There are four main drives for the computer, all of which are classed as core hardware components. Each one uses a different way to store data and each one has different data, read/write, speeds.
Fig 1.0 The Floppy Drive is now obsolete but can still be found in computer fairs
The Floppy Disk used to be the number one storage media until the CD, DVD and Flash Drive (Memory Stick/Pen) arrived on the scene. In order to use a floppy disk you need a Floppy Drive, which has the job of reading (looking at) and writing (storing) data (files) to/from the floppy disk. The floppy drive and floppy disk are virtually obsolete now, due to them being classified as slow (in comparison to other storage technologies) and having a small storage capacity (1.44 MegaBytes or 1,457,664 Bytes), but they can still be used to store valuable, backup data, files (such as Letter and CV Templates). Computer Fairs sell floppy drives for around £16 each and the floppy disks for around £5 a box of 20 disks.
Fig 1.1 The Floppy Disk is still sold in computer fairs and electronic shops
The CD (Compact Disk) was the replacement media for the floppy disk, but is now becoming obsolete itself. In order to read data from a CD you need a CD Player and in order to write data onto a CD you need a CD Recorder (CD Writer).
All CD Drives have a CD Player built into them as standard, and many have a CD Recorder (CD Writer) built into them as well. With the price between them being as small as £5 many retailers no longer sell the cd player only. They only sell the combination (cd recorder and cd player). A CD Player, also known as a CD ROM, allows a program to read data from a CD and then interpret it as Music and/or Data files. A CD Recorder, also known as a CD Burner or CD Writer, does the same job as a CD Player but also allows a program to record Music and/or Data files onto a CD.
A CD Recorder can use either a CD-R or a CD-RW compact disk to store data on. Both CDs can store up to 700MB of data on them and both can store that data in one go or in multi-sessions (bits at a time). The main difference between them is that the CD-RW can be formatted (erased) so it can be rerecorded on again, whereas the CD-R cannot be formatted at all and so can not be rerecorded on again. However, do not think the CD-RW is better because it is not. It is limited by speed.
A CD-R can have data recorded onto it at a maximum speed of 52x, but a CD-RW can only have data recorded onto it at a maximum speed of 12x. In general a CD-R is good for storing permanent data and a CD-RW is good for storing temporary data. As a rule you should always backup (record) your important documents and files onto a CD for safe keeping, as you do not know when you will accidentally delete a document or file from the hard drive for example.
With regards to maximum speeds, if you see something like 52x 32x 52x on the box of a CD-RW (CD Re-Recorder and CD Player) for example the Xs mean the Write, Re-Write and Read Speed. So a CD-RW with 52x 32x 52x speeds means the CD-RW can Write (Record) data onto a Blank CD at 52 maximum speed, Re-Write (Re-Record / Record Over) data onto an Already Recorded On (or Blank) CD at 32 maximum speed and Read (Playback) data from a CD at 52 maximum speed.
The speeds themselves can be measured in KB/Second or MB/Second. 1x speed is 1.32MB Per Second, so 8x speed is 10.56MB Per Second (8 x 1.32). In reality though the maximum speeds might never be reached as the burning (copying) process works by gradually picking up speed as it records and plays back. So the CD-RW might of recorded or played back the data before the maximum speed was reached.
One thing to note about CD Recording is that you need a certain CPU, a certain amount of Memory and a certain amount of Hard Drive space before you can record. The reason for this is because if you copy some files from your hard drive onto a CD the CD Recording program does not normally do a straight copy. It does not copy each file from the hard drive onto the CD. What it does instead is buffer them. This means if you have 600 files to be copied onto a CD, at 1MB each, it creates a buffer-file of 600MB that contains a copy of the 600 original files to be copied. The buffer-file is stored on the hard drive. Once this stage is out the way the CD Recording program then starts copying the buffer-file onto the CD, copying a little piece at a time into Memory before transferring it onto the CD.
One of the main reasons a CD Recording program uses memory, instead of just copying the data straight onto CD, is so that it can check the data for errors before copying it to CD. The more memory a computer has the better the CD Recording program performs, as it can copy more data into memory for example. Another thing to note is that although a CD says 700MB on the cover they are referring to your data plus the data used by the CD Recording program, which it needs to use for its own recording purposes. So really you should knock off about 50MB and say 650MB is for your data.
