This course will cover three basic, but very important issues of the personal computer. Knowledge of these sections will improve the way you make any type of upgrade, whether it be software or hardware, and may even allow you to configure your computer to use its resources to their full potential allowing for better performance. Enjoy the material, and again, I hope that you will find this information useful as well as educational.
There are so many types of processors on the market today that it can be quite confusing to wade through them all, especially for the beginner. All chips are not created equal, and each chip has its own specific characteristics that make it unique.For instance, a chip of the same generation (type and model) may operate at double or triple the speed of others. Fierce competition between chipmakers lays the groundwork for new technological innovations and constant improvements.
Different manufacturers design and build processors to varying specifications. You should be sure that the processor type and model that you choose is compatible with the operating system that runs on your computer. If the processor is not 100% compatible with the installed OS, the computer will not operate at it's best or may not work at all.
Even though there are so many differences in specifications of processors, there are a few things that they all have in common. Without knowing the proper terms and vocabulary, even thinking about purchasing a new processor can make even advanced users nervous. In this section you will familiarize yourself with processor and memory terms.
Processors are known by many names, depending on their function(s)
A Great reference is the History of the CPU page located at http://bwrc.eecs.berkeley.edu/CIC/archive/cpu_history.html
In this section, you will see the terms CPU (Central Processing Unit) and processor. These two terms are used interchangeably throughout the computer industry and for the purposes of this course, we will do the same.
For most beginners, terms like microcode efficiency and internal cache RAMcan sound like a foreign language. To help you pass this course and better understand things, we need to first address the basic and most common terms and their definitions.
We will start with the most important part of the computer. The Central Processing Unit. The CPU is referred to as the processor and can also be called the microprocessor, which essentially is the brain of the computer. It uses logic to perform mathematical operations that are used in the manipulation and handling of data.
The computer also contains what is called a Numeric Coprocessor. The coprocessor is a secondary processor that speeds up operations by taking over some of the main CPU's work. It typically performs mathematical calculations, freeing the CPU to tend to other tasks and operations.
The number of operations that a CPU can process in one second is referred to as the CPU speed. The internal speed of a CPU is called the Clock Cycles,, which is measured in Megahertz (MHz). The faster the clock speed, the faster a computer can perform a specific operation. One Megahertz is equal to one million cycles per second.
The CPU handles data that is contained in instuctions that we give the computer. The largest number of bits that can be processed during one operation is called the Word Size. A step above that is the Data Path, which represents the largest number of instructions that can be transported into the CPU during one operation. This is where your Terms like 8-bit, 16-bit, 32-bit, 64-bit Processor or Computing comes from.
The CPU itself has what is called Internal Cache RAM. This is high speed memory that is located inside the processor chip.
The Basic Internals of most internal parts of most of todays CPUs consist of the following:
This subsection deals with Random Access memory. Memory is basically a series of cells with an address. Each memory cell stores a small piece of information and is identified by a unique address location, much like an email address or street address, so that the processor knows exactly where the cell is and can easily access it. Computers use several different types of memory, each serving a different purpose in the overall operation of things.
RAM, often referred to as main memory, or Primary Memory or Read-Write Memory is a temporary form of memory that the computer uses as a work area. This type of memory is dynamic, meaning that it is constantly changing because of the activity of the CPU. When you shut off the power to the computer, RAM loses everything stored in it. RAM stores program instructions and related data for the CPU to access quickly without the need for extracting the data from a much slower form of memory, such as the Hard Disk.
Generally, The Closer the Memory is to the CPU's ALU and CU, the faster the memory will be. As a result, it will be the most expensive, and the most limited type of memory in terms of availability and size.
Register Memory - This type of Memory is actually located inside the CPU. It tends to be small and measured in bits. The CPU tends to have a limited number of Registers, many of which are for instructions, and special purposes, while others are for general purposes. Registers are accessed duringg any CPU Cycle but they and extremely expensive.
Cache Memory - By Definition, it is the storage of data duplicating original values stored elsewhere. Cached data tends to be more quickly accessible than from its original location. The cache is also used to temporarly store instructions, and information computed to be reused for other calculations, speeding up the time it takes to perform many computing tasks.
