Neel Nirjon

We all use many devices and equipments that run on electricity. Some of these equipments are also electronic devices. For all these to function properly they need uniform power supply. The electric supply in many countries is not uniform. Therefore to make it uniform there is a need for a device. There are many such devices available in the market today. For example UPS (Uninterrupted power supply), Voltage Stabilizer, Constant Voltage Transformer are such devices available today. What is the use of these devices. How to they work? Which of these devices is suitable for you? You will get answer to all these questions in this tutorial.

What is power conditioning?

We can never guarantee that we will get constant power supply. The power supply always has fluctuations. Spikes, Surges, Brownouts, Blackouts and Noise can damage your electrical appliances especially your computer. To prevent this from happening you need a device that does power conditioning.

What is the meaning of Spikes and Surges?

Electricity has to be uninterrupted. If the voltage is higher than the specified level then it is 'Over Voltage. If the voltage is lower than the specified level then it is 'Under Voltage'.

Both Spike and Surge come under 'Over Voltage' category. But there is a small difference between spike and surge. If there is very high voltage for an instant but comes back to normal immediately then it is called 'Spike'. This is also referred as 'Impulse'. If there is very high voltage for a slightly longer period (eg. 1/20 th of a second) then it is called 'Surge'.

What is Brownout, blackout, Sags and Line Noises?

If the voltage is dangerously reduced to very low within a short period of time then it is called 'Brownout'. This is also referred as 'Sags'. When this happens, the computers can be seriously damaged.

If the power supply is totally cut then it is called 'Blackout'. Noises can mix with electromagnetic or radio waves or any signals. This is called 'Line Noises'. This may also reduce the voltage level to very low within a short period of time.

What do you need to do Power conditioning.

There are many devices such as Surge Supressors, Spike Busters, Isolation Transformers, Servo Stabiliser, Constant Voltage Transformers or Uninterruptible Power Supply System. We can choose the most suitable power conditioning device based on the equipment we are going to use and based on the quality of our electrical power supply.

Which power conditioning device is best?

The best power conditioning device is the UPS (Uninterrupted Power Supply). This is capable of handling Spikes, Surges, Brownouts, Blackouts etc.

How can UPS provide power supply when electrical supply is cut?

Many have this doubt. UPS has an internal battery. With this battery charger and an Inverter is also present in an UPS. The inverter converts the 'Direct current' supplied by the battery to 'Alternatinc current' as required by the computer. When there is electrical supply the battery charger charges the internal battery. When there is a power cut, the battery supplies DC which is converted to AC by the inverter and power is supplied to computer.

What if the battery loses its power?

When there is power cut, the required power is taken from the battery. Therefore the battery keeps losing its capacity. If the power supply comes back before the battery is fully flat then the battery charger will start recharging the drained battery.

But if the power supply doesn't come back then the battery keeps supplying until it totally drains out. When the battery drains below a certain level the UPS sounds an alarm for your to shut down your computer and turn off the power and turn off UPS.

How long can an UPS supply power when there is no power?

This depends on the backup time of your UPS. If your UPS has 30 minutes backup then your UPS can supply power for 30 minutes of the power is cut. The higher the backup time of UPS the more expensive.

What other tips for buying UPS?

The backup time of your UPS is the most important you need to consider. Other than that, you should know how many KVA (Kilo Volt Ampere) your UPS has. A computer needs atleast 0.5 KVA to function. If you are planning to connect more than one computer to a single UPS then you need to get an UPS with higher KVA.

What type of battery is used in an UPS?

UPS uses 'SMF' batteries (Sealed Maintenance Free). These type of batteries can be used for 5 to 7 years continuously.

What are the different types of UPS?

There are three types of UPS namely Online, Offline and Line Interactive. 'Offline UPS' directly supplies the electrical supply to the computer without any changes. Only if there is a power cut, the 'Offline UPS' takes over. But 'Online UPS' even if there is power supply it will always supply power from the battery and the power supply is used to continously recharge the battery. 'Interactive UPS' always supplies uniform current by using Ferroresonat Transformer.

Which UPS is cheaper?

Obviously, offline UPS is the cheapest. Online UPS is very expensive. Interactive UPS is between the offline and online.

Can I connect printer to UPS?

It depends on the UPS capacity and the type of printer. Generally laser printer should not be connected to the UPS. Other printers can be connected. But you should have a higer KVA UPS to support.

