Video Cards:
The video card processes binary language so that you can see it on a monitor. It's incharge of determining the color and postion in each pixel on the screen so that you see pictures on the screen. Video cards usually connect to the computer using AGP ports. Newer graphics cards can connect using PCI express ports. Video cards have connectors on them like DVI (Digital Video Interface), TV output and VGA (Video Graphics Array). The DVI is used to connect to a monitor. The TV output can display the monitor's information on a TV and the VGA is an older version of DVI. The GPU (Graphics Processing Unit) on the graphics card is what is responsible for making the decisions for processing the video card's graphical input and output data. It's placed under a fan so it doesn't overheat.
Sound Cards:
The sound card processes the computer's sound data. Sound waves are analog which are waves that travel through matter. Sound cards convert sound waves into digital information which the computer can understand. Sound cards use four components to translate analog and digital information:
An analog-to-digital converter (ADC)
A digital-to-analog converter (DAC)
An ISA or PCI interface to connect the card to the motherboard.
Input and output connections
Some sound cards use a coder/decoder chip called a CODEC which performs both ADCs and DACs. The ADC translates the analog waves of your voice into digital data. It digitizes the sound by taking precise measurements of the wave at frequent intervals. The number of measurements per second is called the sampling rate and is measured in kHz. The faster a card's sampling rate, the more accurate its reconstructed wave is. The DAC performs the same basic steps in reverse. A sound card can use its own memory to provide faster data processing.
Friday, September 29, 2006
Thursday, September 28, 2006
CD's and Hard Disks
CD:
A CD is optical media because it uses light. The CD has three layers, the front, the back which is a metallic surface and another layer of plastic pressed onto it. CD's hold approximately 700 mb. When the laser reads the CD, it sees if the light bounces back or not. If it bounces back then it's a zero. If not it's a one. This is how CD's store data in binary language. To connect with computers the CD uses a Integrated Drive Electronics (IDE) interface.
Hard Disk:
A hard disk is manetic media because it uses magnets. Hard disks are a metallic platter which has billions of magnetic receptors on it. Since magnets have two poles, north and south they can be used to represent binary language zeroes and ones. The actuator arm is a metal arm that reads the disk as it spins.
A CD is optical media because it uses light. The CD has three layers, the front, the back which is a metallic surface and another layer of plastic pressed onto it. CD's hold approximately 700 mb. When the laser reads the CD, it sees if the light bounces back or not. If it bounces back then it's a zero. If not it's a one. This is how CD's store data in binary language. To connect with computers the CD uses a Integrated Drive Electronics (IDE) interface.
Hard Disk:
A hard disk is manetic media because it uses magnets. Hard disks are a metallic platter which has billions of magnetic receptors on it. Since magnets have two poles, north and south they can be used to represent binary language zeroes and ones. The actuator arm is a metal arm that reads the disk as it spins.
Monday, September 25, 2006
Hard Drives and Memory
Today, in class we learnt about hard drives and memory. So the mother board is the heart of the computer. Everything in the computer is connected to it. The computer is run by a small silicon chip called a processor. The two leading companies that manufactur processors are Intel and AMD. The speed of a processor is measured in hertz, which means how many cycles of electricity it can run through.
The hard drive is where the computer stores all it's information. This is where the computer stores the information when the power is off.
RAM (Random Access Memory) is memory that is used for storing information that is in use by current programs. When you turn the computer off, the RAM is cleared. The more RAM memory, the more programs you can run at the same time without slowing your computer down.
The bios of a computer is ROM (Read-Only Memory) memory. The bios tells the computer what to run when you start the computer up. Actions like check the connections to the keyboard, sound card, video card and etc. After this it tells the computer to run Windows or whatever the operating system in use is. The battery on the Motherboard powers the bios. In, ROM memory you can read from it, but you can't write to it.
Flash memory is a type of memory which is a storage medium. It is used in memory cards for Cameras and other devices.
The hard drive is where the computer stores all it's information. This is where the computer stores the information when the power is off.
RAM (Random Access Memory) is memory that is used for storing information that is in use by current programs. When you turn the computer off, the RAM is cleared. The more RAM memory, the more programs you can run at the same time without slowing your computer down.
The bios of a computer is ROM (Read-Only Memory) memory. The bios tells the computer what to run when you start the computer up. Actions like check the connections to the keyboard, sound card, video card and etc. After this it tells the computer to run Windows or whatever the operating system in use is. The battery on the Motherboard powers the bios. In, ROM memory you can read from it, but you can't write to it.
Flash memory is a type of memory which is a storage medium. It is used in memory cards for Cameras and other devices.
Friday, September 22, 2006
Binary Code
We learnt about binary code today. The first computers are thousands of years old. The abacus was one of the first computers. The definition for a computer is anything that we send we send information to, it processes the information and then gives us information back. The computers we use today are electrical computers. They only understand electrical signals. Computers use binary code which is a base two system. In binary, there are only zeroes and ones. In our number system, we use base ten. So we go up to nine and move one column over. In base two you can only go up to one and then you have to mover to the next place value. Every one or zero is called a bit. Computers string bits together into groups of 8 called bytes. 1000 bytes make up a kila byte. 1000 kila bytes make 1 mega byte. 1000 mega bytes make up a giga byte. Finally, 1000 giga bytes make up a terra byte.
