(AS400 Beginner User)- Day-1

iSeries Server: Introduction

 Overview:

This module enables the student to understand the concept iSeries Server architecture and some program information.

 Outline:

Topics covered,

    ·         iSeries History.

• iSeries Architecture.
• Introduction to Login Screen.
• Starting with programming

 Objective:

By the end of this module, the student should be able to:

• Understand iSeries Architecture
• Understand concept of iSeries Server
• Understand the iSeries Hardware
• Concept of LPAR
• Concept of Server Consolidation
• Connect to iSeries Server from Windows Desktop

iSeries History:-

The iSeries is IBM’s latest microcomputer. ISeries server which was formerly known as iSERIES server. iSERIES is one of longest stayed brand name in the computer industry. It was sold under this brand name for 12 years. Its high–end models provide incredible processing and storage capacity, and its software incorporates the latest advances and techniques to provide an efficient, easy- to- use, and seamless environment.

Previous Generation of IBM minicomputers:

The history of the iSERIES starts off with the introduction of the System 3 (S/3) in July 1969. It was IBM’s first entry into “low-end” systems .as till then they were only into large systems. Its processing capabilities would be in today’s micro range, but for its day it did offer some technological advances like using punch cards that were one third the size of traditional punch cards but held 120 percent of the data.

In January 1975, the next member of the S/3X family was introduced. The S/32. It allowed the user to enter commands directly from a keyboard and had a display screen that could show 240 characters. Main memory size for the S/32 was 32K, and it had a13 MB fixed disk.

The next generation came in April 1977. The S/34 supported multiple workstations (printers and terminals) and could handle up to eight local users at a time. It had 256 K of main memory and a 13 MB fixed disk.

The S/38 was the next machine announced in October 1978. It represented a change in architecture. It had 32 MB of memory and 14 GB of hard disk, but more important, it was geared specially for application development. Its utilities and user interface were built to help facilities software development process.

Development continued on the S/34 architecture. The S/36 was introduced in May 1983. It grew to support up to 7 MB of main memory and 14GB of disk storage and 72 workstations.

In June 1988, IBM announced the ISERIES computer family where “AS” stands for Application Systems. It was the expansion of S/38 architecture but also provided application program compatibility with S/36. The ISERIES family also differed from S/3X family in several significant ways.

·         It offered much more compatibility across machines within the family. Programs created on one model of the ISERIES could be transferred and run on any other ISERIES system without any changes. This was not the case with the programs developed on the S/36 or S/38 as they had a different architecture.

Languages

Several programming languages are available which allow the application programmer choose the language most appropriate to the application. The following are some of the available languages.

·         RPG/400

·         CL/400

·         C/400

·         Java/400

·         COBOL/400

·         ISERIES PASCAL

·         ISERIES BASIC

·         Fortan/400

·         ISERIES PL/I

·         RM/COBOL-85

Utilities

Utilities are designed to help the application programmer create programs and to help the system operator manage the system. Some of them are the following,

·         Application Development Tools helps the programmers design screen and menus, create programs, create an edit source file, and generally increase programmer’s productivity.

1.     Programming Development Manager (PDM) provides programmers an easy to use menu interface, each of which can also be accessed directly from the command line.

2.     Source Entry Utility (SEU) provides the capability to enter the edit application program source.

3.     Screen Design Aid (SDA) provides assistance for creating screens.

4.     Report Layout Utility (RLU) enables programmers to create and edit reports images described in data description specifications (DDS) on the system.

5.     Data File Utility helps users add or change records in a data file.

·         Business Graphics Utility (BGU) produces various graphic representations of the data in line, bar and pie charts from existing data.

·         Performance Tools helps the system operator fine tune system operations, such as batch processing to achieve the highest level of performance from the system.

·         Query organizes data for creating reports and summaries from existing database files.

Functions of Operating System iSERIES

An operating system serves several purposes, such as

·         Assuring efficient use of the computer system

·         Handling printed output

·         Scheduling work done by the computer

·         Communicating with users

iSeries Operating System is a powerful operating system designed specially for the iSeries system. The server i5 machines require the new version of OS/400* V5R3, which we’re calling i5/OS. This server includes following facilities:

• Includes a Hyper visor* component, having the capability to run multiple operating systems and a workload manager. For example, today you might have five Windows* servers, two Linux* servers, a UNIX* server and an i5/os server.

