DB2 ON Z/OS

z/OS is the flagship IBM mainframe operating system. z/OS is the robust zSeries

mainframe operating system designed to meet the demanding QoS requirements

for On Demand Business. Here are some highlights:

1) It provides a highly secure, scalable, high-performance base for on demand

applications.

2) It can simplify IT infrastructure by allowing the integration of applications in a

single z/OS image.

Evolution of DB2

In the early 1950s, the disk drive was developed in IBM San Jose, California. In

the late 1960s, as large amounts of data were stored on disk, the research focus

turned to data management systems.

                   At that time, network and hierarchical data management systems were in use.

CODASYL and Information Management System (IMS) were state of the art

technologies for automated banking, accounting, and order processing.

Respected IBM Fellow Dr. E.F. (Ted) Codd worked on a new kind of mathematical

notation, but it took a while for it to receive the attention it deserved. Programs

that would have been five pages long if represented in CODASYL were written by

Codd in single lines. These would be queries such as “Find the employees who

earn more than their managers.”

                From Codd’s paper, a team in IBM research started building System R as part of

a program of research in the relational model of data. The objective of this

system was to handle ad hoc queries (one time) and “canned” queries (executed

many times). For the relational model to be accepted, it had to be proven by an

industrial-strength implementation. That was the goal of the System R project

begun at IBM San Jose Research in 1973.

               Codd believed that computer users should be able to work at a more natural

language level. They should not be concerned about the details of where or how

the data was stored.

At the IBM laboratory, other concepts emerged:

When querying a set of rows, lock the set.

Instead of authorizing columns of a table, make it a view of the columns and

authorize that.

Transactions, like logical units, should be all or nothing.

The research went on until Db2 was the best database to work on Mainframes making billions of transactions per second with ease.