Monday, September 11, 2006
Comptuer Keyboards
Today in class we got a project on The Keyboard. These are some notes on the computer keyboard:
Keyboard Introduction:
The original design for keyboards came from mechanical typewriters. A keyboard’s main function is to act as an input device. Keyboards use switches and circuits to translate keystrokes into signals that the computer can understand. Keyboards can be used to type a document, use keystroke shortcuts, access menus and play games. Most keyboards have between 80 and 110 keys. Although keyboards can have different keys depending on the manufacturer, most keyboards have keys that are the same size and shape.
Keyboard Arrangements:
The layout for most keyboards is known as QWERTY, the same original pattern used for typewriters. The reason it's layed out this way is because when the first typewriters were invented they put the most common letters in hard to reach places so that the metal arms wouldn't keep crashing into each other. Since then, it's been a standard for keyboards. There are some other arrangements such as the Dvorak arrangement. Some people argue that the Dvorak increases typing speed and effiency. However, it's almost the same speed for all keyboard arrangements.
How It Works:
A keyboard has its own processor and a circuitry to carry information to and from the processor. The key matrix is a grid of circuits underneath the keys. Each circuit is broken at a point below the key so when you press a key it completes a circuit and allows some current to flow through. When the processor finds a closed circuit, it matches it with a character map found in its read-only (ROM) memory. This character map tells the processor the position of each key and what combinations of keystorkes represent. Then it sends the information to the computer. Keyboards connect to the computer using a PS/2 or USB connection. The computer’s keyboard controller processes the information and sends it to the operating system. The operating system checks if it is a system level command. If it's not then the information is seen as content (i.e. typing a document) and then sends it to the current application. If the current application does not accept the data then the computer ingores the information. This whole process happens almost instantly.
Ergonomic Keyboards:
Some people say that repeated use of the keyboard can cause injuries like carpal tunnel syndrome. To address this issure ergonomic keyboards were invented to keep the hands in a more "natural" postion when typing. However people still debate on whether or not this pevents injury.
Keyboard Introduction:
The original design for keyboards came from mechanical typewriters. A keyboard’s main function is to act as an input device. Keyboards use switches and circuits to translate keystrokes into signals that the computer can understand. Keyboards can be used to type a document, use keystroke shortcuts, access menus and play games. Most keyboards have between 80 and 110 keys. Although keyboards can have different keys depending on the manufacturer, most keyboards have keys that are the same size and shape.
Keyboard Arrangements:
The layout for most keyboards is known as QWERTY, the same original pattern used for typewriters. The reason it's layed out this way is because when the first typewriters were invented they put the most common letters in hard to reach places so that the metal arms wouldn't keep crashing into each other. Since then, it's been a standard for keyboards. There are some other arrangements such as the Dvorak arrangement. Some people argue that the Dvorak increases typing speed and effiency. However, it's almost the same speed for all keyboard arrangements.
How It Works:
A keyboard has its own processor and a circuitry to carry information to and from the processor. The key matrix is a grid of circuits underneath the keys. Each circuit is broken at a point below the key so when you press a key it completes a circuit and allows some current to flow through. When the processor finds a closed circuit, it matches it with a character map found in its read-only (ROM) memory. This character map tells the processor the position of each key and what combinations of keystorkes represent. Then it sends the information to the computer. Keyboards connect to the computer using a PS/2 or USB connection. The computer’s keyboard controller processes the information and sends it to the operating system. The operating system checks if it is a system level command. If it's not then the information is seen as content (i.e. typing a document) and then sends it to the current application. If the current application does not accept the data then the computer ingores the information. This whole process happens almost instantly.
Ergonomic Keyboards:
Some people say that repeated use of the keyboard can cause injuries like carpal tunnel syndrome. To address this issure ergonomic keyboards were invented to keep the hands in a more "natural" postion when typing. However people still debate on whether or not this pevents injury.
Friday, September 08, 2006
In class today, we learnt about email. There are two types of email. The first is POP3. This is email that is stored on a server and then downloaded to your computer. An example of this is Microsoft Outlook. The other type is web-based email. This does not require any program on your computer and is done through the web. Some examples are Hotmail, Yahoo and Gmail.
When you send an email, there are two more boxes beneath it saying Cc and Bcc. Cc stands for Carbon Copy. It sends a copy of the email to some else. Bcc stands for Blind Carbon Copy. It sends a copy to another person without showing it to the original sender.
We also learnt about spam mail which is junk mail. Most spam filters can filter out spam and send it to your junk email folder. That was pretty much today's lesson.
When you send an email, there are two more boxes beneath it saying Cc and Bcc. Cc stands for Carbon Copy. It sends a copy of the email to some else. Bcc stands for Blind Carbon Copy. It sends a copy to another person without showing it to the original sender.
We also learnt about spam mail which is junk mail. Most spam filters can filter out spam and send it to your junk email folder. That was pretty much today's lesson.
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