Intro 2 Flashcards
Each piece of time–called a _______ gives a process enough time for significant computation.
time slice
Because time slices are so small, humans can’t perceive them, and the system appears to be running multiple processes at the same time (a capability known as _____).
multitasking
When does the kernel run?
Between process time slices during a context switch.
Modern CPUs include a memory management unit (MMU) that enables a memory access schem called __________.
virtual memory
When using virtual memory, a process does not directly access the memory by its ________.
physical location in the hardware
The implementation of a memory address map is called a ________.
page table
Device drivers have traditionally been part of the ____, and they strive to present _____ to ____ in order to simplify the software developer’s job.
kernel
a uniform interface
user processes
Two system calls, ___ and ____, are important to understanding how processes start up.
fork()
exec()
When a process calls fork(), the kernel ______.
creates a nearly identical copy of the process
When a process calls exec(program), the kernel________.
starts program, replacing the current process.
Other than ____, all user processes on a Linux system start as a result of fork().
init
Pseudo-devices look like devices to user processes, but _____.
they’re purely implemented in software.
What is a user?
A user is an entity that can run processes and own files.
Users exist primarily to support ________.
permissions and boundaries
Every user-space process has a ________, and processes are said to run _______.
user-owner
as the owner
What are groups and what is their primary purpose?
Groups are sets of users. The primary purpose of groups is to allow a user to hsare file access to other users in a group.
Where is the shell located?
/bin/sh
Linux uses an enhanced version of the Bourne shell developed by Bell Labs for early versions of Unix. The enhanced version is called ____ or the ______ shell.
bash
Bourne-again
What does it mean when a shell command starts with a #?
Run the command as root
What is the difference between CTRL-D and CTRL-C?
CTRL-D stops the current standard input entry from the terminal (and often terminates a program)
CTRl-C terminates a program regardless of its input or output
