7/27/2011
Types of Computers
Supercomputer
Supercomputer is a broad term for one of the fastest computers currently available. Supercomputers are very expensive and are employed for specialized applications that require immense amounts of mathematical calculations (number crunching). For example, weather forecasting requires a supercomputer. Other uses of supercomputers scientific simulations, (animated) graphics, fluid dynamic calculations, nuclear energy research, electronic design, and analysis of geological data (e.g. in petrochemical prospecting). Perhaps the best known supercomputer manufacturer is Cray Research.\
Mainframe
Mainframe was a term originally referring to the cabinet containing the central processor unit or "main frame" of a room-filling Stone Age batch machine. After the emergence of smaller "minicomputer" designs in the early 1970s, the traditional big iron machines were described as "mainframe computers" and eventually just as mainframes. Nowadays a Mainframe is a very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. The chief difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently. In some ways, mainframes are more powerful than supercomputers because they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe. The distinction between small mainframes and minicomputers is vague, depending really on how the manufacturer wants to market its machines.
Minicomputer
It is a midsize computer. In the past decade, the distinction between large minicomputers and small mainframes has blurred, however, as has the distinction between small minicomputers and workstations. But in general, a minicomputer is a multiprocessing system capable of supporting from up to 200 users simultaneously.
Workstation
It is a type of computer used for engineering applications (CAD/CAM), desktop publishing, software development, and other types of applications that require a moderate amount of computing power and relatively high quality graphics capabilities. Workstations generally come with a large, high-resolution graphics screen, at large amount of RAM, built-in network support, and a graphical user interface. Most workstations also have a mass storage device such as a disk drive, but a special type of workstation, called a diskless workstation, comes without a disk drive. The most common operating systems for workstations are UNIX and Windows NT. Like personal computers, most workstations are single-user computers. However, workstations are typically linked together to form a local-area network, although they can also be used as stand-alone systems.
N.B.: In networking, workstation refers to any computer connected to a local-area network. It could be a workstation or a personal computer.
Personal computer:
It can be defined as a small, relatively inexpensive computer designed for an individual user. In price, personal computers range anywhere from a few hundred pounds to over five thousand pounds. All are based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip. Businesses use personal computers for word processing, accounting, desktop publishing, and for running spreadsheet and database management applications. At home, the most popular use for personal computers is for playing games and recently for surfing the Internet.
Personal computers first appeared in the late 1970s. One of the first and most popular personal computers was the Apple II, introduced in 1977 by Apple Computer. During the late 1970s and early 1980s, new models and competing operating systems seemed to appear daily. Then, in 1981, IBM entered the fray with its first personal computer, known as the IBM PC. The IBM PC quickly became the personal computer of choice, and most other personal computer manufacturers fell by the wayside. P.C. is short for personal computer or IBM PC. One of the few companies to survive IBM's onslaught was Apple Computer, which remains a major player in the personal computer marketplace. Other companies adjusted to IBM's dominance by building IBM clones, computers that were internally almost the same as the IBM PC, but that cost less. Because IBM clones used the same microprocessors as IBM PCs, they were capable of running the same software. Over the years, IBM has lost much of its influence in directing the evolution of PCs. Therefore after the release of the first PC by IBM the term PC increasingly came to mean IBM or IBM-compatible personal computers, to the exclusion of other types of personal computers, such as Macintoshes. In recent years, the term PC has become more and more difficult to pin down. In general, though, it applies to any personal computer based on an Intel microprocessor, or on an Intel-compatible microprocessor. For nearly every other component, including the operating system, there are several options, all of which fall under the rubric of PC
Today, the world of personal computers is basically divided between Apple Macintoshes and PCs. The principal characteristics of personal computers are that they are single-user systems and are based on microprocessors. However, although personal computers are designed as single-user systems, it is common to link them together to form a network. In terms of power, there is great variety. At the high end, the distinction between personal computers and workstations has faded. High-end models of the Macintosh and PC offer the same computing power and graphics capability as low-end workstations by Sun Microsystems, Hewlett-Packard, and DEC.
