process

D-Bus Tutorial

  • by kjohri

1.0 D-Bus

D-Bus is a mechanism for interprocess communication under Linux and other Unix-like systems. D-Bus has a layered architecture. At the lowest level is the D-Bus wire protocol described in the D-Bus Specification. The libdbus library is an implementation of the wire protocol.… Read more

Threads

POSIX Threads Programming in C

  • by kjohri

1.0 POSIX threads

A process is an execution environment in an operating system. A process has code and data segments which are initialized from a program during an exec system call. A process has a thread of execution, wherein instructions are executed as per the value of the program counter register.… Read more

POSIX message queues in Linux

  • by kjohri

1.0 POSIX Message queues

POSIX interprocess comunication (IPC) was introduced in the POSIX.1b standard (IEEE Std 1003.1b-1993) for real time extensions. POSIX message queues have been made available in Linux since the version 2.6.6 (May 2004). POSIX IPC calls are as per the standard but may not be available on older Unix-like systems.… Read more

FIFOs in Linux

  • by kjohri

1.0 FIFO

FIFOs are pipes with a name and are also commonly referred to as named pipes. Pipes are common on Linux command lines but do not have a system-wide name. So, any two processes that wish to communicate using a pipe need to be related, either parent and child or, sharing a common parent, who sets up the pipe and passes its file descriptors to individual processes.… Read more

Pipes in Linux

  • by kjohri

1.0 Interprocess communication

A process is an active operating system entity which executes programs. Normally, a process, like a specialist, does one particular job (well). In real life, there are complex workflows and we, often, have multiple processes collaborating to accomplish certain objectives.… Read more

umask in Linux

  • by kjohri

File Permissions

In Linux, each files has nine permission bits. There are three basic permissions, read (r), write (w) and execute (x), for a file. These three permissions are there for the owner (o) of the file, the group (g) set for the file and the "others" (o).… Read more

htop command – explained

  • by kjohri

1.0 INTRODUCTION

htop is a ncurses based program for viewing processes in a system running Linux. htop is quite similar to the top command. However, since htop is a newer program compared to top, it offers many improvements. htop supports mouse operation, uses color in its output and gives visual indications about processor, memory and swap usage.… Read more

pidstat

  • by kjohri

The best way to use pidstat is to pass a list of process ids with the -p parameter. The -u option reports CPU utilization. The -l parameter displays the process command name and its arguments. And we can optionally put time interval in seconds for the interval between reports and again, optionally, a count for number of reports.… Read more

Linux process execution time

  • by kjohri

Execution time

A process has an execution time associated with it. The execution time comprises of two parts, the user time and the system time. The user time is the time spent by the CPU in executing instructions in user mode.… Read more

Program, Process and Threads

  • by kjohri

PROGRAM

The definition of program is linked to the definition of algorithm. An algorithm is a sequence of finite steps which can be executed mechanically to solve a problem. The key points are that algorithms are self-contained; the steps given are sufficient to solve the problem at hand.… Read more