Introduction to Computer Information Systems/The System Unit
- 1 Data and Program Representation
- 2 The System Unit - The Motherboard and CPU
- 3 The System Unit - Memory, Buses, Ports
- 4 How the CPU Works
- 5 How the CPU Works
- 6 Improving the Performance of Your Computer
- 7 References
Data and Program Representation
Digital data and numerical data
Most computers are digital computers which use a specific language to communicate within itself in order to process information. If there are programs running in the background or a person is typing up a word document for example, the computer needs to be able to interpret the data that is being put into it by the human as well as communicate to working components within itself. This language that digital computers use is called binary code and is a very basic form of language composed of only two figures; 1 and 0. Whereas the English language is composed of 26 figures which we commonly call the alphabet, computers use a language composed of only two figures, hence its name Binary Code. Binary literally means two and refers to anything that consists of, involves, or indicates two.[] The language known as Binary Code operates on a system of 1's and 0's strung together in order to form "bits" of information needed for computing. "Bits" are the smallest unit of data that a binary computer can recognize and every action, memory, storage, or computation that is done through a computer is composed of them. From playing music through your speakers to cropping a photograph, to typing up a document and preparing an important presentation all the way down the line to browsing the internet or picking up on a wifi signal in your area, everything uses "bits" to complete the task needed. "Bits" string into larger lines of information the way letters string into words and then sentences. When "bits" are compounded in this way they are then referred to as "bytes".
"Bytes", which are made up of "bits", are commonly used when referring to the size of the information being provided. For example, a song that is downloaded may contain several kilobytes or perhaps even a few megabytes if it is a whole c.d. and not just a single track. Likewise, pictures and all other documents in general are stored on the computer based on their size or amount of bytes they contain. The amount of information that can be stored onto a computer is also shown or displayed in bytes as is the amount left on a computer after certain programs or documents have been stored. Since bytes can be extremely long, we have come up with prefixes that signify how large they are. These prefixes increase by three units of ten so that a Kilobyte represents 1,000 bytes, a Megabyte represents 1,000,000 bytes or one million bytes, a Gigabyte represents 1,0000,000,000 or one billion bytes, etc. Computers components have become so small that we can now store larger and larger amounts of data bytes in the same size computers resulting in the use of other larger prefixes such as Tera, Peta, Exa, Zetta, and Yotta. Below is a chart outlining the name of the prefix used and powers of ten they symbolize.[]
(from the SI page on Wikipedia):
Representing data in a way that can be understood by a digital computer is called Digital Representation and Binary Code is the most commonly used form of this. Binary Code is a Numerical Representation of data that uses only 1 and 0 to represent every possible number. Mathematics uses 10 symbols ranging from 1 TO 0 and include 2, 3, 4, 5, 6, 7, 8, and 9 as well. This Numerical Representation of data is called the decimal numbering system because it uses ten symbols. As shown on the chart, the prefix deci symbolizes ten. In both systems, the position of each digit determines to which power that number is raised. In the deci-mal system each digit is raised by ten so that the first column equals 1 (10^1) or ten raised to the zero power, the second column equals 10 (10^2) or ten raised to the first power, the third column equals 100 (10^3) or ten raised to the third power and so on. However, since Binary Code only operates with two symbols, each digit is a power of two instead of ten. In binary the first column equals 1 (2^0) or two raised to the zero power, the second column equals 2 (2^1) or two raised to the first power, the third column equals 4 (2^2) or two raised to the second power, the fourth column equals 8 (2^3) or two raised to the third power, and so forth. Because the Binary system takes advantage of so few symbols, the result is that more positions for digits are used to express the same number than in decimal form, leaving long lines of information for even the simplest expressions.
There are a few different coding systems,EBCDIC,ASCII and Unicode. EBCDIC (extended binary coded decimal interchange code) was created for use in mainframes, developed by IBM. The code uses a unique combination of 0’s and 1’s, 8-bits in length, which allows for 256 different combinations. ASCII ( American standard code for information interchange) was created for a more personal use. ASCII uses a 7 bit code, though there is an extended code which adds an extra bit, which nearly doubles the amount of unique characters the code can represent. however Unicode is a much longer string of code, between 8 and 32 bits. With over one million different possibilities, every language can be represented with this code, every mathematical symbol can be represented, every punctuation mark, and every symbol or sign from any culture.