Main Memory - This is the commonly known Computer RAM. There are various types of Momory Modules that you can have in your system, and they will be discussed in the next subsection.
Virtual Memory - is, in fact, not real memory, rather, it is usually part of Hard disk that has been set aside to be used like RAM, in order to increase the amount of Memory the system works with.
RAM Disk - In Contrast, is the use of Physical Memory to create a Virtual, very High-speed Drive.
Shadow Ram - Is a section of RAM that stores a COPY of ROM, because it is easier and faster to access. The CPU in turn accesses this area, instead of trying to access the Real ROM.
DRAM - Dynamic RAM is a type of memory that uses capacitors and transistors to store electrical chrges that represent the data. The capacitors that make up this type of memory needs to be refreshed every millisceond and cannot be reached by the CPU during this time. The frequence that memory has bte be refreshed is known as the Refresh Rate There are many types of Dynamic RAM used over the years:
SRAM - Static RAM is a type of memory that retains the information stored in it as long as power is supplied to the computer, allowing it to refresh. SRAM chips can store only about one-fourth the information that a RAM dynamic RAM chip can store. It is also the technology behind Solid State Storage used in USB Keys, etc.
NVRAM - Non Volatile RAM is the technology used in Memory cards, and other Momory based storage devices - It is basically a form of Static RAM
Read Only Memory - ROM is a special type of memory in which data is written onto a chip during manufacturing. Information strored to ROM is permanent and cannot be changed. The System ROM stores the BIOS - Basic Input/Output System, which is the set of instructions that a computer uses during the first stages of power up and initialization. With out the BIOS, the computer would not have a way to verify that the main hardware components, such as the hard drive, floppy drive, mouse, CD-ROM etc., are installed and working properly.
PROM- Programmable ROM is a special type of memory chip that is manufactured without any configuration. Manufaturers can then "burn in" or program the chip to contain whatever type of configuration and information is needed.
Erasable Programmable Read Only Memory - EPROM maintains its contents and information without the use of electrical power. The stored information of an EPROM chip is erased by removing a protective cover and using special equipmant to reprogram the chip. EPROMs are usually erased using Ultra Violet light.
Electrically Erasable Programmable Read Only Memory - EEPROM - Similar to the EPROM, It is prograamable through a process known as Flashing. Commonly the system BIOS and other similar devices are forms of EEPROM. The Information that that is stored in EEPROM is known as Firmware. EEPROMs are used in many devices, including Modems, NICs, Hard drive Controllers, and even some Hard Drives, and CD Rom Drives to enable them to have Funnctionality Upgrades.
Electrically Alterable Read Only Memory - EAROM - Similar to the EEPROM in functionality, but does not require you to actually Erase all its contents before reprogramming. The tendency is to make changes to only certain parts / values. This behaviour is very similar to RAM, and is usually associated with the term Non-Volatile Random Access Memory - NVRAM. EAROMs usually tend to be Complimentary Metal-Oxied Silicone - CMOS chips, which still require minute amounts of power to keep their information. This is why Most computers will have some form of a CMOS Battery, to preserve this data. It also makes it much easier to clear the CMOS in case of incorrect configuration by just removing the battery.
On every computer there is a collection of files. They include the files that start and run the operating system, the files needed to run applications and programs, and the data files that you create. All of these files have to be saved and stored somewhere, and that somewhere is called data storage. In this section you will learn about the most basic and popular forms of data storage.
Due to the fact that this topic has an unending amount of information that could be included, it will be very short and to the point, containing the absolute basics of Data Storage.
The first step in understanding the basics of data storage is that you must know that you can store data in a wide variety of formats. The format you chose depends on your needs. There are a few things to consider when choosing a type of storage that will be right for you.
When considering a storage type, you should ask yourself four basic questions that will greatly help weed out types that may not be suited for you or your computer.
Should the media be fixed or removable? Fixed media stays with the computer, while removable media can be disconnected and then used with another computer.
How much storage do I need? Are you planning on storing things such as large databases full of information, a few pages of a story, or perhaps your resume.
