site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com On Oct 7, 2006, at 01:59 , Michael Smith wrote: Perhaps you could explain what you mean by "a write has begun or ended"? = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... On Oct 7, 2006, at 10:51 AM, Rick Mann wrote: No, it will work very badly. Please look at the iostat code I referenced yesterday. If you don't follow my advice, please at least let us know the name of your product so that I can avoid it like the plague. Perhaps you can elaborate? I did take a look at iostat, and since it wasn't immediately obvious what it was doing, and I saw the Kauth solution at about the same time, I chose that instead. Maybe if you can explain why that's such a bad approach, I'll reconsider. The kauth hooks were designed for code that needs to be on the hot path; either because it is actively participating in the process of authorising filesystem operations, or because it hooks into an external queueing mechanism that requires precise notification of operations. Your application does not participate in authorisation, and it does not require precise notification. From reading your messages, it's clear that you have little or no understanding of the consequences of injecting code on the hot path: I believe the approach I'm looking at now, Kauth, will miss requests satisfied by the cache. Kauth sits on the application side of the I/O stack, but it only covers authorisable operations. These have no direct relationship with disk I/O. I looked at iostat's code again. I see that it asks the OS for device statistics, but I don't see how that helps me to implement a disk activity indicator. I want to display, within a humanly- imperceptible delay period, an indication that a read or write had begun or ended. My Mac workstation here at home has a disk subsystem capable of around 15,000 IO/sec. What sort of "notification" do you intend to display to the user that each of those I/Os has "begun" or "ended"? This email sent to site_archiver@lists.apple.com