Background of the AS400

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Chapter 1

• Background of the AS/400

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IBM Midrange Background

• Began June 1969
• System 3/x
• Rochester, MN
• Punch card design
• Target low-end commercial small-size batch

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System 3/x Line

• System 3/x Midrange line
• Small, efficient computer
• Single computer model - standard

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System/34

• System/34
• April 1977
• First multi-user minicomputer
• Low-cost computer

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System/38

• System/38
• 1975 research project
• 1978 announced
• Machine independence
• New processor
• User needed to upgrade
• First time contained a relational database
• Object-based architecture
• Ahead of times

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System/36 Upgraded Models

• System/36 upgraded
• Many customers preferred to stay with system/36
  rather-than System/38

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AS/400 History

• Project SilverLake
• 1985 started research
• New machine
• Successor to System/38
• New future machine

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AS/400 History - Continue

• Application System/400 (AS/400)
• June 1988 announced
• Improving at about 10 per year
• Hardware independent untested until 1995
• CISC (Complex Instruction Set Computer)
• Instruction length variable

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AS/400 History - Continue

• Upgrading
• RISC (Reduced Instruction Set Computer)
• Equal instruction length
• From 48-byte to 64-byte word size
• True hardware independence

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AS/400 History - Continue

• Enhanced Series or e-series
• 1994 development began
• Foresaw potential of Internet
• Announced August1997
• New n-way processors up to 12-way
• First package machine
• A server configured and preloaded with SAP
  software

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Layered Design Concept

• Layered Architecture
• Distinguished from traditional computers
• Key to machine independence

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Data Storage and Objects

• Object-based computers
• Everything stored on an AS/400 is an stored as
  an object
• Objects stored in Libraries
• Data stored as
• EDCDIC - Extended Binary Coded Decimal
  Interchange Code
• ASCII - American Standard Code for Information
  Interchange

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Single-level Storage

• No distinction between disk storage and main
  memory
• One large storage area (single address space)
• Memory
• DASD
• Object must be in memory to use or operate on

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Single-level Storage

• Automatic divides object into blocks - pages
• Virtual storage

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Software

• Operating System
• Application Programs
• Job/Program types
• Interactive
• Batch