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Session 11

Introduction to AS/400

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By the end of this section, the student will be able to:

• Define the major difference between the AS/400 and UNIX regarding what is stored

• Define what an object is• Use the AS/400 to create an object• Describe the structure of AS/400 storage• List the four library types in the library list• Use the AS/400 to list the contents of the library list• Describe the function of the two subsystems in the AS/400• Interact with the two subsystems• List the four screen types of the AS/400• Recognize and use each of the screen types• List the two types of help on the system, and describe the circumstances that result

in each type of help being displayed• Use the help system to answer questions in the Lab• Describe the construction of commands in the AS/400• Use commands to perform some basic operations

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AS/400

IntroductionAS/400 (Application Server / 400) is a multiuser, multiprogramming system. The operating system of the AS/400 is called OS/400.

It is based on a different approach to how computers can work.

UNIX / WindowsOn UNIX and Windows operating systems everything is a file. Files are organized in hierarchies of directories.

In the Windows environment, files have extensions that provide meaning to a file. For example, what do the following extensions relate to?

.doc

.xls

.txt

.dll

.exe

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AS/400, continued

AS/400On AS/400 everything is an object.Windows has file extensions, AS/400 has object types:

Windows AS/400files - objectsextensions - object types

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Objects

ObjectsWhat is an object?

object \’äb-jikt\ n 1 : something that may be seen or felt; also : something that may be perceived or examined mentally.

(The New Merriam-Webster Dictionary, Copyright 1989 by Merriam-Webster Inc.)

An example of an object is a ball. It has size, weight, colour, shape It may be made of rubber, plastic, wood, glass... It may be my ball, or it may be your ball.

It has attributes- data

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Objects, continued

Objects, continuedYou can interact with a ball, for example: throw the ball bounce the ball catch the ball

It has operations that can be performed- methods

Objects as defined by computersIn computers, objects have Data and Methods. I could define a ball to a

computer by starting with a basic model called a ball, and then define attributes about the ball:

ball.colour = yellowball.shape = roundball.weight = 200gball.madeOf = rubber

I could then apply methods to the ball:ball.bounce

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Objects, continued

Objects as defined by computers, continuedThe concept of objects in a computer allow you to define as many different objects as you want. All with different Data (attributes), and manipulate them through their Methods independently.

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AS/400

StructureIf a Windows system stores files in directories, where does AS/400 store objects?

Libraries

Whereas Windows also stores directories inside of other directories, AS/400 does NOT store libraries inside of other libraries:

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AS/400

Types of ObjectsObject types that exist in the AS/400 include:

*LIB (remember these cannot be stored in libraries)*OUTQ*FILE*CMD*DOC*DTAQ*AUTL....

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AS/400

Library ListsIn Windows and UNIX when you wish to execute a program, the computer searches the PATH to find your program.

In AS/400 when you wish to find an object, the computer searches the Library List. The library list is stored in a system value called *LIBL

The order that the computer searches the Library List is:SYS - systemPRD - productCUR - currentUSR - user

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AS/400

System Library ListThe system library list contains up to 15 libraries. This list is maintained in the system value QSYSLIBL.

It will contain:QSYS - essential system objects such as programs and commandsQSYS2 - additional system programsQHLPSYS - Help informationQUSRSYS - contains other IBM-supplied objects for various system functions

Product LibraryThe system inserts a product library when the library is needed for some task a user has requested. For example, if a user requests a C program to be compiled, the compiler will be inserted as necessary.

Current LibraryThe current library is a specially designated user library where new objects are created by default. It will be searched before the user library.

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AS/400

User Library ListThe user library list contains up to 25 libraries. This list is maintained in the system value QUSRLIBL.

It will normally include at least:QTEMPQGPL

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AS/400, continued

Library Lists, continuedIn UNIX there are Absolute Paths and Relative Paths. In AS/400 there is the Library List and a version of the absolute path is the Qualified Name.

The qualified name overrides the library list search order, and references a specific object in a specific library.

The format of a qualified name is:

library/object

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AS/400, continued

Managing *LIBLThe user portion of the library list can be managed (CUR and USR library types)

The commands to manage your library list are:

DSPLIBL - display library listCHGCURLIB - change the current (default) libraryADDLIBLE - add a library list entry (to user library list)EDTLIBL - add/change/delete/re-order library list

(more on commands later)

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AS/400, continued

Subsystems of the AS/400The AS/400 has two subsystems:

QINTER - interactiveQBATCH - batch

QINTER handles the interactive session between the user and the computer. If necessary, it will submit batch jobs

QBATCH requires no interaction with a user. It runs until completion. For example, compiling a program requires no interaction with a user. QINTER may be used to tell the computer to compile a program, QBATCH will be given the responsibility of performing the compile. Other batch jobs include the management of the print spool.

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AS/400, continued

AS/400 User InterfaceWindows is a GUI interface. The user interacts with the computer using a mouse to point to icons and perform actions by manipulating those icons.

UNIX is a command line interface. The user interacts with the computer by typing commands.

AS/400 is both command line and menu driven. The operations that are performed on the command line can also be performed through the menus.

For example, the command DSPSYSVAL QAUTOCFG is the same as selecting option 7 from the main menu, then option 8, then scrolling through the list until you find QAUTOCFG, placing a 5 beside and pressing enter.

Because of the menu system, there are four types of screens:MenuData entryInformationalWork-with list

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AS/400, continued

AS/400 User Interface, continuedThis is an example of a Menu screen:

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AS/400, continued

AS/400 User Interface, continuedThis is an example of a Data Entry screen:

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AS/400, continued

AS/400 User Interface, continuedThis is an example of a Informational screen:

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AS/400, continued

AS/400 User Interface, continuedThis is an example of a Work-with screen:

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AS/400, continued

AS/400 Help SystemThere are two types of help available on the AS/400:

Context-sensitive Help Extended Help

Context-sensitive helpContext sensitive help is available by pressing F1 while the cursor is positioned in

a field, or in a column of values.

Extended helpExtended help is available from within Context-sensitive help by pressing F2, or

by pressing F1 while the cursor is not in an entry field or a column of values.

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AS/400, continued

AS/400 Command LineThe commands of the AS/400 are similar to UNIX in that there is a command followed by one or more parameters.

AS/400 expects the parameters to be in a very specific order, unless there is a keyword to identify the parameter.

For example:

DSPSYSVAL QAUTOCFGisDSPSYSVAL SYSVAL(QAUTOCFG)

orCPYF myfile yourfileisCPYF FROMFILE(myfile) TOFILE(yourfile)orCPYF TOFILE(yourfile) FROMFILE(myfile)

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AS/400, continued

AS/400 Command Line, continuedThe format of the commands follow a predictable pattern:

VERB-NOUN

Verbs:CALL- execute a program RST - resetCLR - clear RTV - retrieveCPY - copy SAV - saveCRT - create SBM - submitDLT - delete SND - sendDSP - display STR - startEDT - edit WRK - workGRT - grantINZ - initializeOPN - openRCL - reclaimRCV - receiveRLS - releaseRMV - remove

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AS/400, continued

AS/400 Command Line, continuedVERB-NOUN

Nouns:D - descriptionE - entryF - fileL - listQ - queueDFU - data file utilityRPG - Report Program GeneratorSDA - Screen Design Aid utilitySEU - Source Entry UtilityLIB - libraryOUTQ - output queue (this is a combination of two nouns)MSGQ - message queueJOBQ - job queue...

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