Inside the AS/400: The Book Every AS/400 Developer Has Been Waiting for

396 Pages·1996·23.707 MB·English

by  Frank G. Soltis

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an in-depth look at the system's
design, architecture, and history
BY Frank G. Souris
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Told by Dr. Frank G. Soltis, IBM’s AS/400 chief architect, this
authoritative book looks at the AS/400’s design, architecture,
history — and at some of the people behind the scenes who
created this revolutionary system for you.
Whether you are an executive looking for a high-level
overview or a “bit-twiddling techie” who wants all the
details, demystifies this system, shedding
light on how it came to be, how it can do the things it
does, and what its future may hold — especially in light of
its new PowerPC RISC processors.
advanced application architecture
technology-independent machine interface
objects and object management
integrated database
security and authorization
single-level store
process management
1/0 system
client/server computing
Simply, is written for those who want to
learn more about the AS/400 from someone who knows. It is
written for you, the customer and application developer, who
want to understand how the AS/400 works so you can write
better applications, or simply so you can see what makes
this system tick.
Is the AS/400 magic, or just good design? After reading
, perhaps you will agree that it’s a little of both.
BY FRANK G. Soutis
A Division of
| DUKE COMMUNICATIONS
INTERNATIONAL
Loveland, Colorado
Library of Congress Cataloging-in-Publication Data
Soltis, Frank, 1940-
Inside the AS/400 : an in-depth look at the AS/400’s design,
architecture, and history / by Frank Soltis.
pi rent
Includes index.
ISBN 1-882419-13-8
1. IBM AS/400 (Computer) I. Title.
QA76.8.125919S64 1995
004.2'545—dc20 95-33232
CIP
Copyright © 1996 by DUKE PRESS
ID DUKE COMMUNICATIONS INTERNATIONAL
DUKE Loveland, Colorado
PRESS
All rights reserved. No part of this book may be reproduced in any form by any
electronic or mechanical means (including photocopying, recording, or infor-
mation storage and retrieval) without permission in writing from the publisher.
It is the reader’s responsibility to ensure procedures and techniques used from
this book are accurate and appropriate for the user’s installation. No warranty is
implied or expressed.
This book was printed and bound in the United States of America.
ISBN 1-882419-13-8
2-3 4 S°KP-9F78.6:. 5
2
To the love of my life for more than 31 years, my wife, Sandra.
Acknowledgmenis
As long as 10 years ago, I considered writing this book. Those were the Sys-
tem/38 days, and people such as Paul Conte were encouraging me to write a
book about the System/38 and the people who created it. But it was 1985, and
the System/38 had been declared a “non-strategic” product within IBM. It
was not obvious this system had any future. With the rebirth of the System/38
as the AS/400 in 1988, I began to write a book about the history, the people,
and the development of these two systems. Over the past seven years, I have
continued to plug away at that manuscript. Paul and others have encouraged
me to finish that history book and share the Rochester story with the rest of
the world. Inside the AS/400 does contain a few historical excerpts from that
unpublished manuscript.
Rochester is the most creative site in all of IBM. In the last few years,
IBM has received lots of criticism for its inability to capitalize on its own
technologies and to recognize the emerging needs of its customers. Yet, year
after year, the dedicated men and women in Rochester continue to turn out
creative, successful products that delight our customers and bring financial
rewards to IBM. Rochester has never been very good at winning the “battle
of the foil projectors” at IBM headquarters, but we have always been very
good at winning the battle for customers.
Throughout this book, I have tried to name some of those creative, dedi-
cated people who are responsible for the success of the AS/400. It is an
impossible task, and I have only been able to name a few. For all of you who
are not named, please accept my apologies. Even after 32 years of working
for IBM in Rochester, hardly a day goes by that I don’t feel inspired by the
people around me. Thanks to all of you.
