Different types of Computers

Following are some important types of computers.

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.

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.

Mainframe Computers: Large organizations use mainframes for highly critical applications such as bulk data processing and ERP. Most of the mainframe computers have the capacities to host multiple operating systems and operate as a number of virtual machines and can thus 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. When supplemented with a keyboard and a mouse, microcomputers can be called as 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 serve as the best choices for single-user tasks.

Desktops: A desktop is intended to be used on a single location. The spare parts of a desktop computer are readily available at relative lower costs. Power consumption is not as critical as that in laptops. Desktops are widely popular for daily use in workplaces 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. Its portability and capacity to operate on battery power have served as a boon for mobile users.

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 effectively used as portable audio players, web browsers and smart phones. 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.

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 are consistently in operation as they do not have to be turned on and off and are constantly interacting with the user.

These were some of the different types of computers available today.

CRT Monitor vs LCD Monitor

There are hosts of differences between LCD and CRT monitors with regards to various features and specifications. Know what differentiates these two major monitor technologies.

  CRT monitor                                                             LCD monitor

 









Size and Weight

LCD monitors win over CRT monitors when it comes to physical size. LCD monitors are small, light and require less space. CRT monitors, on the other hand, are big, bulky, heavy and acquire large spaces. LCD monitors can be easily maneuvered between computers, if due to any reason you change monitors. CRT monitors are incompatible for small desks and small places.

CRT monitors are also not easily portable. On an average, a 17 inch CRT monitor weighs around 40 pound and a similar LCD monitor would weigh close to 15 pounds. When it comes to size, the viewable area on a monitor matters. A 17 inch CRT monitor will provide a viewable area of around 16.1 inches whereas a 17 inch LCD monitor will provide complete viewable area, that is 17 inches.

Picture Quality

In general, picture quality in both the CRT and LCD monitors differs slightly. New models of both monitors provide good color display. LCDs lag behind in providing a maximum range of color displays unlike CRT monitors. In terms of sharpness, an LCD running at its native resolution or fixed resolution is better than a CRT monitor that can give unclear edges.

Viewing Angle

CRT monitors can be viewed from any angle while LCD monitors can show different views depending on your angle of viewing. At some angles, the picture may be blurred, faded and unclear in LCD monitors.

Price
LCDs are long term investments and profitable one, though expensive. In the recent years prices of both these monitors have gone down and they're well within the reach of consumers. Since LCD monitors have captured mainstream market of computer monitors, the production of CRT monitors has gone down, drastically.

Power Consumption

CRT monitor power consumption rate is much higher than LCD power consumption rate and this is one of the major CRT monitor problems in the long run.

How to Check RAM on Windows XP

Users of Windows XP have many ways that they can use to check the RAM on their machines. Computer manufacturers have made this a highly simple task so that everyone knows how to check RAM speed as and when they please. This makes a lot of future installations and purchases simpler. Here are 3 ways of how to check RAM on Windows XP.

· Click on the 'Start' menu and wait for the Start menu window to pop up. Right click on 'My Computer', and then click on 'Properties'. Choose the tab that says 'General'. You will be able to view the RAM on your computer here.

· Click on the 'Start' menu and then select the 'Run' option. In the dialog box that opens, type in 'DXDIAG' and then press enter. Your system configuration will open up in the subsequent window that comes.

· The 3rd option for you is to follow this trail of instructions. Click on 'Start' menu, go to 'Programs', go to 'Accessories', go to 'System Tools', and then go to 'System Information'. You can also view your computers RAM and configuration from here.

How to Check RAM on Vista

How to check RAM on Vista is not very different either. You can follow the same methods of clicking on 'Start' tab and then either selecting 'Run' and entering 'DXDIAG' and hitting enter, or you can right click on 'My Computer' and select 'Properties' and then choose the 'General' tab to view your computers configuration. Another path for you to follow is select the 'Start' orb, then go to 'Control Panel' and select 'System Maintenance' in the Classic View. Now select 'System' and then check the system category to view the information about your computers configuration.

How to Check RAM on Mac

People using Apple Macintosh computers also wish to check their RAM for the same purposes. The method is primarily the same, but the options and the items to select are obviously different. Try out this method on how to check RAM on Mac.

· Click on the 'Apple' menu, and then select one of 'About This Macintosh' or 'About This Computer'. Now you need to select the 'More Info' button to get more information and to get what is known as the System Profiler screen. In the subsequent screen that opens you have to search for the 'Hardware' option on the left column and then select the 'Memory' tab. You will now be able to view details about your systems configuration and see how much RAM you have.

Different types of Computers

Following are some important types of computers. 

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. 

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.

Mainframe Computers: Large organizations use mainframes for highly critical applications such as bulk data processing and ERP. Most of the mainframe computers have the capacities to host multiple operating systems and operate as a number of virtual machines and can thus 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. When supplemented with a keyboard and a mouse, microcomputers can be called as 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 serve as the best choices for single-user tasks.