The heart of the computer is the hard disk. Operating System, Software, files created using these software, audio files, video files everything is stored in the hard disk. If the hard disk is corrupted then your computer is useless. Now a days hard disks with high capacity is available in the market. If you are considering to upgrade your hard disk or you have planned to buy a new hard disk then hear are some of the buying tips for hard disk.

1. Get hard disks with high storage capacity. You can buy 40GB, 80GB, 120GB or higher hard disks. If you are one of those who download many mp3 songs from internet to your computer or transfer photos from your digital camera or transfer video from your camcorder then it is advisable to go for more than 80GB harddisks. If you are a gaming addict and install many games from CDs then you can go for even higher capacity.
   
2. You should get a harddisk with a faster interface. For example and IDE/ATA interface is available at 100 MHz or 133 MHz speed. These hard disks are named Ultra ATA/100 and Ultra ATA/133 respectively based on the speed of their interface.
   
3. Buy a hard disk with a suitable interface. Between SCSI and IDE/ATA, SCSI interface is faster and better. But SCSI hard disks are expensive. If you buy a SCSI hard disk then you also need a SCSI host adapter.
   
4. See that the hard disk has high RPM (Rotation Per Minute). There are hard disks with 5400, 7200 and 10,000 RPM. Higher the RPM the better. 7200 RPM hard disks are OK for general home use.
   
5. Check the form factor of the hard disk. 3.5 form factor is suitable for desktop computer and d2.5 form factor is suitable for notebook computer.
   
6. Check and see that 'Seek Time' is very low. Seek time is the time taken to read and write to the hard disk. This is measured in milli seconds.
   
7. 'Access time' should be shorter.
   
8. Also check the support and warranty provided before choosing the brand.
   
9. 'Cache buffer' should be high. It is better to buy a hard disk with at least 2MB cache buffer.
   
10. Check and see whether the hard disk comes with 'Quiet Drive Technology' and 'Shock Protection' features. These features fill increase the life of the hard disk.
    
11. If you are price sensitive then buy the IDE interface hard disks. If price is not an issue then it is better to get a hard disk with SCSI.
    
12. 'Data buffer size' should be at least 2MB.

Some tips on maintaining your computer

1. If you install or remove the hard disk, never touch the PCB portion of the hard disk
   
2. When you fix the hard disk to your computer, use all the screws provided and secure it tightly. Do not use long screws.
   
3. When your computer is ON, do not move or shake your computer. If you need to move then shut down your computer before moving.
   
4. Do not OFF and ON your computer frequently. It is Ok to keep your computer ON for long hours. Shut down only if you are not going to use it for a long time.
   
5. If you do not have a UPS, buy UPS immediately.
   
6. If you suspect that your hard disk is faulty, then do not open it yourself, call your support engineer.

When you ask someone about their computer configuration, they will normally tell you about the CPU speed, RAM memory size, Hard disk size etc. What most computer users do not care much about is the Motherboard. Most don't even know what is a motherboard.

The heart of the computer is the Motherboard. Motherboard is as important to a computer as a foundation is important for a building. Even though you have high capacity hardware for the computer, if the motherboard is not efficient, then those hardware will also not function to their full capacity.

Therefore when you buy a computer or when you upgrade your computer it becomes very important that you get a correct motherboard. Here are the buying tips for a motherboard:

