Computer case

A computer case (also known as the computer chassis, cabinet, tower, box, enclosure, housing or simply case) is the enclosure that contains the main components of a computer. It has also been erroneously called the CPU, however this is an entirely different component. Cases are usually constructed from steel (often SECC - Steel, Electrogalvanized, Cold-rolled, Coil), aluminium, or plastic, although other materials such as wood and plexiglas have also been used in case designs.

Sizes

Cases can come in many different sizes, or form factors. The size and shape of a computer case is usually determined by the form factor of motherboard that it is designed to accommodate, since this is the largest and most central component of most computers. Consequently, personal computer form factors typically specify only the internal dimensions and layout of the case. Form factors for rack-mounted and blade servers may include precise external dimensions as well, since these cases must themselves fit in specific enclosures.
For example, a case designed for an ATX motherboard and power supply may take on several external forms, such as a vertical tower (designed to sit on the floor) or a flat desktop or pizza box (designed to sit on the desk under the computer's monitor). Full-size tower cases are typically larger in volume than desktop cases, with more room for drive bays and expansion slots. Desktop cases—and mini-tower cases designed for the reduced microATX form factor—are popular in business environments where space is at a premium.
Currently, the most popular form factor for desktop computers is ATX, although microATX and small form factors have become very popular for a variety of uses. Companies like Shuttle Inc. and AOpen have popularized small cases, for which FlexATX is the most common motherboard size. Apple Computer has also produced the Mac Mini computer, which is similar in size to a standard CD-ROM drive.
There are mini-tower, midi-tower, big-tower/full-tower. Full tower cases are typically 30 inches or more in height and meant to stand on the floor. They have anywhere from 6-10 externally accessible drive bays with more internal-only. The ratio of external to internal bays is shifting however, as computing technology moves from floppy disks and CD-ROM to large capacity hard drives and network-based solutions. Midtower cases are smaller, about 24" high with 2-4 external bays. A minitower case will typically have only 1 or 2 external bays and stand from 12" to 18" tall.

Layout

Computer cases usually include sheet metal enclosures for a power supply unit and drive bays, as well as a rear panel that can accommodate peripheral connectors protruding from the motherboard and expansion slots. Most cases also a power button or switch, a reset button, and LEDs to indicate power status, hard drive usage, and network activity. Some cases include built-in I/O ports (such as USB and headphone ports on the front of the case). Such a case will also include wires needed to connect these ports to the motherboard.
Major component locationsThe motherboard is usually screwed to the bottom or the side of the case (depending on the form factor and orientation).Form factors such as ATX provide a back panel with cut-out holes to expose I/O ports provided by integrated peripherals, as well as expansion slots which may optionally expose additional ports provided by expansion cards.The power supply unit is often housed at the top rear of the case; it is usually attached with four screws to support its weight.Most cases include drive bays on the front of the case; a typical ATX case includes both 5.25" and 3.5" bays. In modern computers, the former are used mainly for optical drives, while the latter are used for hard drives, floppy drives, and card readers.Buttons and LEDs are typically located on the front of the case; some cases include additional I/O ports, temperature and/or processor speed monitors in the same area.Vents are often found on the front, back, and sometimes on the side of the case to allow cooling fans to be mounted via surrounding threaded screw holes.
Internal access
Tower cases have either a single side panel which may be removed in order to access the internal components or a large cover that saddles the chassis. Traditionally, most computer cases required screws to hold components and panels in place (i.e. motherboard, PSU, drives, and expansion cards). Recently there is a trend toward "screwless" cases, in which components are held together with snap-in plastic rails, thumbscrews, and other methods that do not require tools; this facilitates quick assembly and modification of computer hardware.

Appearance

Through the 1990s, most computer cases had simple rectangular shapes, and were often painted beige. Beige box designs are still found on a large number of budget computers assembled from generic components.
Case modding is the artistic styling of computer cases, often to draw attention to the use of advanced or unusual components. Since the early 2000s, some cases have included clear side panels or acrylic windows so that users can look inside while it is operating. Modded cases may also include internal lighting, custom paint, or liquid cooling systems. Some hobbyists build custom cases from raw materials like aluminum, steel, acrylic, or wood.

