Portability of Data
Syllabus requires you to:
Protocols and standards:
- Explain the need for portability of data, e.g.
- ease of transferring
- graphical and textual data between applications.
- Describe the need of standards for interchanging numerical, graphical
and textual data between different hardware and software platforms.
- Know of the existence, benefits and limitations of standards.
- Understand the protocols and addressing mechanisms used to
support the World Wide Web.
Emergence of standards:
- Recognise the existence of de facto standards based on historic
precedent and sales success in comparison to formal standards.
The British Computer Society (BCS) defines a communications protocol as “a standard set of rules used to ensure the proper transfer of data between devices”. Protocols specify the format of the data and the signals to start, control and end the transfer of data.
Many protocols have been established by the International Telecommunications Union (ITU) and the International Standards Organisation (ISO).
Open Systems Interconnection (OSI)
- One set of protocols that are used when different types of computers are linked together is Open Systems Interconnection (OSI).
- The seven-layer model allows manufacturers to design equipment and software for a particular layer.
- These systems will interconnect with equipment designed for the layer above and the layer below.
TCP/IP (transmission control protocol / internet protocol)
- The Internet uses TCP/IP (transmission control protocol / internet protocol) which is two protocols working together.
- Internet users are able to communicate regardless of the equipment they use.
- TCP/IP specifies how individual signals are sent over the Internet.
- TCP (transmission control protocol) is a protocol that governs high-speed communications within networks.
- TCP/IP relates the to transport (transmission control protocol) and network (internet protocol) layers of the OSI seven-layer model.
Other protocols specify how particular types of data are structured, for example file transfer protocol (FTP) and hypertext transfer protocol (HTTP).
Hypertext transfer protocol (HTTP)
- defines how multimedia web pages are identified, requested and transferred over the Internet.
File transfer protocol (FTP)
- allows a user to transfer files between computers by sending the file in sections or blocks and checking the received data for errors.
Simple mail transfer protocol (SMTP)
- is used to transfer e-mail between computer systems.
Post office protocol 3 (POP3)
- is an e-mail protocol dealing with the transfer e-mail between computer systems that provides more features than SMTP.
Point-to-point protocol (PPP)
- governs communication between two connected computers, e.g. between individual Internet users and an Internet Service Provider via a telephone line.
Serial line Internet protocol (SLIP)
- allows personal computer users to dial in to an Internet service via a telephone line using TCP/IP, giving the user full Internet access.
- Do the exercise and questions at the end of Chapter 60 of the textbook.