1. It is important to know, how much speed of CPU the motherboard can support. For example if you are going to buy a CPU of 2.4 GHz speed then you should buy a motherboard that supports at least 3.06 GHz speed. The reason is, if you want to upgrade later, then you can just upgrade your CPU and reuse the existing motherboard. Therefore try to buy a motherboard that supports greater speed than your CPU speed.
2. Take note of the CPU socket in the motherboard. The socket depends on the CPU. Socket 462 and Socket 478 are some examples.
3. The chipset which controls all the hardware is very important. SIS, VIA, INTEL are some of the companies that manufacture chipsets. Intel 845E, VIA, KM 266 are some of the popular chipsets.
4. Another important thing to note is to check how much RAM memory can be inserted into motherboard. Even if you are going to buy a smaller RAM size, make sure you have free slots for inserting RAM for later upgrade if needed. There are motherboards that can take upto 4GM RAM. Also see which type of RAM is supported. For instance there are SDR RAM and DDR RAM. Some costlier motherboards support both SDR and DDR RAM.
5. In many motherboards the video cards are integrated. This is referred to as 'Integrated Video' or 'Onboard Video'. If you buy a motherboard with this integrated video card then you do not have to buy another video card. So you can play games using these cards. However some higher end games and some software like CAD cannot be used with this video card. Therefore, if you are a game addict or you use video a lot, then make sure that your motherboard comes with a AGP slot, so that in future if you need a more powerful video card then you can buy and insert it here.
6. Many motherboards also come with integrated sound cards. If you buy a motherboard with 'Integrated bchannel' audio then you can save cost on buying another sound card.
7. You can also save cost by buying motherboards with Ethernet, USB 2.0 and FireWire integrated, so that you don't need to buy them separately.
8. Some motherboards also come with RAID (Redundant Array of Inexpensive Devices) support. If you are buying a server then you should go for this. If you are a home user then normally it is not necessary.
9. Motherboards that support bluetooth are available. If you use many wireless devices then you should go for bluetooth supported motherboards.
10. The number of PCI slots also vary in different motherboards. The number of PCI slots vary from 2 to 6. It is better to buy a motherboard with more PCI slots so that you can insert any external devices as and when required.
11. The Font Side Bus (FSB) speed of motherboard ranges from 133MHz to 533MHz. It is obvious that the FSM speed should be high. The motherboard Chipset should be able to handle your CPU speed and the FSB speed of your motherboard. This is called Form Factor. Now, Micro ATX form factor is quire popular.
12. Also note that there should be adequate space around the CPU. This will enable more air flow to the CPU while functioning. If required buy an additional fan.
13. Check that your motherboard comes with the User manual, Driver CDs, Required connection cables etc.
14. The price of the motherboard usually ranges between $60 to $300. You can choose a cheaper motherboard with more features.
15. Some of the popular motherboard manufacturers are Krypton, Asus, Msi, Mercury, Gigabyte and Intel. Choose the one with long warranty period. 

Motherboard buying tips, Motherboard buying tips.  What is a motherboard and what are its features. How to buy motherboard. What is a good motherboard.

Everyday there are many new application software launched. Most of these new applications do not run on old computers. The minimum requirements for most applications are not suitable for old computers. Therefore many, either upgrade the computers or buy a new computer. It is good to upgrade and switch to the latest computer. But then the question arises, what to do with the old computer? Some take the old boxes from their store rooms and put the old computer and store it. Some just don't know what to do with the old computer.

If you are one of those who doesn't know what to do with your old computer, here are some tips to make use of your old computer.

1. Sell your old computer
   
   Your friends, your neighbours, inform everyone you know that you have an old computer to sell. There may be someone who wants to get a computer very cheap. Even if they offer to buy at very very low price, just sell it to them. Remember that old computers do not have much commercial value. It is better than stocking it in your store room for no reason.
   
2. Remove parts and sell
   
   Remove each computer part separately and try to sell individual parts. Some may be looking for just one part of the computer like keyboard, mouse, hard drive, video card or network card. Or try the Yahoo auction website. You can list your computer there and wait for people to bid.
   
3. Donate your old computer free.
   
   Many schools, community centers or even someone poor whom you know may need your computer. Even some voluntary organisations may accept your donation of your old computer.
   
4. Learn about computer hardware
   
   What is a motherboard? what are the components? How to remove and fix hard disk? Where is the RAM in the computer? Which is the power connector? Which is the data connector for harddisks and floppy disks. How to fix them?
   
   If you need to know the answers of these questions then use your old computer to learn about the computer hardware. Open it and learn them.
   
5. Create a computer network
   
   You can connect your old computer to your new computer and create a computer network. You just need two network cards and cables. You can then enjoy the network's benefits. You can use a single internet connection in two computers. You can play Multiplayer Games. You can install the games in these two computers and you can play a two player game with your fried. Isn't it better to play against a person rather than the computer?
   
6. Install Linux and try it
   
   Linux is a free operating system. You can install and try linux in your old computer.

Random Access Memory (RAM) and Read Only Memory (ROM) are essential computer memory. Virtual Memory and Cache are other terms we often hear related to computer memory.

What is RAM?

