Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!jsloan@handies.ucar.edu From: jsloan@handies.ucar.edu (John Sloan,8292,X1243,ML44E) Newsgroups: comp.unix.questions Subject: Re: Roles for mainframe unix and UTS vs. AIX/370 questions Message-ID: <4541@ncar.ucar.edu> Date: 29 Sep 89 22:42:15 GMT References: <21015@adm.BRL.MIL> Sender: news@ncar.ucar.edu Lines: 71 From article <21015@adm.BRL.MIL>, by DMOYNIHA%WAYNEST1.BITNET@cornellc.cit.corn (Dennis P. Moynihan): > We're open to any other general comments you have on mainframe unix > systems and UTS and AIX/370 in particular. Thanks in advance! I don't have any experience specifically with either UTS or AIX, but I do have a few general comments (although from your questions I bet you've already considered them). My perspective is that I spent years as a systems programmer on IBM mainframes (360/65 and 370/3031) under a variety of OSs (OS/MFT, MVT, SVS, MVS); for the past five or six years I've been dealing almost exclusively with UNIX (both BSD and System V). I personally know of two AIX/370 shops, who chose AIX just because they had IBM hardware and hence had IBM support. You may end up using UTS for the same reason. One thing IBM/compatible mainframes are really good at is providing I/O bandwidth, which makes them REALLY attractive as file servers. You may want to consider though, that much of that bandwidth exists in the communication paths between CPUs, channels, and controllers. Once you leave this optimized I/O path, you may find that the channel and/or network speed is not all that fast in comparison. If you use the mainframe as a fileserver over traditional access paths (i.e. Ethernet) then it may turn out you've got this I/O path the width of the Mississippi, all funneling through 2 inch diameter pipe. In those hazy times when I thought about using a mainframe as a file server, I've wondered if there was hardware to channel attach a FDDI-based fiber network; if not, then a way to channel attach multiple Ethernet interfaces, making each interface look to the outside world as if it were attached to a separate file server (different Internet host ids, etc.). I'd probably like to spread those Ethernet interfaces across several channels, too. Depending on the statistical distribution of channel usage for disks, tapes, Ethernet, etc. I might want to try to optimize the combinations (if possible). Finally, do you really need to run UNIX at all? Some possibilities: o Run AIX/UTS as the native operating system. o Run AIX/UTS under VM as a guest operating system. o Run AIX/UTS under PR/SM. o Run TCP/IP+NFS on top of MVS. This latter alternative doesn't give you a big UNIX timesharing engine, but it retains MVS functionality, without the overhead of VM or PR/SM, and could still let you use the big iron as a file server (no claims are made, though, about mapping UNIX file system semantics on top of an MVS VSAM-based file system). There are also network bandwidth/management issues regarding centralizing a heavily-used file server resource; some of those same issues crop up when you just put all your Sun (or whatever) file servers off the same network cable (e.g. together in a computer room). As you come to conclusions, you would be doing the net a service by posting a summary. I for one would be really interested in hearing what you've decided, how you came to your decision, and how it all works out in the end. I hope that eventually EDUCOM publishes another volume similar to their ancient _Campus Computing Strategies_ and their more recent, excellent, _Campus Networking Strategies_, which covers some of these very issues with case studies. Maybe a _Campus Integration Strategies_. John Sloan NCAR/SCD NSFnet: jsloan@ncar.ucar.edu P.O. Box 27588 P.O. Box 3000 NCAR Mesa Lab, Room 42A Lakewood CO 80227 Boulder CO 80307 +1 303 497 1243 Logical Disclaimer: belong(opinions,jsloan). belong(opinions,_):-!,fail.