Mainframe computers

• Whole room of components and peripherals.
• Printer may be away from the terminal
• Dumb terminals attached to a central processing computer
• Water cooled versions steadily being replaced with air-cooled CMOS based machines.

• Specific jobs such as, Operators, Data Administrators.

• several hundred thousand to up to $10 million.
• Examples:
  "Woolworth's $2.5 million IBM Upgrade.1993

The Evolution of S/390

The Evolution of IBM S/390 -- G6 Shines with Copper, (May 3, 1999 ) [online] url: http://www.s390.ibm.com/stories/1999/g6_fact.html

IBM 3090-series

• Model 120E (7.5 Mips)
• Model 600E (79 Mips)

IBM 9672 R series

• Code named Concerto (based on 23 mips, can be configured to a 10 processor version that will do 176 mips - costs $US15,000 per mips!)

 (Stedman,C., 1995 Jun)

memory capacity

• 4Mb - 4Gb+
• Example: IBM 3090-series
  * Model 120E (32 MB)
  * Model 600E (128-256 MB)

storage capacity

Disk:

Tape:

complexity of tasks

number of (simultaneous) users

50 +

Operating System

• Manages resources
• Allocates processor time
• Manages job scheduling
• Manages main storage
• Manages address mapping (conventional, segmented, paged)
• Maintains software protection
• Allocates resources
• Manages devices such as terminals
• Manages files; identification, access, space allocation, protection
• Maintains security; Backup and recovery
• Manages passwords; UserID, Job Control Language
• Provides the hardware interface; Spooling, microprograms, buffering, error checking, data conversion
• Maintains accounting log files; resource usage
• Maintains fault and error logs; Hardware, software, engineers, operators

Four main categories;

• Multi-programming
• Multi-processing
• Time-sharing, and
• real time.

Application

• Customised software
• Data warehouse and data intelligence
• e-commerce
• Enterprise resource planning (ERP)
• Server consolidation.

Development

• Often COBOL or C

complexity of software

• Software generally not portable to other brands

• Extensive vendor support (for a fee!)

Software

Hardware

data sharing

• Centralised data processing

data integrity

• Maintained by the operating system and application program
• Corporate level requirement.

data security

• Data Backed up by computer staff
• High security due to multiple users

[Rev: 11/11/99] Jun-97 © 1997-99 V/2-Com (Verhaart), P O Box 8415, Havelock North, New Zealand.