Science talk weekly
Monitors have come a long way over the years. Today we have a wide range of sleek looking flat screens, in a variation of sizes. These typically are Liquid Crystal Display monitors, better known as LCD monitors. Before I talk about the specifics of LCD monitors, a brief history of the older monitors that we once used. They were the large, heavy, box-like looking monitors called Cathode Ray Tube (CRT) monitors. These had physical vacuum-sealed tubes inside the box, that were filled with special gases. When electricity was passes through the gas, it would create different light colours that could be mixed to form the images you would see on the screen. When looking to buy LCD monitors, once again, as with all PC components, you can find a massive variation in the costs, depending on what model you want to purchase. Size is usually one main factor affecting price, where the larger the screen equates to greater cost. The other two main factors that will affect cost are screen refresh rates, and screen resolution. In simple terms, think of refresh rates as how many times per second the screen can update the image you see. The higher the refresh rate, the more times per second that the image can be updated. As a result, you should see a clearer image if the image is updated more frequently. Have you ever noticed if you are watching something move really fast on the screen it can start to blur? This blurring should be reduced with higher refresh rates. In computer monitors, this can be particularly important if you are playing games that have rapid, twitchy movements, particularly first person shooter (FPS) games like Call of Duty, or racing games. The units used to describe refresh rates are Hertz, abbreviated to Hz. Screen resolution is related to how many pixels are in the monitor. A pixel is like a small square that you can put a colour in. Each of the pixels on the screen act like a mosaic, where together they can be used to make a larger image. If you compared two screens of the same area with different amounts of pixels, the screen with more pixels should effectively have a better resolution, and a sharper image. Even in televisions, pixel counts are advertised, even though you may not realise this! A 1080p television will have a width of 1920 pixels and a height of 1080 pixels. The p doesn’t stand for pixels however, it relates to another factor which I won’t explain, but if you are curious, you can read more about it here: http://www.pcmag.com/article2/0,2817,2413044,00.asp
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When one decides to build or buy a PC, the aesthetics are a factor that people consider. PC cases aren’t just about looks, design considerations also take into account computer performance. As mentioned in previous component articles, heating and cooling challenges are ever present in PC design. Cases can come in various shapes and sizes to optimize cooling, as well as being made from various materials to also assist in cooling. Once again, price seems to dictate design, where the highest performance cases, in terms of cooling potential, and aesthetic looks will be at the top end of cost. Ventilation is important for a case. Air flow is typically generated through positioned fans that will draw cool air from the outside, have it flow over the main motherboard heat sources, and push out the warm air. Some cases are designed to accommodate fully contained liquid cooling systems. These consist of a water pump, pipes, and a heat exchanger that can take the heat away from the heat sources (ie. CPU, GPU etc) instead of using air. Water can conduct heat better than air, however, the challenge of separating water from electricity is the main concern for water cooled systems. Have a look at your current case. Is it purely for function, or does it include aesthetics? Can you see through clear panels and see blinking coloured lights? Or is it just plain? Are there many vents with fans attached, or just one? Even the size and weight is taken into account. Big heavy cases may be cumbersome to transport, but may include greater metal surfaces that help heat transfer away from the CPU. The power supply is the source of electricity for your computer. The external part of the power supply will usually have a kettle cord socket, an on/off switch, and the back of a fan, which will be part of the power supply’s cooling system. On the inside of a PC, the power supply will usually have a number of smaller plugs that can be connected to hardware components within the computer. These include, the motherboard, any physical disk drives such as the HDD or DVD, and even other hardware components like a high powered graphics card. Power supplies will convert the wall power to the appropriate voltage required to run the computer. The will also vary in maximum amounts of electricity they can supply to the computer and its components. Larger power supplies will usually cost more, but this is one circumstance where having the biggest and best will not really benefit you PC much at all.
