Thursday 5 April 2012

Types Of Computers Really, I thought you only get PC's and Laptops?

It's a common misconception. People think there are only two types of computers, PC's (Personal Computers) and Laptops. In fact you get a host of different types. I'll list the most common types here. Each of these types can be subdivided into subtypes.
For instance, server can be subdivided into deskside, rackmount, workgroup or high end servers.
The vendors of these servers mostly depict what types of servers you get, so it's not always a given that these are the different types of servers. It's vendor specific. But one thing is certain, you do get servers.
Let me list the most common types of computers. There's the PC or Personal Computer, Laptops, Servers and mainframes. Of course you can now go and subdivide these into different categories.
Just remember that these categories are sometimes defined by the vendors. It's so they can get a hook of the product in the market. Every vendor wants to be different. They want to make their product unique so they think of different ways to sell their products.
Anyway, lets look at the types of computers individually.
PC or Personal Computer
It's also referred to as a desktop system or desktop PC. Desktop, because you place it on your desk. Well, most of the times. The PC is probably the most common type of computer you get. It has been around since I can remember.
Types of computers. Personal computer
Types of computers Desktop PC
It consists of all the major components as discussed in the section on Computer Components.
What makes it so popular is the fact that it's relatively cheap and you can even build your own PC if you have the knowledge on how to do it. You can buy the components individually and put them together at home.
Yep, you can even "bling" your PC by adding cool lights and stuff. That's cool homeboy. You can custom build your PC.
These days vendors like Apple integrate all the components into the screen or display like the Apple iMac. This not only looks cool, but you don't need that big, bulky computer case that's always in the way.
Other vendors have caught on and are doing the same. I think that this design will be seen much more in the future.


Laptops, Notebooks, Netbooks and tablet PC's
These are all, what is known as, portable devices. They're small and compact and you can carry them around. That's the whole idea with these types of computers.
So what's the difference between a Laptop, Notebook, Netbook and Tablet PC? People use the terms Laptop and Notebook interchangeably. They are essentially the same but the biggest difference is the size.
A laptop is slightly bigger than a notebook and therefore heavier. A notebook is more compact and easier to carry around.
To be honest here, I don't think there is that much of a difference. People often refer to notebooks as laptops and laptops as notebooks. These days it's hardly even noticeable whether it's a notebook or laptop. But who am I to argue.
Types of computers. Laptops
laptop
Netbooks, on the other hand, is a different story. They are ultra compact and very light. Their screen size starts from 7" to about 11". They're not as powerful as laptops and notebooks.
They contain the Intel Atom processor that run at about 1.6 GHz and don't come with more than 1GB of RAM, although this will change in the future.
Some models don't even have a hard disk but uses a micro sd card. The same as they use in cameras and cell phones.
Tablet PC's, is a portable personal computer equipped with a touchscreen as a primary input device. Some have keyboards as well, but their claim to fame is the touchscreen.
The concept of tablet PC's haven't really taken off until recently with Apple's iPad. The reason was that tablet pc's are not very powerful, compared to laptops, so you could not run compute intensive application on tablets.
It also didn't run a proper version of Microsoft Windows, but a customized version of it specifically designed for the tablets. That has, of course, changed and tablets run Windows as normal these days.
Apple, with their iPad has blown new life into the tablet PC world and with Steve Jobs cool marketing tactics has made the tablet a cool thing to have.
Types of computers. Tablet PC
Types of computers tablet PC
They are light which makes it easy to carry around. If you are a business person that has to attend a lot of meetings, then maybe a tablet PC is the way to go.

Servers
So what's a server? Server are computers that typically serve other devices. For instance, when you want to read your email, you connect to a server and the server then serve's your email data to you.
They come in different shapes and sizes and are highly scalable, meaning they can hold more components than conventional PC's. Some servers can scale from a single CPU to multiple CPU's. It all depends on type of server and vendor.
Fujitsu, for instance, has a server called the M9000 that can have up to 64 physical quad core CPU's installed in boards called, the system board. Each of the system boards can take 4 CPU's and you can place up to 16 of these boards in a system.
The memory of these systems can be as much as 4 terabytes. Read more on terabytes here.
Servers rack mounted
Types of computers servers
Servers varies in sizes and are usually rack mounted, meaning they don't stand on your desk but slide into a unit called a rack. They usually run an operating system called UNIX, but windows also has a server version that can be installed.
These servers are very vendor specific and the competition is fierce out there. Some major players include, IBM, Oracle, Fujitsu and HP to name a few.
Don't worry too much about servers here, just know they are there to serve data and applications to clients, which is your PC or laptop that you use.