III, Personal Computer TypesActual personal computers can be generally classified by size and chassis / case. The chassis or case is the metal frame that serves as the structural support for electronic components. Every computer system requires at least one chassis to house the circuit boards and wiring. The chassis also contains slots for expansion boards. If you want to insert more boards than there are slots, you will need an expansion chassis, which provides additional slots. There are two basic flavors of chassis designs–desktop models and tower models–but there are many variations on these two basic types. Then come the portable computers that are computers small enough to carry. Portable computers include notebook and subnotebook computers, hand-held computers, palmtops, and PDAs.
Tower model
The term refers to a computer in which the power supply, motherboard, and mass storage devices are stacked on top of each other in a cabinet. This is in contrast to desktop models, in which these components are housed in a more compact box. The main advantage of tower models is that there are fewer space constraints, which makes installation of additional storage devices easier.
Desktop model
A computer designed to fit comfortably on top of a desk, typically with the monitor sitting on top of the computer. Desktop model computers are broad and low, whereas tower model computers are narrow and tall. Because of their shape, desktop model computers are generally limited to three internal mass storage devices. Desktop models designed to be very small are sometimes referred to as slimline models.
Laptop computer
A small, portable computer -- small enough that it can sit on your lap. Nowadays, laptop computers are more frequently called notebook computers.
Subnotebook computer
A portable computer that is slightly lighter and smaller than a full-sized notebook computer. Typically, subnotebook computers have a smaller keyboard and screen, but are otherwise equivalent to notebook computers.
Hand-held computer
A portable computer that is small enough to be held in one’s hand. Although extremely convenient to carry, handheld computers have not replaced notebook computers because of their small keyboards and screens. The most popular hand-held computers are those that are specifically designed to provide PIM (personal information manager) functions, such as a calendar and address book. Some manufacturers are trying to solve the small keyboard problem by replacing the keyboard with an electronic pen. However, these pen-based devices rely on handwriting recognition technologies, which are still in their infancy. Hand-held computers are also called PDAs, palmtops and pocket computers.
Palmtop
A small computer that literally fits in your palm. Compared to full-size computers, palmtops are severely limited, but they are practical for certain functions such as phone books and calendars. Palmtops that use a pen rather than a keyboard for input are often called hand-held computers or PDAs. Because of their small size, most palmtop computers do not include disk drives. However, many contain PCMCIA slots in which you can insert disk drives, modems, memory, and other devices. Palmtops are also called PDAs, hand-held computers and pocket computers.
PDA
Short for personal digital assistant, a handheld device that combines computing, telephone/fax, and networking features. A typical PDA can function as a cellular phone, fax sender, and personal organizer. Unlike portable computers, most PDAs are pen-based, using a stylus rather than a keyboard for input. This means that they also incorporate handwriting recognition features. Some PDAs can also react to voice input by using voice recognition technologies. The field of PDA was pioneered by Apple Computer, which introduced the Newton MessagePad in 1993. Shortly thereafter, several other manufacturers offered similar products. To date, PDAs have had only modest success in the marketplace, due to their high price tags and limited applications. However, many experts believe that PDAs will eventually become common gadgets.
PDAs are also called palmtops, hand-held computers and pocket computers.
7/26/2011
20 Crazy Things We All Do
1) Why does the glue in a tube not stick to the tube itself?
2) Academic research has detailed reports stating that from a group of four men or women one will most certainly have a mental ailment of some kind or the other. Think about this calculation: if you have three normal friends, then you unfortunately are the fourth one out. In other words, the fourth person with a mental illness is none other than you.
3) Why do we press down hard on the remote control even though we know that the batteries are weak?
4) Watched old (and even newer descriptions in film) about Tarzan. If he is supposed to be living in the wild, what happened to his beard?
2) Academic research has detailed reports stating that from a group of four men or women one will most certainly have a mental ailment of some kind or the other. Think about this calculation: if you have three normal friends, then you unfortunately are the fourth one out. In other words, the fourth person with a mental illness is none other than you.
