the carousel and the grand challenge

• complementary tools for accessing event data

• works at lower level of abstraction than GC

  • files, not objects

• can work with non-event data files

  • important since it doesn’t take much to clog access to tapes
  • 11 MB/sec/drive in principle; 6 MB/sec/drive in practice
  • best case: Eagles take ~20 seconds to load, seek: read ~100 MB files at random and you’ll see no better than 50% bandwidth
  • MDC1,2 naive ftp only saw ~1 MB/sec effective bandwidth for reads

• already works with disjoint staging areas

• can, in principle, work over the WAN

• doesn’t reorganize data, doesn’t provide event iterator, isn’t coupled to analysis code

  • good or bad, depends on what you’re expecting

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