents of files or perform transformations of the text
_______-_______ _______ - Compilers, assemblers, debuggers and interpreters sometimes provided
_______ _______and _______ - Absolute loaders, relocatable loaders, linkage editors, and overlay-loaders, debugging systems for higher-level and machine language
_______ - Provide the mechanism for creating virtual connections among processes, users, and computer systems
Allow users to send messages to one another’s screens, browse web pages, send electronic-mail messages, log in remotely, transfer files from one machine to another
File modification
Text editors to create and modify files
Special commands to search contents of files or perform transformations of the text
Programming-language support - Compilers, assemblers, debuggers and interpreters sometimes provided
Program loading and execution- Absolute loaders, relocatable loaders, linkage editors, and overlay-loaders, debugging systems for higher-level and machine language
Communications - Provide the mechanism for creating virtual connections among processes, users, and computer systems
Allow users to send messages to one another’s screens, browse web pages, send electronic-mail messages, log in remotely, transfer files from one machine to another
