1. COMP2122 Networks in Organisations Richard Henson February 2012

2. Week 4: Overview of Important Network Operating Systems Objective: Objective:  Name significant network operating systems in developments towards today’s organisational networks  Briefly explain features of proprietary products that fulfil particular requirements of a network operating system  Explain a (network) operating system architecture in terms of a multi-layered model

3. Early Operating Systems Each of the early computers was unique Each of the early computers was unique  each had to have its own purpose-built operating system IBM: world’s first mass produced “mainframe” IBM: world’s first mass produced “mainframe”  IBM 701 (1952) purchasers expected to write their the operating system themselves!purchasers expected to write their the operating system themselves! first “mass produced” operating system written by General Motors: GM-NAA I/O in 1956first “mass produced” operating system written by General Motors: GM-NAA I/O in 1956 n adopted by IBM as IBSYS  IBM hugely successful; by 1980s, allegedly bigger than US government (?)

4. First British Operating system Leo 3 was the first mass produced British Computer Leo 3 was the first mass produced British Computer  94 units built 1961-1969 full list of buyers http://www.leo- computers.org.uk/newleo3s.htmfull list of buyers http://www.leo- computers.org.uk/newleo3s.htmhttp://www.leo- computers.org.uk/newleo3s.htmhttp://www.leo- computers.org.uk/newleo3s.htm  each had a loudspeaker connected to the CPU… so operators could tell if it was “looping”  had a multi-tasking operating system called “master program” Some continued in service until 1981 Some continued in service until 1981

5. First Minicomputer & Operating system Produced by Digital Equipment Corporation (DEC) in 1963 Produced by Digital Equipment Corporation (DEC) in 1963  called the PDP-6 “mini” in size compared to mainframes“mini” in size compared to mainframes huge by today's standardshuge by today's standards  operating system called “monitor” evolved into the TOPS10 (1970)evolved into the TOPS10 (1970) ran on the legendary PDP-10ran on the legendary PDP-10 still going until 1988still going until 1988 can get it even now:can get it even now: http://www.inwap.com/pdp10/96license.txthttp://www.inwap.com/pdp10/96license.txthttp://www.inwap.com/pdp10/96license.txt

6. Unix Spin-off (1969) from project MULTICS Spin-off (1969) from project MULTICS  First attempt at a multiuser operating system Consortium including Bell Labs, AT&T,Consortium including Bell Labs, AT&T, n US equivalent of BT at that time FAILED! Too ambitious…FAILED! Too ambitious…  Bell Labs: cut down derivation called UNICS -> UNIX written in assembly language by Ken Thompsonwritten in assembly language by Ken Thompson sharing of processes also being explored in The ARPAnet projectsharing of processes also being explored in The ARPAnet project Commercial Challenge:Commercial Challenge: DEC PDP-7 minicomputerDEC PDP-7 minicomputer needed a general purpose “time sharing” operating system for multiuser use…needed a general purpose “time sharing” operating system for multiuser use… their own os “monitor” had not yet matured into TOPS-10their own os “monitor” had not yet matured into TOPS-10

7. Thompson, Ritchie, “B”, NB, “C” & Unix Thompson looking for a high-level language to develop a time sharing os Thompson looking for a high-level language to develop a time sharing os briefly toyed with Fortranbriefly toyed with Fortran worked with colleague Dennis Ritchie to create their own higher level language – “B”, based on BCPLworked with colleague Dennis Ritchie to create their own higher level language – “B”, based on BCPL http://cm.bell-labs.com/cm/cs/who/dmr/kbman.htmlhttp://cm.bell-labs.com/cm/cs/who/dmr/kbman.htmlhttp://cm.bell-labs.com/cm/cs/who/dmr/kbman.html development of B = newB (NB)development of B = newB (NB) development of NB -> Cdevelopment of NB -> C Unix kernel was rewritten in “C” (1973)Unix kernel was rewritten in “C” (1973)

8. Development of Unix/C “C” compiler completed by Ritchie in 1972 “C” compiler completed by Ritchie in 1972 Further commercial Unix versions (for Honeywell & IBM) released in 1973 Further commercial Unix versions (for Honeywell & IBM) released in 1973 “C” further developed during 1973-7 “C” further developed during 1973-7 Full definition of language as Kernighan & Ritchie “C” (1978) Full definition of language as Kernighan & Ritchie “C” (1978)  rapidly gained universal acclaim Unix still written in “C” to present day! Unix still written in “C” to present day!  32-bit processing from the outset

9. Open Sourceness of Unix AT&T not allowed to be a commercial companyAT&T not allowed to be a commercial company could not sell Unixcould not sell Unix gave a copy away free to any developer who wanted to use it!gave a copy away free to any developer who wanted to use it! many universities contributed to its developmentmany universities contributed to its development Result (in 1979): Unix version 7Result (in 1979): Unix version 7 still recognisable today!still recognisable today!

