LAN System Software
Lecture 7, April 9, 2003
Mr. Greg Vogl
Data Communications and Networks
Uganda Martyrs University
Overview
LAN system software
Client-server software
 Performance and reliability
 Print spooler, backups
 Sharing, licensing
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Popular LAN server OS
Novell NetWare 3.x-6.x
 Microsoft Windows peer-to-peer, server
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April 9, 2003
Data Communications and
Networks: LAN Server Software
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Client-server software
Applications make requests
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Client software runs on client computers
Servers fulfill the requests
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Server software runs on server computers
Redirector
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reroutes I/O requests from local OS to network
Medium interface software
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sends/receives information over the media
Multithreading
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Used by server to service multiple requests
April 9, 2003
Data Communications and
Networks: LAN Server Software
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Performance, Reliability
I/O Optimisation

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Disk caching (memory copy of blocks)
Disk seek enhancement (scheduling)
Fault tolerance
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Read-after-write (as a double-check)
Mirrored disks (two disks with same data)
Redundant array of independent disks
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Data on several disks; one disk for parity
Duplexed server (two servers in parallel)
Clustering (several servers help if one fails)
April 9, 2003
Data Communications and
Networks: LAN Server Software
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Print spooler
Simultaneous peripheral operations online
Allow several users to print at same time
Save jobs to multiple queues
Send jobs to multiple printers
Set/change job priorities
Move/delete jobs from queues
Add/delete or start/stop printers
Attach/detach printers from print queue
April 9, 2003
Data Communications and
Networks: LAN Server Software
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What to back up
Full: all files
Differential: difference from full backup
Incremental: difference from full + incr.
By directory and all subdirectories
Selected list of files to include/exclude
Pattern matching/wildcards
April 9, 2003
Data Communications and
Networks: LAN Server Software
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How to back up
Automatic at specified day/time
Manually start from console or remotely
Compression
Multivolume backup
Logging and reporting of backed up files
April 9, 2003
Data Communications and
Networks: LAN Server Software
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Shared usage
Files for users’ personal preferences

E.g. desktop, start menu, display, sounds
File locking used to prevent
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Contention: 2 users write to same file
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If one is writing, other can only read
Deadlock: 2 users waiting for each other
Access security
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User/group, read/write/execute, file/folder
April 9, 2003
Data Communications and
Networks: LAN Server Software
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Software licenses
Rules for using products
Protect manufacturer
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Copyright protection to prevent software piracy
Prevent loss of investment/profits
Protect and support user
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Prevent equipment damage, injury, etc.
from inappropriate use
Right to a refund, legal rights, resell, etc.
Upgrades, product information, support
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Data Communications and
Networks: LAN Server Software
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How to protect software
Source code is secret (not open)
Source code is copyrighted
Software is copy protected
Software requires special hardware to use
Password protection, code or serial number
Expiration of functions after some days of use
Licence agreements
Legal action (lawsuits) against violators
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Data Communications and
Networks: LAN Server Software
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Types of licences
Single user, single workstation
Single user, multiple workstation
Multiple user, multiple workstation
Restricted number of concurrent users
Server licence (installed on one server)
Site licence (unlimited use at one site)
Corporate licence (unlimited corp. use)
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Networks: LAN Server Software
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Popular LAN Server OS
LAN OS
Vendor
Topology
Protocol(s)
Windows NT
Microsoft
Ring, bus, star
CSMA or token
NetWare
Novell
Ring, bus, star
CSMA or token
Warp Server
IBM
Ring, bus
CSMA or token
AppleTalk
Apple
Bus
CSMA/CD
LANtastic
Artisoft
Ring, bus
CSMA/CD
TOPS
Sun Microsys.
Ring, bus
CSMA/CD
VMS
Digital (DEC)
Ring, bus
CSMA/CD
Vines
Banyan Sys.
Ring, bus, star
CSMA or token
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Networks: LAN Server Software
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NetWare 3.x
Bindery: info database

Files for objects, properties, values
Server-oriented
Info on different servers not synchronised
 No network directory; need multiple logons
 Best for LANs with few servers

One print server for up to 16 printers
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Server/private, dedicated/non-dedicated
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Data Communications and
Networks: LAN Server Software
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NetWare 3.x
security and reliability
User ID/password security

user/group, inherited/explicit file access
No comprehensive management

Mix of diagnostic/monitoring/backup tools
Supports disk mirror/duplexing/RAID
Transaction tracking system
System fault tolerance (SFT)
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Data Communications and
Networks: LAN Server Software
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NetWare 3.x
other features
I/O optimisation
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Elevator seeking, disc caching
Directory hashing for fast file access
Basic accounting info
Message handling services, e-mail
NetWare servers must be dedicated
Supports clients running variety of OS
Access files through a drive letter e.g. F:
April 9, 2003
Data Communications and
Networks: LAN Server Software
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Novell Directory
Services (NDS)
New with NetWare 4.x
Global
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Used for entire enterprise network
Can be replicated, distributed
Hierarchical directory tree of objects
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Root, container, leaf objects have properties
country, user, group, organisation, computer,
server, print server, printer, queue, volume
Schema (template) of defined objects
API used to add objects or properties
April 9, 2003
Data Communications and
Networks: LAN Server Software
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NetWare 4.x interfaces
Other networks/protocols recognised
IBM SNA gateway, X.25 gateway, T1
 SQL server, remote access services

IntraNetWare
Provides Internet protocols, functions
 Web server functions
 TCP/IP and SPX/IPX protocols co-exist
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Data Communications and
Networks: LAN Server Software
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Netware 4.x
other features
Supports up to 1000 users, 256 printers
GUI interface
Disk compression
Supports SMP architectures (>1 CPUs)
On-line documentation
Improved, more secure auditing
Remote management facility
NetWare Loadable Modules e.g. print server
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Data Communications and
Networks: LAN Server Software
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Windows peer-to-peer
Built-in peer-to-peer and client features
All Windows workstation OS are peers

3.11/95/98/Me, NT/2000/XP Workstation
Browse with Network Neighborhood
Password-protected shared resources

Read-only or full
Client for NetWare and NT Server
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User-level access to resources
April 9, 2003
Data Communications and
Networks: LAN Server Software
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Windows NT Server
Application server features
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32-bit OS, up to 4GB RAM
Pre-emptive multitasking, multithreading
Support for multiple processors
NT Domains
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Allow access to multiple servers
Domain server has security database
Secondary domain server is backup
Supports disk mirroring, RAID
Supports NTFS, FAT, HPFS (OS/2)
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Networks: LAN Server Software
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Windows 2000 Server
or NT Server 5.0
Replaced NetWare as most popular NOS
Active Directory (similar to NDS)
One directory of all network resources
 Managed using Web-like interface
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TCP/IP is native protocol (vs. NetBEUI)
Each user has My Documents folder
Wizards for simpler administration
April 9, 2003
Data Communications and
Networks: LAN Server Software
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