1. 光盘：
CD-ROM 是一种嵌入塑料保护外壳的金属光盘。每张光盘都必须制作母版，这是创建 CD 并将数据放置在其上的过程。 CD 是 WORM(一次写入，多次读取)媒体，这是指一旦它们被掌握，就无法更改其上的数据。
2. 磁盘：
磁盘包含由金属或塑料制成的圆盘。磁盘的两侧通常用于存储数据。磁盘涂有磁性氧化物。磁盘被划分为多个同心圆，称为磁道，磁道被划分为存储数据的扇区。
以下是 CD-ROM 和磁盘之间的区别：
| CD-ROM | Magnetic Disks |
|---|---|
| It is metal disc embedded into plastic. | It contains metal or plastic. |
| Sectors in CD-ROM are organized along a spiral. | Sectors in Magnetic disks are organized in concentric track. |
| It has CLV (Constant Linear Velocity). | It has CAV (Constant Angular Velocity). |
| Sectors in CD-ROM have same linear length. | Sectors in Magnetic disks have same angular length. |
| In CD-ROM, data is packed at its maximum density permitted. | In Magnetic disks, data is written less densely in the outer tracks. |
| It takes advantage of all storage space. | It doesn’t use up all storage available. |
| It has to change rotational speed when seeking. | It operates on constant speed, timing marks to delimit tracks. |