The document discusses various topics related to process management in Unix/Linux operating systems. It describes the different states a process can be in, such as ready, running, waiting, zombie, etc. It also explains process creation using fork() and program execution using exec(). Other topics covered include process termination with exit(), waiting for child processes using wait(), process relationships like parent-child, process identifiers, signals, and context switching.
System calls allow user programs to request services from the operating system kernel. They involve a transition from user to kernel mode, where the kernel performs the requested operation before returning control back to the user program. Common system calls include process control, file management, device management, and communication. While essential, system calls can impact performance due to mode switching overhead. Techniques like batching and inline system calls help mitigate this. Remote procedure calls and remote method invocation are invocation methods that allow processes to request services across a network.
HPC Application Profiling and AnalysisRishi Pathak
This document discusses application profiling and analysis. Profiling involves recording summary information during program execution to reflect performance behavior. It can expose bottlenecks and hotspots with low overhead. Profiling is implemented via sampling, which uses periodic interrupts, or instrumentation, which directly inserts measurement code. Tracing records significant execution points to reconstruct program behavior. Profiling provides summary statistics while tracing generates a large volume of event data. Tools like HPCToolkit use sampling and instrumentation to collect metrics that are correlated back to source code to analyze performance.
System calls allow programs to request services from the operating system kernel. Some common system calls include read and write for file access, fork for creating new processes, and wait for a parent process to wait for a child process to complete. The steps a system call takes include the program pushing parameters onto the stack, calling the library procedure to place the system call number in a register, triggering a trap instruction to switch to kernel mode, the kernel dispatching the system call to the appropriate handler, the handler running, then returning control to the user program after completing the operation.
This document discusses application profiling and analysis techniques. It provides an overview of profiling, which records summary information during program execution to expose performance bottlenecks. Profiling can be done through sampling or instrumentation. It also discusses tracing, which records time-stamped events during execution. The document compares profiling and tracing and describes tools like PAPI and HPCToolkit that can be used for profiling applications.
The document describes a system for measuring runtime performance of embedded software. The system makes minor changes to the real-time kernel to add calls to an output function during process switches and interrupts. This enables measurement of execution times, worst-case execution times, and processor utilization through an external logic analyzer. The system was used successfully to evaluate a real-time garbage collector.
Runtime performance evaluation of embedded softwareMr. Chanuwan
The document describes a system for measuring runtime performance of embedded software. The system makes minor changes to the real-time kernel to enable measuring execution times of processes and programs without significantly impacting performance. It was used to evaluate a real-time garbage collector and provided valuable debugging information. The system assigns unique IDs to processes and interrupts and calls an output function on certain events to log identification numbers for external analysis of timing and scheduling.
The document discusses the basic software architecture of a digital switching system. It describes the operating system, database management, and classification of digital switch software. It also provides an overview of a basic call model, including the connect sequence, and discusses the software linkages required during a typical call. Finally, it presents a simplified flow diagram for a call forwarding feature.
The document discusses various topics related to process management in Unix/Linux operating systems. It describes the different states a process can be in, such as ready, running, waiting, zombie, etc. It also explains process creation using fork() and program execution using exec(). Other topics covered include process termination with exit(), waiting for child processes using wait(), process relationships like parent-child, process identifiers, signals, and context switching.
System calls allow user programs to request services from the operating system kernel. They involve a transition from user to kernel mode, where the kernel performs the requested operation before returning control back to the user program. Common system calls include process control, file management, device management, and communication. While essential, system calls can impact performance due to mode switching overhead. Techniques like batching and inline system calls help mitigate this. Remote procedure calls and remote method invocation are invocation methods that allow processes to request services across a network.
HPC Application Profiling and AnalysisRishi Pathak
This document discusses application profiling and analysis. Profiling involves recording summary information during program execution to reflect performance behavior. It can expose bottlenecks and hotspots with low overhead. Profiling is implemented via sampling, which uses periodic interrupts, or instrumentation, which directly inserts measurement code. Tracing records significant execution points to reconstruct program behavior. Profiling provides summary statistics while tracing generates a large volume of event data. Tools like HPCToolkit use sampling and instrumentation to collect metrics that are correlated back to source code to analyze performance.
System calls allow programs to request services from the operating system kernel. Some common system calls include read and write for file access, fork for creating new processes, and wait for a parent process to wait for a child process to complete. The steps a system call takes include the program pushing parameters onto the stack, calling the library procedure to place the system call number in a register, triggering a trap instruction to switch to kernel mode, the kernel dispatching the system call to the appropriate handler, the handler running, then returning control to the user program after completing the operation.
