04-05-2013, 03:58 PM
File Transfer Protocol CLIENT - SERVER APPLICATION
File Transfer Protocol.pptx (Size: 168.41 KB / Downloads: 24)
INTRODUCTION
File Transfer Protocol (FTP) is a standard network protocol used to transfer files from one host to another host over a TCP-based network, such as the Internet.
FTP is built on a client-server architecture and uses separate control and data connections between the client and the server.[1] FTP users may authenticate themselves using a clear-text sign-in protocol, normally in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission that hides (encrypts) the username and password, and encrypts the content, SSH File Transfer Protocol may be used.
The first FTP client applications were interactive command-line tools, implementing standard commands and syntax. Graphical user interfaces have since been developed for many of the popular desktop operating systems in use today,[2][3] including general web design programs like Microsoft Expression Web, and specialist FTP clients such as CuteFTP.
OBJECTIVES
The objective of FTP, as outlined by its RFC, are:
To promote sharing of files (computer programs and/or data).
To encourage indirect or implicit use of remote computers.
To shield a user from variations in file storage systems among different hosts.
To transfer data reliably, and efficiently.
SCOPES
To ensure portability and therefore compatibility.
To ensure our system moves with time i.e. allow for maintenance, upgrades and periodic back up by developed and authorized personnel.
To program the system using the appropriate database design application, platform and programming languages.
CHILD PROCESS
A child process in computing is a process created by another process (the parent process).
A child process inherits most of its attributes, such as open files, from its parent. In UNIX, a child process is infact created (using fork) as a copy of the parent. The child process can then overlay itself with a different program (using exec) as required.
Each process may create many child processes but will have at most one parent process; if a process does not have a parent this usually indicates that it was created directly by the kernel. In some systems, including UNIX based systems such as Linux, the very first process (called init) is started by the kernel at booting time and never terminates. Other parentless processes may be launched to carry out various daemon tasks in userspace. Another way for a process to end up without a parent is if its parent dies, leaving an orphan process; but in this case it will shortly be adopted by init.
EXECUTION OF FORK()
The fork() function is the primitive for creating a child process that can does something in parallel with the main process
After a fork() the main process splits in two parallel process: a parent and a child processes. Both ot them see the fork() return code, but with different values: it returns 0 in the child process and the child's process ID in the parent process.
If process creation failed, fork returns a value of -1 in the parent process.