Multimedia Systems: ADCS 3

1. Multimedia Systems: ADCS 3 Magnetic Media Technology

2. Magnetic Media Tech • Magnetic storage and magnetic recording are terms from engineering referring to the storage of data on a magnetized medium. • Magnetic storage uses different patterns of magnetization in a magnetizable material to store data and is a form of non-volatile memory

3. Magnetic Media Tech • A magnetic storage media, primarily hard disks, are widely used to store computer data as well as audio and video signals. • In the field of computing, the term magnetic storage is preferred and in the field of audio and video production, the term magnetic recording is more commonly used

4. Magnetic Media Tech • Other examples of magnetic storage media include floppy disks, magnetic recording tape, and magnetic stripes on credit cards. • Hard disks are the most common mass-storage devices used on computers, and for making multimedia.

5. Magnetic Media Tech • You will need one or more large capacity hard disks drives. (As Vaughan’s Law of Capacity suggest) “You never have enough memory or disk space” • As multimedia has reached consumer desktops, hard disks manufacturers have built smaller profile, larger-capacity, faster, and less-expensive hard disks.

6. Optical Technology • Optical media technology refers to the optical media devices/optical drives. • Optical drives retrieve and/or store data on optical discs like CDs, DVDs, and BDs (Blu-ray discs) which hold much more information than classic portable media options like the floppy disk. • Optical are known as CD Drive, DVD drive, BD drive, and disk drive.

7. Optical Technology • They are also very commonly used in computers to read software and multimedia distributed in disc form.

8. Optical Technology • Optical drives—along with flash memory—have mostly displaced floppy disk drives and magnetic tape drives for this purpose because of the low cost of optical media and the near-ubiquity of optical drives in computers and consumer entertainment hardware.

9. Hierarchical storage management • Hierarchical Storage Management (HSM) is a data storage technique which automatically moves data between high-cost and low-cost storage media. • HSM systems exist because high-speed storage devices, such as hard disk drive arrays, are more expensive (per byte stored) than slower devices, such as optical discs and magnetic tape drives.

10. Hierarchical storage management • While it would be ideal to have all data available on high-speed devices all the time, this is prohibitively expensive for many organizations. • Instead, HSM systems store the bulk of the enterprise's data on slower devices, and then copy data to faster disk drives when needed.

11. Hierarchical storage management • In effect, HSM turns the fast disk drives into caches for the slower mass storage devices. • The HSM system monitors the way data is used and makes best guesses as to which data can safely be moved to slower devices and which data should stay on the fast devices.

12. Hierarchical storage management • In a typical HSM scenario, data files which are frequently used are stored on disk drives, but are eventually migrated to tape if they are not used for a certain period of time, typically a few months. • If a user does reuse a file which is on tape, it is automatically moved back to disk storage.

13. Hierarchical storage management • The advantage is that the total amount of stored data can be much larger than the capacity of the disk storage available, but since only rarely-used files are on tape, most users will usually not notice any slowdown. • HSM is sometimes referred to as tiered storage

14. Hierarchical storage management • HSM was first implemented by IBM on their mainframe computers to reduce the cost of data storage, and to simplify the retrieval of data from slower media. • The user would not need to know where the data was stored and how to get it back; the computer would retrieve the data automatically.

15. Hierarchical storage management • In practice, HSM is typically performed by dedicated software, such as CommVault, VERITASEnterprise Vault, QuantumStorNext, EMC Legato OTG DiskXtender.

16. Hierarchical storage management • HSM is often used for deep archival storage of data to be held long term at low cost.

17. Tiered storage • Tiered storage is a data storage environment consisting of two or more kinds of storage delineated by differences in at least one of these four attributes: Price, Performance, Capacity and Function. • Any significant difference in one or more of the four defining attributes can be sufficient to justify a separate storage tier.

18. Tiered storage • Examples: • Disk and Tape: Two separate storage tiers identified by differences in all four defining attributes. • Old technology disk and new technology disk: Two separate storage tiers identified by differences in one or more of the attributes. • High performing disk storage and less expensive, slower disk of the same capacity and function: Two separate tiers. • Identical Enterprise class disk configured to utilize different functions such as RAID level or replication: A separate storage tier for each set of unique functions.

19. Note • Storage Tiers are NOT delineated by differences in vendor, architecture, or geometry except where those differences result in clear changes to Price, Performance, Capacity and Function.