This document discusses application profiling and analysis techniques. It provides an overview of profiling, which records summary information during program execution to expose performance bottlenecks. Profiling can be done through sampling or instrumentation. It also discusses tracing, which records time-stamped events during execution. The document compares profiling and tracing and describes tools like PAPI and HPCToolkit that can be used for profiling applications.
The document describes a system for measuring runtime performance of embedded software. The system makes minor changes to the real-time kernel to add calls to an output function during process switches and interrupts. This enables measurement of execution times, worst-case execution times, and processor utilization through an external logic analyzer. The system was used successfully to evaluate a real-time garbage collector.
Runtime performance evaluation of embedded softwareMr. Chanuwan
The document describes a system for measuring runtime performance of embedded software. The system makes minor changes to the real-time kernel to enable measuring execution times of processes and programs without significantly impacting performance. It was used to evaluate a real-time garbage collector and provided valuable debugging information. The system assigns unique IDs to processes and interrupts and calls an output function on certain events to log identification numbers for external analysis of timing and scheduling.
The document discusses the basic software architecture of a digital switching system. It describes the operating system, database management, and classification of digital switch software. It also provides an overview of a basic call model, including the connect sequence, and discusses the software linkages required during a typical call. Finally, it presents a simplified flow diagram for a call forwarding feature.
The document discusses key concepts related to process management in Linux, including process lifecycle, states, memory segments, scheduling, and priorities. It explains that a process goes through creation, execution, termination, and removal phases repeatedly. Process states include running, stopped, interruptible, uninterruptible, and zombie. Process memory is made up of text, data, BSS, heap, and stack segments. Linux uses a O(1) CPU scheduling algorithm that scales well with process and processor counts.
TAU Performance System and the Extreme-scale Scientific Software Stack (E4S) aim to improve productivity for HPC and AI workloads. TAU provides a portable performance evaluation toolkit, while E4S delivers modular and interoperable software stacks. Together, they lower barriers to using software tools from the Exascale Computing Project and enable performance analysis of complex, multi-component applications.
Each Unix task starts as a process with a unique process ID (PID). Processes can be started by the system as daemons or by users through the shell. The 'ps' command lists running processes while 'pgrep' searches for a specific process. Processes go through three stages - fork, exec, and termination. Signals are used to communicate between processes and the 'kill' command sends signals to terminate or suspend processes. Cron executes periodic tasks on a schedule, while 'top' monitors system resources and processes.
Programming Assignment #2CSci 430 Spring 2019Dates.docxstilliegeorgiana
Programming Assignment #2
CSci 430 Spring 2019
Dates:
Assigned: Monday February 4, 2019
Due: Wednesday February 20, 2019 (before Midnight)
Objectives:
ˆ Explore the Process state models from an implementation point of
view.
ˆ Practice using basic queue data types and implementing in C.
ˆ Use C/C++ data structures to implement a process control block and
round robin scheduling queues.
ˆ Learn about Process switching and multiprogramming concepts.
Description:
In this assignment you will simulate a Three-State process model (ready,
running and blocked) and a simple process control block structure as dis-
cussed in Chapter 3. Your program will read input and directives from a
�le. The input describes a time sequence of events that occur. These are the
full set of events you will simulate:
1
Event Description
cpu The processor executes for 1 time step the currently running process
new A new process is created and put at tail of the ready queue
done The currently running process has �nished
wait X The currently running process has done an I/O operation and
is waiting on event X
event X Event X has occurred, the process waiting on that event should
be made ready.
The input �le will simply be a list of events that occur in the system, in
the order they are to occur. For example:
----- simulation-01.sim --------
new
cpu
cpu
cpu
new
cpu
cpu
cpu
cpu
wait 1
cpu
cpu
event 1
cpu
cpu
done
cpu
cpu
cpu
cpu
exit
----------------------------------
Your task is to read in the events, and simulate the creation and execution
of processes in the system as they move through the various three-states of
their process life cycle. You need to:
2
ˆ De�ne a simple process control block (PCB) to hold information about
all processes currently running in your system. The PCB can be a
simple C struct or a C++ class. At a minimum you need to have a
�eld for the process identi�er and the process state (Ready, Running or
Blocked). You need to also keep track of the time step that the process
entered the system, and the number of steps the process has been
running. Minimal credit will be given to programs that at least handle
new events and create a process in a simulated PCB. You probably
need a list or an array to hold the current processes that have been
created and are being managed by your simulated system.
