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Browse Prior Art Database

Machine-Independent Version Numbers

IP.com Disclosure Number: IPCOM000115411D
Original Publication Date: 1995-Apr-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 72K

Publishing Venue

IBM

Related People

Schawer, W: AUTHOR

Abstract

A scheme is disclosed, that allows to recognize version numbers in files independent of the data representation (Intel* or /370*).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 55% of the total text.

Machine-Independent Version Numbers

      A scheme is disclosed, that allows to recognize version numbers
in files independent of the data representation (Intel* or /370*).

      Files containing structured data include a version number in
order to process the structures correctly.  This version number are
usually placed at a well defined point in the file, so that programs
can first check the version, before working on the file.

      If the program must have the ability to accept data in both
data representations (Intel or /370) and convert it, depending on the
input, it would be elegant to determine the version number
independent of the data representation, before the actual conversion.

      Required is a version number, that is the same in Intel and
/370 format.

      The scheme disclosed, uses the fact, that palindromes
(symmetrical numbers, like 3223) look the same in Intel as well as in
/370 format.

      In order to understand, why palindromes solve the problem, the
representation of integral numbers in Intel and /370 format is
explained.  Integral number are represented bytewise in computer
memory.  One byte consists of 2 digits in hexadecimal format (number
to the base of 16).  Depending on the size of the integral number, 2
or 4 bytes are used to represent the number.  Number 1234 is
illustrated in /370 Format in Fig. 1.

In order to convert a number from /370-format to Intel-format the
bytes must be swapped.  Note, that convert...