CD Players with playback speeds of 8x up to 32x are obsolete. Todays average playback speeds are 48x and 52x. A CD Recorder should be in the region of 52x (CD-R Recording speed), 32x (CD-RW Recording speed) and 52x (Playback speed). Although with a CD Recorder it depends on a CD's ability to playback and record at a certain speed as well, as to whether or not the CD Recorder can actually match the speeds it claims it can perform.
The DVD Drive and more precisely the Combo (Combination Drive), which was a replacement for the CD Drive, has also become obsolete due to music/video downloads and storage on Flash Drives (see below). It was once a core hardware component for the computer because many hardware manufacturers used to include software installation disks (i.e. printer installation disks) with their products. Since then manufacturers have put their installation software (i.e. manuals and drivers) as downloadable files on the internet.
Fig 1.2 The DVD Player / The DVD Recorder
A Combo (Combination Drive) consists of a CD Player, CD Recorder, DVD Player and DVD Recorder all-in-one unit (casing). You can still buy these components separately but these days people tend to buy the Combo, because the price works out better. Computer fairs still them.
Fig 1.3 The correct way to hold a DVD
DVDs are exactly the same as CDs except they store more data and are geared towards storing media such as Photograph Albums, DVD Movies and so on. They come in four formats: DVD-R, DVD-RW, DVD+R and DVD+RW. The DVD Drive and DVD work in the same way as a CD Drive and CD as explained above. The DVD can store up to 4.7 GigaBytes of data and up to 8.5 GigaBytes on double layered DVD Drives (Double Layer is like Long Play on a VCR). DVD Players with a built in CD Player and CD Recorder as well should have the following kind of speeds.
(DVD+R Double Layer)
With both CD Recorders and DVD Recorders you should always go down one or two speeds when recording, otherwise the recording might fail (buffer underrun). This is because the amount of data the recording program needs to record in one go might not of been stored (buffered) in time, due to the hard drive being too slow to gather the data for example. A file on your hard drive can be split into two pieces for example if it cannot fit into one complete space on the hard drive. When a recording program needs such a file the computer first puts the two pieces back together to make one complete file. This takes time. Time which could be too slow for a recording program.
A recording program needs to be fed a continuous amount of data for it to work. If it does not get that data in time bad things happen, like data corruption and so on. In other words, it might fill the CD or DVD with spaces instead of data because the spaces were not filled in with data in time. By slowing down the recording speed you are giving the recording program extra time to wait for data to be copied/filled in.
The flash drive, also known as a Flash Pen (because of its pen-like looks and small size) or Flash Memory Stick (because it is a piece of hardware that uses flash memory), creates a logical drive on the computer. It is one of the best gadgets around. It allows you to permanently store your data (files) onto the flash memory chip, so that even when you turn off the computer the data is still on the flash drive.
Fig 1.4 The Flash (Memory) Drive
The beauty of it is its storage capacity and its portability. It is portable not just because it is so small but also because it plugs into a USB Port (Socket), therefore making it portable (pluggable) between computers - Anywhere you take it just plug it into a computer's spare USB port and then look at your files. You can delete files, save files and so on in the same way as you can with a hard drive or floppy disk.
The storage capacity ranges from 1 GigaByte up to 1 TeraByte these days (1GB, 2GB, 4GB, 8GB, 16GB, 32GB, 64GB, 128GB, 256GB, 512GB and 1,000GB), but Windows 10 will probably use 2MB or so to initialize the flash drive (depending on the flash drive). The rest of the memory though will be yours to use. Current prices, from a computer fair or cheap retailer, are approximately £1 per GigaByte or less.
With technology and prices changing every 3 months or so you will probably find your computer has all the drives and drive capacity you need. Meaning, you will probably not need any of the above drives internally. However, all of the above drives are now in external, USB, format which means it is now an affordable/wise option to buy a flash drive for example if you work on different computers from your home and/or your workplace for example.