Resource Sharing Protocols
Original Publication Date: 1979-Sep-01
Included in the Prior Art Database: 2005-Nov-11
Software Patent Institute
John D. Day: AUTHOR [+3]
This article discusses two basic classes of resource sharing protocols: terminal and file transfer job protocols.
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Resource Sharing Protocols
John D. Day
Digital Technology Incorporated
(Image Omitted: This report summarizes recent US and European work on conventions for handling two basic types of remote operations: terminal access to remote hosts and file transfer between hosts.)
There are two major classes of protocols in a general- purpose computer network: communications protocols and resource sharing protocols. Communications protocols, often referred to as lower-level protocols, are primarily concerned with the reliable transfer of data, while resource sharing protocols, often referred to as higher- level protocols, are primarily concerned with performing remote operations. This article discusses two basic classes of resource sharing protocols: terminal and file transfer job protocols.
Terminal protocols establish mechanisms that allow efficient, flexible terminal access to remote hosts. Terminal protocols can also be used as a characteroriented network interprocess communication facility. File transfer protocols allow users to manipulate remote file systems and to transfer files or parts of files from one host system to another. Many of the problems encountered in these protocols recur in more complex forms in the more sophisticated protocols (e.g., network mail protocols, distributed data base protocols) which may be built on top of them.
Since homogeneous network protocols are generally a subset of heterogeneous network protocols in both scope and mechanisms, we will restrict our discussion to heterogenous network protocols.
Probably the most common computer communications requirement today is for terminal access, which is commonly provided by terminal-concentrator networks organized into a star or tree topology. Terminals and terminal concentrators are connected by point-to-point lines to the central data processing center. The point-to-point lines, and in some cases the terminal concentrators, of a terminal- concentrator network can be replaced with a packet-switched network. Replacing a terminalconcentrator network by a packet-switched network can significantly reduce costs and increase reliability.
Terminal access to a network may be provided in one of three basic ways: through a large computer or "host," through a network access machine or "minihost," or through a direct interface. When a large computer is connected to a network, terminals may access the network using special software residing in the host. In the second approach, a dedicated minicomputer provides many of the...