The BITNET ( originally Because It's There NETwork, later referred to as Because It's Time NETwork) was a cooperative computer network. It connected mainframes from scientific institutions and public research institutions in the USA. The first connection was established in 1981 between the City University of New York (CUNY) and Yale University .
BITNET used a uniform communication method that was also used by computer networks such as EARN in Europe and NetNorth in Canada. This created a homogeneous worldwide computer network. At its peak in the early 1990s, around 3500 computers in over 1400 organizations communicated with each other. After that the computers became smaller and more numerous. The internet took over the communication. The BITNET was dissolved.
The focus of the services was initially on communication between computers and between humans and computers.
An important function was the use of computing and storage capacity on remote computers. For example, a scientist in Europe could send a calculation order - or job for short - to a computer installed in the USA and have the results of his calculations printed out in his institute.
Another service was electronic mail (e-mail) for interpersonal communication. These messages were not only sent within BITNET / EARN / NetNorth, but also in networks that used other communication methods.
Listserv , a sophisticated distribution system for electronic mail, enabled effective and secure group communication. There were closed and open distribution lists (mailing lists). The closed lists were reserved for a specific group of people; anyone could participate in the open lists.
BITNET Relay Chat was a service that enabled direct communication between participants who were sitting at their end devices at the same time.
A similar procedure could be used to contact a server to request a file or to subscribe to an open distribution list.
At the beginning of the 1990s, the standardized overall network extended over 52 countries in five continents. The main components of this network were:
- BITNET in the USA , Costa Rica and Mexico ,
- EARN in Europe and Africa ,
- NetNorth in Canada ,
- AsiaNet and CAREN in Hong Kong , India , Korea , Malaysia , Singapore , Taiwan and Japan ,
- RUNCOL and ANSP in South America ,
- GULFNET in the states around the Persian Gulf .
The distinction was not technical but political.
The European Academic and Research Network, EARN for short , was the first European computer network that established a permanent connection between academic institutions in North America and Europe. The first dedicated line for EARN across the Atlantic was switched in 1984.
EARN connected the computers in Europe, Russia, Turkey, Israel, Egypt, Morocco, Algeria, Tunisia and the Ivory Coast. A connection to Australia, Asia, Canada, South America and the Gulf region was possible via BITNET.
Because there were no technical differences between EARN and the other subnets, the same services were available to all participants.
The network protocol and the computer programs were already available at the time of the introduction of BITNET and were used for the internal company network VNET of the IBM company. The network protocol was called Remote Job Entry (RJE), later Network Job Entry / Network Job Interface (NJE / NJI). The Remote Spooling and Communications Subsystem (RSCS), on the basis of which the network initially worked, was part of the VM / CMS operating system , which was used by many universities and research institutions. That's why BITNET originally stood for Because It's There Network. IBM made the process available to the scientific public, and non-IBM computers were also integrated into the computer network. In 1988, corresponding programs for the operating systems VMS (DEC), Unix , NOS ( Control Data Corporation ) and 25 others were available.
The network had a rigid topology. Each computer node had its fixed neighboring nodes with which it communicated directly. If files or arithmetic jobs - programs, data and control information - had to be transferred, they were saved as a whole at a neighboring node and transported from there until they finally arrived at the destination ( store and forward ). Of course, the user did not need to know this internal structure, only the name of the target computer.
The network topology was managed centrally. If computer nodes were removed or new ones were added, the information about the new topology was made available to all administrators.
The computer nodes were connected by dedicated lines whose data transmission rates were designed for the transport of programs and data. Typical transmission rates in the USA were 9.6 kbit / s or 56 kbit / s. Leased lines with a transmission rate of 1.544 Mbit / s were added later.