Thursday, December 10, 2009

A Short History of DB2 for z/OS – Part 1

Let's go back in time... almost three decades ago... back to the wild and woolly 1980s! And watch our favorite DBMS, DB2, grow up over time.

Version 1 Release 1 was announced on June 7, 1983. And it became generally available on Tuesday, April 2, 1985. I wonder if it was ready on April 1st but not released because of April Fool’s Day? Any old-time IBMer out there care to comment?

Initial DB2 development focused on the basics of making a relational DBMS work. Early releases of DB2 were viewed by many as an “information center” DBMS, not for production work like IMS.

Version 1 Release 2 was announced on February 4, 1986 and was released for general availability a month later on March 7, 1986. Wow! Can you imagine waiting only a month for a new release of DB2 these days? But that is how it happened back then. Same thing for Version 1 Release 3, which was announced on May 19, 1987 and became GA on June 26, 1987. DB2 V1R3 saw the introduction of date data types.

You might notice that IBM delivered “releases” of DB2 back in the 1980s, whereas today (and ever since V3) there have only been versions. Versions are major, whereas releases are not quite as significant as a version.

Version 2 of DB2 became a reality in 1988. Version 2 Release 1 was announced in April 1988 and delivered in September 1988. Here we start to see the gap widening again between announcement and delivery. V2R1 was a very significant release in the history of DB2. Some mark it as the bellwether for when DB2 began to be viewed as a DBMS capable of supporting mission critical, transaction processing workloads. Not only did V2R1 provide many performance enhancements but it also signaled the introduction of declarative Referential Integrity (RI) constraints. RI was important for the acceptance of DB2 because it helps to assure data integrity within the DBMS.

No sooner than V2R1 became GA than IBM announced Version 2 Release 2 on October 4, 1988. But it was not until a year later that it became generally available on September 23, 1988. DB2 V2R2 again bolstered performance in many ways. It also saw the introduction of distributed database support (private protocol) across MVS systems.

Version 2 Release 3 was announced on September 5, 1990 and became generally available on October 25, 1991. Two very significant features were added in V2R3: segmented table spaces and packages. Segmented table spaces have become the de facto standard for most DB2 data and packages made DB2 application programs easier to support. DB2 V2R3 is also the version that beefed up distributed support with Distributed Relational Database Architecture (DRDA). Remote unit of work distribution was not available in the initial GA version, but IBM came out with RUOW support for DB2 V2R3 in March 1992.

And along comes DB2 Version 3 announced in November 1993 and GA in December 1993. Now it may look like things sped up again here, but not really. This is when the QPP program for early support of DB2 started. QPP was announced in March 1993 and delivered to customers in June 1993. Still though, fairly rapid turnaround by today’s standards, right?

V3 greatly expanded the number of bufferpool options available (from 5 pools to 80). There were many advances made in DB2 V3 to take better advantage of the System 390 environment: V3 introduced support for hardware assisted compression and hiperpools. It was also V3 that introduced I/O parallelism for the first time.

We’ll stop here for today and continue our short history of DB2 in my next DB2Portal blog posting. See you soon...

1 comment:

Rick Butler said...

Hi Craig, for those interested in this topic there is more info available in Redbook 6763: "The Business Value of DB2 UDB for z/OS"
Chaopter 2 covers "The evolution of DB2 for z/OS"....I had the privilege of collecting the info for that chapter.....