Mike Tomashek managed the development organization in Rochester
that rewrote the internals of the AS/400 operating system for the PowerPC
processors. It was clear in October 1991 that a massive education effort
would be needed for the hundreds of new developers we were going to
hire to write the new code. I had just spent the previous six months lead-
ing the effort to convince the management and technical leadership in
Rochester to adopt the PowerPC technology for the AS/400. Now the pro-
ject had been funded by IBM, and we were authorized to go out and hire
IV
+
our first 200 people. Mike asked me to organize the education effort (in
addition to my role in IBM, I am an adjunct professor and a member of the
graduate faculty at the University of Minnesota). His request seemed rea-
sonable, so I agreed.
As part of this education, I developed and taught the first classes on the
internals of the AS/400. This undertaking would not have been possible
without Jan Schliem working with me. Jan took on the responsibility to
organize and manage the entire education project. That freed me to devel-
op the class, and that class material formed the basis for this book. It was
also Mike Tomashek who convinced me to turn this material into a book.
I also want to thank the Rochester people who reviewed the various
chapters of this book and provided feedback for me. I especially want to
thank two of them, Bruce Jawer and Larry Walsh, for being true believers in
the AS/400 and for encouraging me to finish this project.
Working with the people at Duke Communications over the past few
years has been an enjoyable experience for me. I had my first article pub-
lished in NEWS 3X/400 (now NEWS/400) magazine in 1992, and I have
managed to write something for that magazine every year since then. I have
also enjoyed participating in the magazine’s annual International Confer-
ence in Vail, Colorado, for the past three years. Dave Duke and his staff
have done a marvelous job with the magazine and the conference. When it
came time to select a publisher for this book, Duke Press was a natural
choice. Dave Bernard, the editorial director at Duke Press, worked with me
from the beginning to ensure that we produced a high-quality book. Two
other people, Sharon Hamm and Richard Rubin, are responsible for the
form and content of this book.
Sharon Hamm was the book’s editor. The job of an editor is a difficult
one. She had to handle the seemingly endless number of changes I kept
making to the manuscript and still keep both me and the production staff on
schedule. She did a great job of balancing all these responsibilities. Thank
you, Sharon; it has been a pleasure to work with you.
The person who shaped the final form of this book more than anyone else
was the technical editor, Richard Rubin. Many of you know Richard from
his excellent technical articles, especially in the area of database design. I
tend to look at the AS/400 from the inside out. Richard provided the cus-
tomer view of the system. Whenever I began to get carried away with the
glorification of some technical aspect of the AS/400, Richard would bring
me back to reality by asking, “What does it mean to the customer?”
Richard’s insistence on examples for just about everything and his attention
to detail make this book far more understandable to a wide audience of
readers. Thank you, Richard.
Finally, this book would not have been written at all without the most
important person in my life, my wife Sandra. I was having all kinds of trou-
ble getting started. When she noted that my desk was beginning to look like
Vv
the bridge of the Millennium Falcon, she stepped in, organized my material,
and transcribed the videotapes of my AS/400 architecture class. Those tran-
scriptions formed the first draft of this book. She then took on the roles of
cheerleader, counselor, reviewer, and part-time editor. Thank you for always
being there for me.
I also want to thank our three wonderful sons, Mike, Brian, and Steve. In
spite of their own busy schedules with work and school, they took on addi-
tional responsibilities to give me more free time, and filled in for me on
numerous occasions when I needed their help. For example, during the sum-
mer months, a couple of them unselfishly volunteered to spend their week-
ends racing our Porsche at the various racetracks around the Midwest, so I
could stay home and dedicate more time to finishing this book. Believe me,
I will never be that dedicated, although my time at the track this year is
down to almost nothing. I plan to remedy that situation.
— FS.
