Tree Topology in Computer Networking
Networks can be categorized in several different ways. One method defines the type of a network according to the geographic area it spans. Alternatively, networks can also be classified based on topology or on the types of protocols they support.
* Introduction to Area Networks
* Introduction to Network Topologies
* Packet Switching
* Network Protocols
Types of Network Equipment
Microsoft Xbox 360 Wireless Network Adapter
The building blocks of a home computer network include adapters, routers and/or access points. Wired (and hybrid wired/wireless) networking also involves cables of varying types. Finally, large-scale enterprise networks in particular often employ other advanced equipment for specialized communication purposes.
* What Is a Network Router?
* Routers vs. Hubs vs. Switches
* Wireless Network Hardware
* Network Cables
* Network Adapters
* Modems
* What Is a Lag Switch?
Ethernet
Ethernet - Cables and Switch
Ethernet is a physical and data link layer technology for local area networks. Homes, schools and offices around the world all commonly use Ethernet standard cables and adapters to network personal computers.
* What Is an Ethernet Card?
* CAT5 Ethernet Cables
* Ethernet Patch Cables
* Crossover Cables
* What Is Gigabit Ethernet?
* WoL - Wake-on-LAN
* Autosensing
* Ethernet Q&A Interactive Quiz
Wireless Local Area Networks
Chanalyzer 3 - Interactive Charts and Graphs for Wi-Spy
Wi-Fi is the most popular wireless communication protocol for local area networks. Private home and business networks, and public hotspots, use Wi-Fi to networks computers and other wireless devices to each other and the Internet. Bluetooth is another wireless protocol commonly used in cellular phones and computer peripherals for short range network communication.
Internet Service
Satellite Uplink Station - U.S. Military (1998)
The technologies used to connect to the Internet are different than those used for connecting devices on local area network. DSL, cable modem and fiber provide fixed broadband Internet service, while WiMax and LTE additionally support mobile connectivity. In geographic areas where these high-speed options are unavailable, subscribers are forced to use older cellular services, satellite or even dial-up Internet instead.
Saturday, October 2, 2010
Biological Computers
INTRODUCTION
Biological computers have emerged as an interdisciplinary field that draws together molecular biology, chemistry, computer science and mathematics. The highly predictable hybridization chemistry of DNA, the ability to completely control the length and content of oligonucleotides, and the wealth of enzymes available for modification of the DNA, make the use of nucleic acids an attractive candidate for all of these nanoscale applications
A 'DNA computer' has been used for the first time to find the only correct answer from over a million possible solutions to a computational problem. Leonard Adleman of the University of Southern California in the US and colleagues used different strands of DNA to represent the 20 variables in their problem, which could be the most complex task ever solved without a conventional computer. The researchers believe that the complexity of the structure of biological molecules could allow DNA computers to outperform their electronic counterparts in future.
Scientists have previously used DNA computers to crack computational problems with up to nine variables, which involves selecting the correct answer from 512 possible solutions. But now Adleman's team has shown that a similar technique can solve a problem with 20 variables, which has 220 - or 1 048 576 - possible solutions.
Adleman and colleagues chose an 'exponential time' problem, in which each extra variable doubles the amount of computation needed. This is known as an NP-complete problem, and is notoriously difficult to solve for a large number of variables. Other NP-complete problems include the 'travelling salesman' problem - in which a salesman has to find the shortest route between a number of cities - and the calculation of interactions between many atoms or molecules.
Adleman and co-workers expressed their problem as a string of 24 'clauses', each of which specified a certain combination of 'true' and 'false' for three of the 20 variables. The team then assigned two short strands of specially encoded DNA to all 20 variables, representing 'true' and 'false' for each one.
In the experiment, each of the 24 clauses is represented by a gel-filled glass cell. The strands of DNA corresponding to the variables - and their 'true' or 'false' state - in each clause were then placed in the cells.
Each of the possible 1,048,576 solutions were then represented by much longer strands of specially encoded DNA, which Adleman's team added to the first cell. If a long strand had a 'subsequence' that complemented all three short strands, it bound to them. But otherwise it passed through the cell.
To move on to the second clause of the formula, a fresh set of long strands was sent into the second cell, which trapped any long strand with a 'subsequence' complementary to all three of its short strands. This process was repeated until a complete set of long strands had been added to all 24 cells, corresponding to the 24 clauses. The long strands captured in the cells were collected at the end of the experiment, and these represented the solution to the problem.
THE WORLD'S SMALLEST COMPUTER
The world's smallest computer (around a trillion can fit in a drop of water) might one day go on record again as the tiniest medical kit. Made entirely of biological molecules, this computer was successfully programmed to identify - in a test tube - changes in the balance of molecules in the body that indicate the presence of certain cancers, to diagnose the type of cancer, and to react by producing a drug molecule to fight the cancer cells.
DOCTOR IN A CELL
In previous biological computers produced input, output and "software" are all composed of DNA, the material of genes, while DNA-manipulating enzymes are used as "hardware." The newest version's input apparatus is designed to assess concentrations of specific RNA molecules, which may be overproduced or under produced, depending on the type of cancer. Using pre-programmed medical knowledge, the computer then makes its diagnosis based on the detected RNA levels. In response to a cancer diagnosis, the output unit of the computer can initiate the controlled release of a single-stranded DNA molecule that is known to interfere with the cancer cell's activities, causing it to self-destruct.
Biological computers have emerged as an interdisciplinary field that draws together molecular biology, chemistry, computer science and mathematics. The highly predictable hybridization chemistry of DNA, the ability to completely control the length and content of oligonucleotides, and the wealth of enzymes available for modification of the DNA, make the use of nucleic acids an attractive candidate for all of these nanoscale applications
A 'DNA computer' has been used for the first time to find the only correct answer from over a million possible solutions to a computational problem. Leonard Adleman of the University of Southern California in the US and colleagues used different strands of DNA to represent the 20 variables in their problem, which could be the most complex task ever solved without a conventional computer. The researchers believe that the complexity of the structure of biological molecules could allow DNA computers to outperform their electronic counterparts in future.
Scientists have previously used DNA computers to crack computational problems with up to nine variables, which involves selecting the correct answer from 512 possible solutions. But now Adleman's team has shown that a similar technique can solve a problem with 20 variables, which has 220 - or 1 048 576 - possible solutions.
Adleman and colleagues chose an 'exponential time' problem, in which each extra variable doubles the amount of computation needed. This is known as an NP-complete problem, and is notoriously difficult to solve for a large number of variables. Other NP-complete problems include the 'travelling salesman' problem - in which a salesman has to find the shortest route between a number of cities - and the calculation of interactions between many atoms or molecules.
Adleman and co-workers expressed their problem as a string of 24 'clauses', each of which specified a certain combination of 'true' and 'false' for three of the 20 variables. The team then assigned two short strands of specially encoded DNA to all 20 variables, representing 'true' and 'false' for each one.
In the experiment, each of the 24 clauses is represented by a gel-filled glass cell. The strands of DNA corresponding to the variables - and their 'true' or 'false' state - in each clause were then placed in the cells.
Each of the possible 1,048,576 solutions were then represented by much longer strands of specially encoded DNA, which Adleman's team added to the first cell. If a long strand had a 'subsequence' that complemented all three short strands, it bound to them. But otherwise it passed through the cell.
To move on to the second clause of the formula, a fresh set of long strands was sent into the second cell, which trapped any long strand with a 'subsequence' complementary to all three of its short strands. This process was repeated until a complete set of long strands had been added to all 24 cells, corresponding to the 24 clauses. The long strands captured in the cells were collected at the end of the experiment, and these represented the solution to the problem.
THE WORLD'S SMALLEST COMPUTER
The world's smallest computer (around a trillion can fit in a drop of water) might one day go on record again as the tiniest medical kit. Made entirely of biological molecules, this computer was successfully programmed to identify - in a test tube - changes in the balance of molecules in the body that indicate the presence of certain cancers, to diagnose the type of cancer, and to react by producing a drug molecule to fight the cancer cells.
DOCTOR IN A CELL
In previous biological computers produced input, output and "software" are all composed of DNA, the material of genes, while DNA-manipulating enzymes are used as "hardware." The newest version's input apparatus is designed to assess concentrations of specific RNA molecules, which may be overproduced or under produced, depending on the type of cancer. Using pre-programmed medical knowledge, the computer then makes its diagnosis based on the detected RNA levels. In response to a cancer diagnosis, the output unit of the computer can initiate the controlled release of a single-stranded DNA molecule that is known to interfere with the cancer cell's activities, causing it to self-destruct.
Multiple Graphics Processing Unit
In order to increase graphics performance, two or more GPU’s are used to simultaneously render the graphic. Scan-Line Interleave (SLI) from 3dfx is a method for linking two (or more) video cards or chips together to produce a single output. It is an application of parallel processing for computer graphics, meant to increase the processing power available for graphics. SLI from 3dfx was introduced in 1998. But 3dfx moved out of the scene and the two major players, NVIDIA and ATI technologies have their own multi-GPU solutions.