ˆ You will need a ready queue of some kind. You should use a C++
Standard Template Library (STL) container to manage your ready
queue.
ˆ You will need to implement a simple dispatcher function. Whenever
a cpu event occurs, and no process is currently running, you should
select the next Ready process from the head of your ready queue and
start it running on the processor.
ˆ You need to also implement a simple time slicing mechanism. The
time slice value to use will be passed into your program when it is
started. At the end of a cpu cycle, you should check if the currently
running process has executed for its full time quant ...
Programming Assignment #2CSci 430 Spring 2019Dates.docxdenneymargareta
Programming Assignment #2
CSci 430 Spring 2019
Dates:
Assigned: Monday February 4, 2019
Due: Wednesday February 20, 2019 (before Midnight)
Objectives:
ˆ Explore the Process state models from an implementation point of
view.
ˆ Practice using basic queue data types and implementing in C.
ˆ Use C/C++ data structures to implement a process control block and
round robin scheduling queues.
ˆ Learn about Process switching and multiprogramming concepts.
Description:
In this assignment you will simulate a Three-State process model (ready,
running and blocked) and a simple process control block structure as dis-
cussed in Chapter 3. Your program will read input and directives from a
�le. The input describes a time sequence of events that occur. These are the
full set of events you will simulate:
1
Event Description
cpu The processor executes for 1 time step the currently running process
new A new process is created and put at tail of the ready queue
done The currently running process has �nished
wait X The currently running process has done an I/O operation and
is waiting on event X
event X Event X has occurred, the process waiting on that event should
be made ready.
The input �le will simply be a list of events that occur in the system, in
the order they are to occur. For example:
----- simulation-01.sim --------
new
cpu
cpu
cpu
new
cpu
cpu
cpu
cpu
wait 1
cpu
cpu
event 1
cpu
cpu
done
cpu
cpu
cpu
cpu
exit
----------------------------------
Your task is to read in the events, and simulate the creation and execution
of processes in the system as they move through the various three-states of
their process life cycle. You need to:
2
ˆ De�ne a simple process control block (PCB) to hold information about
all processes currently running in your system. The PCB can be a
simple C struct or a C++ class. At a minimum you need to have a
�eld for the process identi�er and the process state (Ready, Running or
Blocked). You need to also keep track of the time step that the process
entered the system, and the number of steps the process has been
running. Minimal credit will be given to programs that at least handle
new events and create a process in a simulated PCB. You probably
need a list or an array to hold the current processes that have been
created and are being managed by your simulated system.
ˆ You will need a ready queue of some kind. You should use a C++
Standard Template Library (STL) container to manage your ready
queue.
ˆ You will need to implement a simple dispatcher function. Whenever
a cpu event occurs, and no process is currently running, you should
select the next Ready process from the head of your ready queue and
start it running on the processor.
ˆ You need to also implement a simple time slicing mechanism. The
time slice value to use will be passed into your program when it is
started. At the end of a cpu cycle, you should check if the currently
running process has executed for its full time quant ...
The operating system provides programs an environment to execute and users services to run programs conveniently, including a user interface, program execution, I/O operations, file system manipulation, communication, error detection, and resource allocation. An operating system offers these services through system calls that programs make to request services from the kernel, while hiding the implementation details of system calls from programmers through an application programming interface. Key system calls include process creation, memory management, file access, device handling, protection, and networking.
OS | Functions of OS | Operations of OS | Operations of a process | Scheduling algorithms | FCFS scheduling | SJF scheduling | RR scheduling | Paging | File system implementation | Cryptography as a security tool
This document discusses managing and processing processes in a system. It explains that every running program is a separate process with a unique process ID. It describes how to obtain information on running processes, start new processes, and end processes through various commands. It also covers job control in UNIX, allowing users to start, suspend, resume, and kill groups of processes associated with a job.
This document discusses inter-process communication using signals in Unix/Linux systems. It defines what signals are and describes how they allow processes to communicate asynchronously. It provides details on the different types of signals, the default and customizable actions when a signal is received, and examples of handling signals using the signal() and alarm() system calls. It also covers process groups and how they determine which processes receive signals from a terminal's control process.
The document discusses operating system concepts like processor modes, system calls, inter-process communication (IPC), process creation, and linking and loading of processes. It defines an operating system as an interface between the user and computer hardware that manages system resources efficiently. It explains that the CPU has two modes - kernel mode and user mode - to distinguish between system and user code. System calls allow user programs to request services from the operating system by triggering an interrupt to switch to kernel mode. Common IPC mechanisms and their related system calls are also outlined.
