Transcript Multimedia Systems: ADCS 3

Multimedia Systems: ADCS 3
Magnetic Media Technology
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
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
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 massstorage devices used on computers, and
for making multimedia.
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.
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.
Optical Technology
• They are also very commonly used in
computers to read software and
multimedia distributed in disc form.
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.
Hierarchical storage management
• Hierarchical Storage Management
(HSM) is a data storage technique which
automatically moves data between highcost 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.
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.
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.
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.
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
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.
Hierarchical storage management
• In practice, HSM is typically performed by
dedicated software, such as CommVault,
VERITAS Enterprise Vault, Quantum
StorNext, EMC Legato OTG DiskXtender.
Hierarchical storage management
• HSM is often used for deep archival
storage of data to be held long term at low
cost.
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.
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.
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.