Mainframes
Mainframes also nicknamed "heavy metal" or "big iron". These systems are used mainly by large organizations like Banks or the government institutions for things like census or statistics and financial applications.
IBM mainframe
IBM Mainframe
They used to be very big. A System 370 from IBM could easily take up the room of a small house, and that's just the CPU. Then things like hard disk's and backup devices would take up the space of another house.
Things have changed and they are not that big anymore. They are still very expensive. Some companies even use servers instead of mainframes these days.
IBM is one of the major players in the market at the moment. There are other vendors like HP and Fujitsu but IBM is synonymous with mainframe computers.

They run their own special version of operating system and are very specialized systems. They are known for their reliability and scalability.
Companies are moving more and more to servers but there will always be a place for the mainframe.
There you have it, the different types of computers. There might be some that I have left out, but these are main types of computers.
Some also argue that cell phones are also a type of computer. It's got a CPU, Memory and storage in the form of a micro SD card. Strange but true.

Sunday 25 March 2012

What are the Different Types of Computers?

What are the Different Types of Computers?


Based on the operational principle of computers, they are categorized as analog, digital and hybrid computers.
Operational Principle
  1. Analog
  2. Digital
  3. Hybrid



Analog Computers: These are almost extinct today. These are different from a digital computer because an analog computer can perform several mathematical operations simultaneously. It uses continuous variables for mathematical operations and utilizes mechanical or electrical energy.

Digital Computers: They use digital circuits and are designed to operate on two states, namely bits 0 and 1. They are analogous to states ON and OFF. Data on these computers is represented as a series of 0s and 1s. Digital computers are suitable for complex computation and have higher processing speeds. They are programmable. Digital computers are either general purpose computers or special purpose ones. General purpose computers, as their name suggests, are designed for specific types of data processing while general purpose computers are meant for general use.

Hybrid Computers: These computers are a combination of both digital and analog computers. In this type of computers, the digital segments perform process control by conversion of analog signals to digital ones.

This was the classification of computers based on their style of functioning. Following is a classification of the different types of computers based on their sizes and processing powers.
Processing Power
  1. Mainframe
  2. Microcomputers



Mainframe Computers: Large organizations use mainframes for highly critical applications such as bulk data processing and ERP. Most of the mainframe computers have capacities to host multiple operating systems and operate as a number of virtual machines. They can substitute for several small servers.

Microcomputers: A computer with a microprocessor and its central processing unit is known as a microcomputer. They do not occupy space as much as mainframes do. When supplemented with a keyboard and a mouse, microcomputers can be called personal computers. A monitor, a keyboard and other similar input-output devices, computer memory in the form of RAM and a power supply unit come packaged in a microcomputer. These computers can fit on desks or tables and prove to be the best choice for single-user tasks.

Personal computers come in different forms such as desktops, laptops and personal digital assistants. Let us look at each of these types of computers.
Personal Computers
  1. Desktop
  2. Laptop
  3. Netbook
  4. PDA
  5. Minicomputer
  6. Server
  7. Supercomputer
  8. Wearable Computer
  9. Tablet



Desktops: A desktop is intended to be used on a single location. The spare parts of a desktop computer are readily available at relatively lower costs. Power consumption is not as critical as that in laptops. Desktops are widely popular for daily use in the workplace and households.

Laptops: Similar in operation to desktops, laptop computers are miniaturized and optimized for mobile use. Laptops run on a single battery or an external adapter that charges the computer batteries. They are enabled with an inbuilt keyboard, touch pad acting as a mouse and a liquid crystal display. Their portability and capacity to operate on battery power have proven to be of great help to mobile users.

Netbooks: They fall in the category of laptops, but are inexpensive and relatively smaller in size. They had a smaller feature set and lesser capacities in comparison to regular laptops, at the time they came into the market. But with passing time, netbooks too began featuring almost everything that notebooks had. By the end of 2008, netbooks had begun to overtake notebooks in terms of market share and sales.

Personal Digital Assistants (PDAs): It is a handheld computer and popularly known as a palmtop. It has a touch screen and a memory card for storage of data. PDAs can also be used as portable audio players, web browsers and smartphones. Most of them can access the Internet by means of Bluetooth or Wi-Fi communication.

Minicomputers: In terms of size and processing capacity, minicomputers lie in between mainframes and microcomputers. Minicomputers are also called mid-range systems or workstations. The term began to be popularly used in the 1960s to refer to relatively smaller third generation computers. They took up the space that would be needed for a refrigerator or two and used transistor and core memory technologies. The 12-bit PDP-8 minicomputer of the Digital Equipment Corporation was the first successful minicomputer.

