Monthly Archives: March 2017

Ways to Clean Your Computer Keyboard

One of the best ways to keep a keyboard in top condition is periodic cleaning. As preventive maintenance, you should vacuum the keyboard weekly, or at least monthly. When vacuuming, you should use a soft brush attachment to dislodge the dust. Also note that some keyboards have keycaps that come off easily, so be careful when vacuuming; otherwise you may have to dig the keys out of the vacuum cleaner. I recommend using a small, handheld vacuum cleaner made for cleaning computers and sewing machines; these have enough suction to get the job done with little risk of removing your key tops.

You also can use compressed air to blow the dust and dirt out instead of using a vacuum. Before you dust a keyboard with the compressed air, however, power off the computer, unplug the keyboard, and turn it upside down so the particles of dirt and dust collected inside can fall out.

On most keyboards, each keycap is independently removable, which can be handy if a key sticks or acts erratically. For example, a common problem is a key that does not work every time you press it. This problem usually results from dirt collecting under the key. An excellent tool for removing keycaps on almost any keyboard is the U-shaped chip puller included in many computer tool kits. Simply slip the hooked ends of the tool under the keycap, squeeze the ends together to grip the underside of the keycap, and lift up. IBM sells a tool designed specifically for removing keycaps from its keyboards, but the chip puller works even better. After removing the cap, spray some compressed air into the space under the cap to dislodge the dirt. Then replace the cap and check the action of the key.

When you remove the keycap on some keyboards, you are actually detaching the entire key from the keyswitch. Be careful during the removal and reassembly of the keyboard; otherwise, you’ll break the switch. The classic IBM/Lexmark-type Model M keyboards (now made by Unicomp) use a removable keycap that leaves the actual key in place, enabling you to clean under the keycap without the risk of breaking the switches. If you don’t want to go through the effort of removing the keycaps, consider using cleaning wands with soft foam tips to clean beneath the keytops.

Spills can be a problem, too. If you spill a soft drink or cup of coffee into a keyboard, you do not necessarily have a disaster. Many keyboards that use membrane switches are spill resistant. However, you should immediately (or as soon as possible) disconnect the keyboard and flush it out with distilled water. Partially or fully disassemble the keyboard and use the water to wash the components. If the spilled liquid has dried, soak the keyboard in some of the water for a while. When you are sure the keyboard is clean, pour another gallon or so of distilled water over it and through the keyswitches to wash away any residual dirt. After the unit dries completely it should be perfectly functional. You might be surprised to know that drenching your keyboard with water does not harm the components. Just make sure you use distilled water, which is free from residue or mineral content. (Bottled water is not distilled; the distinct taste of many bottled waters comes from the trace minerals they contain!) Also, make sure the keyboard is fully dry before you try to use it; otherwise, some of the components might short out.

Fully drying a keyboard that has been soaked in water can take several days or more, so be prepared to wait. You can use compressed air to greatly speed up the drying process. Even then, if the contaminants were not fully flushed out, the keyboard may still not work correctly. In that case the best results will be obtained by completely disassembling the keyboard, washing and then drying each component individually, and then reassembling. Depending on the value and construction of the keyboard, a replacement may be the best option.

Computer Output Devices


Monitors, commonly called as Visual Display Unit (VDU), are the main output device of a computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form. The sharpness of the image depends upon the number of pixels.

There are two kinds of viewing screen used for monitors.

  • Cathode-Ray Tube (CRT)
  • Flat-Panel Display

Cathode-Ray Tube (CRT) Monitor

The CRT display is made up of small picture elements called pixels. The smaller the pixels, the better the image clarity or resolution. It takes more than one illuminated pixel to form a whole character, such as the letter ‘e’ in the word help.

A finite number of characters can be displayed on a screen at once. The screen can be divided into a series of character boxes – fixed location on the screen where a standard character can be placed. Most screens are capable of displaying 80 characters of data horizontally and 25 lines vertically.

There are some disadvantages of CRT −

  • Large in Size
  • High power consumption

Flat-Panel Display Monitor

The flat-panel display refers to a class of video devices that have reduced volume, weight and power requirement in comparison to the CRT. You can hang them on walls or wear them on your wrists. Current uses of flat-panel displays include calculators, video games, monitors, laptop computer, and graphics display.

