"Craddock, Chris" wrote: > > > There are 3 different code platforms for DB2 - I'm missing > > > some details, so someone please fill in the blanks... > > > > > > - Non-mainframe platforms (Unix-type), which came from > > > another data base product > > > purchased by IBM a long time ago (Sequent?), and has some > > > code shared with > > > Informix > > > - z/OS (the original System R) > > > - z/VSE, z/VM, which IIRC is based on DL/1 > > > > IIRC, DL/I "maps" to IMS.... On VM/ESA (previous shop; many moons > ago) > > we ran "SQL", which probably "maps" to DB2 on z/OS. I think it was > also > > called "SQL" on VSE. > > The first IBM relational product was SQL/DS which ran on VM. System/R > was the original research prototype and it never shipped to the outside > world. DB2 was developed independently of SQL/DS and it had a completely > MVS-centric design that could never have fit into any other IBM > mainframe OS. I don't know if SQL/DS ever ran on VSE, but I am certain > that DB2 never did. > > DL/1 (data language 1) was and is the interface language for IMS/DB and > its successors. It supports access to hierarchical parent/child data > structures with verbs like Get Unique (GU), Get Next (GN) etc. The DL/1 > model is wildly different than any SQL dialect. > > It is true that there are separate code bases for the z and non-z forms > of DB2, but as time passes most new functions are added to the open > platforms first and wherever possible that code is shared with DB2 on z. > > CC >
SQL/DS was actually released on VSE a few months before VM. It was a cleaned-up version of System/R. DB2 was written from scratch to run on MVS. Besides the three mentioned so far there is also a fourth DB2 that is integrated with i5/OS. h ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