As the name suggests, Random Access Memory can find and access the data randomly. Sequential access is the opposite of Random access. In Sequential access, to retrieve the data that is stored in the middle, all the data from the beginning has to be read sequentially until the searched data is found. So it takes time. Where as in RAM, the data can be directly jumped to the middle if necessary without having to read the data sequentially. So the reading is faster. In computers and printers RAM is used. In fact, RAM is the most important memory in computers and printers.

Types of RAM.

Dynamic RAM and Static RAM (SRAM) or two types of RAM. Of these, Dynamic RAM is cheaper and commonly used. Static RAM is very fast. A dynamic RAM has to be refreshed many thousand times in a second. Static RAM does not have to be refreshed.

RAM is a volatile memory. Hence, when there is a power cut, all the data in the RAM memory is lost. RAM is always referred to as the Main Memory. RAM is a READ / WRITE Memory.

All the programs and data that we use in computers have to be first transfered to RAM from hard disk before it can be used. Therefore the higher the RAM size the faster is your computer.

What is ROM - Read Only Memory

ROM also uses Random Access method to read data. The only difference is that the data written to a ROM memory can only be read. You can write to it.

Since RAM is volatile, the data is erased when the computer shuts down or power is cut, but ROM is non volatile. Therefore the data in ROM is always there even when there is no power.

All the computers have a ROM. The most essential programs that are required to start the computer are stored in this ROM memory.

Calculators, Laser Printers use ROM.

PROM - Programmable Read Only Memory - is a part of ROM memory. When manufactured the PROM is empty. Then data is written to it using a special device.

EPROM - Erasable Programmable Read Only Memory - is a type of ROM that can be erased using Ultra Violet rays and then re prorammed with different data or programs.

EEPROM - Electrically Erasable Programmable Read Only Memory - is a type of ROM that can be erased by using current.

What is Virtual Memory?

A part of the hard disk can be used as a Virtual Memory. Generally the size of the virtual memory in a computer is 2 or 2.5 times greater than the RAM memory size in that computer.

Assume you are starting an application. But there are already many programs started previously that is occupying the RAM space. And the remaining space in RAM is not sufficient to use the new application that you are starting. Then the virtual memory is used. Now the Operating System comes into play. It decides which are the applications that are not currently used and then moves them from the RAM memory to the Virtual memory in Hard Disk. Therefore the RAM is now free and the new application can occupy the space and be started.

If the program that is moved to the virtual memory is used again then the Operating System brings that application back from virtual memory to the RAM and some other idle application is moved to the virtual memory.

Therefore the virtual memory is also referred to as Swap memory.

What is Cache ? A part of the main memory (RAM) can be used as Cache or it can be separate chip.

The commands that are often used, or data often used will be kept in this static RAM. This static RAM is called Cache memory.

But there are also Cache memory that comes independently from RAM. Level 1 (L1) and Level 2 (L2) are types of cache memory. The cache integrated inside the microprocessor is categorised as L1 cache. For example Pentium Processor comes with 16KB cache. This is SRAM.

The cache between the Microprocessor and the RAM is L2 Cache. This is also SRAM category.

In order to increase the speed and performance of your computer, buying a new computer is not the only solution. You can upgrade your existing computer. It is not very expensive to upgrade computer. You can upgrade selected parts. Here let us see some tips for upgrading your old computer to speed up your computer and increase performance.

Upgrade the BIOS

BIOS - Basic Input Output System - is a software in your computer. BIOS determines how to communicate with the basic hardware installed in your computer such as Memory, Drives, Display, CPU, Keyboard etc.

After you bought your computer new devices may have been introduced in the market. Security may have been enhanced. There may have been Patches for detecting and rectifying system errors. If you upgrade your BIOS you can get all these.

Go to your Motherboard manufacturer's websites and see if you can upgrade your BIOS. There are also third party BIOS providers. You can buy and upgrade your BIOS software for your old computer.

You can Use Overclock

If the speed of your CPU is not sufficient then you can increase the speed of CPU using Overclock. See your 'User Manual' of your motherboard and see if there is an Overclock upgrade facility.

You can do Overclock by changing the jumper settings in your motherboard. You can search for manuals on how to do this from internet.

But if you do Overclocking the CPU will be overheated very fast. Hence the CPU may get worn out soon. If you do not want to take the risk then do not do overclocking. If the warranty period of your computer is not over then do not do overclocking. Because some comapnies do not give warranty if they come to know that you used overclocking.

Use a new hard disk to Boot.

