If your SATA (Serial Advanced Technology Attachment) hard drive belongs to an emulated PATA (Parallel Advanced Technology Attachment) master/subordinate (master/slave) drive pair, notification about a drive failure in a RAID 1 pair can be delayed several hours, during which time your computer may become unresponsive.
This behavior occurs because PATA does NOT support surprise removal of devices, which means that the hardware cannot notify the operating system that a drive has been removed.
The operating system retries unfinished operations until the they have timed out, which may take several hours. Your system may stop responding during this process.
To workaround this behavior, configure each drive on a separate channel, in master mode. If a drive fails or stops communicating in this configuration, the operating system can detect and remove it.