Introduction to Windows NT/2000

The operating System Zoo

Mainframe Operating Systems – High-End Servers Processes routine jobs without any interactive

user present OS/390 for example

Server Operating Systems Run on Large PC or even on Mainframes Print , file or web services Unix , Windows 2000 , Linux

The operating System Zoo(2)

Multiprocessor Operating Systems Windows 2000 (up to 32 CPUs) , SunOS

PC Operating Systems Running users applications Multimedia support Windows 98/Me/Xp

Real-Time Operating Systems Time as a key parameter (hard dead line) VxWorks , QNX

The operating System Zoo(3)

Embedded Operating Systems Run on a computer not generally thought of as

computer, like TV ,microwave etc. Have some characteristics of real-time systems PalmOS , Windows CE

Smart Card Operating Systems Very small - run on a credit card sized device Some are Java Oriented (based on JVM)

History

DOS 1 – 1980 Windows 3 – 1990 Windows NT – 1993 Windows 95 / 98 / Me Windows 2000 Pro / Server / Advanced /DC Windows XP Home/Pro - 2001 Windows.Net - 2003

Windows Family Roadmap

ClientClient

ServersServers

Home Home PCsPCs

Business Business PCsPCs 32 and 64 bit32 and 64 bit

Windows .Net Servers

Datacenter

Advanced

Small Business

Standard

NTWS

NTServer

Windows 95 / 98

Windows 2000 Product Family Windows 2000 Professional Windows 2000 Server Windows 2000 Advanced Server Windows 2000 Datacenter Server

Windows 2000 Professional

Client version of the Windows 2000 product family Designed to provide a stable, reliable, and fast

platform for end users to run their applications A high-performance, secure-network client computer

and corporate desktop operating system that incorporates the best business features of Microsoft Windows 98 and builds on the traditional strengths of Microsoft Windows NT Workstation

Windows 2000 Professional 4 GB Memory 2 Processors

Windows 2000 Server

A file, print, and application server, as well as a Web-server platform, that contains all the features of Windows 2000 Professional plus many new server-specific functions

Terminal Services For small- to medium-sized organizations 4 GB Memory 4 Processors More Services and connectivity options

Active Directory Network Storage Management

Windows 2000 Advanced Server

A more powerful departmental and application server operating system that includes the full feature set of Windows 2000 Server and adds the advanced high availability and improved scalability required for enterprise and larger departmental solutions

High end enterprise networks 2-node Clustering Load Balancing 8 GB memory 8 Processors

Windows 2000 Datacenter Server A specialized high-end version of Windows 2000

Server designed for large-scale enterprise solutions and optimized for large data warehouses, econometric analysis, large-scale simulations in science and engineering, online transaction processing, and server consolidation projects

Large Database applications 64 GB memory 32 Processors 4-node - Clustering

Characteristics of Modern Operating Systems1. Microkernel architecture

Assigns only a few essential functions to the kernel address space interprocess communication (IPC) basic scheduling

Other functions run in user mode and treated like any other application

Characteristics of Modern Operating SystemsMultithreading

process is divided into threads that can run simultaneously

Thread dispatchable unit of work executes sequentially and is interruptable

Process is a collection of one or more threads Useful when there is no need to serialize, e.g.,

database that deals with several clients

Characteristics of Modern Operating SystemsSymmetric multiprocessing

there are multiple processors transparent to the user these processors share same main memory and I/O facilities All processors can perform the same functions Better performance (speed), availability (fault tolerance), growth,

scaling (wide price range)

Multiprogramming vs. multiprocessing

Operating Systems Concepts

1. Process

2. Memory management

3. Information protection & security

4. Scheduling and resource management

5. Network support

6. The Shell

2000 / NT Architecture

System Components — Kernel Foundation for the executive and the subsystems. Never paged out of memory; execution is never preempted. Four main responsibilities:

thread scheduling interrupt and exception handling low-level processor synchronization recovery after a power failure

Kernel is object-oriented, uses two sets of objects. dispatcher objects control dispatching and synchronization

(events, mutants, mutexes, semaphores, threads and timers). control objects (asynchronous procedure calls, interrupts, power

notify, power status, process and profile objects.)

Kernel — Process and Threads The process has a virtual memory address

space, information (such as a base priority), and an affinity for one or more processors.

Threads are the unit of execution scheduled by the kernel’s dispatcher.

Each thread has its own state, including a priority, processor affinity, and accounting information.

A thread has a state: ready, running, waiting etc.

Kernel — Scheduling

The dispatcher uses a 32-level priority scheme to determine the order of thread execution. Priorities are divided into two classes.. The real-time class contains threads with priorities ranging

from 16 to 31. The variable class contains threads having priorities from 0

to 15. Characteristics of NT priority strategy.

Trends to give very good response times to interactive threads that are using the mouse and windows.

Enables I/O-bound threads to keep the I/O devices busy. Complete-bound threads soak up the spare CPU cycles in

the background.

Kernel — Scheduling (Cont.)

