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Universal host table (RFC0752)

IP.com Disclosure Number: IPCOM000003800D
Original Publication Date: 1979-Jan-02
Included in the Prior Art Database: 2000-Sep-13
Document File: 8 page(s) / 33K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

M.R. Crispin: AUTHOR

Abstract

ABSTRACT:

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 9% of the total text.

NWG/RFC# 752 MRC 2-Jan-79 01:22 nnnnn

A Universal Host Table

Network Working Group Mark Crispin

Request for Comments 752 SU-AI

NIC nnnnn 2 January 1979

A Universal Host Table

ABSTRACT:

The network host table in use at MIT and Stanford is described.

This host table is superior to the NIC and Tenex host tables in several

ways. A binary file, compiled from this host table, is also described.

This file is used by subsystems on MIT's ITS and Stanford's WAITS

timesharing systems for efficiency in host and network lookups.

HISTORY:

As with many other sites on the Arpanet, we found the NIC's host

table unsuited to our needs. Part of the problem was because the NIC

host table was often inaccurate and all too often failed to include

several nicknames in common usage in our communities. In addition, the

NIC host table's format was awkward for user programs to use, especially

those which wanted to have the host table mapped into memory in some

sort of structured binary form for efficient lookups. Finally, the NIC

host table neglects to include some essential information.

The ITS host table was originally designed to be compiled along

with a network handling program (MIDAS, the PDP-10 assembler used, has a

pseudo-op to insert a file into an assembly). In order to make the host

table palatable to the assembler, every comment line began with a

semicolon, and every actual data line began with the word HOST. Each

program which used the host table defined HOST as an assembly macro

before inserting the host table into the assembly.

This worked well for a long while, but as the network grew, hosts

changed their status more frequently and more network programs required

reassembly when the host table was updated. If the appropriate person

for a particular subsystem was not around, it could be a while before

that subsystem updated its host table.

In the spring of 1977, design started on a binary file which would

be placed on a system directory and which all subsystems which wanted to

access host table information would read in. The format was carefully

designed to be general enough to satisfy the needs of all the diverse

subsystems. All of these subsystems required modification to use the

new format but these modifications turned out to be trivial compared to

the benefits from not having to recompile every subsystem.

Later the host table and binary file were imported to the WAITS

NWG/RFC# 752 MRC 2-Jan-79 01:22 nnnnn

A Universal Host Table

system at Stanford, where it eventually replaced the former host table.

Recently, support for multiple networks has been added, including

allowing hosts to be on more than one network, and a more flexible

compiler than assembler macros was...