CS-300 Systems Administration

CS
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300 Systems Administration

Lecture
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OS Concepts, Terminology

What is an OS?

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Supporting software structure on which
application program runs.

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

System Administration?

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Configure an operating system

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Environment for application users.

Early and Modern OS

Three key features:

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

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Controlling access to system storage.

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Protecting OS and application memory.

Early OS

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CPU sharing was periodic; one to pause for
other.

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Critical system files were unprotected.

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No protection for processes and OS kernel.

Modern OS

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Good support for CPU sharing, file protection and
memory protection

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More robust and reliable.

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Share several design concepts.

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Layered design

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Layers are protected and connected through APIs.

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Provide security through careful control of
interaction.

Modern OS (Layered Design)

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

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

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User shell or GUI and application program.

Kernel

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Monolithic Kernel

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Micro
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kernel

Monolithic Kernel

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Older design

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

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Linux, Solaris

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Modern kernel extend to loadable modules.

Micro
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kernel

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Uses a very small task management
component

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Suite of modules, for other resource
management function

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Windows NT, windows 2000, Windows XP,
MacOS X


Hardware Architecture

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Distinction between hardware platform is
important for OS selection.

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Each hardware requires a specific driver which
is critical.

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Help in determine the OS selection.

Application Architecture

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General description of hardware good enough

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Known as application architecture

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

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Linux x86 (one way of describing AA)

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Sometime more description such as Linux x86
libc5 are required.

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DLL Vs loadable
kernel modules.

Linux in historical context

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Re
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implementation and elaboration of UNIX.

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Originated in 1991.

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Linus Trovalds (A finnish graduate student)

Linux Distributions

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All distributions share same kernel.

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Ancillary material along with kernel can vary.

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Distribution vary in:

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Focus

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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???

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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?