lost capacity when re format hard drive 1

[mrsttn]

I re-formatted my 80GB hard drive to NTFS (it was NTFS before) using the format command under windows explorer on my PC running win2000. I left all options in default. It took almost 4 hours to complete, and I now have only 76GB. What happened? This does not look right. 4GB is a lot to loose in formatting. How can I recover my lost capacity? Thanks for any help

 

[soaplover]

Because there are two different definitions of a megabyte and a gigabyte. Hard disk drive capacity is calculated by taking the number of Cylinders x Heads x Sectors x 512 bytes per sector. Hard disk drive manufacturers define a megabyte this way. However, your system's CMOS, FDISK, and Windows Explorer calculate disk capacity based on a megabyte equaling 1,048,576 bytes. Therefore different utilities might report different capacities for the same drive.

For Manufacturers 1mb = 1,000,000 bytes
For Windows 1mb = 1,048,576 bytes
For Manufacturers 1gb = 1,000,000,000 bytes
For Windows 1gb = 1,073,741,824 bytes

//Regards Soaplover

 

[mrsttn]

Thank you for the explanation, so I did not loose any memory from my hard disk based on your definition. But the thing still looks strange because I would have actually gained memory based on your definition.

I took your definition of 1GB under win OS (1,073,741,824) and multiply by 76GB shown under explorer, I now have over 81GB of memory. That ain't right either.

I swear this same disk registered 80GB in another PC running win2000 before I re-formatted it. I was lazy, did not want to clean up the OS and old programs, etc..., so I rebuilt that PC and that's why I reformatted this disk.

 

[wolluf]

mrsttn - soaplover is right - but there are also other definitions of a GB (I've seen 1000^3, 1000^2*1024 1000*1024^2, and 1024^3). Using the third of those definitions, 80,000,000,000 bytes (which is what an 80GB manufacturer's definition disk is) comes out at c. 76GB.