Inter Process communication and Memory ManagementPoonamChawhan1
The document is a lecture presentation on inter-process communication and memory in Linux. It discusses signals and semaphores that allow processes to communicate events. It describes how processes can specify actions in response to signals. The document also covers zombie processes, memory management including virtual memory and demand paging, and provides an abstract model of how virtual memory is translated to physical addresses.
OPERATING SYSTEM SERVICES, OPERATING SYSTEM STRUCTURESpriyasoundar
These slides will help the engineering students for understanding the functionalities of operating system and its structure. Also it will help them for their exam preparation.
Signals are software interrupts that give us a way to handle asynchronous events.Stuck with your System Programming Assignment. Get 24/7 help from tutors with Phd in the subject. Email us at support@helpwithassignment.com
Reach us at http://www.HelpWithAssignment.com
Pipelining is an implementation technique where multiple instructions are overlapped in execution. The computer pipeline is divided in stages. Each stage completes a part of an instruction in parallel.
S4 is a distributed stream computing platform that allows programmers to develop applications for processing continuous streams of data. It is inspired by MapReduce and actor models of computation. S4 aims to provide a simple programming interface, scale using commodity hardware, minimize latency, and use a decentralized architecture. Processing in S4 is done using processing elements that operate on streaming data events in a distributed manner across processing nodes.
This document provides an overview of kernel APIs and system calls. It discusses that the kernel acts as an interface between user applications and hardware, and its objectives include managing communication between software and hardware, controlling tasks, and establishing communication. It describes different types of kernels like monolithic, micro, and hybrid kernels. It also explains important concepts like system calls, which allow processes to request services from the kernel, and examples of common system calls like wait, fork, exec, kill, and exit. Finally, it gives examples of kernel APIs for managing linked lists, including adding/removing entries and moving between lists.
This document discusses process management in operating systems. It defines processes and describes the key components of a process, including program code, data, stack, and process state. Each process is represented by a process control block (PCB) that contains the process state, CPU registers, scheduling information, memory management information, and I/O status. Processes can be created, terminated, and communicate through interprocess communication (IPC). Context switching allows the CPU to rapidly switch between running processes.
The document discusses process management in operating systems. It defines a process as a program during execution, which requires resources like memory and CPU registers. The document outlines the life cycle of a process, including the different states a process can be in like ready, running, waiting, blocked. It describes process creation and termination. The process control block (PCB) contains information needed to control and monitor each process. Context switching allows the CPU to switch between processes. Scheduling determines which process enters the running state. The document lists some common process control system calls and discusses advantages and disadvantages of process management.
This document discusses process management in operating systems. It defines a process as a program in execution. Processes can be either CPU-bound or I/O-bound. The operating system manages processes through functions like creation, scheduling, and context switching. Processes exist in various states like running, ready, waiting, and terminated. The CPU utilizes scheduling algorithms like first come first served and round robin to allocate processes to the CPU. Processes communicate through interprocess communication mechanisms like message passing and shared memory.
The document discusses key concepts related to process management in Linux, including process lifecycle, states, memory segments, scheduling, and priorities. It explains that a process goes through creation, execution, termination, and removal phases repeatedly. Process states include running, stopped, interruptible, uninterruptible, and zombie. Process memory is made up of text, data, BSS, heap, and stack segments. Linux uses a O(1) CPU scheduling algorithm that scales well with process and processor counts.
TAU Performance System and the Extreme-scale Scientific Software Stack (E4S) aim to improve productivity for HPC and AI workloads. TAU provides a portable performance evaluation toolkit, while E4S delivers modular and interoperable software stacks. Together, they lower barriers to using software tools from the Exascale Computing Project and enable performance analysis of complex, multi-component applications.
Each Unix task starts as a process with a unique process ID (PID). Processes can be started by the system as daemons or by users through the shell. The 'ps' command lists running processes while 'pgrep' searches for a specific process. Processes go through three stages - fork, exec, and termination. Signals are used to communicate between processes and the 'kill' command sends signals to terminate or suspend processes. Cron executes periodic tasks on a schedule, while 'top' monitors system resources and processes.
Programming Assignment #2CSci 430 Spring 2019Dates.docxstilliegeorgiana
Programming Assignment #2
CSci 430 Spring 2019
Dates:
Assigned: Monday February 4, 2019
Due: Wednesday February 20, 2019 (before Midnight)
Objectives:
ˆ Explore the Process state models from an implementation point of
view.
