Date: Mon, 30 Dec 1996 12:59:51 +1030 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: aat81@dial.pipex.com (Simon Reading) Cc: grog@lemis.de, msmith@atrad.adelaide.edu.au, se@freebsd.org, freebsd-hardware@freebsd.org Subject: Re: DAT reliability Message-ID: <199612300229.MAA05081@genesis.atrad.adelaide.edu.au> In-Reply-To: <3.0.32.19961224150632.00691884@pop.dial.pipex.com> from Simon Reading at "Dec 24, 96 03:08:04 pm"
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Simon Reading stands accused of saying: > > >Are you sure you're conditioning your DATs correctly? You will find > >that a tape that's been in storage should retensioned (wind to end of > >media, rewind), and must be at room temperature for best results. > >Instructions on this sort of thing are included with most decent > >blank tapes. > The tapes I have used were at 21C, normal pressure and humidity. > I did not retension the tape (unless this was done as part of the Adaptec > Backup 'format' action), but I had used them successfully on the HP C1533, > no problems. I will retension new tapes in future. No instructions were > provided with HP or Sony DDS cartridges. The biggest issue with tape condition and the Sonys is that we will get really poor read performance (lots of soft errors and retrying) ending with a read error on a tape that has been sitting on the shelf for months or has been shipped (vibration causing settling?). A quick wind-to-end and back seems to help immensely. > I doubt whether my problems were to do with conditioning, I am sure that my > SDT-7000 was faulty. I'm not going to argue with this 8) > Do you have any experience of the SDT-7000? Not directly, no. > The SDT-7000 has a drum rotational speed twice that of the SDT-5200 > (as Greg noted, to enhance performance). Running a drive at a > higher speed can only make it more susceptible to mechanical > failure. That presumes that everything else is the same, which isn't even close to valid. The SDT-7000, as has been observed, has a completely different head assembly design. The transport, insofar as any helical-scan transport can be, is pretty good. You can whine all you like about consumer-grade product, but TBH your average consumer-grade transport is pretty bloody good. Sony are going to hurt a lot more with 5% returns on a consumer product than on a computer product. > I would guess that the 5200 has been > out for longer and that any bugs/problems would be more likely to be > observed/sorted out than any with the 7000. The small price difference > between the two models make me think that there has been little change in > the funamental mechanism design and that 8000rpm may be too fast to > transport the tape using the existing mechanism. The price of the unit has little or nothing to do with its cost, design or taste when deep-fried. I've observed over the last few years that as a general rule, most DAT units "just work". I've only met a few "persistent plaintifs" who seem never to be able to get a working unit. > Simon -- ]] Mike Smith, Software Engineer msmith@gsoft.com.au [[ ]] Genesis Software genesis@gsoft.com.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control. (ph) +61-8-8267-3493 [[ ]] Unix hardware collector. "Where are your PEZ?" The Tick [[
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