NVIDIA Corporation reintroduced the name SLI (renamed as Scalable Link Interface) and intends for it to be used in modern computer systems based on the PCI Express bus. SLI is, two graphics processors doing the work of one. Each graphics card is assigned 50% of the visual workload for a given scene and both GPUs render their share concurrently, effectively doubling the output. SLI offers two rendering and one anti-aliasing method for splitting the work between the video cards:
* Split Frame Rendering (SFR): This analyzes the rendered image in order to split the workload 50/50 between the two GPUs. To do this, the frame is split horizontally in varying ratios depending on geometry..
* Alternate Frame Rendering (AFR): Here, each GPU renders entire frames in sequence - one GPU processes even frames, and the second processes odd frames, one after the other.
* SLI Antialiasing. This is a standalone rendering mode that offers up to double the antialiasing performance by splitting the antialiasing workload between the two graphics cards, offering superior image quality. One GPU performs an antialiasing pattern which is slightly offset to the usual pattern (for example, slightly up and to the right), and the second GPU uses a pattern offset by an equal amount in the opposite direction (down and to the left). Compositing both the results gives higher image quality than is normally possible.
ATI technologies have named their multi GPU solution as CrossFire. This technology also makes use of two PCI Express cards. The CrossFire system supports four different rendering modes, each offering their own specific advantages and disadvantages.
* SuperTiling: It divides the screen up like a checkerboard, allocating adjacent squares ('quads') to alternate GPUs. (One card would render the white squares, and the other the black).
* Scissor: Divides the screen into two rectangles, one above the other. This render mode is more commonly known as Split Frame Rendering (SFR), which is how nVidia refers to it in SLI. Using Scissor mode means that the system has to carefully choose the "cutting point" in order to balance the load.
* Alternate Frame Rendering: Alternate Frame Rendering (as the name suggests) sets one GPU to render odd frames, and one the even frames. While this produces a high performance boost, it is incompatible with games using render-to-texture functions because one card doesn't have direct access to the texture buffer of the other.
* CrossFire Super Anti-aliasing: It is intended to improve the quality of the frames rendered. Super AA is able to double the anti-aliasing factor without any drop in frame rate.
NVIDIA Corporation reintroduced the name SLI (renamed as Scalable Link Interface) and intends for it to be used in modern computer systems based on the PCI Express bus. SLI is, two graphics processors doing the work of one. Each graphics card is assigned 50% of the visual workload for a given scene and both GPUs render their share concurrently, effectively doubling the output. SLI offers two rendering and one anti-aliasing method for splitting the work between the video cards:
* Split Frame Rendering (SFR): This analyzes the rendered image in order to split the workload 50/50 between the two GPUs. To do this, the frame is split horizontally in varying ratios depending on geometry..
* Alternate Frame Rendering (AFR): Here, each GPU renders entire frames in sequence - one GPU processes even frames, and the second processes odd frames, one after the other.
* SLI Antialiasing. This is a standalone rendering mode that offers up to double the antialiasing performance by splitting the antialiasing workload between the two graphics cards, offering superior image quality. One GPU performs an antialiasing pattern which is slightly offset to the usual pattern (for example, slightly up and to the right), and the second GPU uses a pattern offset by an equal amount in the opposite direction (down and to the left). Compositing both the results gives higher image quality than is normally possible.
ATI technologies have named their multi GPU solution as CrossFire. This technology also makes use of two PCI Express cards. The CrossFire system supports four different rendering modes, each offering their own specific advantages and disadvantages.
* SuperTiling: It divides the screen up like a checkerboard, allocating adjacent squares ('quads') to alternate GPUs. (One card would render the white squares, and the other the black).
* Scissor: Divides the screen into two rectangles, one above the other. This render mode is more commonly known as Split Frame Rendering (SFR), which is how nVidia refers to it in SLI. Using Scissor mode means that the system has to carefully choose the "cutting point" in order to balance the load.
* Alternate Frame Rendering: Alternate Frame Rendering (as the name suggests) sets one GPU to render odd frames, and one the even frames. While this produces a high performance boost, it is incompatible with games using render-to-texture functions because one card doesn't have direct access to the texture buffer of the other.
* CrossFire Super Anti-aliasing: It is intended to improve the quality of the frames rendered. Super AA is able to double the anti-aliasing factor without any drop in frame rate.
A Brief History of the Abacus
A Brief History of the Abacus
This is a brief history of the abacus and a Bibliography follows. The earliest counting devices known to man were his own hands and fingers. If that wasn't enough, things in nature were used like shells, twigs, pebbles, stones, and so forth. It is a good idea to think about the history of arithmetic, mathematics, writing and recorded information. Man's invention of the computer resulted from man's need to quantify, to count and to do mathematic calculations. Long before the computer, in the Roman Empire, Ancient Asia, and other parts of the World, man was inventing easier and faster ways of counting and calculating.
Definition of Abacus
" The abacus is a device, usually of wood (plastic, in recent times), having a frame that holds rods with freely-sliding beads mounted on them." 2
Counting Boards and the Salamis Tablet
The use of the abacus was pre-dated by the use of counting boards. A counting board had grooves along which one could slide beads or stones. The beads or stones did not have holes in them but only grooves along which they moved on the counting board. "The oldest surviving counting board is the Salamis tablet (originally thought to be a gaming board), used by the Babylonians circa 300 B.C., discovered in 1846 on the island of Salamis." 2 "The oldest surviving counting board is the Salamis tablet (originally thought to be a gaming board), used by the Babylonians circa 300 B.C., discovered in 1846 on the island of Salamis. " 2 Ancient Counting Boards is a Web site that further chronicles the history and use of counting boards, the Salamis tablet(about 300 B.C.) and the improvements of the early counting tablets, how they evolved into the first Roman abacus.
Around 1000 AD the Aztec peoples invented a device similar to an abacus which used corn kernels threaded through wooden frames. This was known as a Nepohualtzitzin. 3 An Aztec abacus would have seven "beads" by thirteen columns5. This abacus dated to around 900 A.D.6.
In an article attributed to Mr. Du Feibao1 the abacus was invented in China having already been "mentioned in a book of the Eastern Han Dynasty, namely Supplementary Notes of the Art of Figures written by Xu Yue about the year 190 A.D." It was during the Song Dynasty (960-1127) that Zhang Zeduan at Qingming Festival painted his famous long scroll, Riverside Scences, picturing an abacus lying beside an account book. 1 The abacus was known to the Chinese as suan-pan. 3
This is a brief history of the abacus and a Bibliography follows. The earliest counting devices known to man were his own hands and fingers. If that wasn't enough, things in nature were used like shells, twigs, pebbles, stones, and so forth. It is a good idea to think about the history of arithmetic, mathematics, writing and recorded information. Man's invention of the computer resulted from man's need to quantify, to count and to do mathematic calculations. Long before the computer, in the Roman Empire, Ancient Asia, and other parts of the World, man was inventing easier and faster ways of counting and calculating.
Definition of Abacus
" The abacus is a device, usually of wood (plastic, in recent times), having a frame that holds rods with freely-sliding beads mounted on them." 2
Counting Boards and the Salamis Tablet
The use of the abacus was pre-dated by the use of counting boards. A counting board had grooves along which one could slide beads or stones. The beads or stones did not have holes in them but only grooves along which they moved on the counting board. "The oldest surviving counting board is the Salamis tablet (originally thought to be a gaming board), used by the Babylonians circa 300 B.C., discovered in 1846 on the island of Salamis." 2 "The oldest surviving counting board is the Salamis tablet (originally thought to be a gaming board), used by the Babylonians circa 300 B.C., discovered in 1846 on the island of Salamis. " 2 Ancient Counting Boards is a Web site that further chronicles the history and use of counting boards, the Salamis tablet(about 300 B.C.) and the improvements of the early counting tablets, how they evolved into the first Roman abacus.
Around 1000 AD the Aztec peoples invented a device similar to an abacus which used corn kernels threaded through wooden frames. This was known as a Nepohualtzitzin. 3 An Aztec abacus would have seven "beads" by thirteen columns5. This abacus dated to around 900 A.D.6.
