When not in use, the sliders in CSS-based drives rest on the disk surface. One of the most significant draw- backs to this direct physical head-media contact is the exposure to stiction where two smooth surfaces, the disk and slider in this case, adhere to each other making their separation extremely difficult without causing significant damage to the components.
To avoid the negative affects of stiction, the surfaces of the disk media in CSS-based drives are roughened in a precision manufacturing process called texturing. Texturing can be uniformly applied over the disk surface or centralized in the inner diameter of the media specifically dedicated to the starting and stopping of the heads, known as the start/stop zone. While such texturing techniques have been satisfactory in the past, the desire to pack more data into the same surface area requires using disk media with ultra-smooth surfaces.
Due to the stiction issue, however, the usage of extremely smooth media is difficult in CSS-based hard drive designs. Limiting texturing to the landing zone area produces other complications, such as the challenge
of ensuring the Read/Write heads fly high enough over the texture bumps to minimize contact upon their assent and dissent. The inability to clear the bumps could result in significantly degraded reliability of the head/disk interface.