ˆ Practice using basic queue data types and implementing in C.
ˆ Use C/C++ data structures to implement a process control block and
round robin scheduling queues.
ˆ Learn about Process switching and multiprogramming concepts.
Description:
In this assignment you will simulate a Three-State process model (ready,
running and blocked) and a simple process control block structure as dis-
cussed in Chapter 3. Your program will read input and directives from a
�le. The input describes a time sequence of events that occur. These are the
full set of events you will simulate:
1
Event Description
cpu The processor executes for 1 time step the currently running process
new A new process is created and put at tail of the ready queue
done The currently running process has �nished
wait X The currently running process has done an I/O operation and
is waiting on event X
event X Event X has occurred, the process waiting on that event should
be made ready.
The input �le will simply be a list of events that occur in the system, in
the order they are to occur. For example:
----- simulation-01.sim --------
new
cpu
cpu
cpu
new
cpu
cpu
cpu
cpu
wait 1
cpu
cpu
event 1
cpu
cpu
done
cpu
cpu
cpu
cpu
exit
----------------------------------
Your task is to read in the events, and simulate the creation and execution
of processes in the system as they move through the various three-states of
their process life cycle. You need to:
2
ˆ De�ne a simple process control block (PCB) to hold information about
all processes currently running in your system. The PCB can be a
simple C struct or a C++ class. At a minimum you need to have a
�eld for the process identi�er and the process state (Ready, Running or
Blocked). You need to also keep track of the time step that the process
entered the system, and the number of steps the process has been
running. Minimal credit will be given to programs that at least handle
new events and create a process in a simulated PCB. You probably
need a list or an array to hold the current processes that have been
created and are being managed by your simulated system.
ˆ You will need a ready queue of some kind. You should use a C++
Standard Template Library (STL) container to manage your ready
queue.
ˆ You will need to implement a simple dispatcher function. Whenever
a cpu event occurs, and no process is currently running, you should
select the next Ready process from the head of your ready queue and
start it running on the processor.
ˆ You need to also implement a simple time slicing mechanism. The
time slice value to use will be passed into your program when it is
started. At the end of a cpu cycle, you should check if the currently
running process has executed for its full time quant ...
Programming Assignment #2CSci 430 Spring 2019Dates.docxdenneymargareta
Programming Assignment #2
CSci 430 Spring 2019
Dates:
Assigned: Monday February 4, 2019
Due: Wednesday February 20, 2019 (before Midnight)
Objectives:
ˆ Explore the Process state models from an implementation point of
view.
ˆ Practice using basic queue data types and implementing in C.
ˆ Use C/C++ data structures to implement a process control block and
round robin scheduling queues.
ˆ Learn about Process switching and multiprogramming concepts.
Description:
In this assignment you will simulate a Three-State process model (ready,
running and blocked) and a simple process control block structure as dis-
cussed in Chapter 3. Your program will read input and directives from a
�le. The input describes a time sequence of events that occur. These are the
full set of events you will simulate:
1
Event Description
cpu The processor executes for 1 time step the currently running process
new A new process is created and put at tail of the ready queue
done The currently running process has �nished
wait X The currently running process has done an I/O operation and
is waiting on event X
event X Event X has occurred, the process waiting on that event should
be made ready.
The input �le will simply be a list of events that occur in the system, in
the order they are to occur. For example:
----- simulation-01.sim --------
new
cpu
cpu
cpu
new
cpu
cpu
cpu
cpu
wait 1
cpu
cpu
event 1
cpu
cpu
done
cpu
cpu
cpu
cpu
exit
----------------------------------
Your task is to read in the events, and simulate the creation and execution
of processes in the system as they move through the various three-states of
their process life cycle. You need to:
2
ˆ De�ne a simple process control block (PCB) to hold information about
all processes currently running in your system. The PCB can be a
simple C struct or a C++ class. At a minimum you need to have a
�eld for the process identi�er and the process state (Ready, Running or
Blocked). You need to also keep track of the time step that the process
entered the system, and the number of steps the process has been
running. Minimal credit will be given to programs that at least handle
new events and create a process in a simulated PCB. You probably
need a list or an array to hold the current processes that have been
created and are being managed by your simulated system.
ˆ You will need a ready queue of some kind. You should use a C++
Standard Template Library (STL) container to manage your ready
queue.
ˆ You will need to implement a simple dispatcher function. Whenever
a cpu event occurs, and no process is currently running, you should
select the next Ready process from the head of your ready queue and
start it running on the processor.
