如何在Mac OS X中检测SSD? [英] How to detect SSD in Mac OS X?

问题描述

是否有可靠，快速，确定性的方式(即不是基准)来检查Mac OS X所开启的系统驱动器是否为固态驱动器?

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?

是否还有其他指标可以说明磁盘如何处理并行访问?我正在尝试调整程序将用于磁盘绑定操作的线程数.

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.

我对原始速度或寻道时间不感兴趣，仅对驱动器而言哪种访问方式(串行或并行)更快.我不希望程序的用户使用iSCSI或RAID. SSD是我的重点，其他任何东西都很棒.

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包含此信息.如何以编程方式阅读它?

Device Characteristics of IOAHCIBlockStorageDevice contains this information. How can I read it programmatically?

到目前为止，我已经知道它是这样的:(以下是伪代码)

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); 
}

---

此处是完整的源代码.我已经验证了它可以与Intel SSD和OCZ Vertex一起使用.

---

Here's complete source code. I've verified it works with Intel SSD and OCZ Vertex.

推荐答案

如果您试图获取此类信息，则最好是IOKit.

If you're trying to get that kind of information, you're best guess is IOKit.

您可以使用 ioreg 命令行工具或 IORegistryExplorer 尝试其中的某些功能.

You can try some of it's functionality using the ioreg command line tool or the IORegistryExplorer.

以下一些代码可能会对您有所帮助.它获取不是RAID也不是分区的所有硬盘驱动器.这不是您想要的，但它可能会让您入门.

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.

#import "TWDevice.h"

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <paths.h>
#include <sys/param.h>
#include <IOKit/IOKitLib.h>
#include <IOKit/IOBSD.h>
#include <IOKit/storage/IOMedia.h>
#include <CoreFoundation/CoreFoundation.h>
#include <IOKit/Kext/KextManager.h>


@implementation TWDevice

@synthesize name, devicePath, size, blockSize, writable, icon;

+ (NSArray *)allDevices {
    // create matching dictionary
    CFMutableDictionaryRef classesToMatch;
    classesToMatch = IOServiceMatching(kIOMediaClass);
    if (classesToMatch == NULL) {
        [NSException raise:@"TWError" format:@"Classes to match could not be created"];
    }

    // get iterator of matching services
    io_iterator_t mediaIterator;
    kern_return_t kernResult;
    kernResult = IOServiceGetMatchingServices(kIOMasterPortDefault,
                                                                      classesToMatch,
                                                                      &mediaIterator);

    if (kernResult != KERN_SUCCESS) {
        [NSException raise:@"TWError" format:@"Matching services did not succed."];
    }

    // iterate over all found medias
    io_object_t nextMedia;
    NSMutableArray *detectedDevices = [NSMutableArray array];
    while (nextMedia = IOIteratorNext(mediaIterator)) {
        NSMutableDictionary *properties;
        kernResult = IORegistryEntryCreateCFProperties(nextMedia,
                                                                                  (CFMutableDictionaryRef *)&properties,
                                                                                  kCFAllocatorDefault, 0);

        if (kernResult != KERN_SUCCESS) {
            [NSException raise:@"TWError" format:@"Getting properties threw error."];
        }

        // is it a whole device or just a partition?
        if ([[properties valueForKey:@"Whole"] boolValue] &&
            ![[properties valueForKey:@"RAID"] boolValue]) {
            TWDevice *device = [[[TWDevice alloc] init] autorelease];

            device.devicePath = [NSString stringWithFormat:@"%sr%@", _PATH_DEV, [properties valueForKey:@"BSD Name"]];
            device.blockSize = [[properties valueForKey:@"Preferred Block Size"] unsignedLongLongValue];
            device.writable = [[properties valueForKey:@"Writable"] boolValue];
            device.size = [[properties valueForKey:@"Size"] unsignedLongLongValue];

            io_name_t name;
            IORegistryEntryGetName(nextMedia, name);
            device.name = [NSString stringWithCString:name encoding:NSASCIIStringEncoding];

            …

            [detectedDevices addObject:device];
        }

        // tidy up
        IOObjectRelease(nextMedia);
        CFRelease(properties);
    }
    IOObjectRelease(mediaIterator);

    return detectedDevices;
}

@end

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