Choosing Optical and Magnetic Disk Drives

Disk drives are the mechanical devices used by your computer to store large amounts of data. They are split in to two types, magnetic and optical, both of different properties.

The main stay of your computer system is the hard disk drive or hard drive. This is fast for a mechanical device (a lot slower than RAM) and so enables large amounts of data to be accessed or stored rapidly by your computer.

The other magnetic device in your computer is the floppy disk. This is now an ancient technology in computer terms, but is so cheap that it is not hardly worth being without one, since practically every home computer on the planet has one. Occasionally hardware drivers are still supplied on floppy disks.

Optical devices make up the rest in the form of CD ROM, CD rewriters, DVD readers, DVD ROM and DVD rewriters. Where as the hard disk tends to be fixed in your system (portable hard drives are however available) the optically read disk, in the format of CD or DVD, makes large amounts of data highly portable.

Floppy Drives - Cheap hardware and media. Slow in operation allowing portability of 1.4 Mb of data.

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Hard Drive - The main mass storage device on your computer. Fast for a mechanical device letting the computer access or save large amounts of data. Tends to be fixed within the computer but can be mounted on a removable tray using up one of the computer bays. Also portable hard drives are available that plug into a computer port. Storage capacity - several hundred Mb. 100Mb is now easily affordable.

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CD ROM disk drives (Compact Disk Read Only Memory) - These devices can read data - music or computer program material - from a CD. Most computer programs are supplied this way. The capacity is around 640Mb.

CD RW disk drives (rewritable)- These are devices that can write data to CDs as well as read them. Two types of media are available, CD R or CD RW.

The CD R is a one shot disk that can only be written to once, get it wrong and its only use is as a drinks mat - now very cheap to purchase and music can be played on any CD player from these disks.

The CD RW can be wiped and written two up to around 1000 times. These cost a little more than the CDR but some older CD player sand CD ROMs, due to the different properties of the disc, can not read or play from them.

DVD ROM disk drives - These have the ability to read data from a DVD disk however since most software is still circulated on CDs, this device is generally used to play movies on the computer.

When computers were slower a hardware MPEG 2 decoder was required, but these days with machine speeds in excess of 1 GHz, this can all be done in software obviating the need for the hardware decoder. The DVD ROM (meaning DVD Read Only Memory) has the capability of reading a CD making it a good choice as a partner to a CDRW in a computer system.

CD RW/DVD disk drives - These are a combination of CD RW and DVD ROM, having the capability to read and write to CDs as well as read a DVD. A better combination is for a separate CD RW and DVD ROM.

DVD +-RW/RAM disk drives - Having similar capabilities as the CD RW but with the ability to read and write to a DVD. The only fly in the ointment is that there are three differing formats DVD RAM (DVD in a cartridge), DVD - RW and DVD + RW as well as the two different disk types DVD R and DVD RW to match the two later systems, giving five disk types - DVD -R, DVD -RW, DVD +RW, DVD +RW and DVD ROM.

This is still an expensive area, but prices are falling. Unless you are in to video editing and wish to store video, the DVD reader and CD re-writer combination of disk drives is the most useful buy. They have the capability to read a DVD and write or read to a CD, but check the specification, as some older DVD writers will only write to certain types of media.