The System Unit - The Motherboard and CPU
"The motherboard can be thought of as the "back bone" of the computer." This quote is from the article Motherboard. Inside the system unit contains the motherboard. The motherboard is the "glue" of the computer. It connects the CPU, memory, hard drive, optical drives, video card, and sound card together. The front of the motherboard are peripheral card slots. The slots contain different types of cards which are connected to the motherboard. The left side of the motherboard contain ports. The ports connect to the monitor, printer, keyboard, mouse, speakers, phone line, and network cables. 
The CPU is the abbreviation for the central processing unit. The computer needs the CPU in order to function correctly. It is known as the brains of the computer where the calculations occur. The microprocessor and the processor are two other names for the central processing unit. The Central processing unit attaches to a CPU socket on the motherboard. A common CPU is called the multi-core CPU. This specific type of CPU is efficient because it allows computers to work on more than one task at a time. Also, these multi core CPU's experience less over heating than the original CPU which causes much less problems to the computer. A typical CPU is two by two inches. 
The System Unit - Memory, Buses, Ports
Memory is used to store data and programs on a temporary or permanent basis, for computers and other digital electronic devices.  There are two main types of memory storage on a CPU.  These include the random access memory or RAM, and the read-only memory or ROM.
The RAM includes the cache memory and registers, which are volatile (meaning the materials are erased when the power to the computer is shut off). RAM stores important information for the main memory when the computer is currently running. This is different than storing a document. In order to save a file permanently to the computer, one needs to store this on a storage medium so it can be recovered at a later date. It will still be erased on the RAM, but will be saved elsewhere. The RAM is measured in bytes, and is typically reliant on how much the CPU can store and hold as well. An easy analogy to remember RAM is by thinking of a mailbox with different slots. There are many different areas where things can be placed.
Registers are temporary for data storage while processing. These can be accessed more quickly than other memory storage devices for the CPU. The larger the register, the faster the CPU performs. Inside the system unit, ROM is attached to the motherboard and is recovered when needed. These files cannot be erased, which is why it is called “read only.” The contents saved to the ROM are kept, regardless if it has power or not.  Lastly, the flash memory is also a nonvolatile memory chip that is used for storage on a computer. An interesting thing about flash memory is that it is starting to replace ROM. Many mobile phones now have flash memory that is embedded into the device. The reason for this is so the life of the product can be updated.
Ports are on the outside of the system unit and they are used to connect hardware devices. There are physical ports and virtual ports. A physical port is a physical connection to a computer where data is transferred. It is when something is physically plugged into the computer or some other device. Virtual ports allow software applications to share hardware resources without having to physical connect to each other or to interfere with one another. 
Almost all PCs come with a serial RS-232C port or a RS-4222 port and they are used for connecting a modem, mouse, or keyboard. They also have parallel ports that are used to connect printers. These are also considered USB ports because they are physical ports and which standardize communications between computers and peripheral. USB ports were created in the mid 1990’s; USB stands for Universal Serial Bus. There are also network ports used to connect a computer to a network. Ethernet was developed in the 1980s and it is a system for connecting a number of computer systems to form a local area network.
A serial port is used to connect modems to personal computers. The term “serial” signifies that data sent in one direction always travels over a single wire within the cable. The last main kind of port is the FireWire, which are used to connect FireWire devices to the computer via a FireWire connector. These are used with mostly digital video cameras and other multimedia devices. 
How the CPU Works
CPU Architecture and Components
As previously discussed on this page, the CPU is a complex piece of the computer made up of many parts. The way these parts all fit together inside the CPU is different in each processor but they contain mainly the same parts from device to device. The most abundant part in the CPU would be the transistor. There are millions of transistors within the CPU. Besides these transistors, there are several parts that make up the CPU. some of these inclue the arithmetic/logic unit (ALU) and floating point unit (FPU), the control unit, and the prefetch unit. The ALU is the part of the CPU that deals with the mathematics involving whole numbers and any functions done with those numbers. The FPU takes care of the mathematics with other numbers like fractions, or numbers with decimal places.  These two parts work hand in hand, using arithmetic and logical processes, to allow you to perform basically any function you perform on your computer. The control unit takes charge in controlling where and when information is transferred two and from the CPU. When information leaves the control unit, it is usually sent to the ALU/FPU where it can be converted into a process. The prefetch unit, as its name implies, fetches data before it is needed. It uses a sequence of processes to guess what information will be needed next, and have it readily available before the time it needed.