Brands
Prominent after-market case manufacturers include Ahanix, Antec, AOpen, Chieftec, Cooler Master, Ever Case, Foxconn, Gigabyte Technology, HEC Compucase, IXIUM, Lian Li,CIRCLE,ODYSSEY,ZEBRONICS, NZXT, OrigenAE, Raidmax, Shuttle Inc., SilverStone Technology, Thermaltake and Zalman.

How to Make My Computer Run Faster With 3 Simple Steps

Is your computer running too slow for you? Are you finding that it takes a long time to boot up, whereas before it was quick as a rabbit? Are you wondering, "How to make my computer run faster ?"If your computer is running at turtle speed, you have come to the right place. In this article, we will outline three simple steps that you follow to make your computer run faster and more efficiently for your needs.

Step #1 - Maintain Your Computer
Are you ready to get started? Great! The first thing you need to think about is the amount of websites that you visit on a daily basis. Did you know that with each website that you visit, you are literally downloading some of these files in efforts to make your computer load them faster the next time you want to access that same website? You are also downloading cookies from websites and saving a history of each site you visit.
All of these can dramatically affect your computer's speed and slow it down if you do not do something about it. So, to get rid of these things, you should make sure to clean it out. You can do this by making sure that you delete temporary files, browsing history, cookies, and empty out the recycle bin on your computer. This should be done regularly, weekly, bi-weekly, or monthly. In fact, some people perform this maintenance daily.

Step #2 -Get Rid Of What You Don't Need
If you have too many programs on your computer, this could really put a damper on its speed. The first thing you need to do is delete any programs that you do not use. This can free up space and free up some speed. At the same time, you need to take a look at the items running on your computer at all times. These things, especially if unneeded, could have a major affect on the speed of your computer.
Therefore, you want to prevent unneeded programs from booting with your computer and running in the background. The safest way to do this is to go into the program options and find a box that says "run at startup" or something similar and uncheck the box. There are other ways, but if you do not know the necessary programs that must run on your computer, it is not a good idea to go those routes.

Step #3 - Clean Out Your Registry
This is something that you will want to download a program for. Cleaning out your registry is not something that you want to do yourself. Your registry is basically the hub of your computer, one wrong move and it could render your computer completely useless. However, cleaning out the registry is a big step, one which must be done because it too can affect the speed of your computer. Left over files, errors, or deleted programs can still remain in the registry.
Registry cleaner downloads are available, download and scan your computer. After the scan, let the registry cleaner make the proper corrections.

How to Repair Rundll32 Error Messages on Start-up - The Easy Way

What is a Rundll32 Error?
Rundll32 refers to errors in the Microsoft Vista or XP windows registry. Prior to the Vista and XP versions - Windows 95, 98 - this was called Rundll error.
The difference is simply the result of 16-bit and 32-bit technology used in the operating system software. Both unfortunately spurt out these error messages either at startup or Windows shutdown.

The Rundll32 File
The Rundll32 file is basically your data manager between your dynamic link library ( .dll ) and many of the peripherals, programs and devices attached to your computer. The Dynamic Link Library is the portion of your OS where all the files that allow multiple programs to run at once on your Windows computer or stored.
The Rundll32 error can be caused by a variety of different problems ranging from malfunctioning hardware to conflicts between programs, and can also be a symptom of a virus, spyware or Trojan being presenton your computer.
The error messages can come at any given time typically triggered by an application attempting to access the .dll library. The most common error message reads something like this...
Typical Rundll32 Error Message

RUNDLL: Error loading C:\windows\system 32\XXXXX.dll. The specified module could not be found.

Basically what this message means is this:
It is telling you in which exact part of the .dll library the error is occurring in & the file that is corrupt. (this is the xxxxx.dll bit. The "C:\windows\system32\" is just telling you that it is part of the 32-bit operating system.
In the majority of cases, these error messages are the result of a corrupt, damaged or deleted file, and in this case, most likely a driver, somewhere on your computer that is causing another program not to run properly.

Fix RUNDLL32 Errors for Good
There is an easy solution to fix nearly all RUNDLL and RUNDLL32 errors. Registry cleaners can do this for you. They scan your registry looking for missing, corrupt or damaged DLL files and repair them. Ultimately, this results in your PC running faster and at optimal performance.

