Preface

This issue contains nine papers and a technicalnote on a variety of subjects, including commu-nications technologies, compilers, program un-derstanding, and expert systems for dump anal-ysis.

The first paper, by Baade, discusses the use of theNetwork Design and Analysis (NETDA) tool toconstruct optimal computer network trafficroutes for use with complex Systems NetworkArchitecture (SNA) networks. The author hastaken advantage of features in NETDA that allowfor the use of actual network traffic data in thedesign of the routings. This approach yields sig-nificant reductions in network utilization withoutreconfiguration of the underlying hardware.

The Open Systems Interconnection (ost) proto-cols have been made part of the Systems Appli-cation Architecture" (SAA™) and are expected tobe implemented across all SAA operating systems.Goldberg and Mouton present the architecture ofthe OSIICommunications Subsystem Base,which provides a portable base for OSI implemen-tations across diverse operating systems with dis-similar architectures. The Base in turn supports theOSI/Communications Subsystem and is capable ofsupporting similar layered communications proto-cols, especially if portability is of concern.

Multimedia instruction provides an opportunityfor industry and academia to move toward an ed-ucational environment in which individualized in-struction is the rule, rather than the exception.Multimedia efforts at California State Universityat Fullerton and at IBM are anticipating future ed-ucational programs that are distributed, modular,multisensory, portable, interruptible, nonlinear,transferable, responsive, engrossing, and enjoy-able. Reisman and Carr describe these efforts,trace their history within the context of individ-ualized instruction, provide a look at recent de-velopments, and project a future educationalmilieu.

248 PREFACE

Sahulka, Plachy, L. Scarborough, R. Scarbor-ough, and White describe the capabilities of a newlevel of FORTRAN-IBM Clustered FORTRAN-that makes it possible to share all the resources oftwo IBM ES/3090 Model 600 systems (up to 12processors and Vector Facilities) executing oneFORTRAN program. These capabilities include dy-namic allocation of real processors at executiontime, to make best use of available actual re-sources and to make the compiled program inde-pendent of resource availability. The authorsdiscuss the associated language extensions, com-piler, library, and high-speed hardware connec-tion between ES/3090 systems.

Turning to another programming language, thenext paper presents the foundations for partialcompilation of the Restructured Extended Exec-utor (REXX) language, which has in turn led to thenew REXX compiler and could affect compilers forother interpretive languages. Pinter, Vortman,and Weiss describe the most important features ofpartial compilation for REXX. These include def-inition of an abstract machine and an intermediatelanguage to support execution, management ofbound variables through a unique symbol tableorganization called lazy hiding, additional symboltable support for compound variables, saving ofmultiple representations of variable values toavoid conversions, and the use of other delayedexecution techniques. Many ofthese features areintended to improve execution efficiency in thecompiled REXX environment.

The dramatic increase in peripheral equipmentfor personal computers has led to a need for ef-ficient means to program their diverse devicedrivers in Operating Systern/z" (OS/2®). The tra-ditional approach utilized assembler languages,but the opportunity exists to use higher-level lan-guages in support of device driver code. The au-thor, Feriozi, constructs a model for devicedrivers built on the C programming language.Efficiency is always a concern with device drivers

IBM SYSTEMS JOURNAL, VOL 30, NO 3, 1991

and with higher-level languages. The author ad-dresses these concerns in several ways, includingthe elimination of the C startup routines and theC run-time library.

Lenz and Saelens show how expert systems andknowledge-based technology can be beneficiallyapplied to the classic area of reading dumps fromthe Multiple Virtual Storage (MVS) operating sys-tem. Their approach also demonstrates how thetechniques learned in knowledge-based systemsfor medical diagnostics, which are fairly ad-vanced, can be reused to develop such systemsfor another area. The data collected on use of thisexpert system-the MVS Dump Analyzer-showthat many problems can be solved through thesystem without having a human consult the dumpat all, and that the average saving in dump anal-ysis is about one half hour. The authors alsopresent their experiences in building the expertbase and in educating people in the use of suchnew technologies.

The IBM Rochester Programming Laboratory hasrecently been in the public view because of itshigh-quality environment and results, as evi-denced by the 1990 Malcolm Baldrige NationalQuality Award. Kan provides a look inside theprocesses used to achieve the necessary qualityresults by writing about the quality models usedto estimate software reliability and to managesoftware development quality. There are fivemodels used, two that span the software devel-opment life cycle and three that are for more spe-cialized purposes. The author points out that thelargest obstacle to successful use of quality mod-els is not the models themselves, but the avail-ability of sufficient, relevant data to support theuse of the model. The history of Rochester's qual-ity achievements can be seen in a simple and un-derstandable form through these models.

Brown shows how the two fundamental aspectsof software-documentation about the softwareand analysis of the source code structure-can bebrought together through tools to aid software de-velopers and maintainers during the life of a soft-ware product. His approach utilizes and inte-grates tools for program understanding andhypertext documentation. The ability to move be-tween these two sources of information and toreadily form the needed correspondences can beof considerable help to those who must analyze

IBM SYSTEMS JOURNAL, VOL 30, NO 3, 1991

software problems and understand existing soft-ware that is new to them.

In a technical note, Appel, Cuomo, Overly, Wal-icki, and Yozzo present the results of their effortsto add images, and particularly those of people, toon-line systems that provide information aboutpeople, such as on-line directories. In particular,they describe the WATINFO system used at theIBM Thomas J. Watson Research Center and itsuse of face images to enhance the appeal of di-rectories and similar systems.

The next issue of the Journal will be a special issuedevoted to papers on APL (A Programming Lan-guage) in celebration of its 25th anniversary.

Gene F. HoffnagleEditor

PREFACE 249