Processes

A ___________ is a program loaded into memory and executing.

process

A process will need certain ___________ such as CPU time, memory, files, and I/O devices to accomplish its task.

resources

A process is the unit of ___________ in most systems.

work

Modern operating systems support processes having multiple ___________ of control.

threads

On systems with multiple hardware processing cores, these threads can run in ___________.

parallel

Early computers allowed only one ___________ to be executed at a time.

program

A process is the unit of ___________ in a modern computing system.

work

A system therefore consists of a collection of ___________, some executing user code, others executing operating system code.

processes

The status of the current activity of a process is represented by the value of the ___________ ___________ and the contents of the processor's registers.

program counter

The memory layout of a process is typically divided into multiple ___________.

sections

___________ section is the executable code.

Text

___________ section contains global variables.

Data

___________ section is memory that is dynamically allocated during program run time.

Heap

___________ section is temporary data storage when invoking functions (such as function parameters, return addresses, and local variables).

Stack

The sizes of the text and data sections are ___________.

fixed

The ___________ and ___________ sections can shrink and grow dynamically during program execution.

stack, heap

A program is a ___________ entity.

passive

A program becomes a process when an ___________ file is loaded into memory.

executable

It is also common to have a process that ___________ many processes as it runs.

spawns

A process can itself be an ___________ environment for other code.

execution

As a process executes, it ___________ state.

changes

The ___________ of a process is defined in part by the current activity of that process.

state

The process is being ___________.

created

Instructions are being ___________.

executed

The process is waiting for some ___________ to occur.

event

The process is waiting to be ___________ to a processor.

assigned

The process has finished ___________.

execution

The global data section is divided into different sections for (a) ___________ data and (b) uninitialized data.

initialized

A separate section is provided for the argc and argv parameters passed to the ___________ ( ) function.

main

The ___________ field refers to initialized data, and bss refers to uninitialized data.

data

___________ is a historical term referring to block started by symbol.

bss

Only one process can be ___________ on any processor core at any instant.

running

Each process is represented in the operating system by a process control block (PCB) - also called a ___________ ___________ ___________.

task control block

The ___________ indicates the address of the next instruction to be executed for this process.

counter

The ___________ vary in number and type, depending on the computer architecture.

registers

This information includes a process priority, pointers to scheduling queues, and any other ___________ parameters.

scheduling

This information may include such items as the value of the base and limit registers and the ___________ tables, or the segment tables, depending on the memory system used by the operating system.

page

This information includes the amount of CPU and real time used, time limits, account numbers, job or process numbers, and so on.

Accounting

This information includes the list of I/O devices allocated to the process, a list of ___________ files, and so on.

open

The PCB simply serves as the ___________ for all the data needed to start, or restart a process, along with some accounting data.

repository

The process model discussed so far has implied that a process is a program that performs a ___________ thread of execution.

single

Most modern operating systems have extended the process concept to allow a process to have ___________ threads of execution and thus to perform more than one task at a time.

multiple

This feature is especially beneficial on ___________ systems, where multiple threads can run in parallel.

multicore

On systems that support threads, the ___________ is expanded to include information for each thread.

PCB

The convention in modern operating systems and compilers is that the ___________ of a process contains temporary data such as function parameters, return addresses, and local variables.

stack

A process control block ___________ a process' states.

contains

A process may transition to the Ready state by which of the following actions? While the process is waiting for completion of an I/O event or an ___________ has occurred or an I/O operation the process is waiting for has completed.

interrupt

A ___________ is a set of commands or processes executed by a batch system.

job

___________ are user-level programs, as opposed to system programs.

User programs

A process is a program loaded into memory and ___________.

executing

A CPU register indicating the main memory location of the next instruction to load and execute is called ___________.

program counter

The ___________ ___________ is the executable code of a program or process.

text section

The ___________ section is the data part of a program or process; it contains global variables.

data

The ___________ section of process memory that is dynamically allocated during process run time; it stores temporary variables.

heap section

The section of process memory that contains the stack, it contains activation records and other temporary data is called ___________ ___________.

stack section

A record created when a function or subroutine is called is added to the stack by the call and removed when the call returns. It contains function parameters, local variables, and the return address and is called ___________ ___________.

activation record

A file containing a program that is ready to be loaded into memory and executed is an ___________ ___________.

executable file

The condition of a process, including its current activity as well as its associated memory and disk contents, is the process’s ___________.

state

A per-process kernel data structure containing many pieces of information associated with the process is called a ___________ ___________ ___________.

process control block

A process control structure that is an execution location is called a ___________.

thread

A process with a single thread executes only ___________ task at a time, while a multithreaded process can execute a task per thread.

one

The objective of ___________ is to have some process running at all times so as to maximize CPU utilization.

multiprogramming

The objective of ___________ ___________ is to switch a CPU core among processes so frequently that users can interact with each program while it is running.

time sharing

The ___________ ___________ selects an available process for program execution on a core.

process scheduler

Each CPU core can run ___________ process at a time.

one

The number of processes currently in memory is known as the ___________ of multiprogramming.

degree

The process control block in the Linux operating system is represented by the C structure ___________.

task_struct

A process's ___________ is the process that created it.

parent

A process’s ___________ are any processes that it creates.

children

A process’s ___________ are children with the same parent process.

siblings

Within the Linux kernel, all active processes are represented using a ___________ ___________ ___________ of task_struct.

doubly linked list

The kernel maintains a pointer-current-to the process ___________ executing on the system.

currently

In general, most processes can be described as either I/O bound or ___________ bound.

CPU