ˆ You need to also implement a simple time slicing mechanism. The
time slice value to use will be passed into your program when it is
started. At the end of a cpu cycle, you should check if the currently
running process has executed for its full time quant ...
The operating system provides programs an environment to execute and users services to run programs conveniently, including a user interface, program execution, I/O operations, file system manipulation, communication, error detection, and resource allocation. An operating system offers these services through system calls that programs make to request services from the kernel, while hiding the implementation details of system calls from programmers through an application programming interface. Key system calls include process creation, memory management, file access, device handling, protection, and networking.
OS | Functions of OS | Operations of OS | Operations of a process | Scheduling algorithms | FCFS scheduling | SJF scheduling | RR scheduling | Paging | File system implementation | Cryptography as a security tool
This document discusses managing and processing processes in a system. It explains that every running program is a separate process with a unique process ID. It describes how to obtain information on running processes, start new processes, and end processes through various commands. It also covers job control in UNIX, allowing users to start, suspend, resume, and kill groups of processes associated with a job.
This document discusses inter-process communication using signals in Unix/Linux systems. It defines what signals are and describes how they allow processes to communicate asynchronously. It provides details on the different types of signals, the default and customizable actions when a signal is received, and examples of handling signals using the signal() and alarm() system calls. It also covers process groups and how they determine which processes receive signals from a terminal's control process.
The document discusses operating system concepts like processor modes, system calls, inter-process communication (IPC), process creation, and linking and loading of processes. It defines an operating system as an interface between the user and computer hardware that manages system resources efficiently. It explains that the CPU has two modes - kernel mode and user mode - to distinguish between system and user code. System calls allow user programs to request services from the operating system by triggering an interrupt to switch to kernel mode. Common IPC mechanisms and their related system calls are also outlined.
Inter Process communication and Memory ManagementPoonamChawhan1
The document is a lecture presentation on inter-process communication and memory in Linux. It discusses signals and semaphores that allow processes to communicate events. It describes how processes can specify actions in response to signals. The document also covers zombie processes, memory management including virtual memory and demand paging, and provides an abstract model of how virtual memory is translated to physical addresses.
OPERATING SYSTEM SERVICES, OPERATING SYSTEM STRUCTURESpriyasoundar
These slides will help the engineering students for understanding the functionalities of operating system and its structure. Also it will help them for their exam preparation.
Signals are software interrupts that give us a way to handle asynchronous events.Stuck with your System Programming Assignment. Get 24/7 help from tutors with Phd in the subject. Email us at support@helpwithassignment.com
Reach us at http://www.HelpWithAssignment.com
Pipelining is an implementation technique where multiple instructions are overlapped in execution. The computer pipeline is divided in stages. Each stage completes a part of an instruction in parallel.
S4 is a distributed stream computing platform that allows programmers to develop applications for processing continuous streams of data. It is inspired by MapReduce and actor models of computation. S4 aims to provide a simple programming interface, scale using commodity hardware, minimize latency, and use a decentralized architecture. Processing in S4 is done using processing elements that operate on streaming data events in a distributed manner across processing nodes.
This document provides an overview of kernel APIs and system calls. It discusses that the kernel acts as an interface between user applications and hardware, and its objectives include managing communication between software and hardware, controlling tasks, and establishing communication. It describes different types of kernels like monolithic, micro, and hybrid kernels. It also explains important concepts like system calls, which allow processes to request services from the kernel, and examples of common system calls like wait, fork, exec, kill, and exit. Finally, it gives examples of kernel APIs for managing linked lists, including adding/removing entries and moving between lists.
This document discusses process management in operating systems. It defines processes and describes the key components of a process, including program code, data, stack, and process state. Each process is represented by a process control block (PCB) that contains the process state, CPU registers, scheduling information, memory management information, and I/O status. Processes can be created, terminated, and communicate through interprocess communication (IPC). Context switching allows the CPU to rapidly switch between running processes.
The document discusses process management in operating systems. It defines a process as a program during execution, which requires resources like memory and CPU registers. The document outlines the life cycle of a process, including the different states a process can be in like ready, running, waiting, blocked. It describes process creation and termination. The process control block (PCB) contains information needed to control and monitor each process. Context switching allows the CPU to switch between processes. Scheduling determines which process enters the running state. The document lists some common process control system calls and discusses advantages and disadvantages of process management.
This document discusses process management in operating systems. It defines a process as a program in execution. Processes can be either CPU-bound or I/O-bound. The operating system manages processes through functions like creation, scheduling, and context switching. Processes exist in various states like running, ready, waiting, and terminated. The CPU utilizes scheduling algorithms like first come first served and round robin to allocate processes to the CPU. Processes communicate through interprocess communication mechanisms like message passing and shared memory.
