1. Network Communications Technology
Chapter 21 Network Operating Systems (NOS)

2. MS DOS and the BIOS Basic Input/Output System MS DOS Firmware in ROM
HW initialize and test
Hardware control routines
Establish a low-level API
Bootstrap
MS DOS
Written for IBM (PC-DOS)
Establishes a higher-level API for application programs
MS DOS
BIOS
Hardware ( Disk drive ,printer
Keyboard, motherboard)
Figure 21.1

3. NetBIOS and NOS
Firmware on the NIC
Figure 21.2

4. Windows NT Communication Model
Network
Neighborhood
WINS
Application
level
Transport Drive Interface (TDI)
Network Interface Drive Specification (NIDS)
NT File System
Drivers
Network Interface Drivers
Network Interface Card ( NIC)
Transport
layer
NWLink
TCP/IP
NetBEUI
DLC
Network Interface
Layer
DHCP
Redirectors
NetBIOS
Driver
Mail Slot
Named
Pipe
Internet Application
Telnet, FTP and Ping
WinSocket Driver
Server
TDI
NDIS
RAS
Figure 21.3

5. Netware and OSI Reference Model
Application
Presentation
Session
Transport
Network
Link
Physical
RPC Application
RPC
NetBIOS
Emulator
NetWare
Shell
IPX
SPX
Ethernet Token Ring FDDI others
ODI NDIS
LAN Drivers
Core
Protocol
Figure 21.4

6. Netware Loadable Models
NetWare Modular Bus
Communication
Services
Data Base
File and Print
Store and Forward
Disk Drivers
NetWare
File System
Figure 21.5