How common is the type of media that I am considering? If the media is not commonly used, it may be incompatable with your computer. For example, if you recieved a 5 1/4" floppy disk (which are pretty much extinct), whould you be able to retrieve the information stored on it using your computer?
What is the cost of the storage media that I am considering? Cost often is the primary concern when looking to add a storage device.
Data is organized on Media in 2 ways. The physical Storage, and the Logical Storage as controlled by the filesystem.
Tracks are the circular rings on the disk platter. Tracks are also known as cylinders.
Sectors are the basic physical storage divisions on a disk that are in Pie Shaped Wedges, from the center to the outside. The Sector Size is based on the Block size a Sector uses on each track. Today this number is still 512 Bytes
Clusters are the logical storage units on storage devices as defined by the Filesystems. Clusters will always be sized based on Sectors. In fact a Cluster is usually X number of Sectors, and X is always a power of 2 (ie 1, 2, 4, 8, 16, 32, 64, etc.).
Cylinder-Head-Sector - CHS - was the type of addressing used in old hard drives, using 20-bits based on the physical number of Cylinders (or tracks), the number of Disk Heads, and the number of Sectors per Track/Cylinder. The values were Limited to 1024, 16, and 63, resulting in only 1,032,192 blocks of 512K. This limited Hard Drive sizes to 504 MB
Extended CHS - ECHS - Was a 24-bit addressing introduced to combat the limitations of CHS. The numbers no longer were representative of the physical layout of the disk, but rather a virtual representation. The 4-bits were used to increase the number of Heads from 16 to 255, resulting in 16,450,560 Blocks, and thus a drive size limit of 8032.5 MB (7.8 GB)
Logical block addressing - LBA is the common scheme used for specifying the location of blocks of data:
This is a summary of the most common types of storage devices.
Hard Disk Drive(HDD) is a storage device that stores large amounts of data. HDD's use a series of magnetically coated disks that store data as ones and zeros. One type of HDD is fixed, which is mounted inside your computer. Although considerd Fixed Devices, it is now fairly easy to have HDD's that are removeable. These includes drives which hook up to USB or Firewire ports on your computer, or even ones that have special slots (like Removable HDD Trays). Newer HDD's have storage capabilities that are in the 100's of gigabytes range.
Drive Arrays are basically made up of multiple physical disks, that look like a single Logical disk. They are very similar to HDDs in many ways, and in fact many server systems and even high performance systems use them for Speed and/or Redundancy. The system sees the array of disks as a single HD. There are many types of drive arrays, and different technologies, however they are beyond the scope of this course. Some common devices that are utilies arrays are Storage Area Networks - SAN, Network Attached Storage - NAS, Redundant Array of Independant Disks - RAID, as well as others.
On the other hand in order to share information, there was the need for Removable Storage
Floppy Disks are a removable plastic disk that stores small amounts of data. This was a very popular type of storage due to its low cost and wide availability. Currently Standard 3.5" floppy disks, commonly used on many home computers can hold 1.44 megabytes of data. Originally Floppy Disks were 8" in size, and stored only about 180 KB.
Compact Discs are optical disks that store medium to large amounts of data. Most CDs can be written to only once, but can be read from infinite times (provided the CD is in good condition). However with the dawn of the new CD writting technology, there are also CDs that can be written and rewritten too many times. CDs can hold anywhere from 540MB to 800MB of data.
Tape is a magnetic media that is commonly used for backup purposes today. It is a slow media for accessing data, but its large capacity and low cost make it ideal for backing up large amounts of data. The storage capacity of tape ranges greatly from a few hundred megabytes, to Gigabytes or even Terabytes when information is compressed. Tapes were the Original Storage Device before Random Access devices like Floppy Disks and Hard Disk were invented.
Solid State Storage - also known as Memory Cards used in cameras and other portable devices, as well as Flash memory, used in USB Keys are forms of Solid State Storage. Basically they use Static RAM technology and in recent years have gained in capacity, wilst the price has been dropping.