In an article attributed to Mr. Du Feibao1 the abacus was invented in China having already been "mentioned in a book of the Eastern Han Dynasty, namely Supplementary Notes of the Art of Figures written by Xu Yue about the year 190 A.D." It was during the Song Dynasty (960-1127) that Zhang Zeduan at Qingming Festival painted his famous long scroll, Riverside Scences, picturing an abacus lying beside an account book. 1 The abacus was known to the Chinese as suan-pan. 3
HARD DRIVE
HARD DRIVE
| |
| Speed Your computer's central processing unit (CPU) spends a lot of time waiting for your much slower hard drive to catch up. While operations inside the CPU are timed in nanoseconds (one billionth of a second), your hard drive operations are limited to mere milliseconds. Although considered very fast by human standards, a millisecond is actually 1,000,000 (one million) times slower than a nanosecond. Comparing the speed of your CPU to your hard drive is like comparing a Ferrari to a turtle. So when you're loading your favorite word processor, for example, your CPU will have to wait until your hard drive can access all of the necessary data and load it into RAM (which also operates in nanoseconds), before it can proceed and give you a blinking cursor, at which point you're ready to type away. Inside A hard drive is made up of several unique components. The most popular of these components are the platters and the read/write heads. The platters are disc-shaped, usually made out of aluminum or glass. Unlike the flexible media in floppy diskettes, these platters cannot bend of flex, which is where the term hard disk comes into play. Another popular term to describe a hard drive is fixed disk, which is derived from the fact that the platters are fixed firmly in place and are not removable. Physically, the operation of a hard drive is similar to a floppy diskette drive: the discs spin while the heads move over them to store or read data in tracks and sectors. Hard drives contain multiple platters with two sides each, where data is stored. For every platter, there is a read/write head, all of which move across the discs at the same time since they are all connected to one arm. Although it is these heads that are responsible for writing data to the discs, they will never actually come into physical contact with the platters. These heads are kept suspended by an extremely thin cushion of air, and thereby float just a fraction of a millimeter above or below the platter. If dust or other small particles ever get into this part of the drive, it would easily be enough to cause the head to come into contact with the platter and do physical damage to it. Also, if a sufficiently large shock were to be applied to the drive while under power, the force could be enough to cause the heads to go crashing into the spinning platters and once again causing physical damage to the drive, not to mention data loss. This is know as a "head crash." Performance The average seek time of the drive is the amount of time it takes for the heads to move from one cylinder on the drive to any other cylinder. The average access time, takes into account the drive's latency. Latency is defined as the average time (in milliseconds) that it takes for a sector to be available after the heads have reached a track. This figure is generally half of the time it would take for the disk to fully rotate once. On a drive with a spin rate of 4,500 RPM, a full rotation would take 13.33 ms, thereby making your latency equal to 6.67 ms. The average access time of the drive is the sum of its average seek time and latency. This gives us the average amount of time that is needed before a sector (chosen at random) can be accessed. The maximum transfer rate Transfer rates come in two different flavors: a disk transfer rate, and a host transfer rate.
A combination of a low average access time and high spin rate is a sign of a drive that will deliver maximum performance. Partitions Every file you store on a hard drive relies on some kind of file addressing system to organize all your data. Among PC's, the most common file system is known as FAT (File Allocation System). Windows 95 uses a modified version of FAT called VFAT (virtual FAT), which adds support for long filenames. Windows NT supports both FAT, and its own NTFS format. NTFS is the most advanced file system. It allows access to partitions up to 16 PB (petabyte) in size. [ Equal 16 million terabytes - 16 followed by 18 zeroes).] Each file system must organize data into segments called clusters. Under the FAT file system, the maximum size of any one cluster is 32KB (32,768 bytes). The maximum number of these clusters is limited to 65,536. When you multiply these two numbers, you come up with what has come to be termed the "2.1GB barrier," referring to the maximum number of bytes that can be allocated on the drive. Keep in mind that every file on your hard drive must occupy at least one cluster. This means that if you had a tiny batch file which was 156 bytes long, the FAT system would automatically allocate an entire cluster to that file, despite the fact that it's so small. What a waste of space. Microsoft later created FAT32 to support partitions larger than two gigabytes and pathnames greater that 256 characters. It also allows more efficient use of disk space since clusters are four kilobytes rather than 32 kilobytes. NTFS supersedes the FAT file system as the preferred file system for Microsoft’s Windows operating systems. NTFS has several improvements over FAT and HPFS (High Performance File System) such as improved support for metadata and the use of advanced data structures to improve performance, reliability, and disk space utilization, plus additional extensions such as security access control lists (ACL) and file system journaling. |
PROTOTYPE COMPUTER MOUSE
PROTOTYPE COMPUTER MOUSE
In 1964, the first prototype computer mouse was made to use with a graphical user interface. Douglas Engelbart's computer mouse received patent # 3,541,541 on November 17, 1970 for a "X-Y Position Indicator For A Display System"
Friday, October 1, 2010
How to Choose a CD, DVD or Hard Drive
There are many devices which can be used to store or write data in your computer system. The options include hard drives, USB/Firewire storage devices, CD writers and DVD writers.
Hard drives are a very essential (and delicate) piece of equipment and are a standard feature on most computers. CD writers are also very common.
USB/Firewire storage devices and DVD writers are currently getting more popular with consumers.
icon
Some hard drives, CD and DVD drives available in the market
This article will give you some tips on selecting proper data storage devices for your PC.
Hard Drives
First, let's cover hard drivesicon. We'll look at some hard drive terms like ATA and SCSI, as well as cover the factors to consider when buying a new drive.
ATA and SCSI
Let's get some terminology out of the way before we go further. In the hard drive world, there are two data access standards, ATA and SCSI (pronounced 'Scar-Zee'). The ATA standard is split further into Parallel ATA (PATA) and Serial ATA (SATA). Most of normal hard drives we're used to rely on the PATA standard. Some newer hard drives use the SATA standard.
SATA allows transfer speeds of up to 150 MBs while PATA gives up to 133 MBs. However, to use SATA, you'll need a Serial ATA controller, a SATA drive and a SATA power cable. The speed difference between PATA and SATA is also not significant unless you have a high-end SATA drive.
The SCSI standard is a very fast hard drive standard used for professional computer systems which demand extremely fast data access. SCSI drives provide an access time of about 9.5ms - which I feel is really not needed for average home use.
Disk Space vs. Price
An important factor to consider is the disk space versus price ratio. When you look at the 30 GB, 40 GB and 80 GBPATA hard drives, you'll find they are very close in price. If you don't mind paying an extra $20 or so, I'd say go for the maximum disk space you can get! If you do a lot of graphics or video editing, you may want to consider larger drives like the Seagate 160 GB hard drive. For the average home user, however, 40 GB to 80 GB of disk space is plenty.
Drive Speed
If data access speed is important to you, you can go for faster SATA drives or SCSI drives. But remember that these drives come at a price premium and may not be necessary for average home use. Another option is to use a RAID setup where multiple hard disks are used to gain drive performance and/or data integrity.
CD Writers
CD writersicon are practically standard issue on all PCs these days. Prices are ridiculously cheap, so there's no reason not to get one, unless you prefer a DVD writer.
Drive Speed
For CD writers, you should generally look for a 40X record speed or faster. If you buy anything that is slower, it will definitely waste a lot of time when you're burning CDs.
Internal or External
You can choose between an internal or external CD writer. Internal drives are best suited for desktop PCs and are the cheapest option. If you want portability and don't mind paying a little more, you can get a FireWire or USB 2.0 external CD-RW drive.
DVD Writers
DVD writersicon are the newest rage in the consumer data storage market. They let you store up to 4.7GB on a single disc several times the amount of on a CD-RW disc. So let's look at some factors to consider when purchasing a new DVD drive.
Drive Speed
One factor to consider when buying DVD writers is drive speed. Most DVD-R drives write at 8X, with some older models supporting only 4X. Personally, I don't think there is significant speed difference between a 8X and 4X drive - so don't spend extra money unnecessarily if you don't have to.
Compatibility
There is a huge range of DVD media formats out there (DVD+R, DVD-R,DVD+R DL), represented by various brands. You need to consider compatibility of your DVD writer with these DVD discs. DVD-R and DVD+R formats are both very compatible with existing DVD players and DVD-ROM drives - so try to get a player that supports those.
Internal or External
You can choose between an internal or external DVD writer. Internal drives are cheaper but it also means you need to deal with the installation hassle and non-portability. External DVD writers come with Firewire or USB 2.0 interfaces and may well be a better choice if you need to move your data around a lot.
Conclusion
To purchase a good storage device, be it a hard drive, CD writer or DVD writer, you need to consider what price you're willing to pay for a given set of features. In my opinion, the DVD burner is fast becoming an essential item in the average home user's PC. If you're building a new computer, you should definitely consider buying a DVD writer on top of your standard hard drive.
Hard drives are a very essential (and delicate) piece of equipment and are a standard feature on most computers. CD writers are also very common.
USB/Firewire storage devices and DVD writers are currently getting more popular with consumers.
icon
Some hard drives, CD and DVD drives available in the market
This article will give you some tips on selecting proper data storage devices for your PC.
Hard Drives
First, let's cover hard drivesicon. We'll look at some hard drive terms like ATA and SCSI, as well as cover the factors to consider when buying a new drive.
