term project grade 9 section b due december 18 find and research one emerging technology not studied...
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CHAPTER 3
ICT IGCSE
Term Project Grade 9 Section BDue december 18
•Find and research one Emerging technology not studied in class. It can be a prototype or already available in the market.•Each student must present their findings
•Must use microsoft powerpoint •Presentation must have pictures and at least 5 slides, including a list of references
•Student should be prepared to answer questions about their topic
The memory that a computer uses as a temporary work area is called Random Access Memory. The computer adds data and removes data from this memory. RAM is erased when the computer shuts off (volatile memory).
When a computer is switch on, the operating system is copied into the RAM, any software that is run (such as Microsoft Excel) is also loaded into RAM and run from there. When a file is loaded (such as an excel file) that is also loaded into RAM.
Main Memory - RAM
Main Memory - ROM
Backing Storage
Backup Copy
Read Only Memory permanently stores data (non-volatile), can not be changed by the user. Usually only contains the instructions to initialize and start up your computer; program cycles in a washing machine/program instructions in games such as gameboys, playstations, etc.
Place where data can be stored long term and be changeable. The only systems that do not need backing storage are those systems that are embedded in things, like washing machines.
Making an extra copy of the data on your computer in case something happens to damage or delete your data.
Comparing Main Memory with Backing Storage It is always faster to access data from main
memory than from backing storage. The processor can only use data and instructions that are in memory.
Data stored in main memory is lost when the computer is turned off but data stored in backing storage is not lost.
When programs are run or data files are loaded the contents are copied from the backing storage to the main memory of the computer
Main memory is much smaller than backing storage. It is far too small to hold the data and programs that would be on the backing storage.
STORAGE DEVICES
Storage Medium = the part that holds the data
Storage Device = the machine that lets you store data on the medium and read data from it
3 Types of Storage Devices
Magnetic
• Tiny areas on the surface of the media can be magnetised in different ways and these store bits in codes that represent characters.
Optical
• Store data on their surface by little ‘pits’ burnt by laser into the surface
Solid State
• Different from magnetic and optical, has no moving parts, fits directly into the computer
Magnetic
• Fixed Hard Disk
• Portable Hard Disk
• Magnetic Tape
• Floppy Disk (almost obsolete)
Optical
• CD/DVD –ROM
• CD/DVD –R
• CD/DVD-RW
• DVD-RAM
• Blu-Ray
Solid State
• Memory Stick/Pen Drive/USB
• Flash Memory
Fixed Hard Drives Used as main storage because
They can store very large amounts of data Access to the data is fast There is no limit to the number of times they
can delete data and then reuse the medium Used to store 3 types of data
Operating system Applications User’s data, files, videos, etc.
These 3 types of data are all stored on the hard disk and then sent to the computers memory when they need to be used.
Stores and retrieves data much faster than a CD/DVD Hard disks can crash. That is when read/write head
crashes down on the surface of the hard disk (can cause data loss); fragile
Portable Hard Disk
More robust than fixed hard disk; but can be damaged if dropped or mishandled
Used primarily to backup files and for transferring large files from one computer to another.
Data access times are fast; data transfer rate is fast; large capacity
Transfer rates are NOT as fast as fixed hard disks; more expensive than other forms of media
Magnetic Tape Magnetic tapes are very thin strips of plastic
that are coated with a magnetic layer and are fed through a read/write head mechanism.
Used in any application that requires an extremely large storage capacity and where the speed of accessing data is not that important. Batch processing Utility billing systems – where all customer bills are
produced at the same time and every customer record has to be processed
Making backups (usually larger organisations) Cheaper than using disks; robust; data transfer
rate is fast Access to data is slow; updating requires a new
tape to be created
More than 60,000 slots for magnetic tape cassettesData Archiving
• There is no need to read through the whole disk to find just one piece of data, which speeds up the process considerably
• Fixed Hard Drive• Portable Hard Drive
Direct Access to Data
• Data is stored one piece after the other• Sequential storage (data is arranged in
some sort of order, for example: alphabetical)
• Magnetic Tapes – used when there is a need to store large amounts of data and where the speed of access is not important.
Serial Storag
e
OPTICAL STORAGE DEVICES
CD/DVD RCD/DVD ROMCD/DVD RWDVD RAMBLU RAY
Properties Uses Advantages Disadvantages
CD/DVD ROM
Read Only Memory
Can NOT be recorded on
Storing music albums, software, games, etc.
More robust and cheaper than hard disks
Data access rates are longer than for hard disks
CD/DVD R
Read & Write Once Memory
CAN be recorded ONCE
Home recordings of music and films; storing and transferring data
Once burned they cannot be accidentally written over
If a mistake is made it must be thrown away
CD/DVD RW
Rewritable optical disks
Can be written over several times
Used for data and recording TV shows, etc. that need to be deleted and rewritten
Can be used more than once
More costly ; Can be accidentally overwritten
DVD RAM
Possible to record and use at the same time
General data storage; archiving
Greater capacity; Longer lasting than other forms of optical media
Expensive; not compatible with most DVD players
Blu Ray Largest capacity
Video games, data, HD movies, camcorders
Highest access speeds and data transfer rates
Expensive
DO NOW IN COPYBOOK
What is the difference between backing storage and main memory?
Solid State Backing Storage Memory Stick/Pen Drive/USB Drive Storage medium and device are the same Can store up to 64 GB of data Used to transport files and backup data
from computer to computer Advantages
More compact than equivalent optical or magnetic media; very portable
More robust than other forms of memory, even surviving being “washed”
Disadvantages More expensive per GB than hard disk
drives
Solid State Backing Storage Flash Memory Cards Can store up to 64 GB of data Used for storing photographs in digital
cameras Used in mobile phones to store phone
numbers, photographs, etc. Used in MP3 players to store music
Advantages More compact than equivalent
optical or magnetic media
Disadvantages More expensive per GB than hard disk drives; can
only be used for a particular number of read/write operations Have lower storage capacity than hard disk drives
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