Get Disk Type in Qt

Get disk type in QT

For linux, you can tell whether the kernel has detected a SSD disk by reading special file

/sys/block/<disk>/queue/rotational

For instance, cat /sys/block/sda/queue/rotational writes 1 if sda disk is HDD and 0 if it's SSD.

For Windows, you can open a drive by opening special file \\.\PhysicalDrive<number>, for instance \\.\PhysicalDrive0. It can the be used with DeviceIOControl to query properties, using IOCTL_STORAGE_QUERY_PROPERTY IO control. It seems StorageDeviceSeekPenaltyProperty may be what you're after, as HDD have a seek penalty while SSD don't. Alas I don't have a windows environment around to test right now.

For portability, I highly doubt such system-dependent information is available in a portable way. You'll have to use #ifdef/#else/#endif macros to select an implementation depending on current target.

How to get the hard disk partition information QT

I find a solution that I think is more helpful Displaying Volume Paths

thank you all any way.

How to determine how much free space on a drive in Qt?

I know It's quite old topic but somebody can still find it useful.

Since QT 5.4 the QSystemStorageInfo is discontinued, instead there is a new class QStorageInfo that makes the whole task really simple and it's cross-platform.

QStorageInfo storage = QStorageInfo::root();

qDebug() << storage.rootPath();
if (storage.isReadOnly())
    qDebug() << "isReadOnly:" << storage.isReadOnly();

qDebug() << "name:" << storage.name();
qDebug() << "fileSystemType:" << storage.fileSystemType();
qDebug() << "size:" << storage.bytesTotal()/1024/1024 << "MB";
qDebug() << "availableSize:" << storage.bytesAvailable()/1024/1024 << "MB";

Code has been copied from the example in QT 5.5 docs

C++ Qt - Get Physical Disk Size (Win32)

I think this issue is mainly cosmetic as a result of inconsistencies in measurements used by Operating Systems and Hard Drive manufacturers. Check this wikipedia page for more information. Perhaps find a way to do the math while treating 1 Kilobyte as 1000 bytes (instead of 1024), 1 Megabyte as 1000 * 1000 and so on -- instead of 1 kilobyte as 1024 bytes etc.

[Qt][Linux] List drive or partitions

You can use /etc/mtab file to obtain a mountpoints list.

QFile file("/etc/mtab");
if (file.open(QFile::ReadOnly)) {
  QStringList mountpoints;
  while(true) {
    QStringList parts = QString::fromLocal8Bit(file.readLine()).trimmed().split(" ");
    if (parts.count() > 1) {
      mountpoints << parts[1];
    } else {
      break;
    }
  }
  qDebug() << mountpoints;
}

Output on my machine:

("/", "/proc", "/sys", "/sys/fs/cgroup", "/sys/fs/fuse/connections", "/sys/kernel/debug", "/sys/kernel/security", "/dev", "/dev/pts", "/run", "/run/lock", "/run/shm", "/run/user", "/media/sf_C_DRIVE", "/media/sf_C_DRIVE", "/media/sf_D_DRIVE", "/run/user/ri/gvfs")

Note that QFile::atEnd() always returns true for this file, so I didn't use it in my code.

QDir::Drives is 4 according to the documentation. It's static integer value of enum item, it doesn't show anything and you shouldn't care about it in most cases. QDir::drives() contains exactly one item (for root filesystems) when executed on Linux.

How can I determine the type of a particular drive?

I'm not sure what you didn't understand about the documentation you linked to...

The sole argument accepted by the function is the root directory of the drive you want to get information about (including a trailing backslash). The function returns a value indicating which type of drive that is. A chart is shown that gives the possible return values and what each of them mean.

For example:

GetDriveType(_T("C:\\"))    // returns DRIVE_FIXED if C:\ is my hard drive
GetDriveType(_T("A:\\"))    // returns DRIVE_REMOVABLE if A:\ is my floppy drive
GetDriveType(_T("D:\\"))    // returns DRIVE_CDROM if D:\ is a CD-ROM drive
GetDriveType(_T("N:\\"))    // returns DRIVE_REMOTE if N:\ is a network drive

It also says that if you want to determine whether a drive is a USB-type drive, you need to call the SetupDiGetDeviceRegistryProperty function and specify the SPDRP_REMOVAL_POLICY property.

How to check that QImage::save() has finished writing to disk?

Your diagnosis of the issue is incorrect. Once image.save has returned, the filesystem is in a consistent state and you can forcibly exit the application at that very point: the file will have correct contents. Whether the on-disk state is consistent is unknown, but all that means is that you shouldn't reset nor forcibly power-off the machine. Your application is free to quit, though.

Your issue is something else. Who knows what: you failed to provide a test case.

It's not necessary to deal with worker threads and objects manually. Leverage QtConcurrent. It's supposed to be easy, and it is. Namely:

class MyWindow : public QWidget {
  Q_OBJECT
  CountDownLatch m_latch;
  Q_SIGNAL void imageSaved(const QString & filename);
  Q_SIGNAL void imageSaveFailed(const QString & filename);
  void saveImage(const QImage & image, const QString & filename) {
    auto lock = m_latch.lock();
    QtConcurrent::run([=]{ // captures this, lock, image and filename
      if (image.save(filename, "PNG", 100))
        emit imageSaved(filename);
      else
        emit imageSaveFailed(filename);
    });
  }
  ...
  // MyWindow's destructor will block until all image savers are done
};

For implementation(s) of CountDownLatch, see this question.

Get current CPU, RAM and Disk drive usage using Qt

You need to use platform specific code to detect resource usage.

For fastest file access to calculate hashes, use memory mapped files (QMemoryFile)

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