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Functions
Each DATANET-30 would perform as a local switching center as well as a forwarding center for
messae;es routed to a destination via one of the other DATANET-30 centers. Automatic alternate
routing is also accomplished in the event that the line between any two centers should become
inoperable or busy for long periods of time. Data processing could be associated with one of the
DATANET-30 centers.
Networks of this configuration require a comprehensive traffic analysis
to insure that the capacity of the network is not exceeded.
Operation
An operator at a remote station on one DATANET-30 wishes to send a message to a remote
station on another DATANET-30 of the network.
The first DATANET-30 receives the message
from the remote station, examines the destination code and determines that the message must
be forwarded to another DATANET-30. When the trunk line is free, the message is forwarded to
the other DATANET-30 where the destination code is examined and the message forwarded to the
intended remote terminal.
With proper coding of destination codes, messages may be simul-
taneously routed to several remote stations (multiple message broadcast).
COMMUNICATION/DATA PROCESSING SYSTEMS
In a direct access computer system, where remote terminals are capable of exchanging information
with a central computer (EDP center) via data communication channels, the definition of the
system depends on the job to be done. An individual system would be tailored to the requirement
of the operating environment. The equipment variations are discussed later.
The list here is a generalized approach to system concepts:
Remote inquiry in real time
Remote file updating in real time
Remote file updating by batch processing
Remote data collection by batch processing
Remote data processing in real time
Computer-to-computer communication
Time sharing in real time
Remote Inquiry
Remote inquiry in real time can be defined as providing a reply to a remote terminal while the
remote terminal is still on the line.
Remote File Updating
Remote file updating in real time is similar to remote inquiry except that the input is data to be
used immediately to update existing records.
The reply to the remote terminal supplying the
data would be an acknowledgment or report of action taken.
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