Servers: They are computers designed to provide services to client machines in a computer network. They have larger storage capacities and powerful processors. Running on them are programs that serve client requests and allocate resources like memory and time to client machines. Usually they are very large in size, as they have large processors and many hard drives. They are designed to be fail-safe and resistant to crash.

Supercomputers: The highly calculation-intensive tasks can be effectively performed by means of supercomputers. Quantum physics, mechanics, weather forecasting, molecular theory are best studied by means of supercomputers. Their ability of parallel processing and their well-designed memory hierarchy give the supercomputers, large transaction processing powers.

Wearable Computers: A record-setting step in the evolution of computers was the creation of wearable computers. These computers can be worn on the body and are often used in the study of behavior modeling and human health. Military and health professionals have incorporated wearable computers into their daily routine, as a part of such studies. When the users' hands and sensory organs are engaged in other activities, wearable computers are of great help in tracking human actions. Wearable computers do not have to be turned on and off and remain in operation without user intervention.

Tablet Computers: Tablets are mobile computers that are very handy to use. They use the touch screen technology. Tablets come with an onscreen keyboard or use a stylus or a digital pen. Apple's iPad redefined the class of tablet computers.

These were some of the different types of computers used today. Looking at the rate of advancement in technology, we can definitely look forward to many more types of computers in the near future.

Types of computer

Types of computer

What are the different types of computers?


Different types of computer systems are nowadays available for different purposes according the user needs.
When you’ll have to order yours or even to build it, you should first define the expected use of your computer.

This step will help you to describe the basic capabilities and know the costs of your system.

What are the different types of computer system?

This is a brief view of the main expressions used to describe your computer.

Personal computers or microcomputers

Microcomputers are built to be used by one person. In fact when you talk about personal computers or its common acronym PC, you always mean microcomputers. For surfing the web, playing games or music, editing and many other tasks… you ordinarily use personal computers either at school, at home or at business.

You’ll find personal computers in two (2) major types: desktop and laptop.

If you opt for a desktop computer you have to set it up in a permanent location. Fortunately you are able to choose your preferred sizes such as a mini, mid or full tower.

You should then add many other devices to complete it such as keyboard, mouse and monitor which can be a CRT or LCD display.

What about Workstations and Servers?

If you need a high-end micro computer you should go for a workstation. This type of computer is recommended if you are working in game development, scientific calculations, engineering or 3D graphics. It is fastest than the common personal computer and even it can be used as server if you need to build a basic network client by example.

The server is generally used for a major client with the purpose to allow many users working together over a network. Servers require powerful processors, large amount of hard disk drives and ram memory.

Types of mobile computers

If you prefer the laptop you’ll go for the mobile or portable system. Your notebook, a common name of laptop, has the advantage to have all the parts built together.

Your notebook has the same computing power to the desktop machine but it is enough lightweight to be portable. If the mobile machine is relatively more expensive it’s because it costs more to design the small components.

Maybe you’ll need greater portability. So a handheld micro computer is your first option. To manage your phone book, diary or taking notes...etc a Personal Digital Assistant (PDA) is useful.

You can also use the Palmtop, a tinier laptop than the PDA, to the same purposes and even more. The Palmtop is designed with a small keyboard and a flip-up screen and is more usable to surf the web while you are on the move.

Types of mini computers

Apart the micro computers, you may consider three other types of computers: the minicomputers, the mainframes and the supercomputers.

Be advised that the name minicomputers does not mean it is slowest than your PC. Surely not! If you plan to build a home network the minicomputers can be used as a mid- range server to serve multiple users.

However with the mainframe you are able to build a large network for several hundred clients. You can process millions of transactions daily with the mainframe because of its high capacity. Most of enterprises such as large organizations, insurance businesses, industry, banking … usually use the mainframe for processing and storing enormous amounts of data every day.

The supercomputer is the fastest machine in the history of computer not only for its size but especially for its capacity. You won’t have to use this powerful system unless you are working with nuclear or aerodynamic companies for example.

Conclusion Through this brief description you had opportunity to learn a lot about the different generation of computer. Nowadays many electronics devices are working like computers. Your iPod, your cell phone or even your watch has an integrated computer application. In the near future you can’t imagine what you are expected as newer types of computer!




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Understanding Your Computer

Understanding the anatomy of a PC is no easy task, even if you've used one every day for years. You may have heard the terms "motherboard" or "central processing unit," but asking most people to define these very essential components is likely to draw blank stares.
Computer
The two main types of computers are portable and desktop. Portable computers come in various shapes and sizes, and include laptops and hand-held devices. Desktops are stationary, typically with a more powerful configuration. Several components are essential to both. Hands down, the most powerful component of a computer is the central processing unit (CPU). Other basic and necessary components include memory, the motherboard, the hard drive and the power supply.
CPU

Central processing unit

The CPU handles all of the computation work and is distinguished by its speed. The higher the speed, the faster the PC. If you're watching high-definition movies or manipulating graphics, then you'll need a computer with fast processing.

