Is there a reliable, quick, deterministic way (i.e. not a benchmark) to check whether the system drive Mac OS X is on is a Solid State Drive?
Is there any other indicator how well disk handles parallel access? I'm trying to adjust number of threads that my program is going to use for disk-bound operations.
I'm not interested in raw speed or seek time, only which type of access – serial or parallel – is faster for the drive. I don't expect users of my program to use iSCSI or RAID. SSD is my focus, anything else is nice-to-have.
Device Characteristics
of IOAHCIBlockStorageDevice
contains this information. How can I read it programmatically?
So far I've figured out it goes like this: (following is pseudocode)
match = IOBSDNameMatching(kIOMasterPortDefault,0,"disk0s2");
IOServiceGetMatchingServices(kIOMasterPortDefault, match, &iterator);
while(entry = IOIteratorNext(iterator)) {
do {
entry = IORegistryEntryGetParentEntry(nextMedia, kIOServicePlane, &entry);
dict = IORegistryEntryCreateCFProperty(nextMedia,
CFSTR(kIOPropertyDeviceCharacteristicsKey), kCFAllocatorDefault, 0);
[dict objectForKey:CFSTR(kIOPropertyMediumTypeKey)];
}
while(!dict && entry);
}
Edit: Here's complete source code. I've verified it works with Intel SSD and OCZ Vertex.
Best Answer
If you're trying to get that kind of information, you're best guess is IOKit.
You can try some of it's functionality using the ioreg command line tool or the IORegistryExplorer.
Here's some code that might help you. It fetches all hard drives that aren't a RAID and aren't partitions. This isn't what you want, but it might get you started.