/// <summary>
        /// Sector refers to physical disk blocks, we can only read complete blocks
        /// </summary>
        public byte[] ReadSectorsUnbuffered(long sectorIndex, int sectorCount)
        {
            bool           releaseHandle;
            SafeFileHandle handle = VolumeHandlePool.ObtainHandle(m_volumeGuid, FileAccess.Read, ShareMode.ReadWrite, out releaseHandle);

            if (!handle.IsInvalid)
            {
                FileStreamEx stream = new FileStreamEx(handle, FileAccess.Read);
                byte[]       buffer = new byte[m_bytesPerSector * sectorCount];
                try
                {
                    stream.Seek(sectorIndex * m_bytesPerSector, SeekOrigin.Begin);
                    stream.Read(buffer, 0, m_bytesPerSector * sectorCount);
                }
                finally
                {
                    stream.Close(releaseHandle);
                    if (releaseHandle)
                    {
                        VolumeHandlePool.ReleaseHandle(m_volumeGuid);
                    }
                }
                return(buffer);
            }
            else
            {
                // we always release invalid handle
                VolumeHandlePool.ReleaseHandle(m_volumeGuid);
                // get error code and throw
                int    errorCode = Marshal.GetLastWin32Error();
                string message   = String.Format("Can't read sector {0} from volume {1}, Win32 Error: {2}", sectorIndex, m_volumeGuid, errorCode);
                throw new IOException(message);
            }
        }
        /// <summary>
        /// Sector refers to physical disk blocks, we can only read complete blocks
        /// </summary>
        public byte[] ReadSectorsUnbuffered(long sectorIndex, int sectorCount)
        {
            bool           releaseHandle;
            SafeFileHandle handle = PhysicalDiskHandlePool.ObtainHandle(m_physicalDiskIndex, FileAccess.Read, ShareMode.ReadWrite, out releaseHandle);

            if (!handle.IsInvalid)
            {
                FileStreamEx stream = new FileStreamEx(handle, FileAccess.Read);
                byte[]       buffer = new byte[m_bytesPerSector * sectorCount];
                try
                {
                    stream.Seek(sectorIndex * m_bytesPerSector, SeekOrigin.Begin);
                    stream.Read(buffer, 0, m_bytesPerSector * sectorCount);
                }
                finally
                {
                    stream.Close(releaseHandle);
                    if (releaseHandle)
                    {
                        PhysicalDiskHandlePool.ReleaseHandle(m_physicalDiskIndex);
                    }
                }
                return(buffer);
            }
            else
            {
                // we always release invalid handle
                PhysicalDiskHandlePool.ReleaseHandle(m_physicalDiskIndex);
                // get error code and throw
                int    errorCode = Marshal.GetLastWin32Error();
                string message   = String.Format("Failed to read sector {0} from disk {1}.", sectorIndex, m_physicalDiskIndex);
                IOExceptionHelper.ThrowIOError(errorCode, message);
                return(null); // this line will not be reached
            }
        }
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        public void WriteSectorsUnbuffered(long sectorIndex, byte[] data)
        {
            if (data.Length % m_bytesPerSector > 0)
            {
                throw new IOException("Cannot write partial sectors");
            }

            if (IsReadOnly)
            {
                throw new UnauthorizedAccessException("Attempted to perform write on a readonly disk");
            }

            bool           releaseHandle;
            SafeFileHandle handle = PhysicalDiskHandlePool.ObtainHandle(m_physicalDiskIndex, FileAccess.ReadWrite, ShareMode.Read, out releaseHandle);

            if (!handle.IsInvalid)
            {
                FileStreamEx stream = new FileStreamEx(handle, FileAccess.Write);
                try
                {
                    stream.Seek(sectorIndex * m_bytesPerSector, SeekOrigin.Begin);
                    stream.Write(data, 0, data.Length);
                    stream.Flush();
                }
                finally
                {
                    stream.Close(releaseHandle);
                    if (releaseHandle)
                    {
                        PhysicalDiskHandlePool.ReleaseHandle(m_physicalDiskIndex);
                    }
                }
            }
            else
            {
                // we always release invalid handle
                PhysicalDiskHandlePool.ReleaseHandle(m_physicalDiskIndex);
                // get error code and throw
                int    errorCode = Marshal.GetLastWin32Error();
                string message   = String.Format("Can't write to sector {0} of disk {1}", sectorIndex, m_physicalDiskIndex);
                FileStreamEx.ThrowIOError(errorCode, message);
            }
        }
        public void WriteSectorsUnbuffered(long sectorIndex, byte[] data)
        {
            if (data.Length % m_bytesPerSector > 0)
            {
                throw new IOException("Cannot write partial sectors");
            }

            if (!m_isReadOnly)
            {
                bool           releaseHandle;
                SafeFileHandle handle = VolumeHandlePool.ObtainHandle(m_volumeGuid, FileAccess.ReadWrite, ShareMode.None, out releaseHandle);
                if (!handle.IsInvalid)
                {
                    FileStreamEx stream = new FileStreamEx(handle, FileAccess.Write);
                    try
                    {
                        stream.Seek(sectorIndex * m_bytesPerSector, SeekOrigin.Begin);
                        stream.Write(data, 0, data.Length);
                        stream.Flush();
                    }
                    finally
                    {
                        stream.Close(releaseHandle);
                        if (releaseHandle)
                        {
                            VolumeHandlePool.ReleaseHandle(m_volumeGuid);
                        }
                    }
                }
                else
                {
                    // we always release invalid handle
                    VolumeHandlePool.ReleaseHandle(m_volumeGuid);
                    // get error code and throw
                    int    errorCode = Marshal.GetLastWin32Error();
                    string message   = String.Format("Can't write to sector {0} of volume {1}, Win32 errorCode: {2}", sectorIndex, m_volumeGuid, errorCode);
                    throw new IOException(message);
                }
            }
        }