Previously, you had different systems-management console to manage the disk, users and passwords on every one of those environments, which usually required more than on person.

The Virtualization Engine technology allows a single system administrator using one console to work with multiple systems simultaneously and mange an entire IT infrastructure fro one point.

IBM Supplies the operating system with the iSeries system. Operating system supports both interactive and batch operations

The operating system includes

·         Work Management

·         Object Management

·         Message handler

·         Control Language

·         Electronic Customer Support

·         Database Management

·         Communications

·         Security

Each item has a definite purpose and responsibility, but they all work together and interact with each other.

·         Work management is responsible for maintaining the workflow throughout the system.

·         Object Management locates objects (such as files and programs) when they are requested

·         Message handler delivers message back and forth between users, between users and the system, and between programs.

·         Control Language provides a set of commands you can use to start your jobs, control your work, and display your messages.

·         Electronic Customer Support gives you online access to IBM service facilities, technical information, and marketing support information.

·         Database management handles data stored in database files, that are where it is stored, how to retrieve it, and the characteristics of a data.

·         Communication all interchanges information or data with remote systems or devices. Security control and limit user access to the system and objects stored in the system programs and database files).

Software Architecture

There are three categories of software on the ISERIES

·         Licensed Internal Code (LIC)

·         Operating system software

·         Application Software

·         Application Software

This top layer software performs user tasks and acts as the primary interface between the user and the server. Application software includes system-supplied functions like Office Vision/400 or PDM(Program Development Manager), Purchased software such as a CASE tool or a Business application like “pay roll system”, and specialized user-developed systems. The application software can execute or call the operating systems and LIC programs. Most of the time users work with the application program and screen to execute functions on the ISERIES.

Operating System Software

This middle layer of software performs many of the housekeeping tasks and manages the system’s resources. It also includes common operating system function, such as copying and deleting files. These functions can be invoked by application programs, from a menu or directly by entering commands at the keyboard. These operating systems commands are known as Control Language (CL).

LIC

The deepest layer of software, the Licensed Internal Code (LIC) is an IBM supplied set of programs that provide the database, security, communications, and other essential functions. Users never interact directly with the LIC, and programmers or system operators cannot change it. It is considered part of the machine itself.

LIC provides majority of the hardware interface and form a buffer between the application programs and the hardware specifies. Any changes to the hardware necessitate corresponding changes to the LIC and not the users application program. This eliminates a whole lot of future maintenance costs.

Another advantage provided by the LIC is that by putting functions such as database and communications into the LIC their performance is enhanced. Time spent in installing and setting up of software is eliminated.

Hardware Architecture

The iSeries system insulates the users from the characteristics of the underlying hardware by use of a layered architecture. Various models of the iSeries family of midrange computers are available to meet the needs of all sizes of business enterprises. However, single operating systems support the entire product line. This means programs can be run on any iSeries system and moved between systems without change.

The iSeries uses multi-processors and two internal storage areas to improve system performance. (Diagram shows the hardware components and their relations to one another). The speed at which a computer operates depends a heavily on the speed of its processors, the speed at which data can be transferred from main storage to the processors, and the amount of work being performed. The iSeries’s hardware architecture addresses each of these key performance issues.

Hardware Components

Essentially, the system processor is the core of the iSeries. It executes the program instructions and performs all math calculations. It can move information 32 bits at a time, that is, it has a word size of 32 bits It also supports 48-bit addressing. All computers store the location of data in an address. The size of the address dictates how many storage spaces the processor can uniquely identify.

However, the architecture of the iSeries allows future computers to use 64-bit addressing, thereby providing the iSeries family of computers with a lot more room to grow.

Dynamic logical partitioning (LPAR) is a system architecture virtualized hardware resources that can be shared by multiple independent operating environments. Originally developed for mainframe computers, LPAR allows the division of a single server into several completely independent virtual servers or logical partitions.

Main Storage

All programs and data that the system processor is executing are contained in main storage. As mentioned earlier, all information is stored in 32-bit words. Information can travel from main memory to the system processor 32 bits at a time.

