Sistemas Operativos de Red (SOR)Sistemas Operativos de Red (SOR)Network Operating Systems (NOS)Network Operating Systems (NOS)

Prof. Rubén Álvaro González BenítezProf. Rubén Álvaro González Benítez

Universidad VeracruzanaUniversidad VeracruzanaMéxicoMéxico

09/04/23

NOS

Architectures Required Services Client NOS Server NOS Examples

Architecture

Peer-to-Peer vs. Client/Server Required Services Client NOS Server NOS

GOLDMAN: CSIS FIG. 09-03

Peer-to-Peer

All workstations are loaded with the same peer-to-peer network operating system. Each workstation is configured as service requester (client), service provider (server), or both.

Client/Server

Client workstations are loaded with specialized client software. Server computers are loaded with specialized server software designed to be compatible with client software.

Printer Server File Server with gateway to other networks.

to other LANs

Peer-to-peer

GOLDMAN: CSIS FIG. 09-03

Peer-to-Peer

All workstations are loaded with the same peer-to-peer network operating system. Each workstation is configured as service requester (client), service provider (server), or both.

Client/Server

Client workstations are loaded with specialized client software. Server computers are loaded with specialized server software designed to be compatible with client software.

Printer Server File Server with gateway to other networks.

to other LANs

Client/Server

APPLICATION

SERVICES

DIRECTORY

SERVICES

INTEGRATION/MIGRATION

SERVICES

Database back-end

engines

Messaging/communication

back-end engines

SUPPORT FOR:

32-bit symmetrical

multiprocessing

Preemptive multitasking

Applications run in

protected memory mode

Multithreading

Global directory or naming

services

All network objects defined

in single location and

shared by all applications

Directory information is

stored in replicated,

distributed databases for

reliability, redundancy,

fault tolerance

Allow multiple different

client network operating

systems to transparently

interoperate with multiple

different server network

operating systems

Provide easy-to-implement

paths for upgrades to

more-recent versions or

migration to different

network operating systems

Required Services

Client NOS

Capabilities OS capabilities Peer-to-peer networking capabilities capabilities of communicating with different

server NOS

Client NOS

OS capabilities 32 bit OS

real-mode device drivers vs. Virtual device drivers direct vs indirect hardware addressing and controlling

Preemptive multitasking Protected memory space Support for symmetrical multiprocessing Multithreading Plug-n-play (PnP)

interrupt setting, DMA channel, memory address, etc.

Client NOS

Peer-to-Peer Networking Capabilities File sharing Printer sharing

Client NOS

Networking capabilities Network Client to Multiple Servers

MAC protocol - ODI (Open Data Link Interface) network transport protocol network redirectors

Remote Access Windows NT RAS Netware Connect

dial-up server remote node server

Server NOS

File Services Printer Services Application services Directory services Integration and migration services Management and administration services Security services Networking and connectivity services

Window NT

Structure Two parts

user mode (protected subsystems) kernel mode (NT executive)

Logon process

Applications

Protected subsystems

(servers)

NT executive

OS/2 client

Win32 client

Posix client

Security subsystem

OS/2 subsystem

Win 32 subsystem

Posix subsystem

User mode

Kernel mode

Message passing

System trap

Hardware manipulation

Object

manager

Security

reference monitor

Process manager

Local procedure

call facility

Virtual

memory manager

I/O manager

File systemsCache manager

Device driversNetwork drivers

Kernel

Hardware abstraction layer

Hardware

System services

The Windows NT Kernel Architecture

Windows NT

Protected Subsystems provides APIs that application programs can

call When an application calls a API, a message is

sent to the subsystem that implements that API routine via NT’s local procedure call (LPC).

