Disk Copy VS Disk image
People always use disk backup software such as Ghost, Genie Backup Manager, Carbonite, etc. However, they are just backup existing system readable data on partition, and they can hardly store the content that exactly same as the origin one.
And there is a big problem, people always complaint that if they used too much disk image to backup or store the file, their disks will be badly hurt. There is no technique support about this issue, though fewer and fewer people get any interested in using this kind of backup software, yet they have to use it until their disk crashed and all data is gone.
The only advantage of it is: compared with the original data, the backed-up data looks the same.
In technique field, disk image is just a basic file copy; it just copies all existing system-readable files from one partition/disk to another. Once it meets bad sector, the copy procedure will be stopped and you can never make a backup by those tools.
According to this kind of situation, here comes the advanced disk copy technique, sector by sector disk copy.
As we already knew, once data was deleted, it is still there waiting for overwrite, but the system can not read yet. That's why you can make data recovery by special data recovery software. To explain sector by sector disk copy in a simple way is that everything on disk will be backup, yes, everything. So the copy will be exactly the same as the original data, even you meet bad sector issue, it can not stop the step of the procedure. LOL, but the backup disk will not form a bad sector, just a blank one.
Here are some advantages of disk copy:
1. data keeps exactly same.
2. faster speed than disk image. We once have a test: use Ghost to clone a partition in which there are 1.5 GB files, Ghost costs us 5 minutes; while use disk copy to backup 80GB disk, it only costs us 60 minutes. About half time of Ghost.
3. the price of hard disk is so cheap. A common 250G disk is only $100 around recently. Do we need any compression when backup data? Of course no. To avoid data loss, no compression is needed.
And from now on, we can give up disk image, use disk copy instead.
You may find step by step tutorial here.