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Lower Cost,

This is the
; third part ofa ..
. series on IBM.
| AS/300, which '.
examines the
and .
limitations of
this midrange <
family of .com-

2 > For years, "6.
/ IBM S/370
V mainframe archi-
tecture has of:
€ feredanad-
l "Ve vanced, sophisti:
cated environment for developing and .
running commercial applications. Many, ::
users remain convinced that the only ""'
real alternative to IBM S/370 systems is.
plug-compatible computers from ven-
dors such as Amdahl. lji
li S/370 systems are so advanced and
so dominant, why are so many of their
users rushing to buy AS/400 systems?
The answer: It's not always easy or cost-
effective to take advantage of the Capa:
bility of S/370 computers. a

| years. As hardware
it was necessary to create a series of
| new operating systems to take advan.

V —, tage of larger memories, new devices

of systems-software
ment the operating-system functions. 3
Each product, including VTAM/NCP,

ed in the original operating systems.

| Support Coste Are High ''
An S/370 installation usually has a

stalled on one or more Computers. Fre-"
guently, a number of.

cost. However, if smaller S/370 us-

| €rs want the full functional

| that the larger lonal capability
Cur similar support.

Improved

< chines with AS/400 computers. In most,

||. 8/870 systems have evolved over 20 '' ——
capability improved,:. (Mi! IK NE
il

Teguirements- It was
also necessary to create a complex set š';
products to supple-

CICS, DB2, IMS, CMS and TSO, added an.
important functional element not inelud:

number of these software products in-

different opera!
of the same ane,

Users have, they must in-

PG WEEK NAPPLIGATION DEVELOPMENT

Raje Ma I

Nea Mu dab ad VU obi mem

: 9370, 4341, of both its customers and itself.
aljikesa Sij Graz and 3090 syse,, Complete replacement of midrange

; have begun replacing these ma- ' /;!, S/370 systems with AS/400-based solu-
ni ' tions is rapidly becoming more popular,
but it is not always appropriate. For ex-
// ample, S/370 systems used for technical
W/ applications such as engineering graph-

cases, these users were unable to keep
up with the most advanced S/370 sys-
tems-software products. Many use the

" DOS/VSE operating system. In the S/370.:/' ics are not candidates for replacement

i ither the: for expen- /'i;by AS/400 computers. And AS/400 sys-
one and tm aodivaže to! V tems are not ea Ja ČLA high :
live without the '//'' availability applications, e appli-

eat NeAVAL CLAN 7%) V cations, large networks or the attach-

desired functional capability: ; ]
The AS/400 offers these users some iment of unusual devices.
significant advantages: '' //://% /%:/ei/" Also, it seldom makes sense to replace
4,9 no future operating-system con-' .///0:l!|, 8/370 applications that do not need ':
versions; He 88 2: 74 (-' changes, especially if they're based on

ilka

% lower support costs;

(an application package in which there is

po
St

oj

|

š Networked with PS/2s for.
istributed processing poWi
Simple, consolidated softwar
4 Limited support guirementsi!

Complete replacemeni of S/370 sy ga
| AS/40O.based solutions is rapid oe an

bp v

Vis to one of the Mvs
from another operal

ds) to
s | |tems and move toward support of
sy [Ee processing and distributed data
k žem MERA IČ

' as lengthy as the original development.

; relational DBMS on

; the AS/4o0g incorporated in

Capability Spur Move to AS/400

€ The cost of support functions such as
systems programming, communications
management, database administration
and operations has grown to represent a
high percentage of total spending on in-
: formation systems (25 percent or more).
% A new application must be developed
rapidly.
' Programming resources are limited.
€ Management is unwilling to spend the
resources needed to support an effective
$/370 environment.
€ Users are unhappy with the time re-
guired to create new systems and are
looking increasingly to PC network:
based solutions to meet their needs.
Moving an application from an S/370
to an AS/400 usually involves complete-
ly replacing the S/370 application. Ideal-
ly, the new application will be package-
based, thus avoiding a complete rede-
sign. Retraining users, along with
creating a new set of interfaces with
other applications, is usually necessary.
Many S/370-oriented organizations are
concerned about the prospect of com-
pletely replacing applications. The origi-
nal applications usually take years to
develop and enhance, and there is a
feeling that a large investment will be
lost in a complete replacement. There is
also a concern that replacement will be

,Faster than Expected

Companies that have moved applica-
tions to the AS/400 have shown, howev-
er, that it can be accomplished more
rapidly than most S/370 organizations
would believe possible, especially if
packaged applications are used. In addi-
tion, it's often possible to significantly
improve the applications during the re-
placement Process, partly because older
and less sophisticated applications are
the best; candidates for replacement.

: It is also possible to improve applica-
tions as they are moved to the AS/400
because it is easier to develop applica-
tions that are fully interactive and use a
the AS/400.

Moving applications from an S/370
environment to an AS/400 environment
is not a simple task. Terms used to de-
scribe the Process include "conversion,"

MN sjese and "downsizing"

e implementation of in
Computing environments, ENI,
Systems Application Archi
accelerate the
from S/370

architectural

The James Martin Produeiai SE Series
an information service EM guar-
Pon . it High Pro
re
head, Mass. (800) 2439 ane
mation i

and Canada) Tech.
nstitute, 741 10th St.
Sa ponica, Calif. poke (213) 394:
% 2
New St. Carnforth, La: LAS" 9,
United Kingdom (i 0524) 734 505. za

k