CS-300 Systems Administration

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9 Δεκ 2013 (πριν από 3 χρόνια και 4 μήνες)

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CS
-
300 Systems Administration

Lecture
-

OS Concepts, Terminology

What is an OS?


Supporting software structure on which
application program runs.


Includes: facilities for managing the computer
system resources and any utility program
needed to maintain and configure the
operating system.

System Administration?


Configure an operating system


Environment for application users.

Early and Modern OS

Three key features:


Sharing the CPU between multiple programs
via a co
-
operative system.


Controlling access to system storage.


Protecting OS and application memory.

Early OS


CPU sharing was periodic; one to pause for
other.


Critical system files were unprotected.


No protection for processes and OS kernel.

Modern OS


Good support for CPU sharing, file protection and
memory protection


More robust and reliable.


Share several design concepts.


Layered design


Layers are protected and connected through APIs.


Provide security through careful control of
interaction.

Modern OS (Layered Design)


Core part: interacts with hardware known as
kernel, loaded into memory when the
computer boots and stay.


Middle Layer: consists of libraries and services
abstraction of computer hardware, loaded as
needed.


User shell or GUI and application program.

Kernel


Monolithic Kernel


Micro
-
kernel

Monolithic Kernel


Older design


Uses a single binary image to provide the
resource management and hardware interface
functions


Linux, Solaris


Modern kernel extend to loadable modules.

Micro
-
kernel


Uses a very small task management
component


Suite of modules, for other resource
management function


Windows NT, windows 2000, Windows XP,
MacOS X


Hardware Architecture


Distinction between hardware platform is
important for OS selection.


Each hardware requires a specific driver which
is critical.


Help in determine the OS selection.

Application Architecture


General description of hardware good enough


Known as application architecture


Defined as combination of the general hardware
architecture and the operating system


Linux x86 (one way of describing AA)


Sometime more description such as Linux x86
libc5 are required.


DLL Vs loadable
kernel modules.

Linux in historical context


Re
-
implementation and elaboration of UNIX.


Originated in 1991.


Linus Trovalds (A finnish graduate student)

Linux Distributions


All distributions share same kernel.


Ancillary material along with kernel can vary.


Distribution vary in:


Focus


Support


popularity

Popular General Purpose Linux
Distributions

Distribution

Website

CentOS

www.centos.org

Debian

www.debian.org

Fedora

Fedora.redhat.com

Gentoo

www.gento.org

Mandriva

www.mandriva.com

openSUSE

www.opensuse.org

RedHat

Enterprise

www.redhat.com

Slackware

www.slackware.com

SUSE

Linux Enterprise

www.novell.com/linux

TurboLinux

www.turbolinux.com

Ubuntu

www.ubuntu.com

Best Distribution???


Ask following questions

Is this distribution going to be around in 5 years?

Is this distribution going to stay on top of the
latest security phase?

Is this distribution going to release updated
software promptly?

If I have problems, will the vendor talk to me?