Browse Prior Art Database

Arbitrary Character Sets (RFC0373) Disclosure Number: IPCOM000003557D
Original Publication Date: 1972-Jul-14
Included in the Prior Art Database: 2000-Sep-13
Document File: 3 page(s) / 7K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. McCarthy: AUTHOR



This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 37% of the total text.

NWG/RFC #373 14 July 1972

NIC 11058 SU-AI


by John McCarthy

It would be nice to be able to have documents stored in computers that

could include arbitrary characters and to be able to display them on

any CRT screen, edit them using any keyboard, and print them on any

printer. The object of this memorandum is to suggest how to get there

from here with special reference to the ARPA network.

Where are we now?

(1) At present, there is 96 character ASCII, and everyone agrees that

it should be included in any larger set.

(2) Many installations are dependent on 64 character sets which do not

even include the lower case latin alphabet.

(3) At the Stanford Artificial Intelligence Laboratory, we have a 114

character set that includes 96 character ASCII and which is

implemented in our keyboards, displays, and line printer

(4) Printers are becoming available that get their character designs

out of memory, for example, the Xerox XGP printer, one of which we are


(5) The IMLAC type display has the character designs in main memory so

that changing the displayed set is just a matter of reloading the


(6) Many display systems share the character generator among many

display units. In some of these, e.g. the Datadisc, arbitrary sets

are probably feasible (using kludgery to be described later), but in

other systems, e.g. our III's arbitrary sets are not feasible.

One possible approach to communication in expanded character sets is

to produce an expanded standard set of characters, perhaps using 8 or

9 bits and expect new equipment to implement this set. This approach

has the disadvantage that it will be very hard to get agreement on

what the next step should be, and even if formal agreement is

realized, many groups will find it in their interest to ignore the


NWG/RFC# 373 JMC 14-JUL-72 12:41 11058


Therefore, I would like to suggest that the next step be to arbitrary

character sets. I suggest implementing this in the following way:

(1) There be established a registry of characters. Anyone can

register a new character. Each character has a unique number, 17 bits

should be enough even to include Chinese. Besides this, each

character has a name in ASCII usually mnemonic. Finally, the

character has a design which is a picture on a 50 by 50 dot matrix.

(2) Besides the registry of characters, there is a registry of

characters sets, which different group...