Control Storage

Control storage is high–speed memory area containing the most often used LIC instructions. All program and operating systems instructions are covered in to simple LIC instructions. The processor’s electronic circuits, in turn, execute these instructions. Rather than having the instructions kept in secondary storage and, when needed, transferred to main memory, the iSeries developers created this specialized storage area for the most frequently used commands. The system processor can access the control storage directly. However, control storage is not large enough to store all the LIC instructions. Some of them are stored in auxiliary storage pool. This is a fancy name for the disk storage area, where less frequently used LIC instructions are kept. If a required instruction resides in the auxiliary storage. Pool, access must be made through slower disk device, and the instructions copied to and then read from the main memory. This process is slower than the processor accessing control storage directly.

Input/Output Bus

The I/O bus is the internal circuitry that provides the high-speed transfer of data between the system processor and the I/O processors. Only one information transfer at a time can occur on the bus. Some of the larger iSeries models can support multiple buses and thereby allow simultaneous transfer of data. Multiple buses increase the overall system communications rate.

I/O Processors

The I/O processors manage all I/O devices attached to the iSeries server. Each of them has separate responsibilities and tasks that are performed simultaneously and in coordination with the system processor. I/O processors free the system processor from having to perform any external device communication work.

Service processor

The service processor is a specialized processor that constantly monitors systems performance. The system operator can communicate directly to the service processor performance The system operator can communicate directly to the service processor through the iSeries control terminal.

When the operator “brings up” the system (performs an initial program load, or “IPL”), he or she is actually requesting a function controlled by the service processor.

System Concepts

iSeries is designed and built as a total system. This means that facilities such as a relational database and a networking capability (and much more) are fully integrated into the operating system and the machine. The user communicates with all these functions through a single control language, or by using the system menus and prompts.

iSeries is designed as a general-purpose business computer; it is optimized for that environment Its design reflects the dominants requirements of that environment, which are:

·         Of use (from the operator’s and the end user’s point of view)

·         Ability to grow and improve the system without disruption

·         Optimization for work in the commercial environment, which is Input/Output rather than compute-intensive.

There are five basic system concepts:

·         Layered machine architecture: This insulates users from hardware characteristics. It enables them to move to new hardware technology at any time, without disrupting their application programs.

·         Object-orientation: Everything that can be stored or retrieved on the system is known as an “object”. Objects exist to make users independent of the internal structure of the machine.

·         Single-level storage: Everything that can be stored or retrieved on the system is known as an “object”. Objects exist to make users independent addressing mechanism. This means that extra main storage or disk storage can be added to the system and used without affecting the application programs. A user or a programmer is not concerned as to where a program or a file is, if they want to use it, they simply name it.

·         Hierarchy of microprocessors: As well as the main System Processor, iSeries has a large number of microprocessors. Every Input/Output (I/O) device type on iSeries has its own microprocessor. This means that requests for data to be written to or read from any I/O device can be delegated to the processor in charge of that device. Meanwhile, the main System Processor executes another application.

·         Operating system. OS/400 or I5 OS is a single entity. Fully integrating all the software components (relational database, communications and networking capabilities etc.) needed for most commercial computing environments.

Layered Machine Architecture

iSeries insulates users from hardware characteristics through layered machine architecture. This layered architecture raises the level of the machine interface creating a high-level machine instruction set that is independent of the underlying hardware implementation.

Figure shows the hardware with the licensed internal code that comprises the high-level machine. iSeries is unusual in that the machine is defined by software, not by hardware. The instructions presented to the machine interface undergo a further process of translation before they are “understood” by the hardware. This process of translation is carried out by licensed internal code. Hardware characteristics change as the technology changes, the user, however, still “sees” the same machine interface. The licensed internal code preserves this interface.

Furthermore, some frequently executed routines (that would reside in the operating system of a conventional machine) have been moved into licensed internal code. This runs faster than a higher-level language, so any applications using routines will realize a performance gain.

Examples of some basic supervisory and resource management functions that have been moved into licensed internal code are validity and authorization checks.

Layered machine architecture means that as new hardware and software technologies emerge, they can employ without affecting applications.

Object Orientation

Objects exists to make users independent of the implementation techniques used in the machine. The “create object” instruction establishes the object’s name and its type. All objects are structured with a common object header, and a type-independent functional portion. An object thus combines the data and the valid methods of using the data into one entity. Therefore only valid methods of using that date are allowed.

This improves the overall integrity of the system and its data. This also permits the system to perform standard object-level functions very efficiently; the object type then determines the way in which a specific object can be used when retrieved. The architecture supports multiple extends to an object.

In other words, a user is not concerned with the space his occupies. The system allocates space automatically.