What Spyware Can Do to Your Computer - The Best Way to Get Rid of It, & The Deletion Method to Avoid

There may be spyware lurking on your computer, and you don't even know it. Actually, I am pretty confident that there IS spyware on your PC, since it is estimated that spyware invades 91 percent of computers with an internet connection.
How dangerous is spyware? It depends on what type is on your PC. Some of them are used as advertising tools. Do you get what seems to be an endless series of pop- ups, or has the home page on your browser changed even though you have done absolutely nothing to it? These are indicators of spyware that focuses on advertising. They're really more of an annoyance than anything else. The spyware you need to be worried about is the kind that is used to keep tabs on your personal banking and credit information. This type of spyware can be used to drain your bank account.
So how do you know what type of spyware is on your computer? You don't, and that is why it is so important that you get rid of it right away. You can try to do this on your own, but you are asking for problems if you attempt this. Spyware can be difficult to detect, and easy to mistake. If you mistakenly delete the wrong file, you could end up deleting a file Windows relies on to operate. Instead, opt for a spyware cleaner, which will scan your PC for intruders, delete them, and work to make sure that they stay off your PC in the future

Main article: Arithmetic logic unit

The ALU is capable of performing two classes of operations: arithmetic and logic.

The set of arithmetic operations that a particular ALU supports may be limited to adding and subtracting or might include multiplying or dividing, trigonometry functions (sine, cosine, etc) and square roots. Some can only operate on whole numbers (integers) whilst others use floating point to represent real numbers—albeit with limited precision. However, any computer that is capable of performing just the simplest operations can be programmed to break down the more complex operations into simple steps that it can perform. Therefore, any computer can be programmed to perform any arithmetic operation—although it will take more time to do so if its ALU does not directly support the operation. An ALU may also compare numbers and return boolean truth values (true or false) depending on whether one is equal to, greater than or less than the other ("is 64 greater than 65?").

Logic operations involve Boolean logic: AND, OR, XOR and NOT. These can be useful both for creating complicated conditional statements and processing boolean logic.

Superscalar computers contain multiple ALUs so that they can process several instructions at the same time. Graphics processors and computers with SIMD and MIMD features often provide ALUs that can perform arithmetic on vectors and matrices.

Control unit

Main articles: CPU design and Control unit

The control unit (often called a control system or central controller) directs the various components of a computer. It reads and interprets (decodes) instructions in the program one by one. The control system decodes each instruction and turns it into a series of control signals that operate the other parts of the computer. Control systems in advanced computers may change the order of some instructions so as to improve performance.

A key component common to all CPUs is the program counter; a special memory cell (a register) that keeps track of which location in memory the next instruction is to be read from.
 
Diagram showing how a particular MIPS architecture instruction would be decoded by the control system.

The control system's function is as follows—notes that this is a simplified description, and some of these steps may be performed concurrently or in a different order depending on the type of CPU:
Read the code for the next instruction from the cell indicated by the program counter.
Decode the numerical code for the instruction into a set of commands or signals for each of the other systems.
Increment the program counter so it points to the next instruction.
Read whatever data the instruction requires from cells in memory (or perhaps from an input device). The location of this required data is typically stored within the instruction code.
Provide the necessary data to an ALU or register.
If the instruction requires an ALU or specialized hardware to complete, instruct the hardware to perform the requested operation.
Write the result from the ALU back to a memory location or to a register or perhaps an output device.

Since the program counter is (conceptually) just another set of memory cells, it can be changed by calculations done in the ALU. Adding 100 to the program counter would cause the next instruction to be read from a place 100 locations further down the program. Instructions that modify the program counter are often known as "jumps" and allow for loops (instructions that are repeated by the computer) and often conditional instruction execution (both examples of control flow).

It is noticeable that the sequence of operations that the control unit goes through to process an instruction is in itself like a short computer program - and indeed, in some more complex CPU designs, there is another yet smaller computer called a micro sequencer that runs a microcode program that causes all of these events to happen.

Arithmetic/logic unit (ALU) This section does not cite any references or sources.
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How computers work

Main articles: Central processing unit and Microprocessor

A general purpose computer has four main sections: the arithmetic and logic unit (ALU), the control unit, the memory, and the input and output devices (collectively termed I/O). These parts are interconnected by busses, often made of groups of wires.

The control unit, ALU, registers, and basic I/O (and often other hardware closely linked with these) are collectively known as a central processing unit (CPU). Early CPUs were composed of many separate components but since the mid-1970s CPUs have typically been constructed on a single integrated circuit called a microprocessor.