10. Silicon Valley, TCP/IP and Unix University of California created The ARPAnet (1969)University of California created The ARPAnet (1969) 1975 onwards: Berkeley, north of San Francisco1975 onwards: Berkeley, north of San Francisco hub for its own unique brand of Unix developmentshub for its own unique brand of Unix developments start of “Silicon Valley” (IT hot spot around SF)start of “Silicon Valley” (IT hot spot around SF) ARPAnet teamARPAnet team developed TCP/IPdeveloped TCP/IP 1980, gained approval through RFC1980, gained approval through RFC operating system that would support TCP/IP arrived in 1983…operating system that would support TCP/IP arrived in 1983… Berkeley Unix (v4.2) packaged with TCP/IP protocol stackBerkeley Unix (v4.2) packaged with TCP/IP protocol stack Sun Microsystems producing the hardware…Sun Microsystems producing the hardware…

11. Bell Labs Unix becomes Commercial… US Dept of Justice broke up AT&T in 1984US Dept of Justice broke up AT&T in 1984 Bell Labs then allowed to sell their Unix source code…Bell Labs then allowed to sell their Unix source code… Fortunately for SCO (Santa Cruz Operations) they had ported Bell Unix to Intel hardware the previous year (!)Fortunately for SCO (Santa Cruz Operations) they had ported Bell Unix to Intel hardware the previous year (!) SCO Unix for PC became a lucrative business marketSCO Unix for PC became a lucrative business market operating system provided security on a PC where DOS couldn’t…operating system provided security on a PC where DOS couldn’t…

12. Bad days for Unix… Unix free by nature from outset Unix free by nature from outset  not so on an Intel PC, thanks to SCO!!!  Bell Labs jealously guarded the source code…  universities lost interest Unix became expensive to buy… and was still not user-friendly or easy to use so even more expensive to own! Unix became expensive to buy… and was still not user-friendly or easy to use so even more expensive to own!

13. Linux From 1992 (Linus Torvalds, University of Helsinki) made free Unix possible again! From 1992 (Linus Torvalds, University of Helsinki) made free Unix possible again!  LINUX – based on his name… Took… Took…  Stallman’s GNU open source Unix which Tanenbaum had developed into MINIX…which Tanenbaum had developed into MINIX…  very stable  secure file system  very efficient, optimised code  earlier versions ran on an Intel 486! Still Unix, still a server-end system Still Unix, still a server-end system  for client-server networking, need client-end software: e.g. Banyan VINESe.g. Banyan VINES

14. Linux Still freely available via Internet! Still freely available via Internet! Huge range of software tools for managing UNIX networks available for download Huge range of software tools for managing UNIX networks available for download Problems (compared to Windows): Problems (compared to Windows):  not as easy to manage  limited on-screen help  limited range of good application software  not all hardware has UNIX/LINUX driver software

15. Operating Systems for PC Ethernet Networks Original Topology (1980s, early 90s): Original Topology (1980s, early 90s):  bus, coaxial cable & BNC connectors (!) DOS? DOS?  No way! not designed for: server end stuffserver end stuff distributed communicationsdistributed communications security…security…

16. Operating Systems for PC Ethernet Networks  two popular client-server operating systems emerged: Novell NetwareNovell Netware n IPX/SPX protocol n not OSI compliant - proprietary & code secret DEC (Digital) PCSADEC (Digital) PCSA n DECnet protocol n OSI & TCP/IP compliant - code open source

17. Netware - late 1980s Novell’s proprietary IPX/SPX network protocol Novell’s proprietary IPX/SPX network protocol  network naming based on MAC address hardwired into network card during manufacturehardwired into network card during manufacture Also, MHS protocol for message- handling and email within the LAN Also, MHS protocol for message- handling and email within the LAN

18. Novell Netware Cool Server stuff… Cool Server stuff…  secure file system based on user, groups, rights & inherited rights  supported mirroring, duplexing, RAID  TTS to reverse incomplete transactions  network resource names, etc. stored as a separate bindery on each server

