When last I wrote on this topic I covered the processor, the motherboard, the RAM, the hard drive, and the power supply. For the most part I'll probably never really talk about the power supply or motherboard again because there's just not that much the average user needs to know. However, the topics I'm going to cover in this post will likely be discussed in greater detail in a later article, so I'm going to keep these descriptions a little shorter.
The items I discussed in Part 1 were the parts of the computer that you really don't interact with directly. Today I'll be discussing the items that involve getting data into, or out of, the computer. I like to think of these as the "higher level" functions. Just like in a human, the brain does the processing of visual stimuli, but it's the eyes that do the actual collection of that stimuli.
Today's topics are video cards, sound cards, network cards, modems, USB ports, removable and optical drives, and input devices. USB ports are virtually always built into the motherboard, but video, sound, and network cards are sometimes part of the basic motherboard, and other times they are separate items. I'll explain further in a moment.
The reason that we use the term "cards" is that in earlier computers the functions were on a separate circuit board that plugged into the motherboard like a card into a slot. We often still refer to them as cards even if they are built directly into the motherboard. The most common reasons for this functionality to be built into motherboards rather than into separate cards are size and cost. Most laptops have video and sound cards built into the motherboard to keep them compact. Most low end desktop computers have the functionality built into the motherboard to save on cost. Most high end desktops still have separate cards because it makes them easier to upgrade, easily repairable, and often offers enhanced performance, especially in terms of video.
The video card is an extremely important part of a computer regardless of whether it is built into the motherboard or a separate card. It is this card that converts the data to a video signal that is displayed on the screen. The video card has an output connector to which the monitor cable is attached. Older video cards used a 15 pin connector known as a VGA cable. Most more recent computers use video cards with HDMI outputs, just like the ones used for high definition televisions. In fact, most newer HD televisions could be used as monitors for computers (though there are reasons they are not used that way frequently). Processing video signals is a highly data intensive activity. The image must be drawn on the screen 50, 60 or even more times per second. It is especially data intensive for high resolution video games. That's why serious video game players use very high end expensive video cards. To make the video of such a game move smoothly requires a very requires a lot of memory and processing. So high end video cards take that functionality away from the main computer processor and use dedicated graphics processors to handle the video tasks. A high end video card can cost well over $1,000. Fortunately most tasks aren't that demanding, so the average basic video card runs only $60 or $70.
- Video Card
The sound card handles the processing of both incoming and outgoing sounds. At one time sound cards used small jacks, like the audio jacks on an iPod, for both speaker output and microphone input. While most computers still have a sound card with these jacks, improvements in electronic processing and circuitry have made it possible to handle these tasks through USB ports. There are still advantages to the old fashioned system though, which I will explain in more detail in a separate post.
- Sound Card
USB ports, as long as we're talking about them, are the replacement for the old methods of input and output on computers. At one time serial and parallel ports were used for this purpose. The problem with them was that they were very slow and there was a technical limitation to the number of devices that could be used simultaneously, and that was a fairly small number. USB is a much faster way of moving data. The number of USB devices that can be used simultaneously is much larger. There is a limit, but it is so high that it is unlikely to be a problem for most people. Another advantage of USB is that in addition to carrying data to printers, external hard drives, keyboards, mice, etc. It also provides power. This means that devices can draw power from the USB port eliminating the need for external power. The amount of power supplied is fine for things like hard drives, but not enough for printers or scanners.
The network card is the component that can permit the computer to connect to a network of computers. It is essential to be able to connect to a network if you wish to use the internet. By far the most common network type today is wireless, also known as WiFi. In this case the card is basically a little radio that communicates with the radio inside another computer or a router. Prior to wireless, and still very common in business environments and hotels, is ethernet. Ethernet is a wired network technology. Ethernet uses cables and jacks that look like phone jacks, only they are slightly larger. Ethernet is faster than WiFi, more reliable, and more secure. But wireless continues to improve.
- Ethernet Card
A modem is the device that at one point was equated with that screeching sound when people would dial up an internet connection. At one time virtually all computers came with modems, but the prevelance of other network types has made this type of modem mostly obsolete. Now if a computer has a modem it is most likely a cellular modem that permits the computer to connect directly to a cell phone provider's network. These aren't nearly as common because they require a service plan with the cell phone company, but for people requiring reliable mobile internet they are very popular.
Optical drives are another item that is starting to become obsolete. The first optical drives were CD Rom drives that could hold data or music. Then DVD drives became popular. They could hold significantly more data than CDs and also allowed you to watch movies on the computer. Then came Blu Ray drives. Again they could hold significantly more data and could play high definition movies. With the advent of streaming movies (a la Netflix), and digital music sales (think iTunes store) have made optical drives less common. Though DVDs are still the most common way to distribute software, fast internet has made downloading software much more common. And in fact some software is now distributed on removable USB drives instead of DVDs, further reducing the need for optical drives.
Removable drives come in a couple of types. External hard drives, just like the ones inside on the computer only connected via USB, are common, cheap, and can store immense amounts of data. For more compact storage USB "Thumb Drives" are small devices that can plug into the USB port of a computer and can be used just like any other hard drive. These too are inexpensive, can store far more than a DVD, and can be tiny. Some are as small as a thumbnail.
- USB Thumb Drive
Finally we come to input devices. By far the most common input devices are keyboards and mice. Both are available in tons of different styles, sizes, and configurations. But they achieve the same basic purposes. To input text, to manipulate on screen objects, and in some cases to draw on screen. There are other devices for input, but these are specialty products used most often by graphic artists, musicians, film editors, and the disabled.
I know this was a long article, and I'm going to keep most of the rest much shorter, but I wanted to get the basics out of the way so that I can start to delve into more interesting subjects. As always don't hesitate to contact me if you have questions or want more information on a specific subject.
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