DC014 Lecture Note & Tutorial

Braille Keyboards












• Braille keyboards are simply standard keyboards





with stickers over each key that provide Braille





representation of that particular key.






• These keyboards provide access to people who





are blind and who are not touch typists.

Large Key Keyboards












• These keyboards are designed similar to





standard keyboards, but with physically





larger keys.




• The larger size provides both a larger target





area and a larger display representation for





each key.

Large Key Keyboards












• These keyboards are designed similar to





standard keyboards, but with physically





larger keys.




• The larger size provides both a larger target





area and a larger display representation for





each key.

Onscreen Keyboards















• These keyboards are virtual keyboards,





displayed directly on a computer screen.

Onscreen Keyboards















• These keyboards are virtual keyboards,





displayed directly on a computer screen.

Alternative Mouse Options














• To help all people use the mouse to access a



computer, alternative mouse options have



been developed that utilize various access




points.





• These include :








 Trackball



 Joystick



 Mouth-controlled mouse

Alternative Mouse Options














• To help all people use the mouse to access a



computer, alternative mouse options have



been developed that utilize various access




points.





• These include :








 Trackball



 Joystick



 Mouth-controlled mouse

Trackball

















• This is ideal for an individual with a disability





preventing them from being able to




accurately move a mouse due to either





limited fine or gross motor control.







• A trackball's stationary nature removes the





need to control the movement





of the entire device.

Trackball

















• This is ideal for an individual with a disability





preventing them from being able to




accurately move a mouse due to either





limited fine or gross motor control.







• A trackball's stationary nature removes the





need to control the movement





of the entire device.

Joystick















• The joystick is a stationary device that





requires only movement of the stick to





control mouse movement on a computer




screen.





• A joystick provides an alternative to a mouse





for people lacking fine motor control or the





ability to grasp and move




a standard mouse.

Joystick















• The joystick is a stationary device that





requires only movement of the stick to





control mouse movement on a computer




screen.





• A joystick provides an alternative to a mouse





for people lacking fine motor control or the





ability to grasp and move




a standard mouse.

Mouth-Controlled Mouse














• This type of mouse is ideally used by




someone completely lacking movement or




usable control in his/her hands.






• Essentially, this type of device is a joystick,




where the user bites the "stick" and moves




his/her mouth to control the mouse on the




screen.

Mouth-Controlled Mouse














• This type of mouse is ideally used by




someone completely lacking movement or




usable control in his/her hands.






• Essentially, this type of device is a joystick,




where the user bites the "stick" and moves




his/her mouth to control the mouse on the




screen.

Alternative Text Entry-Speech Recognition Software


















• Speech recognition software is a computer access




option that allows the user to dictate text into a




computer or navigate the computer using his/her




voice to produce words or dedicated voice




commands.




• Speech recognition software was developed for the




able-bodied population as an alternative means of




text input.

Alternative Text Entry-Speech Recognition Software


















• Speech recognition software is a computer access




option that allows the user to dictate text into a




computer or navigate the computer using his/her




voice to produce words or dedicated voice




commands.




• Speech recognition software was developed for the




able-bodied population as an alternative means of




text input.

Assistive output : Braille printer















• High tech braille devices are available for






students who are blind or visually impaired to





access and produce in braille what appears on






a portion of the computer screen.

Assistive output : Braille printer















• High tech braille devices are available for






students who are blind or visually impaired to





access and produce in braille what appears on






a portion of the computer screen.

Assistive output : screen magnifiers















• A magnifier is software that interfaces with a





computer's graphical output to present enlarged




screen content.






• This type of assistive technology is useful for people





with some functional vision; people with visual




impairments and little or no functional vision usually





use a screen reader.

Assistive output : screen magnifiers















• A magnifier is software that interfaces with a





computer's graphical output to present enlarged




screen content.






• This type of assistive technology is useful for people





with some functional vision; people with visual




impairments and little or no functional vision usually





use a screen reader.

2.5 Storage















• At the end of this lesson, students should be





able to:






• Differentiate various storage capacity





• Identify types of storage media






• Explain the functions of storage media

2.5 Storage















• At the end of this lesson, students should be





able to:






• Differentiate various storage capacity





• Identify types of storage media






• Explain the functions of storage media

Introduction












• Storage holds data, instructions, and




information for future use. Every computer




stores system software and application




software.






• To start up, a computer locates an operating




system (system software) in storage, usually




a hard disk, and loads it into memory (RAM).






• When a user issues a command to start




application software, the operating system




locates the program in storage, such as on a




hard disk or optical disc, and loads it into




memory (RAM).

Introduction












• Storage holds data, instructions, and




information for future use. Every computer




stores system software and application




software.






• To start up, a computer locates an operating




system (system software) in storage, usually




a hard disk, and loads it into memory (RAM).






• When a user issues a command to start




application software, the operating system




locates the program in storage, such as on a




hard disk or optical disc, and loads it into




memory (RAM).

Introduction















• A storage device is the computer hardware





that records and/or retrieves items to and





from storage media.






• Reading is the process of transferring items





from a storage medium into memory.







• Writing is the process of transferring items





from memory to a storage medium.

Introduction















• A storage device is the computer hardware





that records and/or retrieves items to and





from storage media.






