Tham khảo tài liệu 'tiếng anh chuyên ngành công nghệ thông tin part 4', công nghệ thông tin, tin học văn phòng phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Lesson 3 Storage devices There are various types of optical drives CD-ROM systems offer everything from shareware programs to dictionaries and encyclopedias from multimedia databases to 3-D games. A lot of institutions have discovered that CD-ROM is the most economical way of sharing information. In fact one CD-ROM disk 650 MB can replace 300 000 pages of text about 500 floppies which represents lot of savings in distributing materials and corporate databases. In addition CD-ROM drives can play music CDs while you work. Yet CD-ROM technology has one disadvantage you cannot write anything onto a CD-ROM disk. You can only read it like a book. CD-Recorders come in two different forms CD-R and CD-RW. CD-R machines record on CD-R write-once disks allowing you to create and duplicate CDs. They are used to back up hard disks or to distribute and archive information. In fact these systems are the modern version of old WORM write once read many disks. CD-RW machines hold CD-RW rewritable disks that you can erase and re-use just as you would do with a hard disk. The future of optical storage is called DVD digital versatile disk . A DVD-ROM can hold 17 GB about 25 times an ordinary CD-ROM. For this reason it can store a large amount of multimedia software and complete Hollywood movies in different languages. They can also play music CDs and CD-ROMs. However DVD-ROMs are readonly devices. To avoid this limitation companies also produce DVD rewritable drives. Magneto-optical MO drives use both a laser and an electromagnet to record information. Consequently MO disks are rewritable . they can be written to erased and then written again. They usually come in two formats i cartridges can hold more than 2 GB ii floptical disks have capacity of 230 to 640 MB. They are ideal for backup and portable mass storage. A DTD drive B. Read the text again and summarize in the table the most relevant information. Technical specifications Use CD-ROM CD-Recorder DVD Magneto-optical .
