RFC 242 (rfc242) - Page 1 of 10
Data Descriptive Language for Shared Data
Alternative Format: Original Text Document
RFC 242 NIC 7672 Categories: D.4, D.7 DATA DESCRIPTIVE LANGUAGE FOR SHARED DATA L. Haibt A. Mullery Thomas J. Watson Research Center Yorktown Heights, N.Y. July 19, 1971 Introduction A primary consequence of the use of networks of computers is the demand for more efficient shared use of data. Many of the impedements to easy shared data follow from the many diverse ways of representing and making reference to the same data. Almost all of these problems have been known before data was shared through computer networks, but the network facility has simply emphasized the problems. For convenience of discussion, representation differences will be classified in three categories. The first category is one of very local representation - the bit patterns for the character set, for fixed point and floating point numbers. These differences are usually imposed by differences in CPU's and storage devices. Translations from one representation to another at another at this level can usually be made a unit at a time (e.g. computer word by computer word) with the most serious problems occurring when there are some values in one representation scheme which have no corresponding meaning in the other representation scheme, as, for expamble, when trying to translate eight-bit bytes to six-bit bytes. A second category of differences has to do with the representation of collections of data, e.g., their size, ordering and location.