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AS/400s Design Expedites Application

ME serlous disadvantage. If one storage de-
... vice fails and the data on it cannot be

"the system, because a segmerit of nearly
(5% every object on the system may well

(V! have been resident on the damaged de-
[5 vice. Very long recovery times are the

j

' lem on the System/38 and AS/400 by

V improving the reliability of direct-access

V storage devices, providing recovery-sup-
port aids such as journaling and

! checksum protection, and introducing

specialized data-recovery utilities to its

si Ne be
[O Onthe AS/400, single-level '
This is the » addressability makes main memory and
Jfourth part of a .,mass storage appear to the programmer,
series on IBM  '. as a single, enormous pool of memory.'
midrange com: All objects are uccessed by name; pro":
puter familij,Y  " grams and database objects are shared '
the AS/400. - rather than having individual copies for'
The AS/400. .:. each user, and all objects appear to be'!
design incorpo-  " permanently resident in a single large "4: inevitable result.
rates a number memory. Single-level storage frees the
of advanced con- applications developer from disk- and "
cepts that cori- '' memory-management constraints, and '''
tribute to highly ., allows an application to be independent
> productive appli: ', of the configuration of the target 'Y |!
cation develop- platform. la A UDE oj
€ ment. These in-  :' Single-level addressability reguires a
ni . cludea highlevel "very large virtual-memory address to ac-
machine interface, object-oriented de- :,

sign, singlelevel addressability, highly
integrated system functions, an integrat-
ed relational database and advanced en-
gineering. i Vit nalako
| These architectural features effective-
| ly hide the complexity of the system
|. from programmers, operators and users '
| through the use of a single system inter:
|. face. This results in a substantial reduc- !
| tion in the Cost of ownership of the sys-

The AS/400's High-L

di

A funetion in

| tem, particularly in support areas such Mi program
35 systems programming, database sup: ME!
port, network management, operations this layer...
software. iztis yi"
Thearchitecture of the AS/400 de- ;
fines a logical machine instruction set at' Man
a very high level, as illustrated in the". level instruction

figure. This high-level instruction set, is
called the machine interface, Many fune-

| tions traditionally performed by main:

frame operating systems are supported :
as basic instructions in the machine in''

terface, For example, "Create Object" is

a single machine-interface instruction. " '

The high-level interface isolates appli:
cations developers from machine imple- ''

mentations. The approach accommo: '%

set. Fewer oper-
ations are re-

ured to execute
the function.

At this DE

instructions
are translated

into microcode... Microprogram

AS/400
Operating System

technical-support personnel. Facilities to

evel Machine Interface

Instruetion Set Off-Loads Funetions from the
Operating System to the Hardware

User-
Interlaces

and
Software

High-Level Machine Interface

ming Interface

4 recovered, it may be necessary to reload
all the data on all the storage devices on

59 — IBM has sought to address this prob- ,

Development

and inconsistencies. Because each soft-
ware component in conventional Sys-
tems is a self-contained entity, functions
found in one component may be repeat:
ed in others. In addition, highly trained
support personnel with specialized skills
' are needed to manage and control each
specialized software component.

The AS/400 was designed from the
ground up to be an interactive, multi-
user machine. Architectural features
such as single-level addressability are
particularly well-suited to an interac-

' tive, multiuser environment.

All application programs on the
AS/400 are automatically compiled as
re-entrant modules, so one physical copy
of the code is shared by multiple users
of the program. This provides efficient
use of storage, and transaction-process-

ing support is fully integrated with the
operating-system software. No expensive
specialists or laborious tricks of coding
are reguired. Most significantly for us-
ers, interactive processing on the
AS/400 does not "go down." The norm is
100 percent reliability.

Integrated Relational Database
Z, The AS/400 database-management
'system is based on the relational model,
/ and is integrated with both the operat-

ing system and the machine. This pro-

' vides efficient performance for the in-

' formation system because operations
are performed below the machine-inter-
face level in a combination of microcode
and hardware. Moreover, the integrity
of the data is guaranteed because of the
integration of security at the object
level.