How the CPU Works
The Internal Clock
Every computer actually has two different clocks. One is the virtual or system clock that runs and is displayed whenever the computer is on and running. The other is a real-time clock or hardware clock that runs continuously, and is responsible for tracking the correct time and day. This device does not count time in days and hours for example. Instead it just runs a counter at times per second. As far as the century goes, it is the job of the BIOS to track this and save it in the non-volatile memory of the hardware clock. These two clocks run independently on each other. The system clock is physically a small quartz crystal that can be found on the motherboard. It also helps synchronize all computer functions by sending out signals- or cycles- on a regular basis to all parts. Hertz is the unit of measure used to count the number of cycles per second. For example, one megahertz is one million ticks of the system clock. This clock is very important to the CPU because the higher the CPU clock speed, the more instructions per second it could process. A machine cycle is a term often used when discussing the clock. It has four main parts- fetch, decode, execute, and store.
Typical CPU Components (continued)
To round up the simplified inventory of a CPU's guts, we have the decode unit, the registers and internal cache memory, and the bus interface unit. Of the remaining three sections of a CPU, the decode unit is easiest to understand because its job immediately follows the job of the prefetch unit. After the prefetch unit collects the data, the decode unit decodes the data into a language that is easier for the ALU/FPU to understand. It does that by consulting a ROM memory that exists inside the CPU, called microcode.  The registers are used during processing; they're groups of high-speed memory located within the CPU that can be accessed by the ALU and FPU, or for other assorted optimization purposes. While the registers provide the fastest speed of memory, their space is extremely limited. In the cases where the small register space isn't good enough, there are the caches to save the day. The cache is used by the CPU for memory which is being accessed repeatedly, speeding up the access time and having a slightly larger storage than the register.  The bus interface unit does exactly what it sounds like; it buses the data back and forth, connecting the core of the CPU to interact with other components. 
Improving the Performance of Your Computer
Add More Memory and Buy a Larger or Second Hard Drive
When it comes to technology, there is no question that newer is better. New systems are able to process faster, store more, and run more applications at once. However, it is obviously not within everybody’s means to just run out and purchase the newest and greatest technology the minute it hits the market. Technology is expensive, and therefore it is important to know your options. For example, if you have a computer that is a couple of years old, it is not unreasonable to assume that the hard drive and memory on the system are starting to slow down. However, what many people may not know is that buying a new computer is not the only solution to the problem. You can add memory to your old system simply by purchasing a new memory card and installing it into the computer hardware. By doing this, you are saving money and buying yourself a little bit more time with the computer.  Another way to speed up your computer with out having to invest in a whole new one is by buying a second hard drive. When the original hard drive starts to fill up, one can simply purchase either an internal or external hard drive for the computer and drastically increase the operating speed. 
Upgrade Your Internet Connection
If your system seems to be running poorly while using the internet, you may have to upgrade your internet connection. Upgrading your internet connection may become more costly but there is a significant change in the processor. Your first step would be to discuss any upgrades or check if the provider needs to be enhanced in any way. Then find a browser that is suitable for your connection type. With that being stated, you can change the settings on the router in order to speed up the internet connection. In order to prevent your internet connection becoming slower, it’s highly suggested to have a password in order to access the internet. In addition, every computer owner should provide maintenance to their computer in order to prevent viruses or any bugs the computer may receive but it also prevents an internet connection from being slow. In order to do so, keep up with upgrading and cleaning the computer because the more the computer is trying to maintain, the slower the internet connection may become. 
Upgrade Your Video Graphics Card
If you notice that your computer is working slowly but not while your internet is running, there may be a problem with your video graphics card. Similar to the process of upgrading your internet connection, there is also a process in checking your graphics processing unit. To approach this problem, you will need to check which graphics processing unit need to be upgrade. To do so, you need to go to start menu, search for ‘cmd’, right click and select ‘run as an administrator’, this will provide you with the command drop. After that, you will need to type in ‘sfc /scannow’ which will search and provide you a list of the components that may need upgrading. Within the list, find the graphics unit, select hardware you want to upgrade and then select yes to upgrade, which will then upgrade that certain hardware. Within the reading for chapter 2, upgrading your graphics card, it suggests to buy a new graphics card if you are searching for a more drastic change in the graphics processing unit. 