ATA and SCSI
Let's get some terminology out of the way before we go further. In the hard drive world, there are two data access standards, ATA and SCSI (pronounced 'Scar-Zee'). The ATA standard is split further into Parallel ATA (PATA) and Serial ATA (SATA). Most of normal hard drives we're used to rely on the PATA standard. Some newer hard drives use the SATA standard.
SATA allows transfer speeds of up to 150 MBs while PATA gives up to 133 MBs. However, to use SATA, you'll need a Serial ATA controller, a SATA drive and a SATA power cable. The speed difference between PATA and SATA is also not significant unless you have a high-end SATA drive.
The SCSI standard is a very fast hard drive standard used for professional computer systems which demand extremely fast data access. SCSI drives provide an access time of about 9.5ms - which I feel is really not needed for average home use.
Disk Space vs. Price
An important factor to consider is the disk space versus price ratio. When you look at the 30 GB, 40 GB and 80 GBPATA hard drives, you'll find they are very close in price. If you don't mind paying an extra $20 or so, I'd say go for the maximum disk space you can get! If you do a lot of graphics or video editing, you may want to consider larger drives like the Seagate 160 GB hard drive. For the average home user, however, 40 GB to 80 GB of disk space is plenty.
Drive Speed
If data access speed is important to you, you can go for faster SATA drives or SCSI drives. But remember that these drives come at a price premium and may not be necessary for average home use. Another option is to use a RAID setup where multiple hard disks are used to gain drive performance and/or data integrity.
CD Writers
CD writersicon are practically standard issue on all PCs these days. Prices are ridiculously cheap, so there's no reason not to get one, unless you prefer a DVD writer.
Drive Speed
For CD writers, you should generally look for a 40X record speed or faster. If you buy anything that is slower, it will definitely waste a lot of time when you're burning CDs.
Internal or External
You can choose between an internal or external CD writer. Internal drives are best suited for desktop PCs and are the cheapest option. If you want portability and don't mind paying a little more, you can get a FireWire or USB 2.0 external CD-RW drive.
DVD Writers
DVD writersicon are the newest rage in the consumer data storage market. They let you store up to 4.7GB on a single disc several times the amount of on a CD-RW disc. So let's look at some factors to consider when purchasing a new DVD drive.
Drive Speed
One factor to consider when buying DVD writers is drive speed. Most DVD-R drives write at 8X, with some older models supporting only 4X. Personally, I don't think there is significant speed difference between a 8X and 4X drive - so don't spend extra money unnecessarily if you don't have to.
Compatibility
There is a huge range of DVD media formats out there (DVD+R, DVD-R,DVD+R DL), represented by various brands. You need to consider compatibility of your DVD writer with these DVD discs. DVD-R and DVD+R formats are both very compatible with existing DVD players and DVD-ROM drives - so try to get a player that supports those.
Internal or External
You can choose between an internal or external DVD writer. Internal drives are cheaper but it also means you need to deal with the installation hassle and non-portability. External DVD writers come with Firewire or USB 2.0 interfaces and may well be a better choice if you need to move your data around a lot.
Conclusion
To purchase a good storage device, be it a hard drive, CD writer or DVD writer, you need to consider what price you're willing to pay for a given set of features. In my opinion, the DVD burner is fast becoming an essential item in the average home user's PC. If you're building a new computer, you should definitely consider buying a DVD writer on top of your standard hard drive.
Basics of Personal Computer Hardware
Basics of Personal
Computer Hardware
The personal computer (PC) is one complex piece of machinery. Its made up of many individual components that will baffle the uninitiated. To learn about PCs, one has to have a desire to learn and experiment - it took me at several years before I got comfortable with building and maintaining my own computers.
This is not to say that PC technology is terribly hard to learn. All you need to know is the how a basic PC is set up, and what components are required.
icon
Various components that go into a personal computer
After learning the basics, its a matter of self experimentation and reading - with time, you'll be one of the pros! This article aims to provide you with at least some basic knowledge of PCs so that you can move on to learn more if you wish.
The Motherboard
The motherboard is one of the most important components in your PC. The motherboard is the glue that brings all the separate PC components together. There are several factors you need to look at when choosing motherboards, like the form factor (usually ATX), supported CPU, bus speed, supported RAM, form factor, built-in sound/video/LAN. You can learn more about how to select good motherboards in my motherboard guide.
The CPU
The CPU is another important component, since it is the 'brain' of your PC. You'll want to look at either Intel or AMD CPUs. The latest CPU from Intel is the Pentium 4, while that from AMD is the Athlon 64. Both are excellent processors. For further reading, you may also want to check out my CPU guide here.
The Computer Case
The computer case is your computer's housing. You need this to store your components, the largest of which is your motherboard. These days, the PC cases out there come in ATX form, which means they can accomodate ATX motherboards. Learn how to choose a good computer case here.
Computer Memory
Computer memory is also called RAM (Random Access Memory) - think of it as the storage area in the computer's brain. Typically, RAM sizes nowadays come up to 512 MB to 1 GB on average. Computers which are run as full servers typically have memory in the range of 4 GB or more. What are the factors to consider when selecting computer memory? You'll find out in this article on computer memory.
The Monitor
The monitor will be the most expensive component in your system. Newer monitors tend to have large 17-inch or 19-inch LCD screens which are easy on the eyes. There are also conventional CRT monitors which are bulkier but cost much less. If you want to know more about the difference between CRT and LCD monitors, this article on computer monitors will be of help to you.
Hard drives and Floppy Drives
A hard drive is essential for storing your system's data, including the operation system software. Hard drives are extremely sensitive devices and prone to failure, so get your hard drives from respected brands like Seagate, Maxtor and IBM. Floppy drives are important for reading 5.25 inch diskettes - these are fast becoming obsolete with the increasing commercial adoption of USB storage devices like Pen Drives. Still, for a basic computer, I'd still say the floppy drive is necessary. You'll also want to read more about selecting a good hard drive here.
CD-ROM Drives
A CD-ROM drive used to be an 'optional extra' in computers - it is no longer so. Most software packages come in CD format, so you must have a CD-ROM drive to read them. Typically, CD-ROM drives today need to be at least 24X speed to keep up with the newer software applications out there.
The Video Card
Unless you have built-in video on your motherboard, the video card is a must have component because it displays images on your monitor. The latest video cards support 3D graphics rendering and games - they are also the fastest changing technology in the PC world. Learn more about selecting video cards here.
The Keyboard and Mouse
These two input devices are obviously needed, otherwise you can't interact with the computer system. These components are fairly standard stuff and can be purchased at pretty cheap prices.
Optional Components
Next, there are the optional hardware components that need not be in every computer setup. These include: the sound card, the LAN card, as well as CD writers and DVD writers. Without them, the computer system will still be able to function.
The Sound Card
Some may argue that the sound card is an essential component in the PC, since it translates digital signals into analog audio for your listening pleasure. Well, that's true, if you want to play games or run multimedia applications in your PC. Otherwise, it may not be necessary, especially in business environments. The one brand that stands out for sound cards is Creative Labs, I'd recommend you get one of those. And guess what, I've got a guide on choosing sound cards too! Read it here.
The LAN Card
Also known as the NIC (Network Interface Card). Once used only in corporate environments, the LAN card is now increasingly used at home for connecting various computer together to form a network. Many motherboards now also feature built-in LAN ports so you don't have to buy a separate card.
The CD Writer and DVD Writer
These two devices, especially the DVD writer, are selling like hotcakes in the market. Essentially CD writers allow you to burn images of your data into a 600 MB to 700 MB CD, which is really handy for performing data backups. DVD writers are even better, since they allow you to burn data onto a 4.7 GB DVD.
Conclusion
Wow, that's a lot of components we've covered! Considering the huge array of computer products out there, it can prove to be very confusing to the beginner. I hope this article sums up the types of PC hardware available in the market and gives you some idea of what you will and will not need to buy.
Computer Hardware
The personal computer (PC) is one complex piece of machinery. Its made up of many individual components that will baffle the uninitiated. To learn about PCs, one has to have a desire to learn and experiment - it took me at several years before I got comfortable with building and maintaining my own computers.
This is not to say that PC technology is terribly hard to learn. All you need to know is the how a basic PC is set up, and what components are required.
icon
Various components that go into a personal computer
After learning the basics, its a matter of self experimentation and reading - with time, you'll be one of the pros! This article aims to provide you with at least some basic knowledge of PCs so that you can move on to learn more if you wish.
The Motherboard
The motherboard is one of the most important components in your PC. The motherboard is the glue that brings all the separate PC components together. There are several factors you need to look at when choosing motherboards, like the form factor (usually ATX), supported CPU, bus speed, supported RAM, form factor, built-in sound/video/LAN. You can learn more about how to select good motherboards in my motherboard guide.
