11Windows 2000 Product family(Week 3, Monday 1/23/2006)© Abdou Illia, Spring 20062Learning Objective Understand basic functions of OS Describe features of Windows 2000 Detail differences between Windows 2000 product family members3Operating Systems? Program initially loaded into computer memory Program that manages hardware & software resources: Disks, memory, processors, application programs, etc. Key functions:  Ensures that each application gets necessary resources Handles Input/Output operations Provides resource security (directory & file security, users profiles & rights)24Operating Systems? System software routines that sits between application programs and hardware to provide: Interface function Key support servicesUserApplication programOperating systemHardwareInterfaces User communicates w/App. Prg. App. Prg communicates w/OS OS communicates w/Hardware All App. Prg access Hardware through OS according to rules imposed by OSExamples of support services:-Communications w/peripheral devices-Launching a program-Copying a file-Creating a directory-Opening a file5OS: Primary componentsUser interface (shell)File managementDevice managementProcessor (or process)management MemorymanagementCommunication servicesAllows the user to create, delete, modify, and manipulate files.File managementControls communications w/peripheral devicesDevice managementManages comm. Between OS layers and intercomputer communications.Communication servicesManages system’s memoryMemory managementManages processor’s timeProcessor managementProvides mechanism for user and App. Prg to communicates w/OS and request OS supportShell6OS at workShellFile managementDevice managementHardwareOperating system’s layersOpenApplication program layerSteps for opening a file1. User select File/Open from menu2. App. Prg. calls the Open routine in the OS’s Shell3. Shell passes the Open request to File management layer4. File management layer determines where the requested file is located5. If file on local computer, request is passed to Device management layer6. Device management communicates with Hardware layer.LinecommandinterfaceGraphical UserinterfaceVoice-activatedinterfaceOther OS layersOperating SystemUser interface layer37Windows 2000 FamilyWorkstation AWorkstation BWorkstation CServer A family of Operating Systems from Microsoft: Windows 2000 Professional Windows 2000 Server Windows 2000 Advanced Server Windows 2000 DataCenter8Features in Windows 2000 Active Directory (AD) services Enhanced security (using Kerberos version 5) Encrypting file system (EFS) Fault-tolerance (disk, configuration errors recovery, etc.) Clustering support Load balancing support FAT32, NTFS, CDFS, UDF support9Difference between Win 2000 family members Common OS functions No Disk Fault-tolerance Good for managing a network with a few computers in a WorkgroupDisk Fault-ToleranceActive DirectoryClusteringNetwork Load-BalancingWindows 2000DataCenter ServerWorkstation OSNetwork Operating systems410Disk fault tolerance Fault tolerance achieved through disk redundancy  Disk redundancy can be accomplished:Î by installing backup diskÎThrough Software RAID (Redundant Array of Independent Disks)Î by installing RAID drives (Hardware RAID) RAID’s basic idea is To mirror a disk (i.e. to have a disk and its identical image) or To spread (or strip) data across many disksServer’s capability to continue functioning in case of disk failureRAID ControllerServerDisk1Disk3Disk111RAIDRAID 0  Strips data across multiple disk No redundancy Advantage: Fast data access through multiple reads Disadvantage: Loosing one disk results in loosing data on all disksRAID 1 Doesn’t strip data across many disk Mirrors data between two disks Data kept synchronized between two disks Advantage: Fault-tolerance, i.e. If one disk fails, the other continue working until failed disk can be replaced Disadvantage: Only half of available storage space is used.Note: RAID 1 is called Mirrored volumes in W2K Server implementation of RAID12RAIDRAID 3  Spreads data across multiple disks and uses ECC bits for recovery purpose in case of problem ECC bits determined based on data stored on data disks If one data disk fails, disk controller automatically regenerates missing dataData spread across these disksLast disk contains ECC* data for disks 1-4* Error Checking and CorrectingNote: RAID 3 is called RAID-5 volumes in W2K Server implementation of RAID513W2K Disk-Fault toleranceC:G:Ftdisk.sysDataMirrored volumeParityParityParityParityParityParityRAID-5 volumeDisk 1Disk 2Disk 314Directory Service Provides: Single login and Resource lookup.15Active Directory Central Database that store information about all Network resources Tools for performing central management of users, groups, security services, and network resources (create, find, add, remove, configure etc.)Active DirectoryDomain Controller Central Database used for: Resource lookup (Searching for specific resources) User authentication (login)616Active Directory Individual resources are called objects Objects belong to a Classes Each Class has its own attributes & propertiesUser accounts Computers Printers DomainsObject classes• Object name• Object unique Identifier• Required attributes• Optional attributes• Parent relationship• Username• User’s full name• Password• Account description• Remote access OKUsername: JohnFull mane: Johnny DoePassord: 12#$msDescription: Consultant in Sales depart.17Clustering Technique for providing uninterrupted service (even in case of hardware/software failure) Combining two or more servers into one virtual server Services installed on external storage Users connect to the virtual server (167.10.11.5 in illustration) One of the clustered servers provides the service at a time18Load Balancing Load balancing = Distributing the load among multiple computers No External disk containing services to be provided Multiple independent servers configure to participate in the load balancing Same service with the same content on each server Users connect to the virtual server (167.10.11.5 in illustration) Users’ requests are redirected to one server at a time so that the load is distributed among all the serversWebserviceWebserviceWebserviceWebserviceWebserviceVirtual