Flashcards in The Kernel, Programs, and Processes Deck (11):
The Linux kernel is an...?
an environment in which programs run, providing mechanisms for programs to interact with the computer hardware.
Kernel lets programs know when a...?
keyboard key was struck, when the mouse moved, or when a packet destined for the program arrived over the network. It allows programs to access the harddrive, perhaps to read a configuration files or store data.
Programs are files that are...?
stored on a computer's harddrive. It is a series of very basic instructions, that tell the OS what to do and when to do it in a very detailed and specific manner.
Because the tasks that a computer can do vary from one type of CPU to another, and because different OS can be thought of us numbering the tasks differently, programs that are complied for one type of OS will..?
generally not run on the other OS
The copy of a program running in a memory is called a...?
Process. (Note that the same program can be loaded into memory and run more than once, so that at any point the kernel might be running several processes which are instances of the same program)
Linux is a ________ OS
Multitasking. (Means that the kernel gives the appearance of running multiple processes simultaneously. In reality, the kernel is running a single process for a brief amount of time, usually on the order of 50 milliseconds. It then swaps that process out, and swaps in another one for its 50 milliseconds of action. Eventually, the kernel works its way through all of the processes and starts over again. The rapid switching from process to process gives the users of the machine the impression that all of the processes are running simultaneously.)
Linux users often user a special type of program, called a...?
Shell, to interact with the kernel. (the shell runs within a terminal, issuing a prompt and waiting to be told what to do. A user then asks the shell to run a program by typing in the name of the program.)
ps command is commonly used to...?
List processes running on a system. (The ps command without arguments, shows all of the processes that were started from a single terminal (or terminal window in a graphical environment)).
ps aux command shows a detailed list of...?
all processes that are currently running on the system.