The hard drive, also known as the hard disk drive, is the physical component that all of the information is stored on within your computer. It can be abbreviated to HDD, and you may have seen this before. Over time as technology has improved, the amount of information the HDD can hold, or its capacity, has increased. The capacity of a hard drive is one of the main features that identifies this piece of hardware. The unit of measurement that is used to indicate a hard drive capacity is bytes. When reaching a certain amount of bytes, prefixes are used to indicate larger amounts. For example, 1000 bytes = 1 kilobyte. 1000 kilobytes = 1 megabyte. These units, as with all units, have abbreviations that are commonly used (think centimeters is cm and grams is g). Bytes are denoted by a B, kilobytes are kB, megabytes are MB, gigabytes are GB, terabytes are TB and so forth. Off the top of my head, our first home PC (back in the late 80s) had a hard disk drive capacity of about 40 megabytes, which for its time was great! These days, just one high resolution photo with my digital camera is about 40MB. If you were to pop into a computer shop to buy a new HDD, you probably couldn’t get anything smaller than 500GB. If you look at the calculation, 1GB = 1000MB, so 500GB = 500 000MB, which means what I could store on one hard drive today would have needed 12 500 computers that I had as a child. The type of hard drive I have been referring to are comprised of a series of disks (that look like DVD’s, but aren’t) which are called platters. The stack of platters are where the information is stored, and the information is stored as a magnetic signal. The platters are on a spindle, so they can spin around, and a needle will move to the correct location to access whatever information you have asked the computer to access. It works similar to how a needle would shift to different parts of a record to play different songs. There are another type of HDD called a solid state drive (SSD). They do not use the same technology as a traditional drive, and being more modern in their design, have many benefits over the older design. For a start, they don’t have any moving parts, which removes a factor of error that can occur with mechanical parts. Data retrieval is also much faster compared to a traditional HDD, and this is the main reason why you would want to choose an SSD over a HDD. As always though, with greater speed and power in computer comes a greater money cost. To compare the cost of a HDD to a SSD, I have taken prices from today’s (8 Oct 15) MSY price list (http://cdn.msy.com.au/Parts/PARTS.pdf), the 500GB Seagate Barracuda HDD is $63 compared to the 480GB OCZ Arc 100 is $248. You could therefore say, SSDs are approximately 4 times the cost of HDDs. Depending on what you need your PC to do, deciding whether to spend the extra money is one of many financial considerations you need to take into account when buying your PC. As with all of the hardware previously mentioned, the HDD (or SSD) plugs directly into the motherboard, and will usually require plugging into the power source, which will be next week’s hardware item in the spotlight.
The Graphics Processing Unit (GPU) is the fourth component in a series about computer hardware I am going to be talking about. They are typically referred to as a graphics card, because they look a little bit like a card that plugs into your motherboard. Graphics cards have come through many iterations over the past years, and are quite complex pieces of hardware. They are very similar to how your computer works. Being equipped with the information of the previous weeks, you will be able to appreciate how a GPU works. The card itself is made up of a board that has intricate circuitry in it. On the board are the components that do all the graphical processing for a computer. It is like a mini-motherboard, in that on a GPU there will be a processing unit(CPU), memory chips (RAM), and a heatsink for the processor. It also will have some ports and connections that will be visible from the outside of the PC, which provide the connections that allow you to plug your PC into a monitor. Part of the card will have the connections that allow you to plug it into its specific spot on the motherboard. There are different types of GPUs, and motherboards can be setup to take the different types. Some GPUs are designed to be able to run in parallel. The units can be bridged, or joined together, to get even more processing power out of your computer. The GPU is a specialized type of computer that does all of the calculations, drawing and rendering of graphics on your PC. When the computer accesses a program, the CPU will get all of the information and make it work. When there are graphics linked with the program, it then sends information to the GPU telling it to do the drawings. When you are playing a video game, first the GPU will draw a wire outline of the three dimensional object, then it will fill in all of the shapes with colour, and then do its final rendering and textures to complete the image. It doesn’t sound like too much, and you might be thinking, well the CPU could probably do it. Consider this, the GPU will do all of that 60 times per second, which can be quite an intensive job to do, especially if it is doing very rich and detailed fast moving images that one may encounter when gaming.
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How this beganWhat started out as a quick weekly Q&A in my school's paper newsletter has grown into an online multimedia science spot. Archives
October 2015
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