Desktops: A desktop is intended to be used on a single location. The spare parts of a desktop computer are readily available at relative lower costs. Power consumption is not as critical as that in laptops. Desktops are widely popular for daily use in workplaces 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. Its portability and capacity to operate on battery power have served as a boon for mobile users.

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 effectively used as portable audio players, web browsers and smart phones. 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.

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 are consistently in operation as they do not have to be turned on and off and are constantly interacting with the user.

These were some of the different types of computers available today.

Different Types of Computer Viruses

There are Different Types of Computer Viruses could be classified in (origin, techniques, types of files they infect, where they hide, the kind of damage they cause, the type of operating system or platform they attack) etc.

Computer Virus is a kind of malicious software written intentionally to enter a computer without the user's permission or knowledge, with an ability to replicate itself, thus continuing to spread. Some viruses do little but replicate others can cause severe harm or adversely effect program and performance of the system. A virus should never be assumed harmless and left on a system. Most common types of viruses are mentioned below:

Resident Viruses

This type of virus is a permanent which dwells in the RAM memory. From there it can overcome and interrupt all of the operations executed by the system: corrupting files and programs that are opened, closed, copied, renamed etc.

Direct Action Viruses

The main purpose of this virus is to replicate and take action when it is executed. When a specific condition is met, the virus will go into action and infect files in the directory or folder that it is in and in directories that are specified in the AUTOEXEC.BAT file PATH. This batch file is always located in the root directory of the hard disk and carries out certain operations when the computer is booted.

Overwrite Viruses

Virus of this kind is characterized by the fact that it deletes the information contained in the files that it infects, rendering them partially or totally useless once they have been infected.

The only way to clean a file infected by an overwrite virus is to delete the file completely, thus losing the original content.

Boot Virus

This type of virus affects the boot sector of a floppy or hard disk. This is a crucial part of a disk, in which information on the disk itself is stored together with a program that makes it possible to boot (start) the computer from the disk.
The best way of avoiding boot viruses is to ensure that floppy disks are write-protected and never start your computer with an unknown floppy disk in the disk drive.

Macro Virus

Macro viruses infect files that are created using certain applications or programs that contain macros. These mini-programs make it possible to automate series of operations so that they are performed as a single action, thereby saving the user from having to carry them out one by one.

Directory Virus

Directory viruses change the paths that indicate the location of a file. By executing a program (file with the extension .EXE or .COM) which has been infected by a virus, you are unknowingly running the virus program, while the original file and program have been previously moved by the virus.

Once infected it becomes impossible to locate the original files.

Polymorphic Virus

Polymorphic viruses encrypt or encode themselves in a different way (using different algorithms and encryption keys) every time they infect a system.

This makes it impossible for anti-viruses to find them using string or signature searches (because they are different in each encryption) and also enables them to create a large number of copies of themselves.

File Infectors

This type of virus infects programs or executable files (files with an .EXE or .COM extension). When one of these programs is run, directly or indirectly, the virus is activated, producing the damaging effects it is programmed to carry out. The majority of existing viruses belong to this category, and can be classified depending on the actions that they carry out.

Companion Viruses

Companion viruses can be considered file infector viruses like resident or direct action types. They are known as companion viruses because once they get into the system they "accompany" the other files that already exist. In other words, in order to carry out their infection routines, companion viruses can wait in memory until a program is run (resident viruses) or act immediately by making copies of themselves (direct action viruses).

FAT Virus

The file allocation table or FAT is the part of a disk used to connect information and is a vital part of the normal functioning of the computer.

This type of virus attack can be especially dangerous, by preventing access to certain sections of the disk where important files are stored. Damage caused can result in information losses from individual files or even entire directories.

Worms
A worm is a program very similar to a virus; it has the ability to self-replicate, and can lead to negative effects on your system and most importantly they are detected and eliminated by antiviruses.

Trojans or Trojan Horses

Another unsavory breed of malicious code are Trojans or Trojan horses, which unlike viruses do not reproduce by infecting other files, nor do they self-replicate like worms.

Logic Bombs

They are not considered viruses because they do not replicate. They are not even programs in their own right but rather camouflaged segments of other programs.

What is a Computer Virus?

Computer viruses are a major problem for computer users worldwide. It has individuals and even governments worried. Major efforts are going on to tackle it.

What is a Computer Virus?

A computer virus is a man-made program or code that can cause damage to your data and software on a computer. It is able to replicate usually without knowledge and permission of the computer user.

How does it spread?

They are spread unknowingly from one infected computer to another via emails and instant messaging.

Types of Computer Viruses

Trojan horse- These are programs that claim to do one thing but actually do something else (usually damaging activity).