• Reading is the process of transferring items





from a storage medium into memory.







• Writing is the process of transferring items





from memory to a storage medium.

Storage Capacity















• Storage capacity is the amount of data a





storage device can hold.






• Storage capacity is measured in kilobytes





(KB), megabytes (MB), gigabytes (GB),





terabytes (TB), and petabytes (PB).







• The memory or storage capacity is





represented in units which based on bits




and bytes.

Storage Capacity















• Storage capacity is the amount of data a





storage device can hold.






• Storage capacity is measured in kilobytes





(KB), megabytes (MB), gigabytes (GB),





terabytes (TB), and petabytes (PB).







• The memory or storage capacity is





represented in units which based on bits




and bytes.

Relationship among storage capacities















10
• 1 KB = 1024 bytes (2 bytes)






20
• 1 MB = 1024 KB (2 bytes)





30
• 1 GB = 1024 MB (2 bytes)






40
• 1 TB = 1024 GB (2 bytes)






50
• 1 PT = 1024 TB (2 bytes)

Relationship among storage capacities















10
• 1 KB = 1024 bytes (2 bytes)






20
• 1 MB = 1024 KB (2 bytes)





30
• 1 GB = 1024 MB (2 bytes)






40
• 1 TB = 1024 GB (2 bytes)






50
• 1 PT = 1024 TB (2 bytes)

Conversion between units

Conversion between units

Example 1 : Convert 8 GB to KB















• GB  MB  KB







8 GB







= 8 x 1024 x 1024







= 8,388,608 KB
















* Bigger to smaller unit -----> multiply

Example 1 : Convert 8 GB to KB















• GB  MB  KB







8 GB







= 8 x 1024 x 1024







= 8,388,608 KB
















* Bigger to smaller unit -----> multiply

Example 2 : Convert 1200MB to GB















• MB  GB







1200 MB







= 1200/1024







= 1.17 GB
















* Smaller to bigger unit -----> divide

Example 2 : Convert 1200MB to GB















• MB  GB







1200 MB







= 1200/1024







= 1.17 GB
















* Smaller to bigger unit -----> divide

Learning Outcomes :















• At the end of this lesson, students should be





able to:






Identify types of storage media

Learning Outcomes :















• At the end of this lesson, students should be





able to:






Identify types of storage media

2.5.2 Storage Media














• A storage medium, also called secondary storage,





is the physical material on which a computer





keeps data, information, programs and




application.





• Example of storage media include hard discs,





solid state drive, memory cards, network





attached storage devices, magnetic stripe card,





smart cards, RFID tags and NFC tags.




• Another storage option is cloud storage, which





keeps information on servers on the internet.

2.5.2 Storage Media














• A storage medium, also called secondary storage,





is the physical material on which a computer





keeps data, information, programs and




application.





• Example of storage media include hard discs,





solid state drive, memory cards, network





attached storage devices, magnetic stripe card,





smart cards, RFID tags and NFC tags.




• Another storage option is cloud storage, which





keeps information on servers on the internet.

Five (5) Types of Storage Media















1. Solid State Drives







2. Hard Disks






3. USB Flash Drives







4. Memory Cards







5. Optical Discs

Five (5) Types of Storage Media















1. Solid State Drives







2. Hard Disks






3. USB Flash Drives







4. Memory Cards







5. Optical Discs

Solid State Drives















• A solid state drive (SSD) is a flash memory





storage device that contains its own





processor to manage its storage.









• Flash memory chips are a




type of solid state media





and contain no moving





parts.

Solid State Drives















• A solid state drive (SSD) is a flash memory





storage device that contains its own





processor to manage its storage.









• Flash memory chips are a




type of solid state media





and contain no moving





parts.

Advantages












SSDs have several advantages over magnetic hard




disks.






 Faster access time (can be more than 100 times




faster)






 Faster transfer rates






 Quieter operation






 More durable






 Lighter weight






 Less heat generation.






 Longer life

Advantages












SSDs have several advantages over magnetic hard




disks.






 Faster access time (can be more than 100 times




faster)






 Faster transfer rates






 Quieter operation






 More durable






 Lighter weight






 Less heat generation.






 Longer life

Disadvantages















The disadvantages of SSDs are that they





typically






have lower storage capacity than hard




disc.






Data recovery in the event of failure can





be more difficult than for traditional hard





discs.





The cost is higher per gigabyte.

Disadvantages















The disadvantages of SSDs are that they





typically






have lower storage capacity than hard




disc.






Data recovery in the event of failure can





be more difficult than for traditional hard





discs.





The cost is higher per gigabyte.

Hard Disk













• A hard disk, also called a hard disk drive





(HDD) is a storage device that contains one




or more inflexible, circular platters that use





magnetic particles to store data, instructions,





and information.








• Current personal computer hard




disks have storage capacities up




to 20 TB.

Hard Disk













• A hard disk, also called a hard disk drive





(HDD) is a storage device that contains one




or more inflexible, circular platters that use





magnetic particles to store data, instructions,





and information.








• Current personal computer hard




disks have storage capacities up




to 20 TB.

Advantages















HDDs are more affordable compared to other






data storage devices.







HDDs have a larger storage base capacity.







HDDs have a non-volatile memory.







HDDs have a longer lifespan.







Easily replaced and upgraded.