19. Other Features of Netware I/O optimisation: I/O optimisation:  disk caching  elevator seeking (disk accesses ordered according to position on disk)  directory hashing

20. Strengths of Netware  Fast MAC address not IP, fewer headers, less processing of packetsMAC address not IP, fewer headers, less processing of packets  Secure awarded US gov Server Fault Tolerance (SFT) grade IIIawarded US gov Server Fault Tolerance (SFT) grade III n when used with server duplexing

21. Enduring Problems with Netware Only ran on Intel Platform Only ran on Intel Platform Reliant on DOS/Windows at the client end Reliant on DOS/Windows at the client end NDS (Directory Structure) not X500 compliant NDS (Directory Structure) not X500 compliant Not directly compatible with TCP/IP Not directly compatible with TCP/IP  interprocess communication based on IPX/SPX  used MAC addresses (fixed on network card) as unique identifiers, rather than IP addresses Not suitable for peer-peer networking Not suitable for peer-peer networking Not pre-emptive in handling processes Not pre-emptive in handling processes

22. What happened to Netware? V.successful in early 1990s V.successful in early 1990s  better sales than DEC PCSA architecture, even though the latter was OSI compliant (!!) SPX/IPX faster than TCP/IP…SPX/IPX faster than TCP/IP…  70% of the PC network market

23. What happened to Netware Didn’t see what was coming (Microsoft!)… Didn’t see what was coming (Microsoft!)…  DEC mini computers lost market share everyone wanted a PC networkeveryone wanted a PC network main LAN rival DEC was being sold off and “asset stripped”main LAN rival DEC was being sold off and “asset stripped” future looked brightfuture looked bright  BUT… by 1998, Novell Netware sales were sunkby 1998, Novell Netware sales were sunk by 2000, even Oracle stopped supporting themby 2000, even Oracle stopped supporting them only kept in business by merging with Red Hat Linuxonly kept in business by merging with Red Hat Linux

24. More on DEC (Digital Equipment) World’s most innovative computer company for many years… World’s most innovative computer company for many years…  as already stated - first minicomputer: PDP-1 (Programmable Data Processor)PDP-1 (Programmable Data Processor)  first UNIX/C implementation On PDP-5On PDP-5

25. DEC continued… Most successful minicomputer: Most successful minicomputer:  VAX (Virtual Address eXtension) First virtual memory operating system First virtual memory operating system  VMS (virtual memory system) for VAX First commercially successful RISC chip First commercially successful RISC chip  alpha First commercial Internet domain & website First commercial Internet domain & website First successful search engine: AltaVista First successful search engine: AltaVista

26. Organisational Networks in 1990 Business/finance companies: Business/finance companies:  usually IBM networks Science/Technology/Engineering companies: Science/Technology/Engineering companies:  usually DEC networks Smaller companies (SME size...) Smaller companies (SME size...)  couldn’t justify/afford networks!

27. Where did DEC go? Second biggest computer company in the world in 1990! Second biggest computer company in the world in 1990!  over 100000 employees!  with early 90s recession, went into decline… New MD in 1992, only accelerated the decline New MD in 1992, only accelerated the decline  assets sold one by one… unkindest cut – alpha chip to Intel in 1997unkindest cut – alpha chip to Intel in 1997  what was left (VMS) went to Compaq in 1998 sold on to HP…sold on to HP…

28. What happened? As with the downfall of IBM, Netscape and Novell… As with the downfall of IBM, Netscape and Novell…  out-manoeuvred in business  perhaps the name Microsoft might help…

29. Microsoft and VMS… Now long enough ago to be of historical interest… Now long enough ago to be of historical interest…  Dave Cutler, brains behind DEC’s VMS; http://en.wikipedia.org/wiki/Dave_Cutler http://en.wikipedia.org/wiki/Dave_Cutlerhttp://en.wikipedia.org/wiki/Dave_Cutler  went to work at Microsoft in 1988 to develop “a new operating system” (NT)…to develop “a new operating system” (NT)… DEC watching their mini-computers become “dinosaurs” (1990-93) DEC watching their mini-computers become “dinosaurs” (1990-93)  pinned hopes on new RISC chip (alpha)  keen to get their alpha chip onto the original Windows NT…