If you already have a hard disk and it is almost full then you can buy a new hard disk. In which case, you should change your new hard disk as C: drive and your old hard drive as drive D:.

You can make the new drive as Master

The use of Video projector in Offices, Companies and Universities are getting more and more popular. The projector which is also referred to as the 'LCD Projector' and 'VGA Projector' are getting cheaper and cheaper.

Projectors are used to show important programs and presentations. Teachers like projectors as projectors are very useful in teaching. Easy to carry portable projectors are also available in the market.

Here are the buying tips for choosing a good projector

1. There are two types of projectors based on the technology they use. The 'Liquid Crystal Display' (LCD) and the 'Digital Light Processing' (DLP) based projectors. The LCD projectors are very cheap compared to the DLP projectors
   
2. The weight of the LCD projector is very high compared to the weight of the DLP projectors. Therefore those want to carry the projectors easily then you should buy a DLP projector.
   
3. If the size of the projector is small then there will be minimum connections available in the projector. Therefore if you go for more features and do not care about the size then you should choose a bigger projector.
   
4. If you want to be able to connect VCR, VCD or camcorder to the projector then you should check whether these connectors ara available.
   
5. You should check the light brightness of the projector. This is measured in lumens. Different projectors have 1000, 1500, 2000 or 3000 lumens. If you are going to use the projector in a small room then 1000 to 1500 lumens is enough. If you are planning to use your projector in big halls, auditoriums then choose the 3000 or higher lumens projector.
   
6. Also remember that the resolution is very important. If you need sharp and clear pictures then you should choose the projector with high resolution. Projectors are available at 800x600, 1024x728, 1280x1024 resolutions. The price of the projector will increase with the increase in resolution. Also note that the computer monitor's resolution and the projector's resolution should match when you give presentations.
   
7. Also check the contrast ratio of the projector. The ratio should be high for example between 400:1 projector and 2000:1 projector the latter is better.
   
8. See if the VGA, SVideo, Composite Video connectors are available. Similarly check if the 'Audio In' connector is available.
   
9. Check the 'tilt mechanism' provided in the projector. This is used to tilt your projector, upwards or downwards based on your requirement. Usually the projector will rest on four screws which are adjustable. Some brands come with two screws behind and one screw in the center front. You can adjust these screws to adjust the projection to fit the screen.
   
10. Check the life of the 'bulb' in the projector. Check the price of the bulb in case you need to change it.
    
11. See the menu options provided in the projector and whether it is easy to operate using the remote control and whether it is easy to connect to the computer.
    
12. See if the laser pointer comes with the remote control or given separately. The laser pointer with the remote control is better.
    
13. See if the projector can be locked using a password. This is very useful if you do not want unauthorized use.
    
14. Also check if there is a 'control panel lock'. This will prevent the use of projectors without the remote control. So only those who have the remote at hand can operate it.

Those who frequently travel abroad or to other cities use notebooks a lot. While traveling in trains and planes they will work using their notebooks without wasting time.

While at home and office, notebooks use AC power. While in Trains and Planes notebooks depend on the DC power supplied by the battery.

During a 12 hours journey if you would like to use the notebook at least for 6 hours then your notebook's battery should last for at least six hours. During journey if you follow the tips given below you can extend the battery life of notebook computers. Your journey will be successful.

Follow these tips to extend your your notebook battery's life

1. Power off the monitor and the hard disk.
   
   When you are using the computer, if you have to leave the computer to attend to something else then you can power off the monitor and hard disk during that time. This will increase the battery's life. You can make the Windows Operating System carry out this job automatically.
   
   Open the control panel and click on 'Power Options'. In the new dialog box select the 'Power Schemes'. In the 'Running on batteries' section change the time provided in the 'Turn off monitor' and 'Turn of hard disks' to a shorter time. Generally you don't have to change the default settings in the Os. But you can change it if you want it.
   
2. Enable Hibernation
   
   In Windows XP there is a Hibernation feature. Many use the 'Stand by' option instead of hibernation. There is a difference between hibernation and standby. When you are not using the computer you can use both of them. But if you choose hibernation then all your work will be backed up and then the computer will be fully shut down. The battery power will be saved. In stand by mode the battery power is still being used by the computer.
   
   As given in the previous heading, in the 'Power Options properties' dialog box click on the 'Hibernate' tab and select the 'Enable Hibernation' check box.
   
