Hard drive capacity

The hard disk is an important part of the data stored in the personal computer, and its capacity determines the capacity of the personal computer's data storage capacity. This is one of the first parameters that users should pay attention to when purchasing a hard disk.

The capacity of the hard disk is in units of MB (megabytes) and GB (gigabytes). The early hard disk capacity was low, mostly in MB (megabytes). In September 1956, the world’s first disk storage system was manufactured by IBM Corporation. Only 5MB of the district, and today's hard drive technology development of hundreds of GB hard drive is also in the hands of home users. The hard disk capacity is 40GB, 60GB, 80GB, 100GB, 120GB, 160GB, and 200GB. The hard disk technology continues to move forward, and hard disks with larger capacities will continue to be introduced.

After purchasing the hard disk, careful people will find that the capacity of the hard disk in the operating system is not consistent with the official nominal capacity, which is less than the nominal capacity. The larger the capacity, the greater the difference. The nominal 40GB hard disk shows only 38GB in the operating system; the 80GB hard disk has only 75GB; and the 120GB hard disk has only 114GB. This is not the case where manufacturers or dealers are trying to cheat consumers, but hard disk manufacturers have different calculation methods for capacity and operating system calculation methods, resulting from different unit conversion relationships.
As we all know, binary is used in computers, which causes the calculation of the capacity in the operating system to be every 1024 bytes, 1 KB per 1024 bytes, 1 MB per 1024 KB, and 1 GB per 1024 MB; and the hard disk manufacturers are The computational capacity is based on a per-1000 system, which is 1 KB per 1000 bytes, 1 MB per 1000 KB, and 1 GB per 1000 MB. This difference in the system size has caused hard disk capacity to "shrink."

Take the 120GB hard disk as an example:
Manufacturer's capacity calculation method: 120GB=120,000MB=120,000,000KB=120,000,000,000 bytes Calculated as the operating system: 120,000,000,000 bytes/1024=117,187,500KB/1024=114 440.91796875MB=114GB.

At the same time, in the operating system, the hard disk must also be partitioned and formatted, so that the system also occupies some space on the hard disk to provide for the use of system files, so the hard disk capacity and nominal capacity displayed in the operating system will be different.