What feature allows for writing and erasing files on optical media?

The feature that allows for writing and erasing files on optical media is the "Write many or erasable" category, commonly denoted as RW (ReWritable) or other similar terms like RAM (Random Access Memory) and RE (Rewriteable). This type of optical media is designed to be written to multiple times, allowing users to add, update, or delete files as needed.

With RW optical media, the data can be modified without the need to create new discs each time, making it convenient for tasks that require frequent updates or data management, such as backups or temporary file storage. For example, a CD-RW allows a user to erase data that was previously stored and then write new data in its place.

In contrast, Write-once media (like the CD-R) only allows data to be written a single time, and Read-Only Memory (ROM) media cannot be modified after data has been stored. Single Layer (SL) pertains to the physical structure of the media and does not define its write/erase capabilities. Thus, the feature that facilitates both writing and erasing on optical media is the RW designation.