2017-10-11, 1(06 PMTechnology in Action CompletePage 24 of 62blob:binary code that computers understand. CDs and DVDs use a red laser to read and write data. Blu-ray discs get theirname because they are read with a blue laser light, which has a shorter wavelength and can focus more tightly and packmore information on a disc. Blu-ray drives are the fastest optical devices and deliver the high-definition quality video thatlarger displays and monitors demand.FIGURE 6.15 The SSHD drive is a single unit that contains both an SSD and a mechanical harddrive.(Zern Liew/Shutterstock)Should I bother having an optical disc drive?Traditionally, optical media delivered music and movies, but these arenow available through streaming services. Likewise, in the past, software was often installed from a DVD, but now youcan buy almost all software through an online download. Therefore, many lightweight systems have stopped includingoptical drives. For example, ultrabooks are so thin and lightweight they often leave out an optical drive but may include aslot for an SD memory card to allow you to transfer files. You can buy external optical drives, but if you have a need foroptical drives, you’re probably better off purchasing a laptop computer with an optical drive.