Space required for making disk image

[shekhar]

Dear All
I am a newbie and have joined recently. I wanted to know the disk space required to make a drive image. I have a drive with 1 TB capacity with a Windows partition . The used space is about 700GB. If I make an image of this drive, how much space would be required ? Will it be full 1TB or around 700GB ?

The drive is a Seagete drive 15000 RPM speed. How can you calculate the time required to make a disk image of above size i.e. 1TB?

[David (PassMark)]

Depends on the output format that you use.
If you are using RAW (also known as dd) and imaging the drive, then 1TB of drive needs 1TB of space.
If you are imaging the volume (the partition) of 700MB, then you would need 700MB.
If you used a format that does compression (e.g. E01) then the space required depends on the data on the drive and how random it is (which determines compression ratio).
Time required depends on the speed of the source and destination drives and the tool used. Maybe 2 hours for this drive.

[shekhar]

Thank you David for a prompt reply. It helped me.