1.1.2 Computing Basics.txt

Computing Basics 0:00-0:18 As a PC technician, it’s very important that you understand the basic components that make up a computer. Computers are made up of constituent parts that work together to create a functional computer. These parts can be divided into two main categories, hardware and softwa...

Computing Basics 0:00-0:18 As a PC technician, it’s very important that you understand the basic components that make up a computer. Computers are made up of constituent parts that work together to create a functional computer. These parts can be divided into two main categories, hardware and software. Hardware vs. Software 0:19-1:11 Hardware refers to the physical components that are installed inside or connected to a computer system. By itself hardware can’t do much. It needs instructions to tell it what to do. These instructions come from the software. Software refers to instructions, or data, that are stored electronically either on a hard drive or on a special chip. Hardware without software is like a car without a driver. A car has the potential to drive but it needs a driver in order to see the potential. Without a driver the car can’t do anything. The same is true with hardware. Hardware has a lot of potential but it needs software to instruct it to use that potential. The main thing to remember is that hardware is the potential and software is the instructions. In this lesson, we’re going to take a look at the different types of hardware devices that compose a computer system. The first type of hardware we’ll look at is input devices. Input Devices 1:12-3:35 An input device is any piece of hardware that takes information from outside the computer and transfers it inside where the computer hardware can use it. The most common input device is a keyboard. A keyboard takes user inputs and sends them as electrical signals to the internal computer hardware where they are processed. When a key on a keyboard is pressed, an internal chip called the scanning chip, identifies which key was pressed and then sends the appropriate code to the computer. The code could generate a letter in a Word document, a number in a spreadsheet or a command for the computer. Another very common input device is a mouse. A mouse also uses inputs and sends them as electrical signals to the computer, but it does so a bit differently. A mouse tracks movements as x,y-coordinates. The coordinates sent to the computer cause the mouse pointer to move in the same manner. The way a mouse tracks movement depends on the type of mouse being used. The most common type is an optical mouse. An optical mouse uses a light source and a sensor to track movement. A less-common type is a mechanical mouse. A mechanical mouse uses a trackball that the user rolls to move the mouse pointer. The trackball has sensors to identify which direction the ball rolls. Chances are you are very familiar with using these two input devices. Another input device you are also probably familiar with is a touchscreen. If you’ve used a smartphone, tablet, or a computer kiosk, you’ve used a touchscreen. Instead of key presses or movement tracking, a touchscreen takes user input from screen taps. There are two main touchscreen technologies, resistive and capacitive. Resistive touchscreens use two flexible layers that are separated by a gap. Inside the gap is an electrical current. When the screen is tapped, the outer layer depresses and contacts the inner layer creating an electrical signal that identifies x,y-coordinates. The coordinates are then sent to the computer. Capacitive touchscreens use a screen that is coated with a conductive material. An electrical current is then run through the material. When something conductive touches the screen, such as a finger, small sensors identify the touch and generate x,y-coordinates. Capacitive touchscreens are used on smartphones, tablets, and some laptops. Because they require a conductive touch, a non-conductive object, such as gloves or plastic, can’t be used to tap the screen. Resistive touchscreens are typically used for airport or library kiosks. Because they require only pressure, any rigid object can be used to tap the screen. Processing 3:36-4:39 Signals generated by input devices need to be analyzed. This is done using a processing device. A processing device is any hardware component that can analyze and interpret input. The most common processing device is the central processing unit (CPU). The CPU is like the brains of the computer. It processes data according to a set of instructions or software. For example, when the “A” key on the keyboard is pressed, the keystroke information is sent to the CPU where it is processed based on the software that is currently running. If you were running word processing software, the letter “A” would appear at the cursor location in the open document. If you were running a game, it might make the character move to the left. Another processing device is random-access memory (RAM). RAM is used to store processed information so it can be quickly accessed at a later time. For example, if a CPU were to process data from a spreadsheet but still needed to access that data at a later time, the data could be stored in RAM for quick access. RAM is also used to store running software. Storage 4:40-7:27 RAM can also be considered a hardware component called a storage device. A storage device is any hardware component that stores data, either temporarily or permanently. When data is stored temporarily, short-term storage such as RAM is used. It’s important to know that RAM is considered volatile memory, that means it’s not persistent. For example, if