Conversation

Notices

1. HN Tooter (hntooter@mastodon.social)'s status on Saturday, 23-Dec-2017 06:35:57 EST HN Tooter

   Why IBM DB2 is four different DBMS code bases
   http://perspectives.mvdirona.com/2017/12/1187/

   (submitted by fanf2)

   1. clacke (clacke@social.heldscal.la)'s status on Friday, 29-Dec-2017 01:48:37 EST clacke

      in reply to
      This was an interesting read, but only raised new questions. :-)
      
      So, DB/2 is four different codebases because there's generic DB2, DB2 for i, DB2 for Z and DB2 for VM & VSE.
      
      The obvious followup article is why there are three OSes z/OS, z/VM and z/VSE for one and the same IBM mainframe!
      
      Maybe @jasondodd knows?
      
      I mean, obviously historical reasons, but how different are they really?
      1. Jason_Dodd (jasondodd@mastodon.social)'s status on Tuesday, 23-Jan-2018 08:40:32 EST Jason_Dodd

         in reply to

         @clacke @hntooter
         I don't know exactly. Historical reasons for sure. I suppose they have paying customers enough to support them. In a recent talk with folks from IBM I asked about the plans to port some of their cash cows(my opinion) to linux so we can do away with some of those legacy OSs. I was told in no uncertain terms they would not be porting them. When I asked, "Why?" I was told they needed the special hardware for performance reasons.

      2. Jason_Dodd (jasondodd@mastodon.social)'s status on Tuesday, 23-Jan-2018 08:40:58 EST Jason_Dodd

         in reply to

         @clacke @hntooter
         I let that soak in for a bit and then said, "But we've been talking about linux running on mainframe hardware. So that can't be the reason."

         In my opinion it's might be as simple as money. Not only for the mainframe hardware but for all of the software that bridges between the mainframe and other platforms. If those other platforms go away, people needs less bridge/glue software.

         1. clacke (clacke@social.heldscal.la)'s status on Tuesday, 23-Jan-2018 19:08:54 EST clacke

            in reply to
            @jasondodd Yeah, or simply maintaining vendor lock-in. I guess just like with the Mac: A System z is a big hardware dongle for z/*, and making it all run on Linux would hurt hardware sales. That doesn't explain why they maintain their different OSes between themselves, though.
            1. Jason_Dodd (jasondodd@mastodon.social)'s status on Tuesday, 23-Jan-2018 21:51:22 EST Jason_Dodd

               in reply to

               @clacke
               Hardware sales is surely key but I think software is too. Things running on linux lowers the barrier to entry for competing 'glue' software.

               I bet it's complex support and pricing model figures into the reason they have different OSes.

               Makes me wonder, "Why does Google have so many OSes?"

      3. Jason_Dodd (jasondodd@mastodon.social)'s status on Tuesday, 23-Jan-2018 08:41:10 EST Jason_Dodd

         in reply to

         @clacke @hntooter
         I'm not an expert on 3 of the 4, but they seem to be very different from the little I've seen. Actually, I didn't think they all ran on the same HW. Do they?

         1. clacke (clacke@social.heldscal.la)'s status on Tuesday, 23-Jan-2018 19:05:55 EST clacke

            in reply to
            @jasondodd
            
            https://en.wikipedia.org/wiki/IBM_Z#IBM_zSeries_family
            
            > Supports the z/OS, Linux on System z, z/VM, z/VSE, and z/TPF operating systems
            
            I'm assuming the same is true for later models.
            1. Jason_Dodd (jasondodd@mastodon.social)'s status on Tuesday, 23-Jan-2018 21:39:25 EST Jason_Dodd

               in reply to

               @clacke
               Now that I've read that, I did know, but didn't know I knew :)