Vi
Table of Contents
ACKNOWICOOMOMNS: oo oocas-cacccsate-rcaoc euiec qsaea tReteucenc IV
FORO WON er sah Ab ached srssced ekesasesololasioinnctsss RET XV
P13 A RAEN 2 eh ale XVII
The Revolution Begins ccanusar new hnacceis ame XVIII
FOPUIRITOK notre tee es erga loccans tia CASES RRA te Oe enna a ene CRETE XIX
The Early AS/400 (aka System/38) ..............sssssssssccssssssssssscsssssssssssssesssssssssesesosssssessses XIX
The ASI400-POWErPC Union wccissscceeszsctsscsisscssneaiienccteasceuss-dusasctaaeelnu vatdgenevaesae XX
The Technical Development Team .............cccccsssessssesssssesssseessssesssssssssseesssessssveessseeeseny XX]
inhe- Management leat... n..,..c.-cnnseoaantatecaeacn ncainee nitr e XXIII
Eloventh-Hour Ceadersin 25. siscs.sssscisesebco tcasnssamsnettetcumererraseteaetneeeenns XXIV
WHY ATS BOOK 2i er cocete ce tresses corines. armenia an nis etn eet eee XXV
HOW LO CAG LIS: BOOK Msn cey fav ticsccccss ccs vniss heen uiartaatan et ras ee XXVII
Chapter 1: Advanced Application Architecture 0.0.0.0... 1
GONE ArCONECIING tree reer cca eater eran hea Rees 2
AUPTOGraMIMenS VIGQW earn et aren cnc een es en v
EOVOrIs OL AUSITACUOIT ore en mre rr tina uncharacteristic 3
OM WATE DOSION rc weg ete rere cot ena recree ie eave arertn are tea ne reer reat 5
Architectire Classificatiotve 1. acc cance eciemnenet re s cen i
PrOCESSOMCENITIC ATCHILCCIUNC: critosaccece nti ati ison mciney oor tannecc nen rn as nees 8
Application Programming Interface (API)-Centric Architecture .....ssescsssssssesseen 8
High-Level Machine Architecture vasmentng sialty-q amor tos eta erectus vata 9
FUSTORICAl DACKOLOUNIG c. Missings ccseee-csscsnccrcnnsrseacrerceas: ioeez eereiees savraannegess 10
WERE SIN er INIT oes cosssessssackoneccvctscsaus ics ata on ee een eee 18
SLEUO: ROS UCOL LING: SHOOK cars os esac cpseccoris os aeons Sema scianien desu ieee nacre een 20
Chapter 2: The PowerPC Technology ..............scccsssssssssesssssssessnssssseesnnssessesesessseseee 21
TINS POWGIEG AINAIICG reticent oie aie eae Resa ae ane oatnttr eee 21
SERS VOPUTUCTT Oy OWEN Ooty eta ocesk etre cere asrtie onsen niticPes ahestaeanunsdetusiiisanriiaieo 23
The AS/400 Commercial RISC Processor ............c:ccsscscssessssessssesssnssssssesssseesssesssssesssees 29
PowerPC Technology for the AS/400 .ou......csssssssssssssessesssssssssssssssseessessecsssssssssssssneees 31
BIER PGOWPGERG y PACH HITEC LLING st ra coae essere avrs es sicss ncn conders nes atuensevescanPuivernnsednoaVenuysvivessnin 36
Extensions to the PowerPC Architecture ............ccccsscsecsessesestestsnessessensesssssenseneees 39
A 65-Bit ProcessOr? -.ssscsssSstesioeivar stislad eschecconeasnnsdteeiastcassastyeod nemiclees eeesne eset ahsee re ars 40
PowerPC.AS Instructions s.ciccesacsscccataesc osarasadseracnesetonessss etacnceesr aseecee oea riee tieanm 41
AS/400 Processor Implementations 0.0.0... ccscssssssssssesssssseeecssneccssseecesnneeeesnnnesssnneeeess 42
The A30 (Muskie) Processors ........ssssvssssssssssssssevecsssssnsesseessssssecescanscsessessnnerssonsanuesssnassy 42
The. A10 (Cobra) Processors. ...:csistsssapsceecssscascccosotasstestecnstatsntitpristesteeoeetpeoenndeeesaagse 46
CORCHUSIONS 2. isistescccassin;eacess, Sette ntacees eoecrNaen sees alas dasa Ta tees tenor aera 47
Chapter 3: The Technology-Independent Machine Interface ..................0...00 49