The flat-panel display is divided into two categories −

  • Emissive Displays − Emissive displays are devices that convert electrical energy into light. For example, plasma panel and LED (Light-Emitting Diodes).
  • Non-Emissive Displays − Non-emissive displays use optical effects to convert sunlight or light from some other source into graphics patterns. For example, LCD (Liquid-Crystal Device).


Printer is an output device, which is used to print information on paper.

There are two types of printers −

  • Impact Printers
  • Non-Impact Printers

Impact Printers

Impact printers print the characters by striking them on the ribbon, which is then pressed on the paper.

Characteristics of Impact Printers are the following −

  • Very low consumable costs
  • Very noisy
  • Useful for bulk printing due to low cost
  • There is physical contact with the paper to produce an image

These printers are of two types −

  • Character printers
  • Line printers

Character Printers

Character printers are the printers which print one character at a time.

These are further divided into two types:

  • Dot Matrix Printer(DMP)
  • Daisy Wheel

Dot Matrix Printer

In the market, one of the most popular printers is Dot Matrix Printer. These printers are popular because of their ease of printing and economical price. Each character printed is in the form of pattern of dots and head consists of a Matrix of Pins of size (5*7, 7*9, 9*7 or 9*9) which come out to form a character which is why it is called Dot Matrix Printer.


  • Inexpensive
  • Widely Used
  • Other language characters can be printed


  • Slow Speed
  • Poor Quality

Daisy Wheel

Head is lying on a wheel and pins corresponding to characters are like petals of Daisy (flower) which is why it is called Daisy Wheel Printer. These printers are generally used for word-processing in offices that require a few letters to be sent here and there with very nice quality.


  • More reliable than DMP
  • Better quality
  • Fonts of character can be easily changed


  • Slower than DMP
  • Noisy
  • More expensive than DMP

Line Printers

Line printers are the printers which print one line at a time.

These are of two types −

  • Drum Printer
  • Chain Printer

Drum Printer

This printer is like a drum in shape hence it is called drum printer. The surface of the drum is divided into a number of tracks. Total tracks are equal to the size of the paper, i.e. for a paper width of 132 characters, drum will have 132 tracks. A character set is embossed on the track. Different character sets available in the market are 48 character set, 64 and 96 characters set. One rotation of drum prints one line. Drum printers are fast in speed and can print 300 to 2000 lines per minute.


  • Very high speed


  • Very expensive
  • Characters fonts cannot be changed

Chain Printer

In this printer, a chain of character sets is used, hence it is called Chain Printer. A standard character set may have 48, 64, or 96 characters.


  • Character fonts can easily be changed.
  • Different languages can be used with the same printer.


  • Noisy

Non-impact Printers

Non-impact printers print the characters without using the ribbon. These printers print a complete page at a time, thus they are also called as Page Printers.

These printers are of two types −

  • Laser Printers
  • Inkjet Printers

Characteristics of Non-impact Printers

  • Faster than impact printers
  • They are not noisy
  • High quality
  • Supports many fonts and different character size

Laser Printers

These are non-impact page printers. They use laser lights to produce the dots needed to form the characters to be printed on a page.


  • Very high speed
  • Very high quality output
  • Good graphics quality
  • Supports many fonts and different character size


  • Expensive
  • Cannot be used to produce multiple copies of a document in a single printing

Inkjet Printers

Inkjet printers are non-impact character printers based on a relatively new technology. They print characters by spraying small drops of ink onto paper. Inkjet printers produce high quality output with presentable features.

They make less noise because no hammering is done and these have many styles of printing modes available. Color printing is also possible. Some models of Inkjet printers can produce multiple copies of printing also.


  • High quality printing
  • More reliable


  • Expensive as the cost per page is high
  • Slow as compared to laser printer

Types of Computer Hardware You Must Understand

Your computing experience is made up of interactions with hardware and software. The hardware is all the tangible computer equipment, such as the monitor, central processing unit, keyboard, and mouse. The main body of a computer is the system unit. The system unit’s case houses a number of essential components.

1. The central processing unit (CPU) is responsible for processing most of the computer’s data, turning input into output.

As you might imagine, the speed and performance of the CPU is one of the biggest factors that determines how well a computer works. A CPU is a very small, thin silicon wafer that is encased in a ceramic chip and then mounted on a circuit board.

