It Fundamental QUIZ 1

cp/copy - copy file

ls - list contents

ls -l - list contents in a long listing

mv/move - move or rename file

rm/del - delete file

cat, more, less/type - display text file contents

mkdir/mkdir - create directory

rmdir/rmdir - delete directory (must be empty)

cd - change directory

pwd - print working directory

ls -d * - list all files and directories but don’t list the contents

rm -r - deletes all content

rm -ir - asks permission before deleting all items in order, have to say yes before proceeding

touch - create file

sudo useradd = create user

usermod - modify an existing account

chmod - change permission file

chown - can change a file’s ownership and group ownership

chgrp - change a file’s group ownership

rwx - read, write, execute

ugo - user, group, other

read - 4 in numerical

write - 2 in numerical

execute - 1 in numerical

/etc/passwd = go to password 

In passwd “-e” - creates an expiration date for the password

In passwd “-w” - tells use that the account will expire in a number of days

$ - the shell 

.bash_history - shows all commands used since beginning 

!! - repeats last command

Ctrl p - shows the previous used command

Ctrl n - shows the next command 

Head - shows first 10 lines of file

Tail - shows last 10 lines of file

cd .. - move up one level

alias - an extra name for something, can be used to shorten (ex: alias rm = ‘rm -i’, alias md=mkdir)

grep/egrep - search one or more files for the specified regular expression, returning all lines that match

* - means everything

? - means any one character (ex: ls file?.txt lists everything whose name starts with file, has one character, followed by .txt)

Variable - can be created by using (-NAME=value)

echo - outputs whatever you want

command > file - redirects output to file, if file already exists, override it

command » file - redirect output to append to file, if file doesn’t already exist, create it

command < file - redirect input to come from file

command | command - this is known as a pipe, take the output of one command and use it as input to the next

man - manual page, shows basically everything

Sequential access - data in a file is accessed in a linear fashion; to get the last record, you must read all of them. 

Direct access - data in a file is divided into numbered records and accessed directly, by specifying logical record numbers.

Parent directory - the containing directory

Subdirectory - the directory being contained

Root directory - the directory at the highest level

Path -  a text designation of the location of a file or subdirectory in a file system

• Absolute path - a path that begins at the root and includes all successive subdirectories (ex: c:\program files\ms office\winword.exe)

• Relative path - a path name that begins at the current working directory (ex: cancelMag.doc)

CPU - Responsible for executing programs and performing the fetch-execute cycle

Memory - used to store both executable program code and data

• SRAM - cache, registers

• DRAM - main memory

• ROM - read-only memory

Operating System - system software that is an interface between the user and the hardware. Manages, provides, and allows.

Shadow file - is where passwords are stored

Passwd file only shows - “x” as password. 

IPOS Cycle - input (obtaining information from outside the computer through input devices), processing (executing program instructions using the processor instructions and data stored in memory), output (send results of program code to output device including monitor, printer, speaker), storage (hard disk, optical disc, magnetic tape).

Processing (in ipos cycle) include - data movement, i/o, arithmetic/logic operations, and branches

Branches - change to another location in the program

Data movement - move data between CPU and memory

I/O - move data between CPU or memory and i/o device

Arithmetic/Logic operations - computation

Abstraction - a mental model that removes complex details.

IT Roles - system admin, network admin, database admin, web admin, web development, security admin

• System admin - Administer the computers in an organization; install software; modify/update operating system; create accounts; train users; secure system; troubleshoot system; add hardware

• Network Administrator - Purchase, configure, and connect computer network; maintain computer network; troubleshoot network; secure network from intrusion

• Database Administrator - Install, configure, and maintain database and database management system; back up database; create accounts; train users

• Web Administrator - Install, configure, and maintain website through web server; secure website; work with developers

• Web Developer - Design and create web pages and scripts for web pages; maintain websites

• Security Administrator - Install, configure, and administer firewall; create security policies; troubleshoot computer system (including network); work proactively against intrusions

IT Skills - troubleshooting, knowledge of operating systems, system level programming, system security, hardware’

• Troubleshooting - Detect a problem, diagnose its cause, find a solution

• Knowledge of Operating Systems - Operating system installation, Application software installation, User account creation, System monitoring

• System Level Programming - Shell scripts to automate processes, Manipulating configuration files for system services

• System Security - Ensuring proper system security is in place, Following or drafting policies for users, Monitoring for threats

• Hardware - Installing and configuring new hardware, Troubleshooting, replacing or repairing defective hardware

Abstract step - an algorithmic step containing unspecified details

Concrete step - an algorithm step in which all details are specified

Develop an algorithm - top down design (focus on task to be done) and object-oriented design (focuses on the data involved in the solution)

Binary file - file that contains data in a specific format, requiring special interpretation of its bits

Logical address - reference to a stored value relative to the program making the reference

Physical address - actual address in main memory

Single contiguous memory management (logical)- simply an integer value relative to the starting point of the program

Single contiguous memory management (physical) - added to the starting location of the program in main memory

Fixed partitions - main memory is divided into a fixed number of partitions into which programs can be loaded

Dynamic partitions - partitions are created as needed to fit the programs waiting to be loaded

Multithreading - ability of a process to manage its use by more than one user at a time and to manage multiple requests by the same user without having to have multiple copies of the program

Multitasking - execution of multiple tasks (processes, programs, threads etc.) at a time

Multiprogramming - concurrent application of more than one program in the main memory

Multiprocessing - availability of more than one processor per system, that can execute several set of instructions in parallel