Introduction History Significance of mainframe computer
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The document provides an introduction to mainframe computers, including their history and significance. It defines a mainframe as a large computer system that businesses use to host commercial databases and applications requiring high security and availability. Mainframes are designed to support thousands of users and input/output devices simultaneously through centralized control of resources and clustering technologies. They can process large workloads like batch jobs and online transactions concurrently.
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Introduction History Significance of mainframe computer
- 1. Introduction, History and Significance of Mainframe Computer
- 3. 33 What is a computer? • A computer is a digital device which can be programmed to change (process) information from one form to another. – Do exactly as they are told. – Digital devices: Understand only two different states (OFF and ON - 0 and 1)
- 4. 44 Traditional Types of Computers • General purpose computers –Super computer –Mainframe –Personal Computer
- 5. 5 What is a mainframe ? • A mainframe is what businesses use to host their commercial databases, transaction servers, and applications that require a greater degree of security and availability than is commonly found on smaller-scale machines.
- 6. 6 What is a mainframe? (Cont…) Compatibility with operating systems, applications and data Centralized control of resources HW and operating systems share disk access A STYLE of operation Thousands of simultaneous I/O operations Clustering technologies Additional data and resource sharing capabilities
- 7. What are Mainframe operating systems ? • Mainframe = Computer that can support thousands of applications and I/O devices to simultaneously serve thousands of users • Most mainframe computers are sold by IBM, and the operating systems are also provided by IBM • z/OS, is IBM’s foremost mainframe operating system 7
- 8. Why Mainframes ? • The most important features the mainframe provides include: • Encrypt sensitive data as it crosses the network • Protect encryption keys • Provide well-known security configurations that achieve or surpass the industry standard 8
- 9. History: IBM 709 Mainframe Computer This model was in use at Yale in 1963, located in the Watson building on Sachem St, now part of SOM IBM’s last vacuum tube computer, produced from 1957 until 1960
- 10. History: • Mainframe history In 1950s , mainframe computers were physically the largest computers; few businesses could afford them • In the 1960s , with standardized mainframe customers could write business applications that didn’t need specialized hardware or software • In 1964 , the introduction of the IBM System/360 (or S/360™) signalled the start of the 3G : • first general purpose computers 10
- 11. CPU Module from IBM 709 – Dimensions: 8” x 10”
- 12. http://www.cacr.caltech.edu/~mark/IBM709.html IBM 709 Central Processing Unit
- 13. http://www.columbia.edu/acis/history/ibm709.html Frank da Cruz / fdc@columbia.edu / Columbia University Computing History / Jan 2001 Typical IBM 709 Machine Room
- 14. IBM Card Punch of the type used for data entry with the Library’s Machine Aided Technical Processing System (MATPS), managed for many years by Suzanna Lengyel
- 15. 15 Traditional Types of Computers: • First computers, introduced in 1950s • Used by large businesses • Typically supported thousands of users • Very expensive • Used for very large processing tasks • IBM’s new Mainframe – http://www.youtube.com/watch?v=LN4J4mClckA • Mainframe Computers
- 16. Evolving architecture More and faster processors More physical memory and greater virtual memory addressing capability Dynamic capabilities for upgrading HW and SW Enhanced I/O devices and more and faster paths (channels) Sophisticated I/O attachments Increased ability to divide resources into multiple, logically independent and isolated systems, each running its own operating system. Enhanced clustering technologies (e.g. Parallel Sysplex) Architecture describes the organizational structure of a system
- 17. 17 Typical mainframe workloads Batch job Application Program Output Data Application Program Input Data Process data to perform a particular task Online (real time) transaction Query Reply Access shared data on behalf of online user
- 18. 18 Significance objectives • Be able to: – Explain why business data resides on mainframe – List typical uses of mainframes – Describe the benefits of mainframe computing – Outline the major types of workloads for which mainframes are best suited
- 19. 19 Mainframe facts • Mainframes in our midst – Hidden from the public eye • Who uses mainframes? – Most Fortune 1000 companies use a mainframe environment – 60% of all data available on the Internet is stored on mainframe computers • Why mainframes? – Large-scale transaction processing • Thousands of transactions per second – Support thousands of users and application programs – Simultaneously accessing resources – Terabytes of information in databases – Large-bandwidth communications
- 20. 20 Factors contributing to mainframe use Capacity Scalability Integrity and Security Availability Access to large amounts of data Systems management Autonomic capabilities
- 21. 21 Typical batch use Disk Storage databases Tape Storage Sequential data sets Partners and clients exchange information Reports Backups Data update Reports Statistics, summaries, exceptions Residence Main office Branch offices Account balances bills, etc Processing reports Mainframe Processing batch jobs 44 55 Reports 22 1010 11 88 66 33 CREDIT CARD 1234 5678 90121234 5678 9012 VALID FROM GOOD THRU XX/XX/XX XX/XX/XX PAUL FISCHER XX/XX/XX XX/XX/XX PAUL FISCHER 77 99 System Operator Production Control
- 22. 22 Typical online use Disk storage controller Stores database files queries and updates Account activities Office automation systems Mainframe Accesses database Requests ATMs Branch offices Business analysts Inventory control Branch office automation systems Network (e.g. TCP/IP or SNA) 55 66 33 22 44 11 Central office
- 23. 23 Summary • The New Mainframe: – Plays a central role in the daily operations of the world’s largest organizations – and the daily lives of most people. – Is known for its reliability, security, and enormous processing capabilities. – Is designed for processing large scale workloads and serving thousands of users and transactions concurrently. – Is managed by highly skilled technical support staff. – Runs a variety of operating systems.