Windows NT

Two types of protected subsystems environment subsystems

a user mode subsystem that provides an API specific to an OS Win32 subsystem

makes 32-bit Windows API available to application programs provides Windows NT GUI controls all user input and application output

Other subsystems OS/2, 16-bit Windows, and MS-DOS subsystem These system provides APIs but use the Win32 subsystem to

receive user input and to display output

Windows NT

Two types of protected subsystems internal subsystems

security subsystems runs in user mode and records the security policies in effect on

the local computer maintains a database of information about user accounts, any

special privileges the user owns. Accepts user logon information and initiates logon authentication

networking system subsystem workstation service

implements an API to access and manage the LAN Manager redirector

server service implements an API to access and manage the LAN Manager

server

Windows NT

NT Executive consists of components each component has two sets of functions

system services environment subsystems and other executive

components can call internal routines

available only to components within the executive.

Hardware Abstraction Layer

Object

manager

Security

reference

monitor

Process

manager

Local

procedure

call

facility

Virtual

memory

manager

I/O manager

File systems

Cache manager

Device drivers

Network drivers

Kernel

System Services

Kernel

Window NT

Hardware Abstraction Layer (HAL) places a layer of code between the NT executive and

the hardware platform on which Windows NT is running.

hides hardware dependent details such as I/O interfaces, interrupt controllers, and multiprocessor communication mechanisms.

NT Executive

Kernel responds to interrupts and exceptions, schedule threads for

execution, synchronization the activities of multiple processors.

Trap a mechanism for halting an executing thread when an

interrupt or exception occurs, storing the execution state of the interrupted thread, and transferring control to code that handles the condition.

How logon process works

Access token determines

which system resources the user’s threads may access

Logon Process

SecuritySystem

Win32 Subsystem

User Mode

Local Procedure Call

info

A Process w/ AccessToken

How a Win32 program starts

Win32Subsystem

User clicks on

Process Manager

Object Manager

Kerneltrap

User Process

Process Manager & I/O Manager

Win32Subsystem

Process Manager

I/O Manager

CreateProcess

CreateFiles

Native Services

The system services provided by individual components

Environment subsystems implement their API routines by calling NT native services

When a subsystem calls an NT native services, hardware detects the call and transfers control to the NT executives.

The service then runs in kernel mode

Hardware Abstraction Layer

I/O manager

File systemsCache manager

Device driversNetwork drivers

Kernel

System Services

Kernel

OS/2Subsystem

Win32SS

I/O File Systems

I/O system uses an asynchronous I/O model

Support Multiple file systems FAT HPFA (high performance file system) NTFS (NT file system)

extends the capabilities of both FAT and HPFA

NOVELL NetWare

Performance Fault Tolerance NDS File System Security Network Printer

Performance

Directory Caching the process of copying DET and FAT from disk to a file

server’s memory Directory Hashing

the process of indexing the memory-based DET File Caching

it allows a server to store the heavily used files in its memory

Fault Tolerance

Read-after-Write Verification Hot Fix

is dynamic bad block remapping enables disk media defect detection on the fly

Disk Mirring Disk Duplexing Transaction Tracking System

NDS (Name Directory Services)

is a list of objects that represent network resources, such as users, servers, printers, etc.

is physically stored as a set of database files on a server offers benefits, such as

easy of management - integrated management utility single login location-independent resources global management

NDS Objects

Two Types of Objects Container Object Leaf Object

Container Object Root, Organization, Organization Unit

Leaf Object server, user, printer, volume, etc

Object Management

Create and delete NDS objects Move and rename NDS objects Assign rights to objects in the NDS tree Manage properties of objects Group objects Manage inheritance Netware Administrator - GUI-base Utility

NDS Advanced Topics

NDS Replicas keeping NDS running fault tolerance

NDS Partitions partitioning allows you to take a part of the

NDS from one server and put it on another server.

A partition is a logical division of the NDS database

File System

Volume a volume can be mounted or dismounted

Directory Subdirectory File

Netware

Security NDS Security

Object Right - S, B, C, D, R Property Right - C, R, W, A/D self, S

File System Security Directory Rights/Attributes File Rights/Attributes

Netware

Printing Service Print Queue Object Printer Object Print Server Object

LAN Management via Objects

Add a user account by creating a user object and setting up its properties

Add a group by containing a set of user objects Set up printer services by creating a print server

object and by managing a printer object Manage files via volume object Enforce access control by setting up the

properties of file and directory stored in a volume object