Traditionally, it has been PATA (IDE), but many newer computers are using SATA DVD drives.
"Disc" refers to optical media, such as CDs or DVDs. "Disk" refers to magnetic media, such as hard drives. So the answer depends on which drive you are referring to; most have both an "optical disc drive", and a "hard disk drive".
The number of screws that secure an optical drive to the case typically depends on the computer case design and the manufacturer. Generally, most standard PC cases require two to four screws to secure the optical drive in place. Desktop Cases: In standard desktop cases, an optical drive is usually secured with two screws on each side, making it a total of four screws. Some cases, however, may use only one screw per side, making it a total of two screws. Tool-less Cases: Some modern cases feature a tool-less design with brackets or latches to hold the optical drive in place. These may not require any screws at all or might use a couple of screws for added stability. Manufacturer Specifications: Always refer to the specific instructions provided by the manufacturer of the computer case for the exact number and placement of screws needed for securing the optical drive. If you are unsure, check your case manual or inspect the drive bay area to see how the optical drive is intended to be mounted.
if your first boot device is an optical drive, this allows you to boot from a recovery disk or live CD in case of hard drive failure or corruption. This can be useful for troubleshooting computer problems.
ISO 9660 and UDF
ide/eide
The most popular consumer internal drive interface is SATA.
The most popular is a parallel ATA interface.
SCSI (Small Computer System Interface) is the most commonly used storage interface for enterprise servers.
"Disc" refers to optical media, such as CDs or DVDs. "Disk" refers to magnetic media, such as hard drives. So the answer depends on which drive you are referring to; most have both an "optical disc drive", and a "hard disk drive".
Usb devices
That's simple. Put a dick that works in another computer into the drive to see if it works. If it does not you most like need a new drive. You can find a optical drive today for less than $100 sometimes less depending on your laptop.
Most likely you will have to reinstall the drives for the CD and DVD units
Apple Macintosh
Typically EIDE cables connect to IDE Hard-drives and optical drives such as CD and DVD Drives. The cable connects between the motherboard of the computer and the hard-drive or optical drive. Normally most motherboards have two idea buses. You can have to drives per cable. So a total of 4 drives.
This is most often the system partition, or the "C" drive, alternatives include the optical drive if you select that drive, or the floppy disk drive ("A" Drive) on older computers.
optical
I take it your asking the Brand?Every one has their likes and dislikes so look online at the reviews for the ones in your price range. Be aware I believe with the latest MacBook Air's you have to buy Apples external optical drives in order for the external drive to be bootable. I don't think any 3rd party optical drives are bootable for the Air.