Originally Answered: What is the difference between tumour and cancer? A tumor can be benign or cancerous. A benign (non cancerous) tumor is a mass of cells that lacks the ability to invade neighboring tissue.
While portable slim hard drives are meant for carrying around in a backpack or laptop bag, all but the largest 32 TB and 64 TB external hard drives (featured here above) are still small enough for easy transport in a backpack or briefcase.
So a 320GB hard drive has 320,000,000,000 bytes (or so). To your computer's operating system, a GB is 2^30 bytes (1,073741824). So it will report as about 298GB. I'm not sure if that answers your question, but your question isn't precise enough to answer completely.