CPU speed is measured in gigahertz (GHz). The higher this measurement, the faster the CPU can operate. A hertz is a cycle per second; a gigahertz is 1 billion cycles per second. CPU speed is not the only measurement of its performance, though; different CPUs have efficiency-boosting technologies built into them that can increase data throughput in a number of ways.

A fairer comparison between two different CPUs is the number of instructions per second they can perform.

2. Memory consists of computer chips that hold data.

One type of memory, called Random Access Memory (RAM), forms the central pool of memory that a computer uses to operate. The more RAM a computer has, the more applications it can have open at once without the computer’s performance starting to bog down. More RAM can also make some applications perform better in general.

Memory capacity is measured in gigabytes (GB), which is a billion bytes. Most basic computers have at least 4GB today, with higher end systems having 16GB or more. Like the CPU, memory consists of small, thin silicon wafers, encased in ceramic chips and mounted on circuit boards. The circuit boards holding memory are called DIMMs, which stands for dual inline memory module.

3. hard drive stores software.

When the computer is turned off, whatever is on the hard drive remains there, so you don’t have to reload software every time you turn on the computer. The operating system and your applications load from the hard drive into memory, where they run.

Hard-drive capacity is also measured in gigabytes (GB), like memory. A typical hard drive might be 500 GB or even 1 terabyte (1,000 GB) or more. Most hard drives sold today are the traditional mechanical type that use metal platters to store data with magnetic polarity, but a newer type, called a solid state hard drive (SSHD), uses a type of memory, resulting in a fast, quiet, and reliable (but expensive) storage alternative.

4. In addition to the components in the system unit, a computer may come with one or more input devices.

Input devices include keyboards, mice, trackballs, and touchpads.

5. Each computer has some type of display screen.

Depending on the type of computer, the display screen may be built-in, or may be a separate unit called a monitor with its own power cord, as shown. Some displays are touchscreen, so you can use your finger on the screen to provide input to the computer.

Display quality is measured in resolution — that is, the number of pixels (individual colored dots) that comprise the display at its highest resolution. A typical resolution for a notebook PC is 1920 x 1080, for example. The first number is the horizontal resolution and the second one is the vertical resolution.

The aspect ratio of a display is the ratio of its width to its height, expressed in pixels. Displays may either be standard aspect ratio (4:3) or widescreen (16:9). For example, a small device might have a maximum resolution of 800 x 600; if you simplify that to a fraction, it comes out to 4/3.

6. Most desktop and notebook computers come with an optical drive, which is a drive that will read CDs, DVDs, and/or Blu-ray discs.

Optical drives get their name from the way data is written and read on the disc. A laser light shines on the surface, and a sensor measures how much light is bounced back from a certain spot.

Some laptop computers come without DVD capabilities because you can download and install software or play videos and music from the cloud (that is, via the Internet), so it’s possible to get along just fine without the ability to play DVDs. However, most desktop computers still come with a DVD drive.

7. Whatever computer you have, you will probably want to use it to connect to the Internet. That means you will want it to have a network adapter in it.

That capability may be built into the computer, or it may be added to the computer via an expansion board or a device that plugs into a port.

Internet connectivity can be either wired or wireless. A wired connection requires you to connect a cable from the computer to the device that supplies your Internet connection (such as a cable modem). That type of cable and connection is known as Ethernet.

A wireless connection allows the computer to communicate with the Internet connection device through radio waves. The type of wireless connection used for Internet connectivity is called Wi-Fi, or wireless Ethernet.

If high-speed Internet service is not available in your area, you may need to use a dial-up modem to connect using your home telephone line. Dial-up modems are nobody’s first choice — they are old, slow technology and they tie up your phone line.

Has Intel Invented a Universal Memory Tech?

Today’s computers shuttle data around a byzantine system of several different kinds of short- and long-term memory. No wonder, then, that engineers have long dreamed of one memory technology to rule them all, a universal memory that would simplify computing and streamline the path of data.

In March, Intel announced that it will sell to data centers a new kind of solid-state drive, called Optane, that it says could lead to this kind of simplification. Optane drives are nonvolatile, like flash memory, which means that they should use relatively little standby power and that they’re fast, like DRAM. “It really starts to marry the worlds of memory and storage together,” company CEO Brian Krzanich says in a promotional video, over the swells of heroic music. The technology “comes close to being the holy grail of memory,” says Intel executive vice president William Holt in the same video.