30. A tale of intellectual copyright (and smart business) DEC saw NT as their big opportunity to get into the PC server business DEC saw NT as their big opportunity to get into the PC server business  expected Alpha chip platform/Windows NT to be popular  signed away rights to Cutler & co’s code – code used in creating windows NT Microsoft effectively got the technologies behind VMS that they used for NT… for free!!!!Microsoft effectively got the technologies behind VMS that they used for NT… for free!!!! final insult… Intel platform preferred for servers (!)final insult… Intel platform preferred for servers (!) Thanks to HP, and enthusiastic users, VMS lives (!) Thanks to HP, and enthusiastic users, VMS lives (!)  available for download at: http://www.openvms.compaq.com/openvms/freewarehttp://www.openvms.compaq.com/openvms/freewarehttp://www.openvms.compaq.com/openvms/freeware

31. Microsoft & Network Operating Systems Whilst the US government was being defeated in the courts by IBM… Whilst the US government was being defeated in the courts by IBM…  a deal that almost put them out of business was pulled off by the young Bill Gates!  story about IBM negotiations with Bill Gates (regarding his mate Tim Paterson’s os): http://inventors.about.com/library/weekly/aa033099.htmhttp://inventors.about.com/library/weekly/aa033099.htmhttp://inventors.about.com/library/weekly/aa033099.htm  and the tragedy of Gary Kildall (creator of CP/M, main rival to DOS & one time business partner of Steve Jobs)… http://www.businessweek.com/magazine/content/04_43/b3 905109_mz063.htmhttp://www.businessweek.com/magazine/content/04_43/b3 905109_mz063.htmhttp://www.businessweek.com/magazine/content/04_43/b3 905109_mz063.htmhttp://www.businessweek.com/magazine/content/04_43/b3 905109_mz063.htm

32. DOS (Desktop Operating System) As was to be expected from a back-street deal… As was to be expected from a back-street deal…  DOS was an awful operating system…  no way it could be satisfactorily used for even multi-tasking, let alone networking…  no way of logging in as an authenticated user…logging in as an authenticated user… restricting access to resources…restricting access to resources…  to the new (misguided?) computer generation… none of this matterednone of this mattered  by the late 1980s Gates was the 4 th richest person in the world!

33. OS2, Windows, and Windows NT By late 1980s, PCs being used for serious business purposes By late 1980s, PCs being used for serious business purposes  IBM needed a serious operating system for the PC…  Microsoft worked them on OS2  still didn’t see Gates as a rival! At about the same time… At about the same time…  Cutler left DEC… joined Microsoft  scope for a virtual memory operating system… (Windows)(Windows)

34. Windows On the one hand On the one hand  Microsoft were working with IBM on OS2 One the other hand: One the other hand:  they were working on developing Windows and working with software developers to provide applications for Windows…and working with software developers to provide applications for Windows… n users want apps, not operating systems! Guess which one won??? Guess which one won???  you’ve got it… Microsoft now bigger than IBM

35. Windows NT Windows… based on DOS Windows… based on DOS  virtual memory enabled multitasking  but architecture fundamentally flawed… Stopgap while new “serious” operating system being developed… Stopgap while new “serious” operating system being developed… using DEC technology…using DEC technology…  “New Technology” operating system quietly released in 1993  as a disguised front end enhancement to Windows 3.1  known as Windows 3.11 (for workgroups)

36. NT Architecture Industry experts soon noticed that many features were surprisingly similar to VMS… 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 offered But Microsoft’s customers were from a new generation. The commercial desktop product was still basically DOS, but Gates now offered  peer-peer networking and a simple network protocol (NETBEUI)  user-friendly graphical interface  sharing resources on apps  even TCP/IP compatibility…

37. Flexibility of Windows NT (followed the Unix pattern) Operating system kernel hardware Operating system functions & interface Applications

38. Windows NT v Unix v Netware By 1994, three possible network platforms: 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... (!)but Gates by now a past master at exploiting weakness... (!)

39. 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)

40. NT version 4 Released late 1996 Released late 1996  Windows 95 interface & registry  many www features, incl. IIS (web server) Server end: Server end:  designed to support server applications no theoretical limit to number of usersno theoretical limit to number of users  now became a major challenge to Netware (not TCP/IP compatible) & Unix (still not enough apps)  main problem: not scalable

41. The 32-bit Windows NT architecture Secure 32-bit kernel based on VMS Secure 32-bit kernel based on VMS  remains intact to present day  now enhanced to 64-bit (but this was supposed to happen originally with “Windows 5”, to support DECs 64-bit alpha-chip(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 platforms Separated kernel provided the capability for NT, like Unix, to run on multiple platforms  guess who didn’t like that idea!