Overview of the MI Architecture 0... secssssssesssssesssssssscssssesssssessssssssesssseeesssneee 50
A Non-Exocutable Interface: 0:5 -ccc.cctcercccsosocorureveres?csteasnnstso mcauetcebiseceenecescmatrreoesrcesrt s a1
AS/400 Language Compilers’ iciccccsccssssscccencesssececcscresaseecaseusstveesarstsupeesenaenmeetiguateeesntaat 53
Characteristics of the Machine Interface 0.0... .sssssssccsssessssseessssseessssseeessseeessss 59
Working: with Mi Prograims poetic. soscesscursecesececiesttsonssoeronenctsensistetvinesorvarerrtaereentsnenress 60
Creating a Progarn n cesssuedhvesecesshecsnecesescceertuesessceactnasuo rrsasssaaeta sceneencl aeseeasreed1asaeceeeaotria e 61
Destroying @ Progrannt <0. -scac.ccsosessscorseceectnsis rsaqes cestievses esaosenso cnueset sexatsee etn seeerea 62
Program Materialization and Observability .......sssssssssssssesssssscsssssesesssseessssseessssveesssees 62
Inside @ Programm TOMplate —.....csicssesssscsssssc-asecr spsectss osrnaenero stcao traetoigeannsa 65
Thé MI Insttuction’ Formats <5 \ccc.cccasteracnteeennes ceees escaoeme tare e 67
The ME Op-Code i jSaes ce iesacoveson ovsconntey east nsenes taconaung eaten ece cc caeioet a amarante 68
The Op-Code Extender 7.2).S etncsccscccasstoons sesae sceccdeo sehceceo angte eeceo eeee e 68
MI Tnstrnction Examples o...scccscs-scctscnseescantheaessesees ionsettt voamecri ceeerretmneeete ccfieaee 70
CORCHUISOINS ci 5 cc sscsscvsacesonessetescatsancccosscecnrtrooutseu eavrsoae 7ev o incets ccerena eydebeon tvnee 72
Chapter 4: An Integrated System oo. cccssssssssssssssssesessssssssssssnssssssssssssssssssssanssssssss 75
The Integrated Operating SyStene o.::.cs.cccccs.snescsb ennessersessesncsgoeeutease sestaree ecnese Ty
MICFOCODG a. sesscvonsscconosRUoCsGAe iaondcap suGsseien nonesSeber eobep, ol 79
System Licensed Internal Code 9.....:..55.55...-1ccssseisinssesascmageresssouauetpornametaoriatt 81
SLIC Development Environttientt ....ccsecinssstecina ntevt ececes snesese 83
SLIC Kernel Technologies: i.cs.sseccccabsce estaeitc evaeat ceves nneseees 84
System/36 Personality ....cc.cassciesocsvssersisevseaetcaeva avaesrce netaeerc teetnine 85
Something Old, Something NeW. c:.-dvsccsssesseeccesesd saoeeceestcse cteaetuesr epeekeeae 86
Acdvanicedd 36° s.tccssssistecssivenebapedo \enspesecltenysuhtes ality cael en gieee tetas aes aan cae 88
COncluslons: ©) csciijcicicctcot ce cers oe cette ste cnaanen care seas eee 89
Chapter 5: Objects and Object Management ...............ccccccccccsssssssssssssssscessnsnssesees 91
Object Naming: ......i.ccssi.caeectsousaceeeactedncaesun iteiti eaez eelielees 93
0S/400 Objects and MI System Objects ..........ccccccccsssssssssssssssssssvsssssssssssssesssessenssversees 94
Finding Objects: sasissnlsM acierc coane eennaed eeeie aarne nene 96
LAD rearb es sss ctatsstscccpbvnnndsasa vesnvanusvee Sieh ccaee Zonk sate Oe a 96
Shared! FOMGGES stazc.ssscieoWesekcess vasgnakcs leacnet etoos fnasuee sea doeea reetea asen 98
Integrated File System .s.csisessssunestsscsetoegeip seat seroeoce caRoe teses ceeteers nhaestees 98
Accessing ODjOCts ..:..iss.cscsssevsceepsceeeev etcieen eetse nevicecisesie r 101
Capability-Based Addressing :;cccccstenio ance hreeee scrteaeea nent eee 101
Resolving System Poustens .i.:c-ccscoseivc cacten eater tlecnee tye cane one eee oe 102
Vill