Xref: utzoo comp.sys.ncr:495 comp.arch:18296 Path: utzoo!attcan!uunet!aplcen!haven!adm!cmcl2!cmcl2.nyu.edu!gottlieb From: gottlieb@allan.ultra.nyu.edu (Allan Gottlieb) Newsgroups: comp.sys.ncr,comp.arch Subject: Re: Terradata architecures Message-ID: Date: 24 Sep 90 18:34:02 GMT References: <211@bilpin.UUCP> Sender: notes@cmcl2.NYU.EDU Followup-To: comp.sys.ncr Organization: New York University, Ultracomputer project Lines: 27 In-reply-to: nick@bilpin.UUCP's message of 22 Sep 90 15:50:30 GMT I assume others more familiar with Teradata will supply more info but, since it is briefly covered in my book*, I feel obligated to reply :-). Teradata's DBC/1012 is topologically a tree of upto 1024 processors operating in MIMD message-passing mode (no shared memory). The name 1012 stands for 10 to the 12th, i.e. a terabyte. Only the leaves of the tree are processors. Interior nodes form the Y-net. This allows broadcasts down the tree from the root and hence a msg can be sent to the root and then broadcast down. Moreover the Y-net nodes can sort the two inputs from their two children and hence data from the leaves can be sorted "for free" on the way up to the root. A datasystem affords two main sources of parallelism: among (simple) transactions and within (complex) transactions. The DBC is designed for the second category. Ten-relation joins on 4-GB to 10-GB tables have been reported for a 208-processor configuration. Allan Gottlieb NYU Ultracomputer Project * George Almasi and Allan Gottlieb, Highly Parallel Computing Benjamin Cummings ISBN 0-8053-0177-1 -- Allan Gottlieb gottlieb@nyu.edu