3) Why do we press down hard on the remote control even though we know that the batteries are weak?
4) Watched old (and even newer descriptions in film) about Tarzan. If he is supposed to be living in the wild, what happened to his beard?
5) Switched those bulbs that are enclosed in tight plastic shutters? Have you noticed that whenever you go to do that there are always dead bugs inside? How did they manage to get there?
6) Why can't we ever manage to open a plastic bag on the first attempt?
7) Why do they use sterilized needles when injecting a convict on death role?
8) Why does a bank take interest on money when your account is overdrawn? From where do they think you are going to pay them? If you had the cash you would have used it, wouldn't you?
9) Why don't we ever hear jokes about father-in-laws?
10) When statistics claim that the sum of all the stars in the sky is about four billion, people believe it. But, when someone sees a sign on a park bench or board stating "wet paint", they must verify this?
6) Why can't we ever manage to open a plastic bag on the first attempt?
7) Why do they use sterilized needles when injecting a convict on death role?
8) Why does a bank take interest on money when your account is overdrawn? From where do they think you are going to pay them? If you had the cash you would have used it, wouldn't you?
9) Why don't we ever hear jokes about father-in-laws?
10) When statistics claim that the sum of all the stars in the sky is about four billion, people believe it. But, when someone sees a sign on a park bench or board stating "wet paint", they must verify this?
11) How many times will be keep coming back and opening the door to the fridge when we are hungry? Do we really think that food will appear there miraculously?
12) Why does Superman stop bullets with his chest but ducks if after the bullets are over the gun is thrown at him?
13) I'm sure you've heard of the evolutionary claim that mankind has evolved from monkeys. Before I am to believe this, I want to know that if this is so why are monkeys still roaming earth?
12) Why does Superman stop bullets with his chest but ducks if after the bullets are over the gun is thrown at him?
13) I'm sure you've heard of the evolutionary claim that mankind has evolved from monkeys. Before I am to believe this, I want to know that if this is so why are monkeys still roaming earth?
14) If you are sitting by a table and something is accidentally falling off, don't try and prevent its fall. Why? Every time you try, you will accidentally hit and break something else.
15) Why did the Japanese pilots who were planning to crash into American ships wear helmets?
16) Why do people move a vacuum cleaner over a small piece of thread again and again? Why do we pick it up, examine it and then place it back down and move the vacuum cleaner over it to give it a second chance?
17) How come soap bubbles are always white no matter what the colour of the soap?
15) Why did the Japanese pilots who were planning to crash into American ships wear helmets?
16) Why do people move a vacuum cleaner over a small piece of thread again and again? Why do we pick it up, examine it and then place it back down and move the vacuum cleaner over it to give it a second chance?
17) How come soap bubbles are always white no matter what the colour of the soap?
18) Is it winter or summer wherever you are right now? Have you noticed that if it is summer we try and make the house as cold as it would be during winter, and if it is winter, we try and make the house as hot as it would during summer?
19) Why is it that whenever you walk past a mattress dealership, they have large signs advertising a big price reduction?
20) Isn't it silly that when if wandering through one of the large shopping malls someone doesn't pay attention and the cart they are pushing smacks into your toes, and then they say sorry, all we can think of saying is that no harm was done while your toe is aching.
Before I End:
Above you have run into about twenty or so intriguing incidents on life that I or some friend of mine has come across. Most will be familiar to you. Some might not. But, I hope that each one of them will if not make you at least laugh, bring a smile to your face and to your heart.
19) Why is it that whenever you walk past a mattress dealership, they have large signs advertising a big price reduction?
20) Isn't it silly that when if wandering through one of the large shopping malls someone doesn't pay attention and the cart they are pushing smacks into your toes, and then they say sorry, all we can think of saying is that no harm was done while your toe is aching.
Before I End:
Above you have run into about twenty or so intriguing incidents on life that I or some friend of mine has come across. Most will be familiar to you. Some might not. But, I hope that each one of them will if not make you at least laugh, bring a smile to your face and to your heart.
7/19/2011
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