The Toshiba CL15T has an SSD storage medium which is better than most comparable spec notebook PCs that are a similar age to it. Most medium processor core notebook PCs that were launched around the same time as it have an HDD storage medium. Solid State Drives (SSD) store data in semiconductors on a circuit board rather than using magnetic or optical media. Solid State Drives have no moving parts which makes them very fast and reliable.
This portable PC's storage medium (SSD) is actually the best storage medium amongst all medium processor core notebook PCs that were launched around the same time as the CL15T.
An HDD storage medium is the worst storage medium amongst similar types of portable PC.