The CPU
The CPU is another important component, since it is the 'brain' of your PC. You'll want to look at either Intel or AMD CPUs. The latest CPU from Intel is the Pentium 4, while that from AMD is the Athlon 64. Both are excellent processors. For further reading, you may also want to check out my CPU guide here.
The Computer Case
The computer case is your computer's housing. You need this to store your components, the largest of which is your motherboard. These days, the PC cases out there come in ATX form, which means they can accomodate ATX motherboards. Learn how to choose a good computer case here.
Computer Memory
Computer memory is also called RAM (Random Access Memory) - think of it as the storage area in the computer's brain. Typically, RAM sizes nowadays come up to 512 MB to 1 GB on average. Computers which are run as full servers typically have memory in the range of 4 GB or more. What are the factors to consider when selecting computer memory? You'll find out in this article on computer memory.
The Monitor
The monitor will be the most expensive component in your system. Newer monitors tend to have large 17-inch or 19-inch LCD screens which are easy on the eyes. There are also conventional CRT monitors which are bulkier but cost much less. If you want to know more about the difference between CRT and LCD monitors, this article on computer monitors will be of help to you.
Hard drives and Floppy Drives
A hard drive is essential for storing your system's data, including the operation system software. Hard drives are extremely sensitive devices and prone to failure, so get your hard drives from respected brands like Seagate, Maxtor and IBM. Floppy drives are important for reading 5.25 inch diskettes - these are fast becoming obsolete with the increasing commercial adoption of USB storage devices like Pen Drives. Still, for a basic computer, I'd still say the floppy drive is necessary. You'll also want to read more about selecting a good hard drive here.
CD-ROM Drives
A CD-ROM drive used to be an 'optional extra' in computers - it is no longer so. Most software packages come in CD format, so you must have a CD-ROM drive to read them. Typically, CD-ROM drives today need to be at least 24X speed to keep up with the newer software applications out there.
The Video Card
Unless you have built-in video on your motherboard, the video card is a must have component because it displays images on your monitor. The latest video cards support 3D graphics rendering and games - they are also the fastest changing technology in the PC world. Learn more about selecting video cards here.
The Keyboard and Mouse
These two input devices are obviously needed, otherwise you can't interact with the computer system. These components are fairly standard stuff and can be purchased at pretty cheap prices.
Optional Components
Next, there are the optional hardware components that need not be in every computer setup. These include: the sound card, the LAN card, as well as CD writers and DVD writers. Without them, the computer system will still be able to function.
The Sound Card
Some may argue that the sound card is an essential component in the PC, since it translates digital signals into analog audio for your listening pleasure. Well, that's true, if you want to play games or run multimedia applications in your PC. Otherwise, it may not be necessary, especially in business environments. The one brand that stands out for sound cards is Creative Labs, I'd recommend you get one of those. And guess what, I've got a guide on choosing sound cards too! Read it here.
The LAN Card
Also known as the NIC (Network Interface Card). Once used only in corporate environments, the LAN card is now increasingly used at home for connecting various computer together to form a network. Many motherboards now also feature built-in LAN ports so you don't have to buy a separate card.
The CD Writer and DVD Writer
These two devices, especially the DVD writer, are selling like hotcakes in the market. Essentially CD writers allow you to burn images of your data into a 600 MB to 700 MB CD, which is really handy for performing data backups. DVD writers are even better, since they allow you to burn data onto a 4.7 GB DVD.
Conclusion
Wow, that's a lot of components we've covered! Considering the huge array of computer products out there, it can prove to be very confusing to the beginner. I hope this article sums up the types of PC hardware available in the market and gives you some idea of what you will and will not need to buy.
Hardware
Hardware
The hardware are the parts of computer itself including the Central Processing Unit (CPU) and related microchips and micro-circuitry, keyboards, monitors, case and drives (hard, CD, DVD, floppy, optical, tape, etc...). Other extra parts called peripheral components or devices include mouse, printers, modems, scanners, digital cameras and cards (sound, colour, video) etc... Together they are often referred to as a personal computer.
Central Processing Unit - Though the term relates to a specific chip or the processor a CPU's performance is determined by the rest of the computer's circuitry and chips.
Currently the Pentium chip or processor, made by Intel, is the most common CPU though there are many other companies that produce processors for personal computers. Examples are the CPU made by Motorola and AMD.
Chip
With faster processors the clock speed becomes more important. Compared to some of the first computers which operated at below 30 megahertz (MHz) the Pentium chips began at 75 MHz in the late 1990's. Speeds now exceed 3000+ MHz or 3 gigahertz (GHz) and different chip manufacturers use different measuring standards (check your local computer store for the latest speed). It depends on the circuit board that the chip is housed in, or the motherboard, as to whether you are able to upgrade to a faster chip. The motherboard contains the circuitry and connections that allow the various component to communicate with each other.
Though there were many computers using many different processors previous to this I call the 80286 processor the advent of home computers as these were the processors that made computers available for the average person. Using a processor before the 286 involved learning a proprietary system and software. Most new software are being developed for the newest and fastest processors so it can be difficult to use an older computer system.
Keyboard - The keyboard is used to type information into the computer or input information. There are many different keyboard layouts and sizes with the most common for Latin based languages being the QWERTY layout (named for the first 6 keys). The standard keyboard has 101 keys. Notebooks have embedded keys accessible by special keys or by pressing key combinations (CTRL or Command and P for example). Ergonomically designed keyboards are designed to make typing easier. Hand held devices have various and different keyboard configurations and touch screens.
Some of the keys have a special use. There are referred to as command keys. The 3 most common are the Control or CTRL, Alternate or Alt and the Shift keys though there can be more (the Windows key for example or the Command key). Each key on a standard keyboard has one or two characters. Press the key to get the lower character and hold Shift to get the upper.
Removable Storage and/or Disk Drives - All disks need a drive to get information off - or read - and put information on the disk - or write. Each drive is designed for a specific type of disk whether it is a CD, DVD, hard disk or floppy. Often the term 'disk' and 'drive' are used to describe the same thing but it helps to understand that the disk is the storage device which contains computer files - or software - and the drive is the mechanism that runs the disk.Mouse
Digital flash drives work slightly differently as they use memory cards to store information so there are no moving parts. Digital cameras also use Flash memory cards to store information, in this case photographs. Hand held devices use digital drives and many also use memory cards.
Mouse - Most modern computers today are run using a mouse controlled pointer. Generally if the mouse has two buttons the left one is used to select objects and text and the right one is used to access menus. If the mouse has one button (Mac for instance) it controls all the activity and a mouse with a third button can be used by specific software programs.
One type of mouse has a round ball under the bottom of the mouse that rolls and turns two wheels which control the direction of the pointer on the screen. Another type of mouse uses an optical system to track the movement of the mouse. Laptop computers use touch pads, buttons and other devices to control the pointer. Hand helds use a combination of devices to control the pointer, including touch screens.
Note: It is important to clean the mouse periodically, particularly if it becomes sluggish. A ball type mouse has a small circular panel that can be opened, allowing you to remove the ball. Lint can be removed carefully with a tooth pick or tweezers and the ball can be washed with mild detergent. A build up will accumulate on the small wheels in the mouse. Use a small instrument or finger nail to scrape it off taking care not to scratch the wheels. Track balls can be cleaned much like a mouse and touch-pad can be wiped with a clean, damp cloth. An optical mouse can accumulate material from the surface that it is in contact with which can be removed with a finger nail or small instrument.
Monitors - The monitor shows information on the screen when you type. This is called outputting information. When the computer needs more information it will display a message on the screen, usually through a dialog box. Monitors come in many types and sizes. The resolution of the monitor determines the sharpness of the screen. The resolution can be adjusted to control the screen's display..
Most desktop computers use a monitor with a cathode tube or liquid crystal display. Most notebooks use a liquid crystal display monitor.
To get the full benefit of today's software with full colour graphics and animation, computers need a color monitor with a display or graphics card.
Printers - The printer takes the information on your screen and transfers it to paper or a hard copy. There are many different types of printers with various levels of quality. The three basic types of printer are; dot matrix, inkjet, and laser.
* Dot matrix printers work like a typewriter transferring ink from a ribbon to paper with a series or 'matrix' of tiny pins.
* Ink jet printers work like dot matrix printers but fires a stream of ink from a cartridge directly onto the paper.
* Laser printers use the same technology as a photocopier using heat to transfer toner onto paper.
Modem - A modem is used to translate information transferred through telephone lines, cable or line-of-site wireless.
The term stands for modulate and demodulate which changes the signal from digital, which computers use, to analog, which telephones use and then back again. Digital modems transfer digital information directly without changing to analog.
