Viewdata
Encyclopedia
Videotex
Videotex was one of the earliest implementations of an "end-user information system". From the late 1970s to mid-1980s, it was used to deliver information to a user in computer-like format, typically to be displayed on a television.In a strict definition, videotex refers to systems that provide...
implementation. It is a type of information retrieval
Information retrieval
Information retrieval is the area of study concerned with searching for documents, for information within documents, and for metadata about documents, as well as that of searching structured storage, relational databases, and the World Wide Web...
service in which a subscriber can access
Access control
Access control refers to exerting control over who can interact with a resource. Often but not always, this involves an authority, who does the controlling. The resource can be a given building, group of buildings, or computer-based information system...
a remote database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...
via a common carrier
Common carrier
A common carrier in common-law countries is a person or company that transports goods or people for any person or company and that is responsible for any possible loss of the goods during transport...
channel
Channel (communications)
In telecommunications and computer networking, a communication channel, or channel, refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel...
, request data
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
and receive requested data on a video
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...
display over a separate channel. Samuel Fedida
Samuel Fedida
Samuel Fedida is a British telecommunication engineer responsible at Prestel for the development of Viewdata.Fedida had the idea for Viewdata in 1968 after reading a publication with the title The Computer as Communications Device. The first prototype became operational in 1974. In 1977 the system...
was credited as inventor of the system. The access, request and reception are usually via common carrier broadcast channels. This is in contrast with teletext
Teletext
Teletext is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weather and TV schedules...
.
Technology
Originally Viewdata was accessed with a special purpose terminalComputer terminal
A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system...
(or emulation software
Emulator
In computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...
) and a modem
Modem
A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
running at CCITT
ITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
V.23 speed (1200 bit/s down, 75 bit/s up). Today it is normally accessed over TCP/IP using Viewdata client software on a personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
running Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
, or using a Web-based emulator.
Travel industry
Viewdata is still in use today in the United KingdomUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, mainly by the travel industry. Travel agents use it to look up the price and availability of package holiday
Package holiday
A package holiday or package tour consists of transport and accommodation advertised and sold together by a vendor known as a tour operator. Other services may be provided like a rental car, activities or outings during the holiday. Transport can be via charter airline to a foreign country...
s and flight
Commercial aviation
Commercial aviation is the part of civil aviation that involves operating aircraft for hire to transport passengers or cargo...
s. Once they find what the customer is looking for they can place a booking.
The travel industry is trying to move away from Viewdata to a Web based standard. There are a number of factors holding up a move to the Web. Travel consultants have been trained to use Viewdata, they would need training to book holidays on the Internet and the tour operator
Tour operator
A tour operator typically combines tour and travel components to create a holiday. The most common example of a tour operator's product would be a flight on a charter airline plus a transfer from the airport to a hotel and the services of a local representative, all for one price. Niche tour...
s can't agree on a Web based standard.
Bulletin board systems
It was made in the late 1970s and early 1980s to make it easier for travel consultants to check availability and make bookings for holidays.A number of Viewdata Bulletin Board System
Bulletin board system
A Bulletin Board System, or BBS, is a computer system running software that allows users to connect and log in to the system using a terminal program. Once logged in, a user can perform functions such as uploading and downloading software and data, reading news and bulletins, and exchanging...
s existed in the 1980s, predominantly in the UK due to the proliferation of the BBC Microcomputer, and a short-lived Viewdata Revival appeared in the late 1990s fuelled by the retro-computing vogue. Some Viewdata boards still exist, with accessibility in the form of Java
Java (Sun)
Java refers to several computer software products and specifications from Sun Microsystems, a subsidiary of Oracle Corporation, that together provide a system for developing application software and deploying it in a cross-platform environment...
Telnet
TELNET
Telnet is a network protocol used on the Internet or local area networks to provide a bidirectional interactive text-oriented communications facility using a virtual terminal connection...
clients.
External links
- Definition at The Institute for Telecommunication Sciences
- Examples of existing Viewdata boards:
- CCl4
- Haven
- Ringworld (running on the original software and hardware from the time of its original incarnation, accessed via java client)
- The Dwarfen Realm (running emulated through the web)
- Celebrating the Viewdata Revolution Including several Prestel Brochures