The MacBook Air Mid 2012 has an HDD storage media which is better than the SSD storage media found on most laptops of this spec and age. HDD is a traditional storage drive which stores the information on magnetic disks. HDD drives are slower than other forms of storage such as solid state drives (SSD) and flash drives.
This laptop's storage medium (HDD) is actually the worst storage medium across all notebook PCs of a comparable age and type to the MacBook Air Mid 2012.
The best storage medium amongst comparable types of laptop is SSD.
Alternative notebook PCs that have an HDD storage media currently available that you might want to consider include because of it's better review score, the Apple Macbook Pro.