the computer is turned off or loses power, all the data that was stored in RAM is lost. It’s gone forever. You might wonder why you would use a storage device that is erased every time it loses power. You use RAM because it’s extremely fast. Information can be accessed from RAM faster than any other type of storage hardware. But sometimes you need to store information permanently. This is done using long-term storage. Remember, short-term storage is lost every time the computer is shutdown. Long-term storage is considered non-volatile memory. In other words, it’s persistent. This means that even when the computer is turned off, the data stored on the hardware will still be there when you turn the computer back on. There are a variety of long-term storage media. The most common one is a hard-disk drive. Hard-disk drives store information on rotating disks called platters. Another common medium is a solid-state drive (SSD). SSDs use memory chips that are a lot like RAM. However, the information stored on these chips is persistent. Hard disk drives and SSDs can store a lot of data and access it relatively fast but not nearly as fast as RAM. This is why you use both hard drives and RAM to store data. You also have optical-storage media such as CDs, DVDs, and Blue-ray disks (BDs or BRDs). Optical-storage media can be read-only or writable. If a disk is read-only, the information it contains is fixed and can’t be modified or erased. It can only be viewed. An example, a read-only disk is a software CD-ROM or DVD-ROM. The ROM at the end stands for read-only memory. Writable disks on the other hand can be modified. Disks that are writable have an R or an RW. For CD-R, DVD-RW, and BD-R, the R stands for recordable. Unlike their ROM counterparts, these types of disks can have information saved to them. There are two more long-term storage devices to talk about. The first is a flash drive. Flash drives are small, portable devices that use memory chips to store information. These memory chips are very similar to RAM chips. However, the information is persistent. The second device is a secure digital card (SD card). You might be familiar with these. SD cards are used in smartphones, tablets, and digital cameras to store information. They use non-volatile memory. Output Devices 7:28-8:26 All the information that is being input, processed, and stored on a computer is useless unless there is a way to access and view it. This is done by using an output device. An output device is any device that receives data from a computer and outputs it in a physical medium. The most common output device is a monitor. Monitors visually depict the data that is processed by the CPU, whether it’s numbers being calculated in a spreadsheet or aliens running around in a video game. A monitor displays a visual representation of the information being processed. Another very common output device is a printer. Printers take information that is processed by the CPU and prints it on a piece of paper. Both monitors and printers output visual information. There are more than just visual output devices. Another output device is a sound card. Sound cards take digital information and output it as audible signals. Almost all computers have some sort of audio output device. Networking Devices 8:27-9:17 All the devices talked about so far communicate information within a single computer. However there are other hardware components that allow information to be communicated between multiple computers. These are known as networking devices. Networking devices are used to create networks. A network is a group of two or more computers that are connected together. To create a network, a special interface is installed in a computer. A connecting medium is used to connect the computers together. This connecting medium can be a physical wire or even radio signals. With this connection established, two or more computers can take information being processed by the CPU and send it to each other. This makes networking hardware both input and output devices. When one computer is outputting information, the other is inputting information and vice versa. Modular Design 9:18-10:20 There’s one more aspect of computer hardware, it’s called modular design. Modular design is a design approach that standardizes hardware interfaces in order to create modular hardware components. This means that when a monitor that works on one computer is connected to a different computer and still works, the monitor is modular. While this may seem commonplace today, it wasn’t always the case. In the early days of computers, hardware components were proprietary. This meant that if a piece of hardware in your computer died you couldn’t just go to the store and buy a replacement. You had to ship the component, sometimes the entire computer, back to the manufacturer in order to get it fixed or replaced. Luckily this isn’t the case anymore. Because computer hardware is modular and standardized, you aren’t limited to a specific manufacturer or brand when buying and replacing hardware components. For example, if you want to install another hard-disk drive in your computer, you don’t have to buy it from the same company that built your computer. Any brand of hard-disk drive will work. Summary 10:21-10:43 Those are the basic hardware components of a computer system. Remember, there are two main computer component categories. Hardware and software. Hardware’s the potential. Software is the instructions. In this lesson, we looked at the various hardware components that comprise a computer based on the five main functions they perform, input, processing, storage, output, and networking.