Whether 3D XPoint, the mystery technology inside Optane, can live up to this promise is likely to depend on the performance it delivers as well as Intel’s ability to scale up manufacturing using new materials and build out the right market. The 375-gigabyte Optane drive on offer now costs US $1,520, about three times the price of an equivalent solid-state drive.

This first product will enable data centers to do more with a smaller number of servers, says James Myers, who works on nonvolatile memory architecture at Intel. Myers gives an example of servers running a MySQL database, which, among other things, apps use to store instant messages. For a transaction to be useful in such applications, the data needs to be returned fast—within 10 milliseconds. An equivalent flash drive can perform 1,400 useful transactions per second; the Optane drive can perform over 16,000.

The Optane drive was announced with bombast, but the company is coy about the technology behind it. Myers says “3D” refers to the fact that the memory cells are stacked; “XPoint” alludes to the way the memory elements are arranged. While flash memory elements must be read and written in groups, XPoint elements—situated at the crossing point of interconnects—can be addressed individually. Myers says that this architecture, and something inherent to the storage materials themselves, makes 3D XPoint faster than flash memory.

Intel, which initially developed 3D XPoint in conjunction with Micron, won’t say what the technology really is, but this doesn’t seem to bother researchers or analysts. “Everyone seems to think it’s phase-change memory,” says semiconductor analyst Jim Handy. “I don’t care.” What matters to him—and, Intel hopes, its customers—is the performance.

The complexity of today’s memory hierarchy—a combination that often includes magnetic disks and flash for storage and DRAM and static RAM for memory—is a necessary evil. Each technology has its own strengths, so they must be combined. Data are shuttled around from speedy but expensive SRAM caches—which are close to the processor and embedded within it—to slower, less expensive (but still pricey) DRAM. Finally, data are stored in slow but reliable flash or hard-disk drives, or both. Even if it’s not possible to do it all in one memory technology, using only one for working memory close to the processor and one for longer-term storage would help simplify things. Intel says that XPoint memory could provide a speedier alternative to flash memory and magnetic hard disks. The company has also suggested it could supplement or supplant DRAM.

“DRAM is unique in its ability to waste power, so anything you can do to get rid of it is great,” says Handy. For example, Google is thought to store the index of the entire Internet on several power-hungry, quick-access DRAM servers. If the company could switch this over to 3D XPoint—which Intel claims has 10 times the density of DRAM—Google could use fewer servers and thus save power and money, according to Steven ­Swanson, a computer scientist at the University of California, San Diego.

Intel is providing software that will enable computers to operate Optane as memory as opposed to storage, but it will be slow. Optane drive latencies max out at 7 or 8 microseconds—way faster than flash, which takes hundreds of microseconds, but not touching DRAM’s low hundreds of nanoseconds. The Optane drives are fettered by the interface they use: They connect to the storage interface, not the memory interface.

In the short term, Intel’s drives are not likely to replace any existing memory technologies but will instead supplement them, says Swanson, who built a research drive based on the company’s 3D XPoint technology in 2011. Swanson expects the path to memory and storage simplification to be complex because computing systems will have to be redesigned to route data in new ways.

Swanson and Handy believe Intel started with storage to help smooth out some of the risk in launching a new memory technology. Making Optane a memory requires new circuit board designs and cooperation from programmers. To get those, Intel needs to show that there is a market for 3D XPoint and demonstrate its reliability. Intel says that a product using a memory interface will be out in 2018. Even using the interface, 3DXPoint still won’t be quite as fast as DRAM, but Intel promises that it will be denser and less expensive.

The success of this new memory, then, will hinge on data centers taking it up in a less than ideal initial form while the company works on scaling up production. Even though the flaws in today’s memory and storage hierarchy are universally acknowledged, trying to change it is a risky move. “Almost all memory companies have one or two potential competitors to this technology, and they’re all waiting to see what happens before they jump into [a] big investment,” says Swanson.

Memory enthusiasts disagree about whether a true universal memory is even physically possible. It is perhaps most useful as a goal to guide the computer industry forward. “The concept of the universal memory is attractive because the idea is to simplify,” says Wei Lu, a computer scientist at the University of Michigan and chief scientist at Crossbar, a resistive RAM startup company. “We have a big-data problem, and today’s computers are fundamentally not good at this.”