Transcript CIT 500: IT Fundamentals

CIT 500: IT Fundamentals
Who am I?
http://faculty.cs.nku.edu/~waldenj
James Walden
– Assistant Professor of Computer Science
– [email protected]
– Interests:
• Secure Software Engineering
• Security Metrics
Course Administration
Web Site
http://faculty.cs.nku.edu/~waldenj/classes/2009/fall/cit500
Notes, readings, and assignments on web site.
Assignment submission
Use submit program to submit assignments.
Contact Information
Email: [email protected]
Phone: (859) 572-5571
Office Hours: M 9:30-10:30, T 9:00-10:00
Class Goals
1. Administer a computer using a CLI.
2. Explain filesystem organization, including inodes
and links.
3. Explain package management, including how it
solves the dependency problem.
4. Explain system processes and their relationships,
including booting and scheduling.
5. Automate common system administration tasks
using shell scripts.
Topics
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Operating Systems
UNIX
Logging In
The Shell
File Commands
What is an Operating System?
Program to help you use the hardware:
– CPU
– Memory
– Disk
– Other I/O: graphics, sound, printers, etc.
Properties provided by an Operating System
– Ease of use.
– Efficiency.
– Fairness.
– Reliability.
– Security.
Layered View of a Computer System
Two Views of an OS
Top-down
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E.g., The OS performs the task of dealing with
complicated hardware resources and gives you a
comprehensive and simple machine, ready to use.
In this way, the OS provides a virtual machine.
Bottom up
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E.g., the OS decides how much space how much
RAM space is to be allocated to a program before it is
loaded and executed.
In this way, the OS is viewed as a resource manager.
Operating System Services
• Execution of a program
• Input and output operations performed by
programs
• Communication between processes
• Error detection and reporting
• Manipulation of all types of files
• Management of users and security
CLI vs GUI
CLI
– Input device is a keyboard.
– Communicate by typing in a computer language.
Graphical User Interface
– Input is taken from a point-and-click device.
– Communicate by filling out forms.
Types of Operating Systems
Single-user, single-process system
– MS-DOS, MacOS 9, MS Windows 3.1.
Single-user, multiprocess system.
– MS Windows 95, 98, ME.
Multiuser, multiprocess system
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MS Windows NT, XP.
UNIX.
VMS.
Mac OS X.
Real time systems
– QNX
– RTLinux
– VxWorks
UNIX Family Tree
What is Linux?
The Linux Kernel
– OS kernel started by Linus Torvalds.
– Developed by thousands across the world.
– Coordinated via the Linux Kernel Mailing List.
Linux Distributions
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OS kernel + libraries + tools.
Over 600 Linux distributions exist.
File /etc/lsb_release identifies distribution.
Family tree at
http://en.wikipedia.org/wiki/File:Gldt.svg
Kernel History
0.01
1.0
1.2
2.0
2.2
2.4
2.6
First version released by Linus (1991).
First release (x86 only) in 1994.
Supports other CPUs (Alpha, MIPS) in 1995.
SMP support, more architectures (1996).
Efficient SMP, more hardware support (1999).
LVM, Plug-n-Play, USB, etc. (2001).
Scalability (embedded, NUMA, PAE, sched),
kernel pre-emption, User-mode linux (2003).
Version Numbering: A.B.C.D
A: Major version
Changed twice: 1.0 (1994), 2.0 (1996)
B: Minor version
Even numbers are stable releases
Odd numbers are development releases
C: Minor revision
Not so minor in 2.6 as development continues.
D: Bug-fix / security patch release
First occurred with NFS bug in 2.6.8.1
Official policy as of 2.6.11
Kernel Versions
mm: Andrew Morton tree
New patches, almost ready for distribution.
ac: Alan Cox tree
Distribution trees
RedHat
Mandrake
Debian
Gentoo, etc.
Obtaining the Kernel
CSC 660: Advanced Operating
Systems
Slide #17
Linux Supported Architectures
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ARM
DEC Alpha
Freescale 68k
HP PA-RISC
IBM Power, PowerPC
IBM zSeries, System/390
Intel Itanium, Itanium II
Intel x86, x86-64, including Xbox
MIPS, including PS2, PSP
OpenRISC
Sun SPARC
Distributions
Community distributions:
– Debian
– Gentoo
Commercially supported distributions:
– Fedora
– Red Hat Enterprise
– Mandriva
– OpenSUSE
– Ubuntu
Live CD or USB distributions:
– Knoppix
– Puppy
– Slax
Why so many distributions?
System types:
– Desktop
– Server
– Specific embedded devices
Usage types:
– Home user
– Power user
– Enterprise
User groups
– Language
– Music
– Science
Where is UNIX used?
Servers
– 13% Linux, 49% UNIX, 38% Windows.
Network equipment
– Firewall, IDS, managed switches, routers.
Cell Phones
– About 8% of market.
– SymbianOS has 47% market share.
Embedded devices
– DVRs, TVs, MP3 players, VOIP phones, printers, cameras.
Desktops
– MacOS X 10%, Linux 1-10%.
Logging On and Logging Off
General Categories
– Local Area Network (LAN) Connection.
– Internet Connection.
– Stand-Alone Connection.
For the first lab, we will be logging onto
kosh.nku.edu
Connecting via PuTTY on a MS Windows Box
Structure of a UNIX command
#command [[ - ] option(s)] [option argument(s)] [command argument(s)]
Examples:
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$
$
$
$
ls
ls
ls
lpr
-la
-la m*
-Pspr -n
3
proposal.ps
File Maintenance Commands
• What is File Maintenance?