Here is a basic conversion chart for storage quantities and their equivalents:
Due to confusion that has been caused by us the "Greek" prefixs for Metric/SI units, and Data/Information processing, In 1999, the International Electrotechnical Commission (IEC) published an ammendment to its standard on Letter Symbols to be used in Electric technology. This Standard (60027) had ammendments made to Part 2, on binary prefixes has resulted in some public interest in the standard and is still being widely discussed in the computer community, as it attempts to finally settle the confusion about whether a kilobit corresponds to 1000 bits or 1024 bits.
As a result, the standard approved the use of new prefixes: kibi-, mebi-, gibi-, tebi-, pebi-, exbi-,. to be used in specifying binary multiples of a quantity. The names come from the first two letters of the original SI prefixes followed by bi which is short for "binary". It also clarifies that, from the point of view of the IEC, the SI prefixes only have their base-10 meaning and never have a base-2 meaning.
In 2005, Another ammendment was made ti include zebi- and yobi-, thus matching all standard SI prefixes with their binary equivalences
Over the last few years, the use of the new binary Prefixes has become more common, and many organizations, like CIPM, and IEEE have decided to adopt these standards
The importance is in the fact that as this standard gets adopted more you will be required to use the proper prefix. Already many sites are using the binary prefix.
The other important fact is when it comes to Storage and Capacity, the difference between the two can have quite an impact!
The table below will give sizes for Binary, and Decimal values (and their proper Name/Symbols) and the Percentage Difference (% diff)
Name - Symbol | Metric (Marketting) Value | Binary ( * REAL * ) Value | %Dif | |
---|---|---|---|---|
Decimal (Metric/SI) | Binary (IEC) | |||
kilo - k | kibi - Ki | 103 = 1 KB = 1,000 B | 210 = 1 KiB =1,024 B | 2.4 % |
Mega - M | Mebi - Mi | 106= 1 MB = 1,000,000 B | 220= 1 MiB = 1,048,576 B | 4.86 % |
Giga - G | Gibi - Gi | 109 = 1 GB = 1,000,000,000 B | 230 = 1 GiB = 1,073,741,824,B | 7.37 % |
Tera - T | Tebi - Ti | 1012 = 1 TB = 1,000,000,000,000 B | 240 = 1 TiB = 1,099,511,627,776 B | 9.95% |
Peta - P | Pebi - Pi | 1015 = 1 PB = 1,000,000,000,000,000 B | 250 = 1 PiB = 1,125,899,906,842,624 B | 12.6 % |
Exa - E | Exbi - Ei | 1015 = 1 EB = 1,000,000,000,000,000,000 B | 250 = 1 EiB = 1,152,921,504,606,846,976 B | 15.3 % |
Zetta - Z | Zebi - Zi | 1015 = 1 ZB = 1,000,000,000,000,000,000,000 B | 250 = 1 ZiB = 1,180,591,620,717,411,303,424 B | 18.1 % |
Yotta - Y | Yobi - Yi | 1015 = 1 YB = 1,000,000,000,000,000,000,000,000 B | 250 = 1 YiB = 1,208,925,819,614,629,174,706,176 B | 20.9 % |
Computers process, manipulate and send data according to instructions from a user. Each computer has input and output interfaces to allow you to connect input or output devices. The input device allows information to enter the computer, and the output device allows information to exit the computer. Without providing the ability to enter and extract information, the computer is nothing more than an expensive box of colored lights. In this section you will learn about the basic and most common I/O devices.
You will also learn about the basic Connection types used for I/O Devices. and the different clasess of devices. Only the most common connectors will be introduced in thihs section, however A more advanced version will be presented in future upgrades.
There are a number of types of I/O methods. Even Reading And Writing To/From Storage devices, and even memory can be considerd a form of I/O. There are two general Types of I/O:
Input is the method by which information is provided to the computer, as well as other electronic devices. There are many different types of devices for Input, and input is not necessarily just basecd on devices. Input can also be obtained from data and other more exotic methods.
The Keyboard is the most common type of input device. The keyboard takes in information in the form of numbers and letters. The numbers and letters are then translated into instructions that the computer must perform. The computer translates literally what is entered, so as many of you know, any typing mistakes usually result in an error. When choosing a keybaord, make sure your choice is based on comfort and required featcures. The keyboard is the device that you will use the most when completing any type of computing task.