In order for computers to operate at their maximum efficiency, users must be aware of the importance of system maintenance because, over a period of time, one may notice a reduction in system performance. This can be attributed to a number of common factors that lead to the degradation in performance. One major reason is hard drive fragmentation. As more programs are installed onto the hard drive, the pieces of the files that are on those programs take longer to be located. The longer pieces of the program become shorter and fragmented, leading to a longer waiting period for the user as the computer searches for these scattered pieces. Related to this, although not nearly as detrimental to system performance as fragmentation, is the cluttering of pieces and references to uninstalled programs in the operating system. For Windows users, this occurs in the Registry. After the user uninstalls a program, there are references to that program left behind in the Registry that can possibly impact performance. However, performance is not necessarily the issue here. For example if the user is going to update the system by switching from an Nvidia graphics card to an AMD one, it might be a good idea to not only uninstall all drivers and related programs but also to clean the Registry of any references to the Nvidia drivers and software (in order to avoid possible conflicts when the AMD card is installed). This will ensure a “clean” install of both the hardware and software components. A free registry cleaner utility one can use is CCleaner.
Temporary files (e.g. from web browsers and installation programs) can take up valuable storage space if they are not removed after extended periods of times. Also, users should be aware of the programs they are installing and decide which specific programs are to run at startup. Too many programs can slow down the initial startup time of the computer because it must launch program after program. Only those programs that are necessary should be included, and to check for this, click Start (in the lower-left Windows icon) and enter the command msconfig in the search tab. This will open the System Configuration window. Programs that run at startup are listed under the Startup tab. Here the user can enable or disable programs, which can affect startup time.
Another important factor in determining system performance is the corruption of system files by malware. Viruses, worms, trojans, spyware, and other forms of malware can infect a system by various means, so it is important for the user to be aware and defensive. Anti-virus programs and other security software provide protection from malware, so it is recommended that a user has some sort of program installed and regularly scans the system for any traces. One free anti-virus program, among many, is AVG.
Lastly, dust can accumulate in and on heatsink fans (e.g. processor and graphics card), case fans, ports, power supplies, and motherboards. Every internal component can accumulate dust, and this can be a major issue for system integrity because dust acts as an insulator by trapping heat. Fans with too much dust do not operate efficiently because the fins do not spin quickly, which further exacerbates the heating problem. Not only that, but dust can also cause electrical shorting of the circuits, which can irreversibly damage components. To clean the computer, power off the system, which includes turning off the power supply. It should not be connected to any source. Then open the case and use a can of compressed air to blow out the dust wherever it may be. The goal is to rid the case of any remnants of dust. Following this and the other tips listed above will help ensure reliable performance and a longer lifespan for the computer.
Application Software: Programs that enable users to perform specific tasks on a computer, such as writing letters or playing games.
Computer: A programmable, electronic device that accepts data input, performs processing operations on that data, and outputs and stores the results.
Data: Raw, unorganized facts.
Information: Data that has been processed into a meaningful form.
Computer Network: A collection of computers and other hardware devices that are connected together to share hardware, software, and data, as well as to communicate electronically with one another.
Hardware: The physical parts of a computer system, such as the keyboard, monitor, printer, and so forth.
Internet Appliance: A specialized network computer designed primarily for Internet access and/or e-mail exchange.
Operating System: The main component of system software that enables a computer to operate, manage its activities and the resources under its control, run application programs, and interface with the user.
Output: The process of presenting the results of processing; can also refer to the results themselves.
Software: The instructions, also called computer programs, that are used to tell a computer what it should do.
Storage: The operation of saving data, programs, or output for future use.
URL: An Internet address (usually beginning with http://) that uniquely identifies a Web page.
Web browser: A program used to view Web pages.
World Wide Web (WWW): The collection of Web pages available through the Internet.
Web server: A computer that is continually connected to the Internet and hosts Web pages that are accessible through the Internet. 
1) What is the key element of the CPU?
2) What are the connectors located on the exterior of the system unit that are used to connect external hardware devices?
3) What is an electronic path over which data travels?
4) _________ are locations on the motherboard into which _________ can be inserted to connect those cards to the motherboard.
5) What is used to store the essential parts of the operating system while the computer is running?
6) The ______________________ consists of a variety of circuitry and components that are packaged together and connected directly to the motherboard
7) A _________ is a thin board containing computer chips and other electronic components.
8) The main circuit board inside the system unit is called the ___________ .
9) Before a computer can execute any program instruction, such as requesting input from the user, moving a file from one storage device to another, or opening a new window on the screen, it must convert the instruction into a binary code known as ____________.
10) In order to synchronize all of a computer's operations, a __________ is used. 
1) Transistor 2) Ports 3) Bus 4) Expansion slots, Expansion cards 5) RAM 6) Central Processing Unit 7) Circuit Board 8) Motherboard 9) Machine Language 10) System Clock