Random access memory (RAM)

Your computer can't function without memory. RAM is the hardware inside the computer that stores information. Get a minimum of 512 megabytes -- memory is even more important than the speed of the processor. The more RAM a computer has, the more smoothly the PC will run when using several programs at once. While adding more memory later isn't time consuming, getting what you need when you purchase the computer is worthwhile and may be more cost effective.

Motherboard

The motherboard provides the connections within the computer and hosts the RAM, microprocessor and drive controllers. The microprocessor is the brain of the computer and controls the operations, while the drive controllers enable the computer's hard drive to work. The motherboard should have at least two USB ports to plug in a digital audio player or additional memory drive.

Hard drive

All data created on the computer, whether it's homework, business files or personal data, are stored on the hard drive. It has a much larger capacity than the RAM.

Power supply

The last of the mandatory computer components is the power supply. While it may be the simplest, it's absolutely essential for allowing the computer to work. Enough said.
Ethernet

Modem

With the Internet being the center of the world for many of us, access to it could actually move to the essential list. Most PCs have a modem for dial-up Internet access and an Ethernet port for broadband access. For a wireless connection, you'll need a wireless network adapter, also standard on most computers.

CD/DVD drive

A CD or DVD drive (also known as an optical drive) is the readable and/or writable drive that allows users to read from and write to a CD or DVD. Most PCs have an optical drive that can read CDs and DVDs, and for not much more money, you can get a drive that writes, too.

Audio/visual extras

Determine whether additional items such as sound cards, graphic cards, video cards or speakers fit your needs. If you want to run games or multimedia programs faster, then many of these options can prove beneficial. Integrated sound is already adequate on most computers, but upgrading to surround sound is a desirable option.
Monitor

Keyboard, mouse and monitor

The keyboard allows users to enter commands, and the mouse is an interface with the same function. The monitor, serving as a desktop computer screen, comes in various sizes. A small monitor is typically around 17 inches, while greater than 20 inches is considered large. The higher the resolution on the monitor, the better the graphics card you'll need to run games or video-intense applications. If you're undecided, you can't go wrong with a 22-inch digital monitor.

Operating system and software

After you've made all the hardware decisions, determine what pre-installed software you'll need for your computer. Select the latest version of an operating system such as Microsoft Windows, the best-selling operating system for years. Also purchase an anti-virus program such as Norton or Trend Micro, and choose from other programs such as word processing and spreadsheets.
So much for thinking you couldn't understand a PC from A to Z! This ultra-complex machine deserves our thanks. After all, functioning without a computer these days would be like living in the dark.

computers

Types of Hard Drive Formatting


Types of Hard Drive Formatting
2.2.2 Types of Hard Drive Formatting
The two types of hard drive formatting are low and high level. Low level formatting creates the track and sectors on the drive. These tracks and sectors form the physical blocks of storage of 512 bytes each.
High level formatting is file system specific, including Microsoft (DOS, FAT, and NTFS) and Open Source Initiative (OSI) varieties (ext2, ReiserFS, and XFS). Low level formatting is done by the hard drive vendor. High level formatting is done when the OS is installed.
High level formatting creates the hard drive's file system and allows the OS to store files by dividing them into smaller pieces and saving them in separate clusters (a grouping of sectors) on the disk. The OS uses this file system to keep track of the placement and sequence of each piece and to identify which sectors on the disk are free and available for new files. The computer can then assemble the different pieces when a file is viewed or executed.

Why Understand File Systems?
Different OS, different file systems
Poor documentation
File location
Hidden data
File deletion

Why Understand File Systems?

2.2.3 Importance of File Systems

A file system has two basic functions that impact the computer's performance:
. mapping physical spaces on the drive to logical addresses that comprise files
. read/write capability to open, change, and delete files
Understanding how these functions work on different file systems is the foundation for responding to a security incident. Most file systems are related directly to a particular OS, although some OSs combine file systems.
To discover where files are located and how they are distributed, you need to know how to access and modify system settings when necessary. This is especially important because files can be hidden.
Typically when a user deletes a file, the file system does not permanently erase (wipe) the file from the hard drive. It simply creates a flag that tells the OS that the sector can be reused. Knowing how to rebuild files from the file system is one of the most important skills of the forensic examiner.
The forensic examiner has access to deleted files and to files contained in swap space, which is part of the virtual memory created on the hard drive by the OS. Swap space files are described later in this module.