Resident virus- These dwell in the RAM memory and work by overcoming and interrupting all of the operations executed by the system including corrupting of the files and programs that are opened and closed.

Direct action virus- This has a main purpose of replicating and taking action when it is executed. The batch file of this virus is always found in the root directory of the hard disk.

Overwrite virus- These are characterized by the fact that they delete the information that is contained in the files that they infect, and this renders the files as being partially or even totally useless once they have been infected.

Boot virus- These affect the boot sector of a floppy or hard disk.

Macro virus- These infect files that are created using certain applications or certain programs that contain macros.

E-mail virus- These can infect your desktop email system. They proliferate through e-mail messages and usually replicate by automatically e-mailing copies to all entries in your e-mail address book.

Worm- These are programs that are able to replicate on their own over computer networks. It scans a network for computers with same security hole that it can exploit to infect that machine, scan other machines for that security loophole, and continue replicating itself independently.

One should use licensed anti-virus software to protect one's computer from computer viruses.

Different Types of Memory Cards

Since the last 10 years or so, there have been many different types of memory cards introduced in the market. These memory cards are small storage devices that are easily portable. These are solid state cards, that is, no movable parts, perfect to be used in different devices, like digital cameras, music players, cell phones, etc. Let us take a look at some of the types of computer memory cards.

Compact Flash Memory Cards
Compact Flash or CF memory cards were created by SanDisk way back in 1994. These computer memory types has a memory controller and a flash memory chip. This chip was contained in a miniature casing that is 42.8 mm wide and 36.4 mm high. This makes it smaller than a matchbox. According to the dimensions, there are two types pf compact flash cards available that includes:

· Type I Compact Flash cards - 42.8mm x 36.4mm x 3.3 mm

· Type II Compact Flash cards - 42.8mm x 36.4mm x 5.5 mm

Memory Stick Cards
The memory stick. also known as MS or MS cards are one of the types of computer memory cards that were created by Sony and SanDisk in partnership in January 2000. These memory cards are based on NAND flash memory circuits and are really very small in size. They are just about 21.5 mm x 50.0 mm x 2.8 mm and weigh just 4 grams. One can access data by connecting the memory stick card with an edge connector of 10 pins. There are two types of memory stick cards available:

· 'Normal' Memory Stick

· 'Magic Gate' (for protection of copyrighted documents)

Multimedia Cards
Multimedia card (MMC) are types of memory cards that were created by SanDisk and Siemens together in 1997. These memory cards were based on a combination of read only memory (ROM). It is therefore used for applications and flash memory for read/write. These cards are very small and come in size of about 24.0 mm x 32.0 mm x 1.4 mm and weigh about 2.2 grams. One can access data by connecting the card with 7 pins. There are two types of multimedia cards based on the different voltages:

· Multimedia cards 3.3 V that has a notch on the upper left hand corner

· Multimedia cards 5 V that has a notch on the upper right hand corner

Secure Digital Memory Cards
The secure digital or SD cards are computer memory type cards created by Matsushita Electronic, SanDisk and Toshiba in January 2000 together. This card is designed keeping in mind the latest electronic audio and video devices. It is based on the NAND type flash memory circuits. It is just 24.0mm x 32.0mm x 2.1mm in size and weighs 2 grams. The SD cards come in three formats:

· Standard SD cards

· MiniSD card - This is a 21.5 mm x 20 mm x 1.4 mm card for digital cameras, mobile phones

· MicroSD cards - This is a 15 mm x 11 mm x 0.7 mm card for mobile phones and smaller devices. This is the smallest type of memory card available.

SmartMedia Cards
Toshiba and Samsung have created the SmartMedia memory cards together. It is based on the NAND type flash memory circuit. It is 45.0 mm x 37.0 mm x 0.76 mm in size and weighs 2 grams. It has become obsolete today and is found in older devices that needed memory cards larger than 128 MB.

xD Picture Card
The xD picture card or eXtreme digital are types of computer memory cards that were made by Fuji and Olympus in August 2002. It is based on NAND type flash memory circuits. This memory card is just 20.0 mm x 25.0 mm x 1.7 mm in size and weighs only 2 grams. They are used mainly for digital cameras and are being replaced by SD cards.

Computer Memory Types

There are many computer memory types and subtypes which are categorized depending upon their role in the computer system. However, in this article we have focused on the most basic types of computer memory

Memory is one of the most important things that is incorporated into computers, be it laptop computers or PCs. There are various computer memory types installed, depending upon the actual need for functioning and specifications of the system. The computer memory relates to the many devices and components that are responsible for storing data and applications on a temporary or a permanent basis. It enables a person to retain the information that is stored on the computer. Without it, the processor would not be able to find a place which is needed to store the calculations and processes. There are different types of memory in a computer that are assigned a task of storing several kinds of data. Each has certain peculiarities and capacities.

