Lecture 2

Server Administration-System Component-

Lecture 2 System Component

• Goal: Assemble Component of a human Computer Community

– System Definition– Hardware Handling– Operating System– Filesystems– Process & Job Control – Ipv6 Networks

What is the ‘System’

• In System Administration:– Word System is used to refer both the operating system of a computer and often, collectively the set of all computers that cooperate in a network.

• Human-computer system ?– An Organized Colaboration between humans and Computers to solve a problem or provide service.

• Network Infrastructure: – Human– Host Computer– Network Hardware

• Layer 1,2,3 Devices

Human Computer System (depedencies)

Hardware Handling

• To be a system administrator it is important to have a basic appreciation of the frailties and procedures surrounding hardware

• All electronic equipment should be treated as highly fragile and easily damaged, regardless of how sturdy it is. Today we are far too blasé towards electronic equipment.

Hardware Handling

– DO NOT! Insert / Remove Power Chords without ensuring it switched off

– Read Manuals– Interfaces & Connectors – Handling Components (Conductive wrist strap)– Disk (Common Disk Types)

– SCSI (Small computer Software interfaces )» SCSI 1, SCSI 2, Wide SCSI, SAS (Hotplug), Etc» SCSI Controller Usually Connected to PCI BUS

– IDE (Integrated Drive Electronics)» ATA ( Advance Technology Attachment )

Hardware Handling

– Memory • Different sizes, Different Speed• When Purchasing a Memory Please remember :

– Physical Size of the Memory Plugins ( Choose the appropriate socket)

– Capacities & Data Rates – ECC RAM Tolerant from external noises – RAM Slots Particulary Order

Another Aspect of Hardware

• Lightning – Fuse ? Transistor & CMOS Chips burn out much faster than any fuse

– Electronic Spike/ Surge Protectors • Power– UPS

• Heat – Metals Expand the Heat Significantly– Increased Temperature Increased Noise Level Reduce Network Capacities

• Cold– Sudden change from hot to cold Chip Damage

• Humidity – Static Electricity builds up

Operating Systems

• OS Key Element– Technical Layer of Software

• Driving Hardware in Computers

– Filesystem• Provides a way for organizing files logically

– User Interface• Enables users to run their own programs and manipulate their files in a simple way

Operating Systems

• Core Software Systems– Kernel : Responsible to allocating and sharing resources

– Assisted by Supporting Services (Paging, RPC, FTP, WWW, Etc)

• Distributed OS – Escaping the hardware boundaries

• Network Operating Systems

Operating Systems

• Distinguish OS & GUI – Windowing System is GUI– OS Share resources and provides functionality– The Issue arises when …– OS Can have any number of different Windowing Interfaces

Operating Systems

• Multiuser OS – Allow multiple users to share the resource in a single host

– Protected by Unique Identity• Username• Private Login Area

– Simulate Virtual Workstations for each users

Operating System

• The Legacy Of Insecure OS– Home computer revolutions Network revolution– Traditional OS not addressing security issues– No Limits on what a determined user can do

• Slowly replaced by an OS designed with resource sharing (including networking)

Operating Systems

• Securable OS – Unix and NT secure ?– By Its Nature security is not an achievable goal

– Aspiration that includes accepted level of risk

– Mechanism basic level preventive security possible

– Why Windows, DOS, Macintosh are so susceptible to virus attacks?

– Properly configured and bug free Unix/NT (ownership, permissions)

Operating Systems

• Shell or Command Interpreters– Todays common OS provide graphical window systems for all kinds of tasks

– Poorly suited to system administrations– Shells write simple programs called scripts or batch files, its simplify repetitive administrative tasks

Operating Systems

• Logs And Audits– List of transactions which have taken place – Go back and see what happened in a given time– Full systems auditing vast amount of disk spaces

– Auditing Issue in connection with security– Non-repudiation

Operating Systems

• Privileged accounts– Unix : root / super user– Windows : Administrator (doesn’t have automatic access to everything such does root)

– Administrator & root accounts should never be used for normal work (Too Much Power)