3. Change the BIOS setting
   
   Electricity related settings can also be determined in the BIOS settings. If there is a difference between the time you have given in Windows and the time you have given in BIOS then the time given in the BIOS will override the time given in the windows. Therefore make changes accordingly to make these two settings same.
   
4. Decrease the screen brightness
   
   When you use the notebook in battery reduce the screen's brightness. This will extend battery's life.
   
5. Remove unwanted hardware from your notebook
   
   Whether you use or not, all the hardware connected to the computer will consume power. You can use the mouse pad provided in the notebook instead of an external mouse.
   
6. Disable unused devices
   
   Disable unused devices such as Wi-Fi, Infrared while not in use. You can disable them either through appropriate menu options or by right clicking the system tray icons in the task bar.
   
   Also disable Anti-virus software, scheduler, Instant messaging etc. This will increase battery life. After your journey you can enable them again.
   
7. Do not run unwanted applications
   
   During journey you may use VCD, DVD etc to view movies. This will consume lot of battery power. So use them wisely.

Flash memory cards are used in Notebook computers, Digital cameras, Music players, PDAs and Car Stereos. Since these flash memories are cheap and the storage capacity ranges from 8MB to 1GB many people are buying these cards.

There are many types of flash memory cards. There are also USB drives and external hard disks in the market. So before you buy any cards you should first find out whether it is suitable for your notebook or computer. In this article we shall discuss about flash memory cards.

Difference between normal memory and flash memory

In an ordinary memory chip there are many cells. Each cell has either 0 or 1 state. When this cell is charged, its state will change. Which means if it was 1 then it will change to 0 and if it was 0 it will change to 1.

Remove the charge from the memory chip and the cells in the chip will forget their states. It will no longer retain its state.

But a flash memory is different. Even if the power is disconnected from the flash memory chip the cells in flash memory will still remember and retain its last state. This is the speciality of the Flash memory.

Thats why flash memory is better than the normal memory. But even flash memory has its disadvantages. The speed of a flash memory is too slow. Generally the speed of flash memory is 1Mbps. But flash memory with double or triple this speed are also available. The price of flash memory is more expensive than normal memory.

Types of flash memory

1. Smart Media
   
   Smart Media cards were first introduced at 2.7" size and at a thickness of a playing card. Since it could be easily bent the possibility of getting spoiled is high. Smart Media cards can be used in digital cameras and music players. If you want to use this in your computer you need to buy a PC card adapter. The smart media card with 1.8" length, 1.5" breadth and 0.06" thickness are not widely in use.
   
2. Compact Flash
   
   Compact Flash cards are used in Digital cameras, notebooks, PDAs, Music players and car stereos. Compact Flash cards are available with 4GB storage capacity and 1.4" length, 1.7" breadth and 0.2" thickness. Research is being done to increase the storage capacity of compact flash cards to 16GB.
   
3. Memory stick
   
   Many companies are now manufacturing memory sticks. There are many types of memory sticks which are used in digital cameras, notebooks, PDAs, music players and car stereos. Some even get confused between Memory stick, Memory stick duo, Memory stick & select, Memory stick pro. The size of each of these types of memory sticks are different. The storage capacity also differs 128MB, 256MB, 1GB, 2GB and 4GB.
   
4. Secure digital
   
   As though the confusion in memory stick is not enough secure digital type of flash memory are also available. Secure digital flash memory cards can also be used in digital camera, notebooks, PDAs, Music players and car stereos. All popular brands manufacture secure digital cards. Computer experts predict that secure digital cards have very good future. The secure digital cards are very small in size. The size of usual Secure Digital cards (SD card) is 1.2x0.9x0.07.
   
   More recently MiniSD cards are available which are even smaller in size (0.8x0.8x0.5). The storage size is 256MB or 512MB.
   
5. XDPicture cards
   
   Fuji and Olympus cameras use XDPicture cards in their digital cameras. The size of XDPicture cards is 1.0x0.8x0.5. The storage capacity of XDPicture cards are 512MB or 1GB.

Is it possible to store 2GB to 4GB of data in a device half the size of your pen? If you asked this question a few years back the answer is NO. But now it is very much possible. These are called USB drives or THUMB drives.

Those drives like pen drive or thumb drive that can be inserted to your USB (Universal Serial Bus) port in your computer is an USB drive.