Modems are measured by the speed that the information is transferred. The measuring tool is called the baud rate. Originally modems worked at speeds below 2400 baud but today analog speeds of 56,000 are standard. Cable, wireless or digital subscriber lines can transfer information much faster with rates of 300,000 baud and up.
Modems also use Error Correction which corrects for transmission errors by constantly checking whether the information was received properly or not and Compression which allows for faster data transfer rates. Information is transferred in packets. Each packet is checked for errors and is re-sent if there is an error.
Anyone who has used the Internet has noticed that at times the information travels at different speeds. Depending on the amount of information that is being transferred, the information will arrive at it's destination at different times. The amount of information that can travel through a line is limited. This limit is called bandwidth.
There are many more variables involved in communication technology using computers, much of which is covered in the section on the Internet.
Scanners- Scanners allow you to transfer pictures and photographs to your computer. A scanner 'scans' the image from the top to the bottom, one line at a time and transfers it to the computer as a series of bits or a bitmap. You can then take that image and use it in a paint program, send it out as a fax or print it. With optional Optical Character Recognition (OCR) software you can convert printed documents such as newspaper articles to text that can be used in your word processor. Most scanners use TWAIN software that makes the scanner accessable by other software applications.
Digital cameras allow you to take digital photographs. The images are stored on a memory chip or disk that can be transferred to your computer. Some cameras can also capture sound and video.
Case - The case houses the microchips and circuitry that run the computer. Desktop models usually sit under the monitor and tower models beside. They come in many sizes, including desktop, mini, midi, and full tower. There is usually room inside to expand or add components at a later time. By removing the cover off the case you may find plate covered, empty slots that allow you to add cards. There are various types of slots including IDE, ASI, USB, PCI and Firewire slots.
Depending on the type notebook computers may have room to expand . Most Notebooks also have connections or ports that allows expansion or connection to exterior, peripheral devices such as monitor, portable hard-drives or other devices.
Cards - Cards are components added to computers to increase their capability. When adding a peripheral device make sure that your computer has a slot of the type needed by the device.
Sound cards allow computers to produce sound like music and voice. The older sound cards were 8 bit then 16 bit then 32 bit. Though the human ear can't distinguish the fine difference between sounds produced by the more powerful sound card they allow for more complex music and music production.
Colour cards allow computers to produce colour (with a colour monitor of course). The first colour cards were 2 bit which produced 4 colours [CGA]. It was amazing what could be done with those 4 colours. Next came 4 bit allowing for 16 [EGA and VGA ] colours. Then came 16 bit allowing for 1064 colours and then 24 bit which allows for almost 17 million colours and now 32 bit and higher allow monitors to display almost a billion separate colours.
Video cards allow computers to display video and animation. Some video cards allow computers to display television as well as capture frames from video. A video card with a digital video camera allows computers users to produce live video. A high speed connection is required for effective video transmission.
Network cards allow computers to connect together to communicate with each other. Network cards have connections for cable, thin wire or wireless networks. For more information see the section on Networks.
Cables connect internal components to the Motherboard, which is a board with series of electronic path ways and connections allowing the CPU to communicate with the other components of the computer.
Memory - Memory can be very confusing but is usually one of the easiest pieces of hardware to add to your computer. It is common to confuse chip memory with disk storage. An example of the difference between memory and storage would be the difference between a table where the actual work is done (memory) and a filing cabinet where the finished product is stored (disk). To add a bit more confusion, the computer's hard disk can be used as temporary memory when the program needs more than the chips can provide.
Random Access Memory or RAM is the memory that the computer uses to temporarily store the information as it is being processed. The more information being processed the more RAM the computer needs.
One of the first home computers used 64 kilobytes of RAM memory (Commodore 64). Today's modern computers need a minimum of 64 Mb (recommended 128 Mb or more) to run Windows or OS 10 with modern software.
RAM memory chips come in many different sizes and speeds and can usually be expanded. Older computers came with 512 Kb of memory which could be expanded to a maximum of 640 Kb. In most modern computers the memory can be expanded by adding or replacing the memory chips depending on the processor you have and the type of memory your computer uses. Memory chips range in size from 1 Mb to 4 Gb. As computer technology changes the type of memory changes as well making old memory chips obsolete. Check your computer manual to find out what kind of memory your computer uses before purchasing new memory chips.
The hardware are the parts of computer itself including the Central Processing Unit (CPU) and related microchips and micro-circuitry, keyboards, monitors, case and drives (hard, CD, DVD, floppy, optical, tape, etc...). Other extra parts called peripheral components or devices include mouse, printers, modems, scanners, digital cameras and cards (sound, colour, video) etc... Together they are often referred to as a personal computer.
Central Processing Unit - Though the term relates to a specific chip or the processor a CPU's performance is determined by the rest of the computer's circuitry and chips.
Currently the Pentium chip or processor, made by Intel, is the most common CPU though there are many other companies that produce processors for personal computers. Examples are the CPU made by Motorola and AMD.
Chip
With faster processors the clock speed becomes more important. Compared to some of the first computers which operated at below 30 megahertz (MHz) the Pentium chips began at 75 MHz in the late 1990's. Speeds now exceed 3000+ MHz or 3 gigahertz (GHz) and different chip manufacturers use different measuring standards (check your local computer store for the latest speed). It depends on the circuit board that the chip is housed in, or the motherboard, as to whether you are able to upgrade to a faster chip. The motherboard contains the circuitry and connections that allow the various component to communicate with each other.
Though there were many computers using many different processors previous to this I call the 80286 processor the advent of home computers as these were the processors that made computers available for the average person. Using a processor before the 286 involved learning a proprietary system and software. Most new software are being developed for the newest and fastest processors so it can be difficult to use an older computer system.
Keyboard - The keyboard is used to type information into the computer or input information. There are many different keyboard layouts and sizes with the most common for Latin based languages being the QWERTY layout (named for the first 6 keys). The standard keyboard has 101 keys. Notebooks have embedded keys accessible by special keys or by pressing key combinations (CTRL or Command and P for example). Ergonomically designed keyboards are designed to make typing easier. Hand held devices have various and different keyboard configurations and touch screens.
Some of the keys have a special use. There are referred to as command keys. The 3 most common are the Control or CTRL, Alternate or Alt and the Shift keys though there can be more (the Windows key for example or the Command key). Each key on a standard keyboard has one or two characters. Press the key to get the lower character and hold Shift to get the upper.
Removable Storage and/or Disk Drives - All disks need a drive to get information off - or read - and put information on the disk - or write. Each drive is designed for a specific type of disk whether it is a CD, DVD, hard disk or floppy. Often the term 'disk' and 'drive' are used to describe the same thing but it helps to understand that the disk is the storage device which contains computer files - or software - and the drive is the mechanism that runs the disk.Mouse
Digital flash drives work slightly differently as they use memory cards to store information so there are no moving parts. Digital cameras also use Flash memory cards to store information, in this case photographs. Hand held devices use digital drives and many also use memory cards.
Mouse - Most modern computers today are run using a mouse controlled pointer. Generally if the mouse has two buttons the left one is used to select objects and text and the right one is used to access menus. If the mouse has one button (Mac for instance) it controls all the activity and a mouse with a third button can be used by specific software programs.
One type of mouse has a round ball under the bottom of the mouse that rolls and turns two wheels which control the direction of the pointer on the screen. Another type of mouse uses an optical system to track the movement of the mouse. Laptop computers use touch pads, buttons and other devices to control the pointer. Hand helds use a combination of devices to control the pointer, including touch screens.
Note: It is important to clean the mouse periodically, particularly if it becomes sluggish. A ball type mouse has a small circular panel that can be opened, allowing you to remove the ball. Lint can be removed carefully with a tooth pick or tweezers and the ball can be washed with mild detergent. A build up will accumulate on the small wheels in the mouse. Use a small instrument or finger nail to scrape it off taking care not to scratch the wheels. Track balls can be cleaned much like a mouse and touch-pad can be wiped with a clean, damp cloth. An optical mouse can accumulate material from the surface that it is in contact with which can be removed with a finger nail or small instrument.
Monitors - The monitor shows information on the screen when you type. This is called outputting information. When the computer needs more information it will display a message on the screen, usually through a dialog box. Monitors come in many types and sizes. The resolution of the monitor determines the sharpness of the screen. The resolution can be adjusted to control the screen's display..
Most desktop computers use a monitor with a cathode tube or liquid crystal display. Most notebooks use a liquid crystal display monitor.
To get the full benefit of today's software with full colour graphics and animation, computers need a color monitor with a display or graphics card.
Printers - The printer takes the information on your screen and transfers it to paper or a hard copy. There are many different types of printers with various levels of quality. The three basic types of printer are; dot matrix, inkjet, and laser.
* Dot matrix printers work like a typewriter transferring ink from a ribbon to paper with a series or 'matrix' of tiny pins.
* Ink jet printers work like dot matrix printers but fires a stream of ink from a cartridge directly onto the paper.