42. Windows NT Architecture Supports pre-emptive multitasking & multithreading Supports pre-emptive multitasking & multithreading  good for centralised control Secure file system (NTFS) Secure file system (NTFS) Applications have separate address spaces (unlike DOS/Windows… crash!) Applications have separate address spaces (unlike DOS/Windows… crash!)  up to 4 Gb of memory  up to 16 Eb of disk space (1Eb = 2 60 bytes)

43. NT architecture (continued) Server products have scope for huge additional functionality… Server products have scope for huge additional functionality…  offered as services Problems: Problems:  much code outside the kernel was new; bugs had to be ironed out  each server had its own security database; considerable problems for scalability

44. Windows 2000 The big one!!! The big one!!!  Designed to merge: peer-peer networking capabilities of Windowspeer-peer networking capabilities of Windows client-server requirements of LANsclient-server requirements of LANs Microsoft technologies with Internet technologiesMicrosoft technologies with Internet technologies  Yet could still work with “DOS-based” i.e. Windows 3.x/95/98 clients Microsoft’s own “history of Windows” (client- end/desktop versions):Microsoft’s own “history of Windows” (client- end/desktop versions): n http://www.microsoft.com/windows/winhistorydesktop.mspx http://www.microsoft.com/windows/winhistorydesktop.mspx http://www.microsoft.com/windows/winhistorydesktop.mspx

45. Windows 2000 Scalable Scalable  Active Directory X500 compliant directory serviceX500 compliant directory service even developed with aid of RFCseven developed with aid of RFCs multiple domainsmultiple domains enterprise-wide security & resource-sharingenterprise-wide security & resource-sharing  arguably much better than NDS finished off Novell Netware…finished off Novell Netware…

46. Windows 2000 Secure… (!) Secure… (!)  secure remote authentication with help from Active Directory…with help from Active Directory…  Kerberos (IETF, RFCs)  PKI-ready (IETF, RFCs)  terminal services remote log on with minimal computing resourcesremote log on with minimal computing resources

47. More Recent OS Developments Novell survived (as a company) by: Novell survived (as a company) by:  merging with developers of Linux  continuing to support “legacy” Netware systems HP kept VMS customer base… 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… Linux (very) slowly gaining popularity…

48. Windows Server Developments since 2000 2003 Server 2003 Server  more improvements to active directory  64-bit version available! 2008 Server 2008 Server  file system enhancements  active directory: directory tree extendeddirectory tree extended better management tools (larger networks)better management tools (larger networks) Although Bill Gates may have retired, Steve Cutler is still with them (helped with “Azure” and now…Xbox) Although Bill Gates may have retired, Steve Cutler is still with them (helped with “Azure” and now…Xbox)  http://www.amd.com/us- en/assets/content_type/DownloadableAssets/Micr osoft_Video_Statement.wmv http://www.amd.com/us- en/assets/content_type/DownloadableAssets/Micr osoft_Video_Statement.wmv http://www.amd.com/us- en/assets/content_type/DownloadableAssets/Micr osoft_Video_Statement.wmv

49. Client-side Developments… Microsoft Domination… Microsoft Domination…  XP: finished off the evolution from Windows 95/98  Vista: mainly a desktop change not universally appreciated!not universally appreciated! mobile devices started to have:mobile devices started to have: n CPUs & operating systems (!) n user interfaces & use apps… Reaction to Vista… Reaction to Vista…  Apple became popular  other “mobile” desktops became popular Windows 7 stopped the rot… Windows 7 stopped the rot… Windows Mobile: good platform for apps Windows Mobile: good platform for apps  but Windows client-end dominance lost for good…

50. So, which Server operating system would the larger company use today? IBM, or other “mainframe”? IBM, or other “mainframe”?  why not? Windows 2008 very popular with finance industry & previous IBM customers! Windows 2008 very popular with finance industry & previous IBM customers! Unix (incl Linux) popular with previous DEC customers Unix (incl Linux) popular with previous DEC customers  still cheaper than Windows  still more complicated, but suits companies that value and develop technologies

51. And the small business? Lot of contradictory advice Lot of contradictory advice  use Linux!  use Windows  Don’t bother? use virtualisationuse virtualisation outsourceoutsource use The Clouduse The Cloud Who should they listen to? Why? Who should they listen to? Why?

52. And tomorrow? Important for people involved in procurement for and management of networks Important for people involved in procurement for and management of networks  Windows 2012 due (much change?)  Unix/Linux?  others? Time to do a little research... Time to do a little research...