Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!batcomputer!eacj From: eacj@batcomputer.tn.cornell.edu (Julian Vrieslander) Newsgroups: comp.sys.mac Subject: Comparing performance of Quantum and Imprimis hard disks Message-ID: <9009@batcomputer.tn.cornell.edu> Date: 6 Oct 89 04:32:01 GMT Reply-To: eacj@tcgould.tn.cornell.edu (Julian Vrieslander) Organization: Cornell Theory Center, Cornell University, Ithaca NY Lines: 34 Keywords: Imprimis Quantum hard disk I've been following the recent discussions here about hard drive reliability, and especially the comments on the 3.5" Quantums and the 5.25" CDC/Imprimis Wrens. I've also found some possibly contradictory performance comparisons for these drives. Maybe someone here can clear this up. I have some data sheets from Imprimis which claim read and write rates of about 9 megabits/sec for a 100 meg Wren V. They claim that a Quantum Pro 80 runs at about 6 megabits/sec under the same conditions. But the fine print under the chart says that the Quantum's diskcache was turned off (hmm..). "SCSI Evaluator" was used as the benchmark. Micronet makes a similar claim: they say that their 5.25" Wrens are at least 66% faster than any 3.5" drive with equivalent capacity. But SuperMac and GCC both claim that their Quantums measure peak throughputs of 2 megabytes/sec (I assume this means 16 megabits/sec). When I asked for a sustained transfer rate, GCC gave me a figure of 1.25 megabytes/sec (10 megabits/sec), but the tech rep did not know the test conditions. This seems like a big discrepancy, and I'm curious to know if different benchmark conditions, different drivers, etc. would be sufficient to explain it. Have any of you done any independent performance comparisons of products built on Wrens and Quantums (especially the ~100 meg units)? In an earlier posting, someone claimed that the Quantums do not have caching. But the SuperMac and GCC brochures say that these devices have 64k look-ahead caches. How does such a cache work? And why would Imprimis disable it for their throughput test? -- Julian Vrieslander Neurobiology & Behavior, W250 Mudd Hall, Cornell University, Ithaca NY 14853 UUCP: {cmcl2,decvax,rochester,uw-beaver}!cornell!batcomputer!eacj INTERNET: eacj@tcgould.tn.cornell.edu BITNET: eacj@CRNLTHRY