Similar to Unit 3.2 Process Control.ppt (Process Control and Scheduling) (20)
- The Unix operating system originated from the MULTICS project in the 1960s. Bell Labs researchers Ken Thompson and Dennis Ritchie developed the first version of Unix in 1969.
- Unix became popular due to its portability, simplicity, and ability to support complex programs built from simpler ones. It introduced a hierarchical file system, consistent file format, and multi-user capabilities.
- Over time, Unix evolved into two main versions - System V (SVR) and Berkeley Software Distribution (BSD). Linux was later developed as a Unix-like system and shares many similarities with SVR.
Beyond Degrees - Empowering the Workforce in the Context of Skills-First.pptxEduSkills OECD
Iván Bornacelly, Policy Analyst at the OECD Centre for Skills, OECD, presents at the webinar 'Tackling job market gaps with a skills-first approach' on 12 June 2024
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
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Unit 3.2 Process Control.ppt (Process Control and Scheduling)
1. Sanjivani Rural Education Society’s
Sanjivani College of Engineering, Kopargaon-423 603
(An Autonomous Institute, Affiliated to Savitribai Phule Pune University, Pune)
NAAC ‘A’ Grade Accredited, ISO 9001:2015 Certified
Department of Computer Engineering
(NBA Accredited)
Prof. A. V. Brahmane
Assistant Professor
E-mail : brahmaneanilkumarcomp@sanjivani.org.in
Contact No: 91301 91301 Ext :145, 9922827812
Subject- Operating System and Administration (CO2013)
Unit III- The Structure of Process, Process Control and
Process Scheduling
2. Content
• Process state and transitions,
• Layout of the system memory,
• Context of the process,
• Saving the context of the process,
• Manipulation the process address space,
• Sleep,
• Process creation,
• Signal,
• Process termination, Awaiting the process termination,
• Invoking other program, Process Scheduling
• Case Study - Access Control, Rootly Powers and Controlling Processes
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
3. Process Control – Scheduling
• The relationship between the system calls and memory management algorithms
is shown in the following diagram:
• Almost all calls use sleep and wakeup so its not shown in the figure. exec also interacts with the
file system algorithms
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
4. Process Creation
• The only way to create a new process in UNIX is to use the fork system call. The
process which calls fork is called the parent process and the newly created
process is called the child process.
• pid = fork();
• On return of the fork system call, the two processes have identical user-level
context except for the value of pid. pid for the parent process is the process ID of
the child process. And pid for child process is 0. The process 0 is the only process
which is not created via fork.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
5. • The steps followed by the kernel for fork are:
• It creates a new entry in the process table.
• It assigns a unique ID to the newly created process.
• It makes a logical copy of the regions of the parent process. If a regions can be
shared, only its reference count is incremented instead of making a physical copy
of the region.
• The reference counts of file table entries and inodes of the process are increased.
• It turned the child process ID to the parent and 0 to the child.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
7. Fork creating a New process context
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
8. Signals
• Signals inform processes of the occurrence of asynchronous events. Processes
may send each other signals with the kill system call, or the kernel may send
signals internally.
• There are 19 signals in the System V (Release 2) UNIX system that can be
classified as follows:
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
9. Signal Classifications
• Signals having to do with the termination of a process, send when a process exits or when a process invokes
the signal system call with the death of child parameter.
• Signals having to do with process induced exceptions such as when a process accesses an address outside its
virtual address space, when it attempts to write memory that is read-only (such as program text), or when it
executes a privileged instruction or for various hardware errors.
• Signals having to do with the unrecoverable conditions during a system call, such as running out of system
resources during exec after the original address space has been released
• Signals caused by an unexpected error condition during a system call, such as making a nonexistent system
call (the process passed a system call number that does not correspond to a legal system call), writing a pipe
that has no reader processes, or using an illegal "reference" value for the lseek system call. It would be more
consistent to return an error on such system calls instead of generating a signal, but the use of signals to
abort misbehaving processes is more pragmatic.
• Signals originating from a process in user mode, such as when a process wishes to receive an alarm signal
after a period of time, or when processes send arbitrary signals to each other with the kill system call.
• Signals related to terminal interaction such as when a user hands up a terminal (or the "carrier" signal drops
on such a line for any reason), or when a user presses the "break" or "delete" keys on a terminal keyboard.