Object orientation gives a strong foundation for new technologies such as artificial intelligence. The object-oriented iSeries architecture lends itself very well to the utilization of object-oriented techniques for the representation of knowledge in an expert system.

Single-level storage

All system storage (whether main storage or disk storage) is addressed in the same way. This single, device independent addressing mechanism means that to run program, a user calls its name. The iSeries is independent of an objects physical location, and the type, capacity and number of disk units on the system.

What this means is that application programs do not require modification in order to take advantage of new storage technologies. Users can leave all storage management entirely to the machine.

Hierarchy of microprocessors

iSeries has a Main System Processor as well as arrange of other processors, each dedicated to a particular I/O device type. What this means is that when the main system processor encounters a request for data to be written to or read from any I/O device, that request is delegated to the particular microprocessor dedicated to that I/O device. Meanwhile, the system Processor continues with another application program.

This design provides iSeries with its outstanding performance in the commercial, transaction-based environment. It also means that the latest microprocessor technology can be easily utilized at any time without disrupting the rest of the system.

Operating System is a single entity

The above drawing shows the traditional approach for system software. As well as the basic operating system, further software components, providing facilities such as a relational database management system, support for various communication environments, support for an interactive environment, software to implement security, etc. are needed. Sometimes third parties provide these. The integration of these software components always needs careful attention. Customer would need to be certain that the release levels of the various components are compatible.

iSeries System Architecture

One of the iSeries most important strengths and a key to its success is system architecture. This architecture is based on some unique concepts that had them origin in the System/38 the predecessor to the iSeries architecture a basic understanding of that architecture is necessary to understand DB2/400. With thought in mind this chapter discusses the following iSeries architectural concepts.

·         High-level Machine Interface

·         Single-level Storage

·         Object-Oriented Architecture

·         Capability-based Addressing

·         Integrated Relational Database

The iSeries High-Level Machine Interface:

The iSeries High level Machine Interface isolates and insulates the System Instruction set from the actual hardware that is used to implement the system. The system instruction set is actually implemented in micro code as high-speed control storage. This control storage, which is driven by an independent microprocessor, provides the interface for the instruction set to the actual hardware.

The high-level MI provides a great deal of flexibility in designing the system and providing user functions and facilities since the actual iSeries instruction set does not have to be implemented in hardware or turned into a processor chip. This lets systems engineers design a functionally rich, broad-based instruction set at the MI level instead of at the operating system level or as a separate layer of software residing above the operating system.

The high-level MI also lets iSeries designers react very to new advanced hardware technologies. Since the iSeries instruction set is isolated and insulated from the actual hardware, it is very easy to implement advanced technology hardware as it becomes available. The old hardware is removed, the new hardware installed, the control storage is updated to reflect the advanced technology hardware, and the iSeries is IPL ed and ready to run with the new technology. No modification have to be made to the iSeries instruction set, thus preserving IBM’s investment in the Operating System and the user’s investment in application programs.

Single-level Storage

Unlike most computer systems the iSeries utilizes a single-level storage design. Under this design the iSeries considers that main memory is the only storage medium on the iSeries that all objects reside in main memory. The iSeries architecture supports a 64-bit address, but only 48 bits are currently in use.

Both disk and main memory use the same uniform virtual addressing mechanism. However from the Operating System standpoint all objects on the system are referenced by name only and not virtual address. At the MI level below the operating system, internal system directory associates an objects name with the virtual address it was given when the object was created. A send internal system directory keeps track of object that are currently in main memory.

Since main memory is volatile and its contents disappear whenever is lost at a permanent updated copy of each object is stored on disk and referenced by its virtual address. An auxiliary storage directory on disk associates a virtual address with a physical disk address. iSeries object is given a virtual address when it is created, and is associated with that address until the object is deleted. In this way single-level storage functions as a permanent virtual addressing mechanism that exists even when the system is not powered on.

When a program is called or a database file needs to be accessed. Operating System passes the name of the object to the MI. The name is translated to its associated virtual address and the internal system directory is checked to see if the virtual address is currently in main memory. If the virtual address is already in main memory, Security checking is done for the object and the program or file is made available for use at the appropriate level of security. If the virtual address is not in main memory the object is brought into main memory by accessing its virtual address in the auxiliary storage directory on disk. Which points to the objects physical disk address. The internal system directory is then updated to reflect that the virtual address is in main storage.

