CD-ROM
Short for Compact Disc-Read Only Memory, CD-ROM drives or optical drives are CD players inside computers that can have speeds in the range from 1x and beyond, and have the capability of playing audio CDs and computer data CDs. Below is a picture of the front and back of a standard CD-ROM drive.
Interfaces
Below are the different interfaces that allow a CD-ROM and other disc drives to connect to the computer.
- IDE / ATA - One of the most commonly used interfaces used still today to connect disc drives to the computer.
- Panasonic - Older proprietary interface.
- Parallel - Interface used with old external CD-ROM drives.
- PCMCIA (PC Card) - Interface sometimes used to connect external disc drives to laptop computers.
- SATA - Replacing IDE as the new standard to connect disc drives.
- SCSI - It is highly recommended to get a card that matches the CD-ROM drive as some of the earlier drives had proprietary SCSI interfaces. Otherwise, a SCSI-2 card is recommended.
- USB - Interface most commonly used to connect external disc drives.
CD-ROM transfer speeds
Below is the standard transfer rates and access times of the majority of CD-ROM drives. The below figures are averages you can expect to find on each speed of CD-ROM drive. These averages may be slower or faster than your CD-ROM drive and to where the CD-ROM is accessing the data from the CD-ROM. In general the higher this number is the faster the transfer rate or in the case of a disc burner the faster the write rate.
| Drive speed | Transfer rate (BPS) | Access time (ms) |
| Single-speed (1x) | 153,600 | 400 |
| Double-speed (2x) | 307,200 | 300 |
| Triple-speed (3x) | 460,800 | 200 |
| Quad-speed (4x) | 614,400 | 150 |
| Six-speed (6x) | 921,600 | 150 |
| Eight-speed (8x) | 1,228,800 | 100 |
| Ten-speed (10x) | 1,536,000 | 100 |
| Twelve-speed (12x) | 1,843,200 | 100 |
| Sixteen-speed (16x) | 2,457,600 | 90 |
| Eighteen-speed (18x) | 2,764,800 | 90 |
| Twenty-four-speed (24x) | 3,686,400 | 90 |
| Thirty-two-speed (32x) | 4,915,200 | 85 |
| One-hundred-speed (100x) | 15,360,000 | 80 |
| CAV drives (12x - 24x) | 1,843,200 - 3,686,400 | 150-90 |
- Further information about the trailing x on a CD-ROM can be found on our x definition.
- What does max mean on 24x max CD-ROM drive?
- Computer CD-ROM help and support.
Also see: CD definitions, Storage