What is CD-RW? An In-depth Look at Re-writable CDs

CD-RW is an important pillar of computer data. But what is it, exactly?

Since its inception in 1982, the CD-RW has been a vital pillar for data storage and preservation. For over four decades, these optical discs have provided a secure haven for movies, TV shows, images, games, personal data, documents, and more.

But what exactly is a CD RW disc? And what does a CD RW drive do? Are they even compatible anymore, especially now that most laptops or computers don't come with functional CD RW drives? Let's find out.

What is CD-RW?

CD-Rewritable, commonly abbreviated as CD-RW, was introduced in 1997. It is one of the latest iterations in the patent CD or optical disc formats. CD-RW is an optical disc storage medium that can be written to and read from using a CD burner or a CD drive.

MagneOptical (MO) technology was the standard for rewritable CDs before CD-RW, which was called CD-MO. The standard ensured that there was an unerasable area on the disc, so that a CD-ROM drive could read it.

Then came rewritable CDs, or CD-RWs, which use phase-change technology and have reflectivities of 15-25%, well below that of CD-Rs.

There are, however, a few things to know about CD-RWs:

• It was developed by a subcommittee of the International Organization for Standardization (ISO) called the Compact Disc (CD) Working Group.
• The technology was introduced in 1983 and updated in 1990.
• It was one of the first three formats designed for digital audio use, alongside Digital Audio Tapes (DAT) and LaserDiscs.
• CD-RWs can be erased and rewritten as needed, multiple times.

However, it can't be used to record new data if it was previously used to store music or other content. Also, a scratched CD RW may become unreadable – even for a powerful CD/DVD drive.

Therefore, a CD-RW must be blank or have 0 MB of data on it to be written to. Also, the disc must be erased again if data is to be rewritten to it.

Advantages and Disadvantages of CD-RW

CD-RWs were one of the revolutionary technologies of their time, and many attribute the success of USB flash drives to the appeal of writable data storage, especially given its reusable nature. However, the era of any spinning disk is gradually coming to an end, and in 2022, it is genuinely outdated.

However, although CD-RWs are pretty old, they have their fair share of advantages. On the other hand, they also have some disadvantages. Thus, for your convenience, here's a comparison between them:

Advantages

• CD-RW was the first type of CD that allowed you to run/play data directly from the disc without having to copy it elsewhere first.
• You can easily write media to it, and it's relatively faster than CD-R.
• It can directly boot Windows without needing an installation process.
• With appropriate hardware, such as a CD-RW drive, it supports rewritable media.
• It is much faster than CD-R.
• It can be read by a DVD-RW drive.
• It can be accessed in Windows just like any other media partition.

Drawbacks

• It's mostly outdated by 2022.
• DVD/CDs are rarely used anywhere other than gaming consoles.
• They can be cumbersome to handle.
• They can become unusable with age or scratches.

Comparing CD-RW and CD-R

CD-RW and CD-R are two entirely different formats, with the former being an evolution of the latter. Since CD-R is an older technology, it comes with several limitations.

However, to help you understand the difference, here is a table for reference:

While this list shows the main specifications for CD-R and CD-RW, there is little comparison in terms of speed and performance. To better understand, let's delve into some key factors that include:

Reusability:

A CD-R has a reflective metal dye coating, whereas a CD-RW uses a special metal layer, but the principle is the same. This ensures that a CD-R can be written to only once, meaning that no further data can be added once a CD-R has been used.

[[File:CD-R disc bottom side.png|alt=A rainbow-like CD-R bottom|height=352|width=702]]

On the other hand, CD-RW is erasable. Once data is written to it, thanks to that specialized layer mentioned earlier, the data can be deleted and rewritten. Both CD-R and CD-RW benefit from their specific Sector Constant Linear Velocity (Z-CLV) method.

[[File:CD-RW non-shiny side.jpg|alt=The non-glossy side of a CD-RW|height=529|width=700]]

Once data is written to a CD-R, it becomes a read-only CD-ROM. CD-RWs, however, remain rewritable, though they are not ideal for long-term storage of data, for which CD-R is better suited.

Speed:

The speed range for CD-Rs is similar to CD-RWs, with various types available. However, the most common CD-R is the 4x version, which can write about 600 KB of data per second. CD-RWs, on the other hand, tend to have faster speeds, commonly available at 8x, 10x, and 12x speeds.

In both formats, CLV comes into play again, with CD-RW coming out on top because of its higher writing capability. In other words, it can write at 1x speed at 1,352 KB per second, whereas CD-R cannot exceed 1,008 KB per second at 4x speed.

Compatibility:

Compatibility is one of the main issues with CD-R and CD-RW. Although they look so similar, they are actually quite different. This is mainly due to the fact that some CD drives cannot burn CD-RWs, and vice versa.

The comparison is less relevant now that DVD-RW drives can write both CD-R and CD-RW.

Bottom line

Well, there you have it, the pros and cons of CD-RW. We've not only looked at the advantages but also the disadvantages. While it outperforms CD-R in many ways, the latter has its edges in certain aspects, particularly in data security.