* Laser printers use the same technology as a photocopier using heat to transfer toner onto paper.
Modem - A modem is used to translate information transferred through telephone lines, cable or line-of-site wireless.
The term stands for modulate and demodulate which changes the signal from digital, which computers use, to analog, which telephones use and then back again. Digital modems transfer digital information directly without changing to analog.
Modems are measured by the speed that the information is transferred. The measuring tool is called the baud rate. Originally modems worked at speeds below 2400 baud but today analog speeds of 56,000 are standard. Cable, wireless or digital subscriber lines can transfer information much faster with rates of 300,000 baud and up.
Modems also use Error Correction which corrects for transmission errors by constantly checking whether the information was received properly or not and Compression which allows for faster data transfer rates. Information is transferred in packets. Each packet is checked for errors and is re-sent if there is an error.
Anyone who has used the Internet has noticed that at times the information travels at different speeds. Depending on the amount of information that is being transferred, the information will arrive at it's destination at different times. The amount of information that can travel through a line is limited. This limit is called bandwidth.
There are many more variables involved in communication technology using computers, much of which is covered in the section on the Internet.
Scanners- Scanners allow you to transfer pictures and photographs to your computer. A scanner 'scans' the image from the top to the bottom, one line at a time and transfers it to the computer as a series of bits or a bitmap. You can then take that image and use it in a paint program, send it out as a fax or print it. With optional Optical Character Recognition (OCR) software you can convert printed documents such as newspaper articles to text that can be used in your word processor. Most scanners use TWAIN software that makes the scanner accessable by other software applications.
Digital cameras allow you to take digital photographs. The images are stored on a memory chip or disk that can be transferred to your computer. Some cameras can also capture sound and video.
Case - The case houses the microchips and circuitry that run the computer. Desktop models usually sit under the monitor and tower models beside. They come in many sizes, including desktop, mini, midi, and full tower. There is usually room inside to expand or add components at a later time. By removing the cover off the case you may find plate covered, empty slots that allow you to add cards. There are various types of slots including IDE, ASI, USB, PCI and Firewire slots.
Depending on the type notebook computers may have room to expand . Most Notebooks also have connections or ports that allows expansion or connection to exterior, peripheral devices such as monitor, portable hard-drives or other devices.
Cards - Cards are components added to computers to increase their capability. When adding a peripheral device make sure that your computer has a slot of the type needed by the device.
Sound cards allow computers to produce sound like music and voice. The older sound cards were 8 bit then 16 bit then 32 bit. Though the human ear can't distinguish the fine difference between sounds produced by the more powerful sound card they allow for more complex music and music production.
Colour cards allow computers to produce colour (with a colour monitor of course). The first colour cards were 2 bit which produced 4 colours [CGA]. It was amazing what could be done with those 4 colours. Next came 4 bit allowing for 16 [EGA and VGA ] colours. Then came 16 bit allowing for 1064 colours and then 24 bit which allows for almost 17 million colours and now 32 bit and higher allow monitors to display almost a billion separate colours.
Video cards allow computers to display video and animation. Some video cards allow computers to display television as well as capture frames from video. A video card with a digital video camera allows computers users to produce live video. A high speed connection is required for effective video transmission.
Network cards allow computers to connect together to communicate with each other. Network cards have connections for cable, thin wire or wireless networks. For more information see the section on Networks.
Cables connect internal components to the Motherboard, which is a board with series of electronic path ways and connections allowing the CPU to communicate with the other components of the computer.
Memory - Memory can be very confusing but is usually one of the easiest pieces of hardware to add to your computer. It is common to confuse chip memory with disk storage. An example of the difference between memory and storage would be the difference between a table where the actual work is done (memory) and a filing cabinet where the finished product is stored (disk). To add a bit more confusion, the computer's hard disk can be used as temporary memory when the program needs more than the chips can provide.
Random Access Memory or RAM is the memory that the computer uses to temporarily store the information as it is being processed. The more information being processed the more RAM the computer needs.
One of the first home computers used 64 kilobytes of RAM memory (Commodore 64). Today's modern computers need a minimum of 64 Mb (recommended 128 Mb or more) to run Windows or OS 10 with modern software.
RAM memory chips come in many different sizes and speeds and can usually be expanded. Older computers came with 512 Kb of memory which could be expanded to a maximum of 640 Kb. In most modern computers the memory can be expanded by adding or replacing the memory chips depending on the processor you have and the type of memory your computer uses. Memory chips range in size from 1 Mb to 4 Gb. As computer technology changes the type of memory changes as well making old memory chips obsolete. Check your computer manual to find out what kind of memory your computer uses before purchasing new memory chips.
Thursday, September 30, 2010
basic computing skills
This series of columns on basic computing skills was inspired by a friend who, while smart in every way, was unable to perform the simple task of copying a file on her computer from one folder to another.
Her conundrum made me realize there are a lot of people who use personal computers every day but can only do what they need to do and not much more. They don't know the very basics of computer literacy.
For the past eight months, I've been offering up tips on the most-needed computing skills, and this column is the last one. (You can see the others at chron.com/computing101.) This final installment comes full circle, looking at working in Windows, the most common personal computing platform. Yep, this is the column my friend needs to read!
Copying files and folders. All versions of Windows store files, programs and documents in folders. You move around in folders using Windows Explorer, the file manager that launches when you double-click on My Computer in Windows XP, or Computer in Windows 7/Vista. At some point, you're going to need to copy or move a file from one folder to another.
The simplest is to open the folder that contains the file, as well as the folder to which you want to copy or move it, and align them so you can see both. To move the file, simply click-and-hold on the file using your mouse cursor and drag it from the old folder into the new one. To copy a file, so that it appears in both folders, right-click on it and choose Copy from the menu that appears. Then, right-click in an open area in the destination folder, and choose Paste.
You can do the same thing with folders, as well.
And here's a bonus tip: If you've put a flash drive into a USB port on your computer, you can easily send a copy of a file to it by right-clicking on the file, choosing Send To ... and then selecting the flash drive from the menu that appears.
Create a new folder. Suppose you want to create a new folder. You might want to better organize some photos, or store documents you need for a project. To do this, just right-click inside any other folder's Explorer window (or on the Desktop, if you like), then click New, followed by Folder. The folder appears, with the words New Folder highlighted. Don't click on anything else, just start typing, and the "New Folder" placeholder name will be replaced by what you write.
Finding a downloaded file. For some reason, locating a file downloaded from the Web seems to particularly befuddle some folks. But in many cases, depending on the browser you're using, you'll be shown where it's going to go when you start the process, and you may be able to specify where to put it.
When you click on a file for downloading in Internet Explorer, you'll be asked whether you want to save it or run it, if it's a program file. Choose Save, and a dialog box will open. Look carefully at the box: It will show you where the file is about to be saved. If you don't want it there, you can use the box to navigate to a different destination, such as your Desktop.
Firefox automatically saves downloads for you in a pre-specified folder — usually in your documents\downloads folder - but you can change this default location in Firefox's settings. You can also right-click on the Downloads window that appears and choose Open Containing Folder from the menu to see where files are stored.
Uninstalling software. Installing software is usually a simple matter of clicking on an installer and following the prompts. But removing or uninstalling a program is another matter. Too many Windows users still think it's OK just to find the folder containing a program and put it in the Recycle Bin. That's how you do it on a Mac, but that can be disastrous on Windows, which deposits pieces of a program all over your hard drive.
Instead, you'll want to use a module in the Control Panel designed just for this purpose. Click the Start Menu, then Control Panel. In Windows XP, look for Add/Remove Programs; in Windows 7/Vista, it's called Programs and Features. Open it to see a list of installed programs. You can double-click any of them to start the removal process.
These are the most common tasks I see users struggling with. If you'd like to learn more Windows basics, Microsoft has a set of tutorials for all three popular versions at windows.microsoft.com/en-US/windows/help.
Her conundrum made me realize there are a lot of people who use personal computers every day but can only do what they need to do and not much more. They don't know the very basics of computer literacy.
For the past eight months, I've been offering up tips on the most-needed computing skills, and this column is the last one. (You can see the others at chron.com/computing101.) This final installment comes full circle, looking at working in Windows, the most common personal computing platform. Yep, this is the column my friend needs to read!
Copying files and folders. All versions of Windows store files, programs and documents in folders. You move around in folders using Windows Explorer, the file manager that launches when you double-click on My Computer in Windows XP, or Computer in Windows 7/Vista. At some point, you're going to need to copy or move a file from one folder to another.
The simplest is to open the folder that contains the file, as well as the folder to which you want to copy or move it, and align them so you can see both. To move the file, simply click-and-hold on the file using your mouse cursor and drag it from the old folder into the new one. To copy a file, so that it appears in both folders, right-click on it and choose Copy from the menu that appears. Then, right-click in an open area in the destination folder, and choose Paste.