Floppy drives and hard drives are secured to your computer using screws. Therefore they are permanently fixed to your computer. To disconnect and install it in another computer is not an easy task. Moreover these drives need power cables and data cables separately to function. But an USB drive is entirely different.

It is very easy to use an USB drive. You just have to insert the USB drive into your computer's USB port. You need not open the computer's cabinet for this. There is not data cable or power cable in USB drives.

As soon as you insert the USB drive into your USB port you can start using it. You need not install any software to use this. Reason: The newer Operating Systems such as Windows XP and most of the linux distros know how to detect these USB drives automatically. Immediately the OS will mount the USB drive to your computer and assign a drive letter such as E: or F: and will be available in your usual file explorer such as windows explorer.

If your Operating System is old (such as Windows 98) then you may have to install the appropriate driver software for your USB drive. The driver comes in the CD together with the drive or you can download the driver from the manufacturer's website.

What is bootable USB drive?

Just like the bootable floppy disk or a bootable CD you can also boot the computer using a bootable USB drive. But your computer's BIOS should support this facility.

Buying tips for USB drive (Thumb drive, pen drive, jump drive etc)

1. Storage size of USB drive
   
   USB drives are also called as Pen drive, Thumb drive, Jump drive, Key chain drive etc. These drives come in various storage capacities. USB drives are available from 16MB to 4.4GB.
   
2. Speed of USB drives
   
   Currently the USB2.0 is the standard widely in use. The speed of USB 2.0 is 480 MBPS. You may think that USB 2.0 based USB drives will have this 480 Mbps speed. But in reality there are three types of speed in USB drives.
   
   They are Low speed, Full speed and High speed. Low speed refers to a mere 1.5 Mbps speed. Do not get misled by the 'Full speed' term. Full Speed USB drives have 12 Mbps speed. Only 'High speed' or 'hispeed' USB drives have 480Mbps speed. Remember to buy USB drives that are faster to read and write.
   
   So do not just see whether it is USB 2.0 but also see the speed.
   
3. Write Protected USB drives
   
   See if the USB drive has a write protect switch. Because if you do not want to accidentally delete the files or do not want to accidentally write to it then this switch will be useful.

Nowadays digital cameras are replacing conventional film cameras. It is true that many people prefer to buy digital cameras then normal cameras. There are many reasons for this change. With digital cameras there is no need to keep the film safe. No need to wait to see the photos until the whole film roll is finished. No need to bring to a studio to print. The advantages of buying a digital camera are many. So many want to buy digital cameras.

But what are the different types of digital cameras? How much is its price? Which digital camera to choose? And many such questions are common while buying digital cameras.

Here are the buying tips for choosing a digital camera. The price ranges from $120 to $700. So based on your budget and your requirements you should choose the various features in a digital camera.

• Compared to digital cameras with CMOS sensors, digital cameras with CCD sensor is better. The CCD sensor cameras are smaller in size and produce a better quality.
  
• The resolution should be high. 640x480, 1024x768, 768x1280, 1024x2048 are some of the resolutions in digital cameras.
  
• The camera memory should also be high. If you need greater clarity the digital camera's internal memory should be high. Generally 2, 8 or 16MB internal memory camera's are available. So choose a higher one.
  
• See the interface of the digital camera to a computer. Both USB interface and Parallel ports are available. But a USB interface camera is better because of the speed and easy to use features.
  
• A camera with Viewfinder is good. Using this you can view the picture other than from the LCD.
  
• Optical zoom is most important. Even if it is expensive choose the camera with an optical zoom
  
• See if you can increase the camera's memory. Compact Flash card, smart media or Memory sticks can be used to increase the camera's memory. Never choose a camera in which you cannot change the camera's memory.
  
• Usually in order to print the photos, you will have to first copy the photos from digital cameras to the computer and then print it from the computer. But there are cameras which can be directly connected to the printer to print. If printing photos are your main job then choose a camera that can directly connect to a printer
  
• Some digital cameras are capable of capturing short videos. If you need this feature then see if the camera has this feature.
  
• Choose the digital camera with a fast shutter speed. If you are buying a digital camera for use in your profession then you should have a camera with very high shutter speed.
  
• See if the camera is user friendly and easy to use. See if the buttons are easy to press.
  
• See if the camera is designed such that your fingers never come in between the flash or the lens. Choose a camera that is designed based on Ergonomics.