Why Mainframes

1
Why Mainframes?

• KSU MISA Presentation November 2007
• Mo Motayar
• Allstate IT Consultant
• Service Manager
• Sylvia Seeber
• Allstate Enterprise Command Center Training
  Coordinator Analyst

2
General Information

• Mainframe is the grandfather of the PC/Server
• Has been around since the Mid 60s
• It is designed for true multi-tasking
• It is comprised of Virtual Systems or Multiple
  Virtual Systems (MVS)
• Allstate uses IBM OS390 MVS

3
What is not like a PC or server

• Used by multiple users at the same time
• Does not need frequent reboots
• It is not high maintenance
• Can fail over to multiple CPUs unlike PC
• Different memory is used for different tasks
• Has full time operators and schedulers
• Generates detailed error logs
• It does not have sophisticated GUI

4
What is like a PC or server

• It is comprised of the same set up
• CPU
• Memory
• Common Pathways
• It carries instructions without user commands
• It uses DASD (Direct Access Storage Device) and
  tape for storage (silos)

5
Since the 60s

• TCP/IP is now possible
• Connectivity to the internet
• Huge use in e-commerce and government
• Costs have decreased dramatically,
• Storage costs are in terra bytes vs. mega bytes
• It is not as labor intensive as a PC or server
  would for hundreds of users workstations

6
Why do large organizations use it

• Processing large amounts of data at once
• Used by thousands at once
• Stores huge amounts of historical data
• Retains memory, data is not lost,
• for large companies this is very critical
• It has multiple CPUs for large processing
• Allows for failover without loss of productivity

7
What it can do

• Process a large number of jobs (user defined
  actions) at the same time.
• Users can simultaneously access for tasks
• Can be used for printing large jobs
• It operates 24 by 7 without interruption
• No multiple reboots.

8
Some terms to know

• JCL Job Control Language
• Used to provide direction on a how job runs
• CICS Customer Information Control System
  (transactions)
• JES Job Entry System (used by operators)
• TSO Time Sharing Option
• Allows access for multiple users
• Spool old term for Cache
• IPL Initial Program Load or reboot

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Necessary Resources

• Programmers
• Schedulers for batch jobs
• Operators
• Maintain the health of system
• Run single jobs
• Handle incidents
• System administrators for upgrades and
  maintenance
• Vendors for escalation

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• Thank You
• Questions?