' The database implementation sup-
ports two kinds of files: physical and
»logical. A physical file is'a data struc-

iste tes in the machines underiy-. ME Hardware Micr ture consisting of rows (or records) and
se pennology without any impact si o edbyjihe zan: Columns (or fields), each having the
ications. 8] prine neh machine. RELE attributes and record length.
ŠI Kb ; ia. ; h es provide al
Ni N AJ Funetions of the High-level Machine interface: 'the IRSAO, ss PE Na of
In effect, applications pam ne » Reduces the number of operations the machine must pertorm 'namically. This flexibility o£ function, in
Current models of the AS/400 Ni be $'' " Insulates the applications and operating system from the hardware sombination with the performance and
able to take advantage of new technolo- » ip ceHty of the AS/400, provides
ses. tko ut reg Miring conversion. sie ; RE tai user information-retrieval
s is an objectoriented sys- keč ; RE A, ms and contributes to a reduction
jega. programs, data files, guenes librar Nm Ni MR Me o ae m Orae. re
les, ice deseriptions, user profiles ; ; incorporates a
sil are autonomous objects that interact. « The 45/400 was designed from the ground up to be an inter. vW?ber of sophisticated engineering fea-
by passing messages to one another. Ac- ''! ive, multiuser hine. Archi noč usually found in mi
a o obleci je bv object nam raliec active, maci Architectural features such as in high end ne, The main processor
lon—a key characteris- | ( ni ' m models incorpo
'tic of object oriented The ob-'' spore SEČU Are wellsuited to that environment, IBM fastest bipolar chip technology,
ject-oriented design of the AS/400 frees ''' dli — ee zid a yrith a cycle time of 60
je arplicationa from low- !' | VakGA Čile kme PROU iR ii nemci y chips.
Concerns with information retriev: commodate all the primary and V VIH main mirror: si has been called the SAA
al and storage. It also provides a uni- Ary storage on te system. ne AS/AOO line ed Sepe ke OC: kem o otncat week TI] examine sa
a interface to all objecis, a high de '' supports a 48 bit address ihot alo ga Hi Sa: sr ate AS/400 has been inte-
go a zad integrityi k enan 281 trilion bytes of informa: //5.Focus on Integration, Simplicity Arehteciure a ono A PPlication
powerful security features, š to be individually addressed, This is! " Integration and imi So OO. JJ
An object can be visualized as a con- "| signifi l a lon and simplicity are the cen-
(alner holding information. Objecta con. |. BE bit addresu snope noj ee Pri | rabrinatokej io o a a a Sori
s portion and an asso- "' tem/570 MN MAO si sepa- ' an service updated guar-
Ciated ioragi maca fuciienal poe na Ja alu(ranleki ks njejes ši Hi rate systems-software products on tradi- terly, is available through High Pro-
bne obj o ore a definition o£/; even more. Already the AB/AOO Rain HH into kare a rated | ducttvity Software Inc, of Marble.
the object, whleh includes the objavi). uli ep prb "ji, into the AS/400 hardware and operat- head, Mass. (800) 242-1240. For infor.
teme, object type and object authoriza.'<|' that can access more than 18 guintillion %, omete VN O luni Ro OI epi oseki pis 3,
me pray, the AS/400 ensures "V! virtual Thus, the 4ijA Pita nje (role paši, a za lenih OE ]
Y operations valid for the object! : i igli Sys- nsfer Institute, St. s)
type are performed agar neč, ei b pokra si He to explolt new ij sem security and coramunications. ' Santa Monica, Calif. 90402 (213) 394
ti oa authorized users gain nocesa to they become avallable during the 1990«.[ eb tle layered software com- 2906. In Europe, contact Savani, 2 Il
object. um, |: z Slave je zg |, Ponenta of conventional mainframe sys- New St, Carnforth, Lancs., LA5 9BX ||
billty does, ea in an overjap of functions United Kingdom (0524) 73 505. R
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