- 24. Key terms – Architecture – Batch Processing – Compatibility – Data integrity – High Availability – IBM System z – Infrastructure • Mainframe • Online transaction processing (OLTP) • Punched card • RAS • Scalability • Security
Notes de l'éditeur
- Despite the predominance of mainframes in the business world, these machines are largely invisible to the general public, the academic community, and indeed many experienced IT professionals. Instead, other forms of computing attract more attention, at least in terms of visibility and public awareness. That this is so is perhaps not surprising. After all, who among us needs direct access to a mainframe? And, if we did, where would we find one to access? In truth, we are all mainframe users, whether we realize it or not.
- Today, computer manufacturers don’t always use the term mainframe to refer to mainframes. Instead, most have taken to calling any commercial-use computer—large or small—a server, with the mainframe simply being the largest type of server in use today. IBM, for example, now refers to its mainframes as zSeries servers. We use the term mainframe in this textbook to refer to computers that can support dozens of applications and input/output devices to simultaneously serve thousands of users. The presence of a mainframe often implies a centralized form of computing, rather than a distributed form of computing. Having data centralized in a single mainframe repository saves customers from having to manage updates to more than one copy of their business data, and increases the likelihood that the data is current.
- The first computer that Fred used, programming in Fortran
- Today, computer manufacturers don’t always use the term mainframe to refer to mainframes. Instead, most have taken to calling any commercial-use computer—large or small—a server, with the mainframe simply being the largest type of server in use today. IBM, for example, now refers to its mainframes as zSeries servers. We use the term mainframe in this textbook to refer to computers that can support dozens of applications and input/output devices to simultaneously serve thousands of users. The presence of a mainframe often implies a centralized form of computing, rather than a distributed form of computing. Having data centralized in a single mainframe repository saves customers from having to manage updates to more than one copy of their business data, and increases the likelihood that the data is current.
- A batch job is submitted on the computer, reads and processes data in bulk, and produces output. A batch job can last for hours. While batch processing is possible on distributed systems, it is not as commonplace as on mainframes because distributed systems often lack: Sufficient data storage Available processor capacity or cycles Sysplex-wide management of system resources and job scheduling. Mainframes serve a vast number of online transaction processing (OLTP) systems. These are often mission-critical applications that businesses depend on for their core functions. Some industry uses of online systems: Banks – ATMs, teller systems for customer service Insurance – Agent systems for policy management and claims processing Travel and transport – Airline reservation systems Manufacturing – Inventory control, production scheduling Government – Tax processing, license issuance and management.
- Reliability Involves the use of high-quality hardware and software components, and extensive self-checking and self-recovery by hardware components. Availability The ability of hardware to detect and automatically replace failing hardware elements, and for system software to detect, isolate, and recover failing software components. Serviceability Through well-defined units of replacement, the hardware and software can often be non-disruptively serviced or upgraded, with little or no impact to the operational system. A secure computer system prevents users from accessing or changing any objects on the system, including user data, except through system-provided interfaces that enforce authority rules. Mainframe computers can provide a very secure system for processing large numbers of heterogeneous applications that access critical data. By scalability we mean the ability of the hardware, software, or a distributed system to continue to function well as it is changed in size or volume; for example, the ability to retain performance levels when adding processors, memory, and storage. The need to support applications of varying ages imposes a strict compatibility demand on mainframe hardware and software, which have been upgraded many times since the first System/360 mainframe computer was shipped in 1964. Applications must continue to work properly. Thus, much of the design work for new hardware and system software revolves around this compatibility requirement. Each new generation of mainframes has added improvements in one or more of the following areas: More and faster processors More physical memory and greater memory addressing capability Dynamic capabilities for upgrading both hardware and software More sophisticated automated hardware error checking and recovery Enhanced devices for input/output (I/O) and more and faster paths (channels) between I/O devices and processors Sophisticated I/O attachments, such as LAN adapters with extensive inboard processing Increased ability to divide the resources of one machine into multiple, logically independent and isolated systems, each running its own operating system Enhanced clustering technologies, such as Parallel Sysplex, and the ability to share data among multiple systems.
- Consider the following elements at work in the scheduled batch process: 1. At night, many batch jobs executing programs and utilities are processed. These jobs consolidate the results of the online transactions executed during the day. 2. The batch jobs generate reports of business statistics. 3. Backups of critical files and databases are made before and after the batch window. 4. Reports with business statistics are sent to a specific area for analysis during the following day. 5. Reports with exceptions are sent to the branch offices. 6. Monthly account balance reports are generated and sent to all bank customers. 7. Reports with processing summary are sent to the partner credit card company. 8. A credit card transaction report is received from the partner company. 9. In the production control department, the operations area is monitoring the messages on the system console and the execution of the jobs. 10. Jobs and transactions are reading or updating the database (the same database used by online transactions) and many files are written to tape.
- Common online transactions using a mainframe: 1. A customer uses an ATM, which presents a user-friendly interface for various functions: Withdrawal, query account balance, deposit, transfer, or cash advance from a credit card account. 2. Elsewhere in the same private network, a bank employee in a branch office performs operations such as consulting, fund applications, and money ordering. 3. At the bank’s central office, business analysts tune transactions for improved performance. Other staff use specialized online systems for office automation to perform customer relationship management, budget planning, and stock control. 4. All requests directed to the mainframe computer for processing. 5. Programs running on the mainframe computer perform updates and inquires to the database management system (for example, DB2). 6. Specialized disk storage systems store the database files.