Network File Services

Network File Services
An Introduction

Prof. David Bernstein
James Madison University

Computer Science Department

bernstdh@jmu.edu

Network File System (NFS)

History:
- Developed by Sun Microsystems (1985)
Purpose:
- Provide access to files on other systems as if they are local
Notes:
- Based on UNIX file system but supported on many operating systems
- v2 uses UDP; TCP available starting in v3

NFS Client-Server Architecture

Server:
- Provides access to files/directories that are exported
Client:
- Accesses remote files/directories that are mounted (as a directory in UNIX and a letter in MS-Windows)

An Exercise

Getting Started:
- Whast happens when you enter commands like pwd, cd and ls in a shell?
Continuing:
- Can we design a system that allows us to do the same thing over the network?

NFS and UIDs

A Requirement:
- The user needs to have the same UID on both the client machine and the server machine
Managing User Information:
- Network Information Service (NIS) (originally called Sun Yellow Pages) eliminates the need for clients to maintain user information

Network Information Service (NIS)

Server:
- The machine that contains the files to be shared (e.g., passwd, group, hosts)
- ypserv installs the NIS server software
- domainname sets the NIS domain name (which should be different from the DNS name)
Client:
- Uses the server for authentication and other services
- ypbind installs the NIS client software
- yppasswd can be used to change the password
- ypcat can be used to list information on the server

Server Message Block (SMB)/Common Internet File System (CIFS)

History:
- Developed by IBM in the 1980s
Terminology:
- The server "shares"
- The client "maps" or "uses"
- Uses the Universal Naming Convention (UNC) (e.g., \\NETBIOS-NAME\Directory)