You can do the same thing with folders, as well.
And here's a bonus tip: If you've put a flash drive into a USB port on your computer, you can easily send a copy of a file to it by right-clicking on the file, choosing Send To ... and then selecting the flash drive from the menu that appears.
Create a new folder. Suppose you want to create a new folder. You might want to better organize some photos, or store documents you need for a project. To do this, just right-click inside any other folder's Explorer window (or on the Desktop, if you like), then click New, followed by Folder. The folder appears, with the words New Folder highlighted. Don't click on anything else, just start typing, and the "New Folder" placeholder name will be replaced by what you write.
Finding a downloaded file. For some reason, locating a file downloaded from the Web seems to particularly befuddle some folks. But in many cases, depending on the browser you're using, you'll be shown where it's going to go when you start the process, and you may be able to specify where to put it.
When you click on a file for downloading in Internet Explorer, you'll be asked whether you want to save it or run it, if it's a program file. Choose Save, and a dialog box will open. Look carefully at the box: It will show you where the file is about to be saved. If you don't want it there, you can use the box to navigate to a different destination, such as your Desktop.
Firefox automatically saves downloads for you in a pre-specified folder — usually in your documents\downloads folder - but you can change this default location in Firefox's settings. You can also right-click on the Downloads window that appears and choose Open Containing Folder from the menu to see where files are stored.
Uninstalling software. Installing software is usually a simple matter of clicking on an installer and following the prompts. But removing or uninstalling a program is another matter. Too many Windows users still think it's OK just to find the folder containing a program and put it in the Recycle Bin. That's how you do it on a Mac, but that can be disastrous on Windows, which deposits pieces of a program all over your hard drive.
Instead, you'll want to use a module in the Control Panel designed just for this purpose. Click the Start Menu, then Control Panel. In Windows XP, look for Add/Remove Programs; in Windows 7/Vista, it's called Programs and Features. Open it to see a list of installed programs. You can double-click any of them to start the removal process.
These are the most common tasks I see users struggling with. If you'd like to learn more Windows basics, Microsoft has a set of tutorials for all three popular versions at windows.microsoft.com/en-US/windows/help.
Basic Computer Operations
How Computers Work
Input: Information and programs are entered into the computer through Input devices such as the keyboard, disks, or through other computers via network connections or modems connected to the Internet. The input device also retrieves information off disks.
Output: Output Devices displays information on the screen (monitor) or the printer and sends information to other computers. They also display messages about what errors may have occurred and brings up message or dialog box asking for more information to be input. The output device also saves information on the disk for future use.
Processing: The CPU or central processing unit is sometimes called the Control Unit and directs the operation of the input and output devices. The Coprocessor or the Arithmetic-Logic Unit does arithmetic and comparisons. The memory or RAM temporarily stores information (files and programs) while you are using or working on them. The BIOS or basic input/output system controls the dialogue between the various devices.
Keyboard Layout and Data Entry
ENTER or RETURN - Moves the cursor down one line and to the left margin. Enter also process commands such as choosing an option in a dialog (message) boxes and submitting a form.
DEL or DELETE - Deletes the character at cursor and/or characters to the right of the cursor and all highlighted (or selected) text.
BKSP or BACKSPACE - Deletes the character to the left of cursor and all hightlighted text.
SPACE BAR - Moves the cursor one space at a time to the right
SHIFT KEY - Use the shift keys to type capital letters and to type the upper character on keys with two characters on them
CAPS LOCK - Locks the keyboard so it types capital letters (a light goes on when caps lock is on)
TAB - Moves the cursor five spaces to the right (number of spaces are usually adjustable). Tab moves to the next field in a form or table (Shift-Tab for previous field).
ESC or ESCAPE - Cancels a menu or dialog box
ARROW KEYS - Moves the cursor around document without changing text
FUNCTION KEYS or F KEYS - Access commands by themselves or in combination with the three command keys; CTRL, SHIFT, and ALT
Keyboard
Command or Special Keys
Command keys normally do nothing on their own but work in combination with other keys. Each piece of software uses the command keys differently though there is a move to standardize some functions. The Control key or Ctrl is often used to access commands. The Alternative key or Alt is often used to access menus. The Shift key is used to type CAPITAL LETTERS. As well the command keys are all used to move through documents and edit text faster and easier. As well many computers have Special keys design specifically for the particular computer. Apple computers have the Apple keys and Macs have Command keys. Many keyboards now have a Windows key specifically for Windows 9x and newer systems. Many older computers also have special keys used for a variety of different functions.
Some Notebook or Laptop keys are left out because of space limitations and they usually have a Special function key which allows other keys to double for the missing ones.
Basic Typing Rules
Place one space between each word, after a punctuation mark and at the end of a sentence. Always start a sentence with a capital letter. Use capitals for names, addresses, provinces and countries, places, organizations, businesses, associations, schools, colleges, universities, days of the week, months, holidays, nationalities, ethnic groups and languages.
Learning the keyboard is the first step to learning computers. Learning involves practice. It really is as simple as that. There are two kinds of typing.
The first is called Touch Typing. The Touch Typist uses the Home Keys (asdf for the left hand and jkl; for the right) and all the fingers on both hands as well as the thumbs for the Space Bar while typing. There are many commercial and public domain programs that are designed to teach this method.
The other method is some times called 'Hunt and Peck' or depending on finger strength 'Search and Destroy'. This involves using one or more fingers on one or two hands to type. It is a perfectly acceptable way of using a computer and many people get along fine with this technique.
Input: Information and programs are entered into the computer through Input devices such as the keyboard, disks, or through other computers via network connections or modems connected to the Internet. The input device also retrieves information off disks.
Output: Output Devices displays information on the screen (monitor) or the printer and sends information to other computers. They also display messages about what errors may have occurred and brings up message or dialog box asking for more information to be input. The output device also saves information on the disk for future use.
Processing: The CPU or central processing unit is sometimes called the Control Unit and directs the operation of the input and output devices. The Coprocessor or the Arithmetic-Logic Unit does arithmetic and comparisons. The memory or RAM temporarily stores information (files and programs) while you are using or working on them. The BIOS or basic input/output system controls the dialogue between the various devices.
Keyboard Layout and Data Entry
ENTER or RETURN - Moves the cursor down one line and to the left margin. Enter also process commands such as choosing an option in a dialog (message) boxes and submitting a form.
DEL or DELETE - Deletes the character at cursor and/or characters to the right of the cursor and all highlighted (or selected) text.
BKSP or BACKSPACE - Deletes the character to the left of cursor and all hightlighted text.
SPACE BAR - Moves the cursor one space at a time to the right
SHIFT KEY - Use the shift keys to type capital letters and to type the upper character on keys with two characters on them
CAPS LOCK - Locks the keyboard so it types capital letters (a light goes on when caps lock is on)
TAB - Moves the cursor five spaces to the right (number of spaces are usually adjustable). Tab moves to the next field in a form or table (Shift-Tab for previous field).
ESC or ESCAPE - Cancels a menu or dialog box
ARROW KEYS - Moves the cursor around document without changing text
FUNCTION KEYS or F KEYS - Access commands by themselves or in combination with the three command keys; CTRL, SHIFT, and ALT
Keyboard
Command or Special Keys
Command keys normally do nothing on their own but work in combination with other keys. Each piece of software uses the command keys differently though there is a move to standardize some functions. The Control key or Ctrl is often used to access commands. The Alternative key or Alt is often used to access menus. The Shift key is used to type CAPITAL LETTERS. As well the command keys are all used to move through documents and edit text faster and easier. As well many computers have Special keys design specifically for the particular computer. Apple computers have the Apple keys and Macs have Command keys. Many keyboards now have a Windows key specifically for Windows 9x and newer systems. Many older computers also have special keys used for a variety of different functions.
Some Notebook or Laptop keys are left out because of space limitations and they usually have a Special function key which allows other keys to double for the missing ones.
Basic Typing Rules
Place one space between each word, after a punctuation mark and at the end of a sentence. Always start a sentence with a capital letter. Use capitals for names, addresses, provinces and countries, places, organizations, businesses, associations, schools, colleges, universities, days of the week, months, holidays, nationalities, ethnic groups and languages.
Learning the keyboard is the first step to learning computers. Learning involves practice. It really is as simple as that. There are two kinds of typing.
The first is called Touch Typing. The Touch Typist uses the Home Keys (asdf for the left hand and jkl; for the right) and all the fingers on both hands as well as the thumbs for the Space Bar while typing. There are many commercial and public domain programs that are designed to teach this method.
The other method is some times called 'Hunt and Peck' or depending on finger strength 'Search and Destroy'. This involves using one or more fingers on one or two hands to type. It is a perfectly acceptable way of using a computer and many people get along fine with this technique.
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