REPRINTED FROM IBM SYSTEMS JOURNAL, VOL26, NO 3, 1987; © 1987, 1999 454 ZACHMAN 0018-8670/99/$5.00 © 1999 IBM IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 VOL26, NO 3, 1987, REPRINT ZACHMAN 455 456 ZACHMAN VOL26, NO 3, 1987, REPRINT IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 VOL26, NO 3, 1987, REPRINT ZACHMAN 457 458 ZACHMAN VOL26, NO 3, 1987, REPRINT IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 VOL26, NO 3, 1987, REPRINT ZACHMAN 459 460 ZACHMAN VOL26, NO 3, 1987, REPRINT IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 VOL26, NO 3, 1987, REPRINT ZACHMAN 461 462 ZACHMAN VOL26, NO 3, 1987, REPRINT IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 VOL26, NO 3, 1987, REPRINT ZACHMAN 463 464 ZACHMAN VOL26, NO 3, 1987, REPRINT IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 VOL26, NO 3, 1987, REPRINT ZACHMAN 465 466 ZACHMAN VOL26, NO 3, 1987, REPRINT IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 VOL26, NO 3, 1987, REPRINT ZACHMAN 467 468 ZACHMAN VOL26, NO 3, 1987, REPRINT IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999 VOL26, NO 3, 1987, REPRINT ZACHMAN 469 470 ZACHMAN VOL26, NO 3, 1987, REPRINT IBM SYSTEMS JOURNAL, VOL38, NOS 2&3, 1999