Basic Computer Memory Types Explained

Random Access Memory (RAM)

RAM is a location within the computer system which is responsible for stacking away data on a temporary basis, so that it can be promptly accessed by the processor. The information stored in RAM is typically loaded from the computer's hard disk, and includes data related to the operating system and certain applications. When the system is switched off, RAM loses all the stored information. The data remains stored and can be retained only when the system is running.

When the RAM gets full, the computer system is more likely to operate at a slow speed. The data can be retrieved in any random order. Generally, there are two types of RAM; namely Static RAM (SRAM) and Dynamic RAM (DRAM). When many programs are running on the computer simultaneously, the virtual memory allows the computer to search in RAM for memory portions which haven't been utilized lately and copy them onto the hard drive. This action frees up RAM space and enables the system to load different programs.

Read Only Memory (ROM)

This type of memory is active, regardless of whether the system is turned on or is switched off. It is a kind of permanent non-volatile storage memory. As the name 'read only' suggests, the contents in it cannot be changed or modified. It is an integrated circuit which is pre-programmed with important data that should necessarily be present for the computer to carry out its normal functionalities.

Cache
Cache is a kind of RAM which a computer system can access more responsively than it can in regular RAM. The central processing unit looks up in the cache memory before searching in the central memory storage area to determine the information it requires. This rules out the need for the system to search for information in larger and bigger memory storage areas, which in turn leads to a faster extraction of data.

Computer Hard Drive

These devices are important data storage components that are installed in the CPU. Their memory ranges widely, and a user may choose the memory depending on the data needed to be stored and accessed. Nowadays, hard drives having a memory capacity of 120 gigabytes to 500 gigabytes are normally used.

Flash Memory

This is a non-volatile kind of memory which is intended to contribute to portable storage and a convenient transfer of data from one computer to another. The data in it can be erased and re-programmed as per the user's requirements. It only has a specific number of erase and write cycles that it can withstand, after which it creates a tendency to lose out on the stored information. Memory cards and USB flash drives are some modes of this type of memory storage.

Computer Motherboard Parts

In the modern computer, the motherboard or the primary circuit board (PCB), is the heart of the machine. The computer motherboard is the device that is solely responsible for ensuring that all the devices and components of the machine are connected to the microprocessor. These devices, that the motherboard powers and regulates, are storage devices, hard disks, graphics cards and sound cards. All these devices, without which the machine cannot function, are either inbuilt in the motherboard or are connected via computer motherboard slots or sockets.

Simply put, it is the motherboard that ensures that each of these computer motherboard components are powered and communicate with each other effectively. The first motherboards that were invented had very few computer motherboard components, and the only things present on those motherboards were the processor and slots, to connect other devices. But today's machines have motherboards containing a wide variety of features and tremendous potential for future upgrades. Read more about computer buying.                                        

Peripheral Component Interconnect (PCI) slot
Normally, the number of PCI slots on the motherboard could be anywhere between 1 and 6. The peripherals like graphics cards, sound cards, ethernet cards, modems and DVD recorders are attached here, and the slots are 32 bit slots.

Central Processing Unit (CPU) socket
This socket is the home for your computer's processor. There are 2 types of sockets that are commonly used by the major processors (Intel and AMD), these are Pin Grid Array (PGA) and the Land Grid Array (LGA).

Motherboard Battery Compartment
When you shut your system down, your data is stored in a battery on the motherboard. This computer motherboard battery is placed inside the battery compartment that is present on the surface of your motherboard.

RAM slots (DIMM and SIMM)
These are the slots that hold the RAM chips of your computer. They are usually of two types - DIMM (Double Inline Memory Module) and SIMM (Single Inline Memory Module). Memory chips of different sizes can be attached here.

Power Connector
The motherboard requires the power to function properly and this power supply comes from the main power connector. There are usually two main types of connectors - 20 + 4 pins (when there are two connectors on the same motherboard), and the 24 pins.

Apart from these computer motherboard components, the following are computer motherboard parts that have specific purposes for connecting to hardware devices. These connectors show up on the back panel of the computer, once the entire machine is assembled and mounted.

PS/2 Connectors
Every motherboard contains two PS/2 connectors, one for the keyboard and one for the mouse.

USB (Universal Serial Bus) Port
There are many of these ports across the back panel. They are used for connecting external devices like USB flash drives, external hard disks, ipods, mp3 players and cameras.

Game Port
This port is mostly used to connect the devices that are used for gaming purposes, like joysticks.

Display Connector
This port is used to connect the computer monitor of the machine to the back panel.

Sound Card Connector
Your sound devices like headphones and mics are connected here. 

This computer motherboard information should illuminate the many purposes of the various computer motherboard parts that are standard requirement for every computer to function properly.