• Signals for tracing execution of a process.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
10. Checking and Handling Signals in the Process State Diagram
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
14. Process Groups
• The system has to identify processes by "groups" in some cases, for instance, a
signal might relate to all the processes which are ancestors of the login shell. The
kernel uses the process group ID to identify groups of related processes that
should receive a common signal for certain events. It saves the group ID in the
process table.
• The setpgrp system call initializes the process group number of a process and sets
it equal to the value of its process ID.
• grp = setpgrp();
• where grp is the new process group number. A child retains the process group
number of its parent during fork.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
15. Sending Signals from Processes
• Processes use the kill system call to send signals.
• kill (pid, signum);
• where pid identifies the set of processes to receive the signal, and signum is the signal number
being sent. The following list shows the correspondence between values of pid and sets of
processes.
• If pid is a positive integer, the kernel sends the signal to the process with process ID pid.
• If pid is 0, the kernel sends the signal to all processes in the sender's process group.
• If pid is -1, the kernel sends the signal to all processes whose real user ID equals the effective user
ID of the sender (real and effective user IDs are studied later). If the sending process has effective
user ID of superuser, the kernel sends the signal to all processes except processes 0 and 1.
• If pid is a negative integer but not -1, the kernel sends the signal to all processes in the process
group equal to the absolute value of pid.
• In all cases, if the sending process does not have effective user ID of superuser, or its real or
effective user ID do not match the real or effective user ID of the receiving process, kill fails.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
16. Process Termination
• Processes on the UNIX system exit by executing the exit system call. When a
process exits, it enters the zombie state, relinquishes all of its resources, and
dismantles its context except for its process table entry.
• exit (status);
• where status is the exit code returned to the parent. The process may
call exit explicitly, but the startup routine in C calls exit after the main function
returns. The kernel may call exit on receiving an uncaught signal. In such cases,
the value of status is the signal number.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
17. The algorithm for exit
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
18. Awaiting Process Termination
• A process can synchronize its execution with the termination of a child process by
executing the wait system call.
• pid = wait (stat_addr);
• where pid is the process ID of the zombie child, and stat_addr is the address in
user space of an integer that will contain the exit status code of the child.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
19. The algorithm for wait
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
20. Invoking Other Programs
• The exec system call overlays the address space of a process with the contents of
an executable file.
• execve (filename, argv, envp)
• where filename is name of the file being invoked, argv is a pointer to array of
character pointers which are arguments to the program in the executable file,
and envp is a pointer to array of character pointers which are the environment of
the executed program. There are several library functions that call exec,
like execl, execv, execle, and so on. All call execve eventually. The character strings
in the envp array are of the form, "name=value". C programs can access the
environment variables by accessing the global variable environ, initialized by the
C startup routine.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
21. The algorithm for exec
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
22. The User ID of a Process
• There are two user ID associated with a process, the real user ID and the effective
user ID or setuid (set user ID). The real user ID identifies the user who is
responsible for the running process. The effective user ID is used to assign
ownership of newly created files, to check file access permissions, and to check
permission to send signals to processes via the kill system call. The kernel allows a
process to change its effective user ID when it execs a setuid program or when it
invokes the setuid system call explicitly.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
23. • A setuid program is an executable file that has the setuid bit set in its permission
mode field. When a process execs a setuid program, the kernel sets the effective
user ID fields in the process table and u-area to the owner ID of the file. To
distinguish the two fields, let us call the field in the process table the saved user
ID.
• setuid (uid);
• where uid is the new user ID, and its result depends on the current value of the
effective user ID. If the effective user ID of the calling process is superuser, the
kernel resets the real and effective user ID fields in the process table and u-area
to uid. If its not the superuser, the kernel resets the effective user ID in the u-area
to uid if uid has the value of the real user ID or if it has the value of the saved user
ID. Otherwise, the system call returns an error. Generally, a process inherits its
real and effective user IDs from its parent during the fork system call and
maintains their values across exec system calls.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon
24. Changing the Size of a Process
• A process can increase or decrease the size of its data region by using
the brk system call.
• brk (endds);
• where endds becomes the value of the highest virtual address of the data region
of the process (called its break value). Alternatively, a user can call
• oldendds = sbrk(increment);
• where increment changes the current break value by the specified number of
bytes, and oldendds is the break value before the call. sbrk is a C library routine
that calls brk. The kernel checks that the new process size is less than the system
maximum and that the new data region does not overlap previously assigned
virtual address space.
DEPARTMENT OF COMPUTER ENGINEERING, Sanjivani COE, Kopargaon