The five flavors of DB2
I asked Jeff Jones of IBM to explain the various DB2 code lines to me. His answer was so clear that I asked further permission to post it verbatim. Here it is. The main takeaway is that one shouldn’t confuse the shared-everything z/OS (mainframe) version with the more loosely-coupled Unix/Linux/Windows version.
1. DB2 9 for z/OS (CAM note: i.e., mainframe) is a unique code base designed in cooperation with and integrated tightly with the operating system (z/OS) and the hardware (System z). That said, our development and administration tools (the externals of the product), as well as the SQL language supported, are built to be nearly the same across DB2 platforms. DB2 9 for z/OS has a shared-resource architecture similar to Oracle RAC. Parallel Sysplex and other specialized System z hardware enable this high performance, high reliability scenario (that even Oracle has said is well built). Born in 1983.
2. DB2 9 for Linux, UNIX and Windows is a second unique code base. (CAM note: i.e., “open systems”) Roughly 10% of that code base is reserved for platform-specific code to optimize to threading, security, clustering etc. across Linux (quite a few), UNIX (AIX, Solaris, HP-UX) and Windows (many versions). This code base is designed for portability given that we don’t own the underlying hardware in all cases (as we do for DB2 on System z). Much tooling is shared across the other DB2 platforms. Born in 1993.
http://ibm.com/db2/9
http://ibm.com/software/data/db2/linux/validate < --- Linux platforms supported NOTE: DB2 for Linux runs on all four IBM servers (System z, System p, System i and System x), same code base.3. DB2 for System i is actually part of the i5/OS operation system, and is one of the older DB2s. Note that DB2 for Linux and DB2 for AIX 5L also run on System i. There is much flexibility on this platform. (System i and System p are both built on POWER processors, hence the AIX 5L sharability.) Again, tooling is interoperable across platforms in many cases. Born in 1980 on System/38. (CAM note: The file system/DBMS and OS were always closely coupled on the System/28 and it’s successor the AS/400. Lack of a C compiler also for many years kept other software away from the system.)
http://ibm.com/servers/eserver/iseries/db2
4. We still support but do not market DB2 for VM and DB2 for VSE, older System z operating systems. Formerly known as SQL/DS, and quite a long history. (CAM note: That would be IBM’s original relational DBMS.)
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why do I only see 4 items?
Look again. 🙂