Date: Wed, 3 Apr 1996 11:02:50 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: Brett_Glass@ccgate.infoworld.com (Brett Glass) Cc: terry@lambert.org, bde@zeta.org.au, freebsd-hackers@freebsd.org, freebsd-hardware@freebsd.org Subject: Re: Hacked kernel with option to disable "green" mode Message-ID: <199604031802.LAA19519@phaeton.artisoft.com> In-Reply-To: <9603038285.AA828546177@ccgate.infoworld.com> from "Brett Glass" at Apr 2, 96 03:43:16 pm
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> > Actually "fixing" the problem requires making the driver aware of drive > > spin downs and making it deal with it transparently instead of screwing > > up by passing an error to higher level code. > > This is one way to solve the problem. However, disabling spindowns is also > a viable solution. Why not offer both? Uh... because it's impossible to offer the spindown disabling safely in a drive/controller independent fashion? The 0xFB for the Seagate is not the same as is used by all other "green" hard disks, if they even support it in the first place... > > Disabling the spindown is not what I'd call "making the code 'green > > aware'"... > > No, but it is both a performance enhancement and a way to ensure that > things work. That's the problem... it can't ensure this because you can't send the command reliably. But you can reliably recover from a spin-down, if your disk driver has been written correctly. So the generic soloution must be to recover from spindown, not to disable it. > That's why I'd propose using config flags -- so that the system will be > able to perform adequately during installation and immediately thereafter > -- AND a utility that could change the setting later on. Both could be > based on some of the kernel hacking I've already done here. This works for Seagates for people who have multiple systems so that they can build kernels. This *is* better than the situation before, but it effectively leaves a lot of wires sticking out of the case. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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