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Pace 78

CPE WEEKNAPELICATION DEVELOPMENE,

JULY 17, 1989

€ APPLIEH INTELLIGENCE.

SAA s Standards, Tools Promise Big Productivity Gains

7 doing it can be sp

This is Part 2
of a series of
articles on
IBM s Systems
Application Ar-
chitecture
(SAA). Integrat-
ed computing
environments
such as SAA
ul have a ma-
jor impact on

the software
technologies of
O the '90s.
k SAA is based

on a well-defined architecture and a set
of consistent standards that define how
applications are built. The use of stan-
dards and architectures is not new to
the computer industry. Standards orga-
nizations have been in place for years.

There is always a conflict between

standards-setting organizations and ven:
dors developing proprietary products. A
primary function of standards is to cre-
ate an open environment. However, ven-
dor-imposed standards are often de-
signed to lock customers into a propri-
etary environment. Some de facto
standards are set simply because one
product, becomes widely used.

The standards for databases, commu-
nication facilities and languages have all
iocused on the functionality supported
by these technologies. Over the last, few
years the importance of standard appli-
calon architectures has emerged. Many

"un developing standard application envi:
ronments.

Standards organizations are wrestling
with the same issues. The Open Soft:
ware Foundation was organized to ad-
dress the issues of Unix environments
and is using IBM's AIX as the basis for
the future development of a Unix stan:
dard. lis goal is to provide an open
(ramework for application development
that does not lock a customer into a sin-
gle-vendor environment.

The American National Standards In:
stitute is also looking at these issues and
is working on a standard for the critical
base technology of a repository. A re-

pository will contain full application
specifications that can then be used to
generale applications for particular en-
vironments. A common repository of de-
me pralcatlovs is an essential] compo-
nent of computer-ajided softw: i-
Pole čer, software engi

1e value of specifvir standard applica-
tion-enabling osorno ona
repetitive aspect of application

ment can be identified soki

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a are re aartaivo eflort to — Without an integrated application envi. <3 pa kma the programmer to terly, is available ihrough High Pro:
indan eu. ar eCAUON environments — ronment. there : ie RASLI oa specify logi Y (he components of th uctivitu Sofhnaro Im | Se
will be tena e architecture. The result for buliding intert aces, interface, such as menus and forms, head, Mass. (800) sie Ika oo
forme, > Producivity gaj that runs on one machine can't Ujeta These standard constructs do not have mation on seminars please dli sala
(a SAA Provides standards for three jp. Po Led to another because the tools for jo pon ete, but simply logical — the United States acid Canada, Tech:
— 'erfaces to a machine: the Core tea. SAbIAE the interface are totaliy dir. > Poet The tools do the rest. nology Transfer Institute, 741 10th St.
ee LJA): o Camneo Pragi ae Ee A... Common Cogira Sery Santa Monica, Calif. 90402 (213) 39%,
— ming Interi Program- — The CUA ad Sa 'Lomm Services ) bie 394
JB interf (CP; and the Common s 1€ UUA addresses both these issues. — The CCS ia iha orala 8305. In Europe, contact Savant, 2
s s Ne simplif xa z oe she programmer. United Kingdom (0524) 734 505

— theaj

The vast amounts of code needed to
connect different machines is completely
hidden. The programmer simply uses
high-level verbs that specify program-to-
program communications.

Again, the repetitive work of connect:
ing machines is isolated and encapsulat-
ed by the SAA architecture. The archi-
tecture allows the programmer to con:
centrate on application logic rather than
on communication implementation. Only
the logical connections between pro-
grams need to be specified. Furthermore,
these connections are specified in a con-
sistent, standard fashion, independent of
machine environment.

Common Programming Interface
The CPI contains language standards
and service standards. The provision of
common in-house'services makes SAA a
powerlul standard. As shown in the
graph, the language, user-interface, com-
munications and in-house services are
all specified as part of the CPI. The
graph also illustrates that application
modules developed using CPI services
exactly mirror the architectural bound-
aries of CPI.
Another important service supplied
by the CPI is database access. There are
many different types of data- and file-
management facilities available today,
and each reguires different implementa-
OH PrGA HA IHIEHABE. ii Im—. . tions in different environments. The pro-
KOREN SJE | | use and learn how to use it.
| CokiKlUHIcaManI Database | li With SAA, relational database mani šine v
[ IhteHace |. H erlace Further- o

Communication Services (CCS).

Let.s look at. how each of these encap-
sulates some of the repetitive work of
application development.

interface, eliminating much of the de-
bate over what; the interface will look
like. Then it specifies the tools that will
be used to enable that design, thus pro-
viding for consistent tools across differ-
ent hardware and software environ-
ments. In both cases, the architecture
isolates and encapsulates a portion of
the repetitive programming work.

The design chosen for the CUA is a
good interface design, based on Xerox's
research and popularized by the Macin-
tosh. It was further -refined and devel-
oped through user-interface studies at
IBM, which enhanced it. with technology
acguired from firms with excellent user-
interface reputations, such as Metaphor.

Developlig Applleatlons for SMA 4
< Cote Slieuld Be Divided tate Modules 'rhat Mlireh BAA'«
CoiiititoH Progratitnip iHterPace FuHello

zz, PrograHimable
LA, url

Common User Access

Every application has a user inter-
face. The developer must design the user
interface and implement; it. In the past,
user interfaces were developed at the
convenience of the programmer. The us-
ability of the interface was secondary to
simply getting the application to work.

Today, everyone recognizes the value
of a good user interface—it changes the
relationship between users and applica-
tions. Poorly designed interfaces make

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Breški
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Dialogi

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| ervices agement becomes the standard.

ntertaceš Intettac8 more, the interface to relational —..—.

dija — databases—Strucettred Aery Language
(SGL)—is consistent. from environment

to environment. Because SOL deals only
with the logical access of data, the pro-
grammer is freed from having to write
code to a physical database design.
Again, the data access and retrieval is
isolated and encapsulated for enhanced
programmer produtctivity.

SAA and the tools that enable it pro-
vide a powerful means for programmers
to avoid many of the repetitive and dif:
ficult tasks of application development
that are not directly related to applica-
tion-functional logic. It does this by
architecturally isolating certain elements
of application design, specifying stan-
dards for those elements and providing
tools that enable the standards.

Every organization using SAA will
certainly benefit from SAA, but even
larger benefits can be gained by extend-
ing the architecture to better model its
own application-development process.

Next week, T'1l desceribe the planning
functions that are reguired today to pre-
pare (or the integrated computing envi-

Hm
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i: Database || (H-H6us8
Atcešš, ||  Servleea
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či
bile

Applleatiah Modulkš

John Avakian

SAA provides a powerful means for programmers to avoid
manyy repetitwve and difficult tasks of application develop-
ment not directly related to applicatio Junctional logic.

OEM SN NI 5 po
the user a slave to the application and
force the user to learn an alien syntax

— that is unigue to the application, With a
 Bood interface, the user is in control and

There are two levels of tools specified
for enabling CUA interfaces. One is the
presentation interface, which gives the
programmer a high degree of control!