What does all this have to do with DB2/400? If you think about the process just outlined. It becomes apparent that only one copy of a specific object can be in main memory at any given point in time. If two or more users need to access the record or sets records in a file, only one copy of that data is in main storage and all users can share it. Single-level storage provides a single consistent copy of data which in most cases inherently shareable across the entire system.

Server Consolidation:

Server consolidation is an enabling technology encompassing not just hardware, but software services. The goal is to optimize and simplify your existing I/T infrastructure - not just the servers, but the entire end-to-end infrastructure. The objective being to provide a stable foundation for new solution deployment: e-business, enterprise resource planning, supply chain management and business intelligence. The iSeries can play a vital role for companies eager to reduce server administration costs by relocating existing servers and replacing smaller servers, and can help you gain efficiencies by moving applications running on multiple servers onto a single server.

The iSeries provides four solutions for companies intending to improve their IT operations through server consolidation:

• iSeries consolidation with logical partitioning (LPAR)
• Linux
• Lotus Domino

Concept of LPAR:

The new LPAR functionality provided by OS/400 V5R1 gives you unprecedented application flexibility. The reallocation is done without the need to shut down and restart the partition. Also, a portion of an individual processor can be assigned to a partition, giving you a fine degree of control over the system and optimizing usage. The possibilities are striking. For example, a company with operations on both sides of the Atlantic could allocate resources to its European operations while they’re open, then simply reallocate those resources to the North American operations as the day progresses.

Consolidating your systems with LPAR can help to provide:

• Substantial cost savings for fewer systems and data centers
• Improved availability management and service levels
• Faster deployment of e-business and modernized applications
• Increased ability to rationalize and modernize networks
• Centralized international operations with separate languages and time zones

With LPAR on the iSeries, companies have both the power and flexibility to address multiple system requirements in a single machine. LPAR lets you run up to 32 independent servers—each with its own processors, memory and disks—within a single iSeries. And there’s high-speed TCP/IP communication between partitions, entirely within the iSeries; applications can communicate with one another without sending data out through the I/O adapters and onto your network.

  

LOGIN SCREEN

Where user has to enter the USERID,PASSWORD for entering in iSeries.

                                  Sign On                                     

                                              System  . . . . . :   S653278B  

                                              Subsystem . . . . :   QINTER    

                                              Display . . . . . :   QPADEV0009

                                                                              

               User  . . . . . . . . . . . . . .          user name                    

               Password  . . . . . . . . . . . .                              

               Program/procedure . . . . . . . .                              

               Menu  . . . . . . . . . . . . . .          Enter Password                   

               Current library . . . . . . . . .                              

                                                                              

                                                                               

                                                                              

                                                                              

                                                                               

                                                                              

                                                                              

                                                                               

                                                                              

After entering user and password press enter.

With full authority Main Menu looks like this:

MAIN                           OS/400 Main Menu                                

                                                             System:   S653278B

 Select one of the following:                                                  

                                                                                

      1. User tasks                                                            

      2. Office tasks                                                          

      3. General system tasks                                                  

      4. Files, libraries, and folders                                         

      5. Programming                                                           

      6. Communications                                                        

      7. Define or change the system                                           

      8. Problem handling                                                      

      9. Display a menu                                                        

     10. Information Assistant options                                         

     11. Client Access/400 tasks                                               

                                                                               

     90. Sign off                                                               

                                                                               

 Selection or command                                                          

 ===>                                                                           

                                                                               

 F3=Exit   F4=Prompt   F9=Retrieve   F12=Cancel   F13=Information Assistant    

 F23=Set initial menu                                                           

                                                                               

When user have some authority then Main Menu looks like this:

  

MAIN                           OS/400 Main Menu                               

                                                             System:   S653278B

 Select one of the following:                                                  

                                                                               

      1. User tasks                                                             

      2. Office tasks                                                          

                                                                               

      4. Files, libraries, and folders                                          

                                                                               

      6. Communications                                                        

                                                                                

      8. Problem handling                                                      

      9. Display a menu                                                         

     10. Information Assistant options                                          

     11. Client Access/400 tasks                                               

                                                                               

     90. Sign off                                                              

                                                                                

 Selection or command                                                          

 ===>                                                                          

                                                                                

 F3=Exit   F4=Prompt   F9=Retrieve   F12=Cancel   F13=Information Assistant    

 F23=Set initial menu

                          

                               

This is The MAIN MENU screen with COMMAND LINE.