PO WEEKNAPPLICATION DEVELOPMENT

APPLIED INTELLIGENCE

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MAY 22, 1989

V The AS/400 ls Justifiably Popular—but It Has Its Limits

ond part of a
series on IBM s
AS/400 mid-
range family of
computers. The
AS/400 is an
important com-
ponent of IBM's
strategy to pro-
vide greatly en-
tency and con-
nectivity across

na

UE
zi MARTIH multiple sup-
ported envi-

The AS/400 has been an immediate
market success, even though its full ca-
pability is just beginning to be under-
stood. This week, I'll examine the keys
to its success, as well as its limits.

Some reasons why the AS/400 is so
popular include the following;

e System/3X compatibility. IBM
stopped most of its development work
on the System/36 and System/38 in the
summer of 1986 and focused on the

AS/400. By mid-1988, many of the

990,000 System/3X users were ready for

something newer and better. The

AS/4005 ability to run System/3X appli-

cations with a limited conversion effort
ensured it an initial surge of orders
from System/3X users primed for an
upgrade.

e Database capability. The AS/400 is a

database computer, not a general-pur-
pose computer to which database-man-
agement software has been added. As a
result, it offers advanced relational da-
tabase features without the perfor-
mance degradation normally associated
with relational processing.

6 Cost of ownership. The combination
of AS/400 architecture and features
makes it a very affordable computer,
particu zbil when the cost of support
functions (systems programming, data-
base support, network management, op-
erations and software) are considered.
e Downsizing option. Some organiza-
tions, particularly those faced with an
expensive conversion from IBM's
DOS/VSE to the MVS operating system,
are switching to networked AS/400s.

e Advanced architecture. The AS/400
incorporates all of the innovative fea-
tures of the System/38 architecture, in-
cluding a high-level machine interface,
object orientation, single-level address-
ability, a large address space, integrated
system software and a machine-integrat-
ed relational database-management sys-

e Ease of use. The AS/400 offers a
great deal of capability without the
need for numerous complex interfaces.
6 Avanilability of applications.
System/3X compatibility allowed the
more than 8,000 application packages
available for System/3X to be rapidly
available on the AS/400.

€ Connectivity. The AS/400 is easy to
connect to other IBM computers and to
a wide variety of non-IBM computers
and devices. Čonnectivity with IBM-com-
patible PCs is especially strong. Support
for šteje Network Architecture —
(SNA LU 6.2 is provided by Advanced

Program-to-Program Communications,
which gives AS/400 users a flexible and
simple-to-use method for building net-
works of computers.
e First major implementation of
SAA, IBM has made it clear that the set
of standards called Systems Application
Architecture (SAA) will form the foun-
dation for future software products.
The AS/400 provides more SAA capa-
bilities than any other computer envi-
ronment, and its advanced architecture
offers a more practical and workable
approach to relational processing. Al-
though the current relational database
lacks some important features (such as
relational integrity), the DBMS more

system matures during the 1990s. The
design also provides for the introduction
of new technology such as optical stor-
age and large solid-state memorles with-

out affecting applications design.

Problems and Limitations
Overall, the AS/400 has met; or ex-
ceeded its original design objectives;

however, a few problems have yet, to be
resolved satisfactorily. The AS/400's cur-

rent limits include the following;
e Missing SAA languages. Not avail-

able yet are C, FORTRAN, SAA Control

Language (REXX), Cross System Prod-

uct (CSP) and SAA Guery (OMF). Sup-
port for C and an execution-only version

Simplicity: The AttractioH of IBM's A8/400

How tle AS/400 Cotiipares with Traditiotial Systettis"

Traditional Systems
' Applications sold as separate modules
» Specialized experts needed to support
each module
Basic Office
| Interactive SuppoH
Supervisor/Job Scheduler
Corrimunications
O Database
Secutity
Graphics
Operatirig System

internal Code

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14

John Avakian

The AS/400 provides the most SAA capabilities, and its
advanced architecture offers a means of relational
processing—but the relational database lacks Jeatures.

than makes up for this by being afford-
Ne and easy to use. |
mpared with traditional syste

the AS/400 provides an poseda
tem-software structure. As illustrated,
traditional systems provide separate
system-software packages for graphics,
basic office, security, communications,
database and so on. The AS/400 com-
bines these software layers into one
comprehensive system-software module
identical for all models, which makes it,
poselbje to offer high in odopajjo with-
out unnecessary complexity.

The AS/400's design makes it unlikely
that its users will face operating-system

of CSP are likely to be available in 1989,

and the remaining lan
than mid-1990.

6 Tape-backup devices. The fastest
backup tape currently offered is the
IBM 2440, which isn't fast enough to
back up very large disk configurations
(more than 10 gigabytes) in a reason:
able time. The faster 3422 has been an:
nounced for the AS/400, but it won't be
available until the fourth guarter.

6 Recovery. The recovery from com-
plete failure of a disk drive can be com-
plex and slow. This is caused by the
way in which single-level addressability
is implemented. If a disk drive fails and
cannot be read, it's necessary to recon-

guages no later

struct the contents of all disk drives.

A number of optional facilities are
available to reduce the risk of needing
to completely rebuild all disk files. For
example, the option of Checksum Pro-
tection offers significant protection, but
there's an associated overhead, and re-
covery time is often a matter of hours.
6 On-line transaction processing. The
recovery limitations of the AS/400 make
it impractical now for certain critical
transaction-processing applications that
reguire high availability.

e Fault tolerance. The AS/400 is cur-
rently impractical to use in certain situ-
ations where either fault tolerance or
very high availability is reguired.

6 Technical computing. The AS/400
currently lacks hardware floating-point

capability, so it can't be used for num-
ber-intensive computing. This limitation

may be resolved by IBM during 1989.

e System/36 mode performance. Al-
though the facility that allows the
AS/400 to run System/36 applications
after a simple migration is generally
guite effective, it does reguire more
computer resources than if System/36
applications had been written to take
full advantage of the AS/400.

e Entry price. The cost of owning even
a small AS/400 is well over $50,000 (in
most cases this includes hardware, sys-
tem software, applications software,
training and so on). A lower entry price
is needed to bridge the gap between PC
solutions and the current low end of the
AS/400 line.

e Application-development tools.

There are relatively few good tools

available for application development

on the AS/400.

6 Connectivity with 3270 work-
stations. It can be difficult to create
networks with both AS/400 and Sys-
tem/370 systems if the workstations on
the System/370 systems include older
9210-type workstations. Of ten, the most
significant problem is the limitation of
the 3270s keyboard.

e Support of non-SNA devices. The

AS/400 currently lacks connectivity to
many non-SNA devices, such as certain
Unix workstations, Macintosh comput-

ers or other devices that use the TCP/IP
protocols.

o Office automation. The AS/400 was
announced with an adeguate—but not
superior —office-automation capability.
The AS/400 Office functions will be en-
hanced through the availability of the
IBM OfficeVision Family of office prod-
ucts announced last week. However,
these new office products will not likely
be fully available until mid-1990.

Next week, Ill evaluate the AS/400 as
an alternative to the widely used IBM
System/370 architecture. B
The James Martin Productivity Serie:
an information service updated guar-
terly, is available through High Pro-
ductivity Soft ne. of Marble-

ftware I :
head, Mass. (800) 2442-1230. For infor-
mation on seminars, please contact (in.
the United Stateh oni ŠinJji, ije,
nology Transfer Institute, 741 10th Si
Santa Monica, Calif. 90402 (213) 394-
8305. In Europe, contact Savant, 2
New St., Carnforth, Lancs., LA5 9BX
United Ki n (0524) 734 505.

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