Week 13: Windows Networks

• By the end of this session, you should be able to:Explain the basic architecture of

Windows Server architectureCompare Windows Servers with other

contemporary server operating systems for a variety of business purposes

Windows NT• Windows… based on DOS

virtual memory enabled multitaskingbut architecture fundamentally flawed…

• Stopgap while new “serious” operating system being developed…

• using DEC technology… “New Technology” operating system quietly

released in 1993as a disguised front end enhancement to Windows

3.1known as Windows 3.11 (for workgroups)

NT Architecture• Industry experts soon noticed that many

features were surprisingly similar to VMS… oddity… VMS + 1 = WNT (!!)

• But Microsoft’s customers were from a new generation. The commercial desktop product was still basically DOS, but Gates now offeredpeer-peer networking and a simple network

protocol (NETBEUI)user-friendly graphical interfacesharing resources on appseven TCP/IP compatibility…

Flexibility of Windows NT(followed the Unix pattern)

Operating system kernel

hardware

Operating system functions & interface

Applications

Windows NT v Unix v Netware• By 1994, three possible network

platforms:Novell: fast, proven, scalable, well

established, but proprietary (NDS & IPX/SPX)

Unix: robust, scalable, open source & Internet ready but complex, & limited apps

Windows NT: neither robust nor scalable• but Gates by now a past master at

exploiting weakness... (!)

Progressive Development of Windows NT

os kernel (diff versions of NT available for diff CPUs)

range of CPUs, motherboards

Operating system functions & interface (Windows)

Applications (Windows apps -> NT apps)

NT version 4• Released late 1996

Windows 95 interface & registrymany www features, incl. IIS (web server)

• Server end:designed to support server applications

• no theoretical limit to number of usersnow became a major challenge to Netware

(not TCP/IP compatible) & Unix (still not enough apps)

main problem: not scalable

The 32-bit Windows NT architecture

• Secure 32-bit kernel based on VMSremains intact to present daynow enhanced to 64-bit

• (but this was supposed to happen originally with “Windows 5”, to support DECs 64-bit alpha-chip

• Separated kernel provided the capability for NT, like Unix, to run on multiple platformsguess who didn’t like that idea!

Windows NT Architecture

• Supports pre-emptive multitasking & multithreadinggood for centralised control

• Secure file system (NTFS)• Applications have separate address

spaces (unlike DOS/Windows… crash!)up to 4 Gb of memoryup to 16 Eb of disk space (1Eb = 260 bytes)

NT architecture (continued)• Server products have scope for

huge additional functionality…offered as services

• Problems:much code outside the kernel was

new; bugs had to be ironed outeach server had its own security

database; considerable problems for scalability

Windows 2000• The big one!!!

Designed to merge:• peer-peer networking capabilities of Windows• client-server requirements of LANs• Microsoft technologies with Internet

technologiesYet could still work with “DOS-based” i.e.

Windows 3.x/95/98 clients• Microsoft’s own “history of Windows” (client-

end/desktop versions): http://www.microsoft.com/windows/winhistorydesktop

.mspx

Windows 2000

• ScalableActive Directory

• X500 compliant directory service• even developed with aid of RFCs• multiple domains• enterprise-wide security & resource-sharing

arguably much better than NDS• finished off Novell Netware…

Windows 2000

• Secure… (!)secure remote authentication

• with help from Active Directory…Kerberos (IETF, RFCs)PKI-ready (IETF, RFCs)terminal services

• remote log on with minimal computing resources

More Recent OS Developments

• CISCO grew with Microsoft NT series…• Novell survived (as a company) by:

merging with developers of Linuxcontinuing to support “legacy” Netware systems

• HP kept VMS customer base…once DEC alpha chip was history, developed

new Intel-based hardware platform (Integrity) to interface with VMS kernel

• Linux (very) slowly gaining popularity…

Windows Server Developments since 2000• 2003 Server

more improvements to active directory64-bit version available!

• 2008 Server file system enhancementsactive directory:

• directory tree extended• better management tools (larger networks)

• Although Bill Gates retired, Steve Cutler is still there (helping with “Azure”, Xbox, etc…)http://www.amd.com/us-en/assets/content_type/D

ownloadableAssets/Microsoft_Video_Statement.wmv

Client-side Developments…• Microsoft Domination…

XP: finished off the evolution from Windows 95/98Vista: mainly a desktop change

• not universally appreciated!• mobile devices started to have:

CPUs & operating systems (!) user interfaces & use apps…

• Reaction to Vista…Apple became popularother “mobile” desktops became popular

• Windows 7 stopped the rot…• Windows Mobile: good platform for apps

but Windows client-end dominance lost for good…

Server operating systems for the larger company today…

• IBM, or other “mainframe”? why not?

• Windows 2008 & 2012 Server very popular with finance industry & previous IBM customers!

• Unix (incl Linux) popular with previous DEC customersstill cheaper than Windowsstill complicated, but suits companies

that value and develop technologies

And the small business?• Lot of contradictory advice

use Linux!use WindowsDon’t bother?

• use virtualisation• use BYOD (or don’t!)• outsource• use The Cloud

• Who should they listen to? Why?

And tomorrow?

• Important for people involved in procurement for and management of networksWindows 2016 due (much change?)Unix/Linux?others?

• Time to do a little research...