Scheduling can occur when a thread enters the ready or wait state, when a thread terminates, or when an application changes a thread’s priority or processor affinity.

Real-time threads are given preferential access to the CPU; but 2000 does not guarantee that a real-time thread will start to execute within any particular time limit. (This is known as soft realtime.)

Executive

Object Manager Naming Objects Virtual Memory Manager Process Manager Local Procedure Call Facility I/O Manager Plug-and-Play Manager

Virtual Memory Manager

The design of the VM manager assumes that the underlying hardware supports virtual to physical mapping a paging mechanism, transparent cache coherence on multiprocessor systems, and virtual addressing aliasing.

The VM manager in NT uses a page-based management scheme with a page size of 4 KB.

The NT VM manager uses a two step process to allocate memory. The first step reserves a portion of the process’s address

space. The second step commits the allocation by assigning space

in the NT paging file.

Volume and File Structure

Sector , Track , Cylinder Cluster Partition - Volume - RAID

File System

FAT16 – DOS , Windows95 , NT FAT32 – Windows32/Me/2000/Xp NTFS – WindowsNT/2000/Xp

File System

File-Allocation Table

FAT

File System

The fundamental structure of the NT file system (NTFS) is a volume. Created by the NT disk administrator utility. Based on a logical disk partition. May occupy a portions of a disk, an entire disk, or span across

several disks. All metadata, such as information about the volume, is stored in

a regular file. NTFS uses clusters as the underlying unit of disk allocation.

A cluster is a number of disk sectors that is a power of two. Because the cluster size is smaller than for the 16-bit FAT file

system, the amount of internal fragmentation is reduced.

File System — Internal Layout NTFS uses logical cluster numbers (LCNs) as disk addresses. A file in NTFS is not a simple byte stream, as in MS-DOS or

UNIX, rather, it is a structured object consisting of attributes. Every file in NTFS is described by one or more records in an

array stored in a special file called the Master File Table (MFT). Each file on an NTFS volume has a unique ID called a file

reference. 64-bit quantity that consists of a 48-bit file number and a 16-bit

sequence number. Can be used to perform internal consistency checks.

The NTFS name space is organized by a hierarchy of directories; the index root contains the top level of the B+ tree.

File System — Recovery

All file system data structure updates are performed inside transactions that are logged. Before a data structure is altered, the transaction writes a

log record that contains redo and undo information. After the data structure has been changed, a commit

record is written to the log to signify that the transaction succeeded.

After a crash, the file system data structures can be restored to a consistent state by processing the log records.

File System — Security

Security of an NTFS volume is derived from the 2000 object model.

Each file object has a security descriptor attribute stored in this MFT record.

This attribute contains the access token of the owner of the file, and an access control list that states the access privileges that are granted to each user that has access to the file.

Windows NT (2000) -NTFS

Networking

Stand Alone Domain – PDC , BDC

Network Environment

UNIXSystems

MicrosoftNetworks

RemoteAccess

Macintosh

Netware

Windows NT

NDIS

Network Device Interface SpecificationNetwork Device Interface Specification

NWLinkNWLinkNETBEUINETBEUI TCP/IPTCP/IP

Token RingToken RingEthernetEthernet FDDIFDDI

Protocols

TCP/IP: Routable organization protocol to connect Internet world

NWLink: IPX/SPX-compatible protocol to connect Netware Server

AppleTalk: Service for Macintosh clients DLC: Used to connect printer or SNA

mainframes

DHCP Service (1)DHCP Server

DHCP DatabaseIP Address 1IP Address 2

….

DHCP Client

DHCPClient

Non-DHCP Client

IP Address 1

IP Address 2

DHCP Service (2)

Dynamic Host Configuration Protocol Assigning IP to DHCP client Automatically Centralize and Manage the allocation of

TCP/IP configuration information The client receives a valid IP address

WINS Service (1)WINS Server

WINS Client

Registration RequestUSER3=210.65.182.24

USER3

USER1

IP inquire forUSER3

USER3=210.65.182.25

WINS DatabaseUSER1 210.65.182.22USER2 210.65.182.23USER3 210.65.182.24

WINS Service (2)

Windows Internet Name Service Resolve the computer name to IP

address Update the WINS database dynamically

DNS Service

Domain Name Service Distributed database providing a hierarchical

naming system for identifying hosts on the Internet

Connect to Internet system using Internet naming conventions

Maintain a consistent hierarchical naming scheme across an organization

IIS Service

Internet and Intranet Internet Information Server Publish resources and services on the

Internet on private intranet Use HTTP, Gopher, FTP to provide

information

CSNW (1)Netware Server

NT workstationwith CSNW

NT workstationwith CSNW

SharedResources

CSNW (2)

Client Service for Netware Connect to file and print resources

directly Support Netware 2.x or later

GSNW (1)NetwareServer

NT Serverwith GSNW

Windows Client Windows Client

GSNW (2)

Gateway Service for Netware Create non-dedicated gateway to Netware

resources Avoid the license problem Manage a simple network envirenment

Component Base

DLL COM DCOM – COM+ .NET