The Mouse is the second most common type of input device. You use the mouse for basic navigation, selection, and drawing in the user environment. The mouse movements are translated into computer instructions in the form of motion and button selection. To start a mouse operation, simply move the mouse pointer on the screen until it is in the desired position and click the appropriate mouse button.
Joystick and other game controllers are another form of Input device that is common among gamers. These devices use various signals to interpret the motions. Older Joysticks used Analog signals, which were continuous, and provided angle changes, and lots of other information. Digital devices relied on On/Off signals in a number of different directions. In older systems, Digital devices were slower to respond, but as technology has improved, the Digital devices are now much more percies, and tend to have many more features. Some devices even provide Output through the use of Lights and Force Feedback to make the experience even more realistic.
Microphones are also an input device that take sounds and do something with them. Thata sound can be either Recorded, to a file, transmitted over the internet through chat programs, or Voice-over-IP - VoiP technology, or even processesd by Speech Recognition software to take the place of Keyboards and Mice.
Cameras are the final input device that will be discussed. Weather in the form of a digital camera that takes still pictures or movies, or a Web Cam that allows others to see you through instant messageing and video sharing software.
Above, the most common Input devices were provided. Yet there are many more, and some examples are listed below, with a quick description of their use
Output is the method by which information is provided by the computer, as well as other electronic devices. There are many different types of devices for Output, and Output is not necessarily just basecd on devices. Output can also be provided in other more exotic methods.
The monitor is the most common type of output device. It may look like a simple television, but it's not. The monitor allows the human eye to interact with the computer. Without a monitor, the computer's output capabilities would be very very limited. Imagine if the only available form of output were in printed or audible format. The monitor allows the computer to translate computer data into text and graphics, and then display them on the screen. There are several types of computer monitors available based on different technology and standards. The internal workings of the devices are essentially the same.
Printers are output devices that produce a hard copy result in the form of printed text and graphics. Printers differ from other types of output devices because they not only transfer an image to paper, but they must also move the paper through the entire process.There are several types of printer available based on different technology and standards. Most printer types basically operate the same. Some of the most common printer types include the Dot Matrix, Inkjet/BubbleJet/DeskJet, Thermal, and Laser.
Plotters are output devices that also do printouts, but use pens and draws actual lines. They are mostly used in Architectural and Engineering fields in order to print diagrams and blueprints. Since pens are used, Plotters could print high quality colour long before inkjet and Colour Laser technology was available. Plotters can also print on very large paper.
Speakers are also an output device. The provide audio feedback and play sounds. Without speakers many games and functions on todays computers would be extremely boring. Today there are many types of speakers, and some systems can have as many as 8 speakers connected! Speekers are also used in Speach Synthesis and Reading software, which are extremely important for the visually impaired.
Above, the most common Output devices were provided. Yet there are some more, examples are listed below, with a quick description of their use
Many devices use a combination of both Input and Output, and can thus be considered Hybrid Devices. Most Storage devices are a form of these Hybrid devices, however they are already covered in Data Storage section. The other most common area that Hybrid devices are those used for communications
Network Interface Card - NIC - After Storage Devices, it Is the most common form of Hybrid device used today. It allows computers to communicate with each other. It is what enables most of us to communicate with each other over the Internet
Modems function as both an input and output device that allows computers to communicate with one another over great distances. The modem achieves this by converting digital signals from a computer into analog audible tone signals that can be transmitted over a telephone line. This process is called Modulation. The signal stays in this analog form until it reaches it's destination, when the modem that is connected to the recieving computer gets the analog signal and coverts it back into a digital signal that the computer can understand. This process is called Demodulation. If you take a closer look, this is how we get the name "modem". MO from MOdulation and DEM from DEModulation. MODEM. It's a beautiful thing. Unfortunately, it is fairly dated, and not used much longer.
There are many other types of Devices that utilze both Input and Output, howeverr most are based on either Communicataions or Storage.
The pictures below represent somme Common Connectors found on Computer Cases.
Below are the Description of the Ports seen Above
Here are some hints to help with your exams (Based on Frequent requests from writers.