The document discusses network operating systems (NOS). It covers the architectures of peer-to-peer and client/server networks. It also describes the required services, capabilities, and functions of client and server NOS, including examples like Windows NT and Novell NetWare. Key topics covered include NDS directory services, file systems, performance, fault tolerance, security, and printing services in NetWare.

1. Universidad Veracruzana
México
Sistemas Operativos de Red (SOR)
Network Operating Systems (NOS)
Prof. Rubén Álvaro González Benítez
21/07/09

2. NOS
 Architectures
 Required Services
 Client NOS
 Server NOS
 Examples

3. Architecture
 Peer-to-Peer vs. Client/Server
 Required Services
 Client NOS
 Server NOS

4. Peer-to-peer
P e e r-to-P e e r
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.
C lie nt/S e rve r

5. All workstations are loaded with
the same peer-to-peer network
operating system.
Each workstation is configured as
service requester (client), service
Client/Serverprovider (server), or both.
Client/Server
Client workstations are loaded to other LANs
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.
GOLDMAN: CSIS
FIG. 09-03

6. Required Services
APPLICATION DIRECTORY INTEGRATION/MIGRATION
SERVICES SERVICES SERVICES
Database back-end Global directory or namingAllow multiple different
engines services client network operating
Messaging/communication network objects defined
All systems to transparently
back-end engines in single location and interoperate with multiple
shared by all applications different server network
SUPPORT FOR: Directory information is operating systems
32-bit symmetrical stored in replicated, Provide easy-to-implement
multiprocessing distributed databases for paths for upgrades to
Preemptive multitasking reliability, redundancy, more-recent versions or
Applications run in fault tolerance migration to different
protected memory mode network operating systems
Multithreading

7. Client NOS
 Capabilities
 OS capabilities
 Peer-to-peer networking capabilities
 capabilities of communicating with different
server NOS

8. 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.

9. Client NOS
 Peer-to-Peer Networking Capabilities
 File sharing
 Printer sharing

10. 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

11. Server NOS
 File Services
 Printer Services
 Application services
 Directory services
 Integration and migration services
 Management and administration services
 Security services
 Networking and connectivity services

12. Window NT
 Structure
 Two parts
 user mode (protected subsystems)
 kernel mode (NT executive)

13. The Windows NT Kernel Architecture
Logon OS/2 Win32 Posix
Applications process client client client
OS/2 Posix
Protected subsystem subsystem
subsystems
(servers) Security Win 32
subsystem subsystem
User
mode
Kernel
mode
System services
Local I/O manager
Object Security Process procedure Virtual
NT executive manager reference manager call memory
File systems
monitor facility manager Cache manager
Device drivers
Message
passing Network drivers
Kernel
System Hardware abstraction layer
trap
Hardware
manipulation Hardware

14. 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).

15. 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

16. 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

17. 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.

18. System Services
Local I/O manager
Object Security Process procedure Virtual
File systems
manager reference manager call memory
Cache manager
monitor facility manager
Device drivers
Network drivers
Kernel
Kernel
Hardware Abstraction
Layer

19. 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.

20. 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.

21. How logon process works
 Access token determines
 which system resources the
user’s threads may access
Logon
Process
info
Security Win32
System A Subsystem
Process
w/ User Mode
Access
Token
Local Procedure Call

22. How a Win32 program
starts


trap
Kernel User clicks on
Process
Win32 Manager
Subsystem
Object
User Process Manager

23. Process Manager & I/O
Manager
Win32
Subsystem
Create Create
Process Files
Process I/O
Manager Manager

24. Native Services
 The system services provided
 by individual components
OS/2 Win32
Subsystem SS  Environment subsystems
implement their API routines by
calling NT native services
System Services
 When a subsystem calls an NT
I/O manager native services, hardware
File systems detects the call and transfers
Cache manager control to the NT executives.
Device drivers
Network drivers
 The service then runs in kernel
Kernel
Kernel mode
Hardware Abstraction Layer

25. 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

27. NOVELL NetWare
 Performance
 Fault Tolerance
 NDS
 File System
 Security
 Network Printer

28. 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

29. 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

30. 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

31. NDS Objects
 Two Types of Objects
 Container Object
 Leaf Object
 Container Object
 Root, Organization, Organization Unit
 Leaf Object
 server, user, printer, volume, etc

32. 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

33. 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

34. File System
 Volume
 a volume can be mounted or dismounted
 Directory
 Subdirectory
 File

35. 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

36. Netware
 Printing Service
 Print Queue Object
 Printer Object
 Print Server Object

37. 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