History of personal computers

The capabilities of the PC have changed greatly since the introduction of electronic computers. By the early 1970s, people in academic or research institutions had the opportunity for single-person use of a computer system in interactive mode for extended durations, although these systems would still have been too expensive to be owned by a single person. The introduction of the microprocessor, a single chip with all the circuitry that formerly occupied large cabinets, led to the proliferation of personal computers after about 1975. Early personal computers - generally called microcomputers - were sold often in Electronic kit form and in limited volumes, and were of interest mostly to hobbyists and technicians. Minimal programming was done by toggle switches, and output was provided by front panel indicators. Practical use required peripherals such as keyboards, computer terminals, disk drives, and printers. By 1977, mass-market pre-assembled computers allowed a wider range of people to use computers, focusing more on software applications and less on development of the processor hardware.

Throughout the late 1970s and into the 1980s, computers were developed for household use, offering personal productivity, programming and games. Somewhat larger and more expensive systems (although still low-cost compared with minicomputers and mainframes) were aimed for office and small business use. Workstations are characterized by high-performance processors and graphics displays, with large local disk storage, networking capability, and running under a multitasking operating system. Workstations are still used for tasks such as computer-aided design, drafting and modelling, computation-intensive scientific and engineering calculations, image processing, architectural modelling, and computer graphics for animation and motion picture visual effects.

Eventually the market segments lost any technical distinction; business computers acquired color graphics capability and sound, and home computers and game systems users used the same processors and operating systems as office workers. Mass-market computers had graphics capabilities and memory comparable to dedicated workstations of a few years before. Even local area networking, originally a way to allow business computers to share expensive mass storage and peripherals, became a standard feature of the personal computers used at home.

Artical Source By:-http://en.wikipedia.org/wiki/Personal_computer#History

Timeline of Computer History

WHAT THE TIMELINE IS 
This timeline explores the history of computing from 1939 to 1994. Each year features illustrated descriptions of significant innovations in hardware and software technology, as well as milestones in areas such as commercial applications and artificial intelligence. When appropriate, biographical sketches of the pioneers responsible for the advances are included.

source by :-http://www.computerhistory.org/timeline/

VIA C7 -M Processor

While VIA is known more as a chipset manufacturer than anything else, the company has had its own line of x86-based processors for a while now. You might remember the company briefly reviving the 'Cyrix' processor brand back in 2000, before moving on to its own 'C3' processors a year later. While the C3 did not do particularly well in the marketplace, VIA's processors were notable for one major reason; they were (and are) extremely cool running and economical on power. One of the selling points of the original C3 was that it could be easily run using passive cooling only, and so it found some following for embedded-type applications.
VIA recently announced plans for another in the 'C' line of processors, this time dedicated to mobile use. The VIA C7-M is the mobile version of the C7 processor which was released in May of 2005. The VIA C7-M is slated to become available in November 2005 in speeds of 1.5GHz or 1.8GHz. During a recent briefing by the company, PCSTATS was shown the CPU in its A2 stepping.

Desktop Processors

Desktop Processors 
Desktop Processors
Processor
Frequency
Bus Speed
L2 Cache
Price
Intel® Core™2 Extreme processor X6800
2.93 GHz
1066
4MB
$999
Intel® Core™2 Duo processor E6700
2.66 GHz
1066
4MB
$530
Intel® Core™2 Duo processor E6600
2.40 GHz
1066
4MB
$316
Intel® Core™2 Duo processor E6400
2.13 GHz
1066
2MB
$224
Intel® Core™2 Duo processor E6300
1.86 GHz
1066
2MB
$183

Mobile Processors
Processor
Frequency
Bus Speed
L2 Cache
Voltage

Intel® Core™2 Duo processor T7600
2.33 GHz
667
4MB
1.0375–1.3V

Intel® Core™2 Duo processor T7400
2.16 GHz
667
4MB
1.0375–1.3V

Intel® Core™2 Duo processor T7200
2.00 GHz
667
4MB
1.0375–1.3V

Intel® Core™2 Duo processor T5600
1.83 GHz
667
2MB
1.0375–1.3V

Intel® Core™2 Duo processor T5500
1.66 GHz
667
2MB
1.0375–1.3V