• File and Directory Structure
– Home Directory
– Current Working Directory
File Maintenance Commands
Viewing the Contents of Files
– cat, more, less
# cat > myfile
This is an example of how to use the cat command
to add plain text to a file
<Ctrl-D>
# more myfile
This is an example of how to use the cat command
to add plain text to a file
CIT 140: Introduction to IT
Slide #28
File Maintenance Commands
Creating, Deleting and Managing Files
– cp, mv, rm, ls
# cp myfile myfile2
# mv myfile2 renamed_file
# mv “latest revisions october.txt”
laterevs.txt
# rm renamed_file
# ls
Desktop
Mail
myfile myfile2
# ls –al
CIT 140: Introduction to IT
Slide #29
File Maintenance Commands
Creating, Deleting and Managing Directories
– mkdir, cd, pwd, rmdir
# mkdir first
# cd first
# pwd
/home7/smithj/first
# cd
# pwd
/home7/smithj
# cp myfile myfile2
# ls my*
myfile myfile2
# rmdir first
rmdir: first: Directory not empty
Obtaining Help with man
Obtaining Help with man
man [options][-s section] command-list
# man ls
User Commands
ls(1)
NAME
ls - list contents of directory
SYNOPSIS
/usr/bin/ls [-aAbcCdfFghilLmnopqrRstux1@] [file...]
/usr/xpg4/bin/ls [-aAbcCdfFghilLmnopqrRstux1@] [file...]
DESCRIPTION
For each file that is a directory, ls lists the contents of
the directory. For each file that is an ordinary file, ls
repeats its name and any other information requested. The
output is sorted alphabetically by default. When no argument
is given, the current directory is listed. …
Other Forms of Help
whatis
# whatis login setenv
login
login (1)
- sign on to the system
setenv
set (1)
- shell built-in functions to
determine the characteristics for environmental variables
of the current shell and its descendents
apropos
# apropos web
neon
installer
smcwebserver
wbem
neon (3)
- HTTP and WebDAV client lib
installer (1m) - Solaris Web Start installer
smcwebserver (1m)
- start the Sun console
wbem (5)
- Web-Based Enterprise Mgmt
Utility Commands
Examining System Setups
– whereis, whoami, uname
# whoami
smithj
# whereis mkdir
mkdir: /usr/bin/mkdir
# uname –a
Linux kosh.nku.edu 2.6.16.29-xen #5 SMP Sun Oct
15 13:23:34 BST 2006 i686 GNU/Linux
SunOS zappa 5.9 Generic_112233-07 sun4u sparc
SUNW,Ultra-250
Communication Commands
– write username
Command Aliases
• The alias command creates new names for commands.
• Syntax for the alias command is:
alias name=string
Identifying the Running Kernel
> uname
Linux
> uname -r
2.6.16.29
> cat /proc/version
Linux version 2.6.16.29-xen
(shand@endor) (gcc version 3.4.4
20050314 (prerelease) (Debian
3.4.3-13)) #5 SMP Sun Oct 15
13:23:34 BST 2006
Investigating the Running Kernel: /proc
###: directory for each running process
cpuinfo: processor information
devices: supported hardware
diskstats: disk performance statistics
meminfo: memory usage information
modules: linux kernel modules
net: directory of network information
partitions: linux disk partitions
swaps: swap files/partitions in use by kernel
self: link to ### directory for current process
Process information
> ls -alF /proc/self
dr-xr-xr-x 2 jw jw 0
-r-------- 1 jw jw 0
-r--r--r-- 1 jw jw 0
lrwxrwxrwx 1 jw jw 0
-r-------- 1 jw jw 0
lrwxrwxrwx 1 jw jw 0
dr-x------ 2 jw jw 0
-r--r--r-- 1 jw jw 0
-rw------- 1 jw jw 0
-r--r--r-- 1 jw jw 0
lrwxrwxrwx 1 jw jw 0
-r--r--r-- 1 jw jw 0
-r--r--r-- 1 jw jw 0
-r--r--r-- 1 jw jw 0
dr-xr-xr-x 3 jw jw 0
-r--r--r-- 1 jw jw 0
CSC 660: Advanced Operating
Systems
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Slide #38
attr/
auxv
cmdline
cwd -> /proc/20041/
environ
exe -> /bin/bash*
fd/
maps
mem
mounts
root -> //
stat
statm
status
task/
wchan
Process information
> cd /proc/self
> cat cmdline ; echo
-bash
> cat environ | tr '\0' '\n' | head -8
ENV_SET=1
MANPATH=/usr/local/man:/usr/man:/usr/share/man
PATH=/usr/ucb:/usr/bin:/bin:/sbin:/usr/sbin:/usr/local/bin
TERM=xterm
SHELL=/bin/bash
EDITOR=vim
VISUAL=vim
PAGER=less
> ls -l fd
total 4
lrwx------ 1 jw jw 64 2005-12-29 13:50 0 -> /dev/pts/3
lrwx------ 1 jw jw 64 2005-12-29 13:50 1 -> /dev/pts/3
lrwx------ 1 jw jw 64 2005-12-29 13:50 2 -> /dev/pts/3
Logging Off
Exit
# exit
Logout
Connection to zappa.nku.edu closed.
Ctrl-d will do the same thing.
References
1. Syed Mansoor Sarwar, Robert Koretsky, Syed
Ageel Sarwar, UNIX: The Textbook, 2nd
edition, Addison-Wesley, 2004.
2. Nicholas Wells, The Complete Guide to Linux
System Administration, Thomson Course
Technology, 2005.