Re: AHCI Error?
Re: AHCI Error?
- Subject: Re: AHCI Error?
- From: Chris Sarcone <email@hidden>
- Date: Thu, 11 Sep 2008 10:28:00 -0700
Brian --Apple's SMART sample code does not do this:
http://developer.apple.com/samplecode/SMARTQuery/listing3.html
All it does is query the IDENTIFY data to see if SMART is supported and that is not necessary with 10.4.9 or later because IOKit publishes the property key "kIOPropertySMARTCapableKey" in device objects who are SMART capable; this latter method is used by the bug sample code.
In addition, our app has been using this same SMART code for 4 years without issue on Panther and Tiger. Only in Leopard did we start seeing these bogus error returns at random.
Panther and Tiger did not exist with AHCI capable systems. Those systems were most likely PATA and Gen 1 SATA. In addition HDDs have changed a lot over the number of computers for many years.
However, I did make a change to our code to get the IDENTIFY data and test if SMART is enabled and if not enable it. This seems to have helped, as there were no bogus errors during a 10 hour run of querying the status every 4.5 minutes. But in that time period, never did the device report SMART was disabled. So it appears Leopard changed something so that IDENTIFY must be executed before reliably querying for SMART status.
No, nothing has changed here. Fair enough, but the header doc for the method is ambiguous on how to interpret non-standard errors:
As mentioned, future versions might not return such errors. As I said this code worked without issue under Tiger and Panther, so something in Leopard changed.
Nothing has changed except we did transition to Intel-based systems.
-- Chris
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