– “Behind every great powers, come a great responsibility”

Unix Like and Windows Computer

Unix Like and Windows Computer

Filesystem

• Very heart of what system administrations about

• Unix Filesystems– Hierarchical filesystem• Directories and subdir form a tree• Index node/ inode stored in special part of an OS• Inode contain an extensible system of pointers to the actual disk block• Inode contains essential information needed to locate a file on the disk• /

Unix / Unix like file hierarchy

• Hierarchical Filesystem– /– /bin (executable)– /etc– /usr (application)– /usr/bin (OS executable)– /usr/sbin – /usr/local/ (user custom software)

– /sbin (system binaries)– /sys (build the system kernel)

• /export (diskless clients)• /dev (devices nodes)• /home (separate login files)

• /root• /var (spooling & log)

Symbolic link & Hard link

• Symbolic link– Alias to another file

• (ex:unix ln -s fromfile /other/directory/tolink )• Hard link – Duplicate directory from an inode in filesystems

• ex: unix– % date > hardfile ( create the file )– % ls -l -rwx-xr-x 1 john users 605 Nov 18 12:25 hardfile – % ln hardfile project/hardfile2 – % ls -l projects/hardfile2 -rwx-xr-x 2 john users 605 Nov 18 12:25 hardfile

• Ignored by filesystem designers

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File access control

• Restrict privilege to files on the system• Unix records information ( who create & allowed to access)

• Username (uid), login name (text string)

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File access control

• Restrict privilege to files on the system, create– Read, write dan execute – CHMOD (Change Mode)– CHOWN (Change Owner)

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File access control (cont)

• CHMOD Change permissions or mode of file – chmod a+w myfile– chmod +x myfile– Chmod 755 *

• Chown & chgrp Change user & group ownership – Ex : chown mark ~mark/testfile– Chgrp www ~mark/www/tmp/cgi.out– Chown mark.www ~mark/www/tmp/cgi.out

• Umask change default permissions for files & directories (how to calculate ?- Simple)– Umask 022 default permission for file is 666-022 =644– Umask 022 default permission for directories is 777-022=755

– Umask 077 file = 600– Umask 077 directories = 700

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Access Control List

• Modern replacement for file mode & Permissions

Windows file model

• File system layout– DOS Legacy A: B: C: D:– NTFS (NT Filesystem) hirarkial file system file dan direktori– Direktori memiliki owner tapi tidak ada group membership– %SystemRoot% biasanya C:– Links dan shortcut– Access Control List

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Network Filesystem Models

• NFS SUN Open standard Unix

• How local storage accessed but over a network

• ONC RPC (Open Network Computing Remote Procedure Call)

Process & Job control

• Unix process model– Users start process from a shell command line/ click icon in a windows manager

– Every unix process have a PID (Process ID), PS Command

– Background process (Start from a shell using the special char &)

– Child Process & Zombies• When process start child of the original • Form a hierarchis• When child killed then becomes defunct/zombies

Process & Job Control

• Environment Variables– Text String Variables– Set by users in shell env– Configuration information to software

Network Environment

• OSI Layer• IP Address• Subnet & Broadcast• Interface Settings• ARP• NAT

IPv6

• 2001:0700:0700:0004:0290:27ff:fe93:6723• 2001:700:700:4:290:27ff:fe93:6723

Assignment

• Silahkan Spesifikasi Server dengan minimum configuration sebagai berikut:– 4 Server dengan Xeon 2.4 GHz – RAM ECC-DDR 3 Max 192 GB – Harddrive SCSI – Support Unix/Linux – Gigabit Ethernet

• Sertakan harga, usahakan seminimum mungkin (cantumkan harganya dan dimana belinya)

• Full equipped misalkan max hard drive , max DDR 3 RAM • Rak dan UPS • Catatan:

– Kumpulkan sampai tanggal 23 sept jam 23.59– Tugas kelompok– Subject: Tugas1AdserA_KOM_[NamaKetuaTim]– Dikumpulkan ke rakhmadhany@gmail.com atau rakhmadhany@yahoo.com

Thanks

Thanks and see you next week