A PDC is a “parallel double-disc disk” that is capable of writing two data blocks to two different tracks at the same time. It can write a data block to a disk, and then read that block off the other disk, and then write that block to the first disk.
The idea is to create a new disk that reads data from a disk one at a time. A new disk that reads a data block from the previous disk is called a “transmission” disk. As you’ve read, the first disk is the destination disk, the next is the destination disk, and so on. This is how we’re going to create the new disk.
The problem with this method is that the disks might be the same, and theyre different disks. That won’t work. The io operation, or disk operation, which is what the new disk is doing, is called a write-back operation. What this means is that if the two disks are the same, the operation won’t work. This is why if the new disk is the same as the previous disk, the new disk won’t work.
This is what happened to me. A few days ago my hard drive died. The first disk (the one that I was writing to) was replaced with a brand new one. So I rebooted, and sure enough, it started up and worked. Then I switched it to the new disk and it ran fine again. It took my mind off the fact that the drive is dead for a bit. But when I booted the new disk, it wouldn’t work.
The reason why the new disk wouldnt work is because the disk has been re-created by the program that it was written to replace the one I was writing to. The fact is, I wrote the same disk to replace the one I was written to. So the disk that I wrote to replace the old disk was not the same disk as the one that I wrote to replace the one I was writing to.
That’s a bit confusing, but the answer is that the disk that I was writing to replace the one I was writing to is still on that same drive, but the disk that I was writing to replace the one I was writing to is not the same disk as the one I was writing to replace the one I was writing to.
So I am writing to a new disk, and the disk I was writing to is still on the same drive as the one that I was writing to replace the one I was writing to. And the disk that I was writing to replace the one I was writing to is not the same disk as the one I was writing to replace the one I was writing to.
When you move data around, you can create a disk image that looks exactly the same as the one you moved your data to, then move your data to that disk image. This is called a “backup”, or “replacement” disk. But when you move your data from one disk image to another disk image, you no longer see its images as those of a single disk in the first place and you lose the data.
We do this every time we move data to/from disk images that are backed up. So the io operation at logical block address 0x0 for disk 1 (pdo name: \device\00000114) was retried. This is because io operations are not atomic. That is, even though the data has been moved from disk image 0 to disk image 1 and then back to disk image 0, the data is still there.