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The first personal computers were made available in the 1970s and were so simplistic that they were sold in kits, which could easily be put together by the consumer. The famous Apple-1 was the first personal computer to come with a fully assembled circuit board. However, one still had to provide a case, power supply, keyboard, and display for their Apple-1. When comparing today’s personal computers to the first models, one can see how advanced computer technology has become over a short period of time. For instance, gigabytes, MP3′s, AVI’s, USB’s, UPS’s and dual cores are terms that never existed in the 1970s, but are all common terms today when discussing computer technology. When today’s computers become damaged, a computer repair firm that specializes in PC repair and IT consulting in Cleveland, Ohio can help one understand what went wrong with their complex machine, how it will be fixed and maintenance tips.

Computer manufacturers do not work with consumers on a personal level when it comes to computer repair. When one sends their damaged computer to its manufacturer, it requires a mailing fee. Then the usual repair time is a couple of weeks to a month. After the repair is made, the consumer then has to wait at least a week before they receive their computer. The computer manufacturer may only disclose what was repaired in the consumer’s copy of the work order or receipt, but will not tell the consumer how the computer failed or how it was repaired. If the consumer calls the manufacturer with questions, they have to go through a hierarchy of employees starting from the bottom.

One blogger on Askville.Amazon.com, said when he contacted HP to troubleshoot one of its computers it took them two hours and then another hour to authorize the return. The blogger said it took two weeks before HP sent the repaired computer back to him. He also said when he contacted Dell to troubleshoot one of its latest computer models, he was put on hold excessively before he was able to authorize the return. He said it took Dell three weeks to send him back the repaired computer.

A computer repair company that specializes in PC repair and IT consulting in Cleveland, Ohio can offer certified computer technicians who will work with the PC owner one on one at their home or office.  This not only allows quicker repairs, but also gives the PC owner the opportunity to establish rapport with the computer repair firm, allowing an opportunity for discounts and other deals on services. A PC owner has the chance to ask questions about how their computer failed to understand how to avoid it from happening again. For example, a computer technician from a computer repair company that specializes in PC repair in Cleveland, Ohio can inform the PC owner what Web sites to avoid to prevent the downloading of adware, spyware and viruses to keep their computer performance at optimal level after the repair is made. A computer technician from this type of firm can inform a PC owner to use surge protectors to prevent electrical damage after replacement of the damaged part.

Since computers are complex machines a lot more can go wrong with them other than virus infection and electrical damage. A computer repair company specializing in PC repair and IT consulting in Cleveland, Ohio can get to know the PC owner and their computer habits, since its computer technicians are able to work with the consumer on a personal level. This means the firm will know what maintenance tips to tell the consumer to keep their computer running for a long time and to save them money. Here are a couple of examples:

Never turn the computer off with the power switch until Windows has shut down
This will prevent permanent hard drive defects and Window problems from occurring. Use the Ctrl + Alt + Delete keys to restart the computer if it crashes.
Use an USP, uninterruptible power supply for the computer
This prevents the computer from crashing during power outages and protects it from low and high voltage shortages (some say a USP is more superior than a surge protector)
Back up important data on at least two separate physical drives
-Hard drive failure is a common occurrence
Run Scandisk and Defragment at least once a month
This can prevent crashes
Never unplug peripherals from the computer when it is powered up
This can short out the motherboard
Keep at least 600 MBs of C: drive free
This can keep the computer from running slow. Windows XP and Vista requires 400-600 MBs.
Use a firewall program
A firewall program prevents hackers from gaining access to the computer system
Keep every software disk
Disks can contain important drivers that need to be reloaded

Computers are complex machines that require certified experts to fix them the right way. When a computer needs repair, a computer repair firm that specializes in PC repair and IT consulting in Cleveland, Ohio can offer more than a computer manufacturer. The firm can offer the right expertise at one’s home or office to make the repair faster, offer better deals, and gives maintenance tips to save PC owners money.

Overview

The selection and deployment of access point antenna equipment affect network performance and availability. The signal strength or amount of energy radiated from an antenna has to do with antenna type and access point transmit specifications. It is expressed as effective isotropic radiated power (EIRP) and expressed as the sum of access point transmit power plus antenna gain minus cable loss. Cable length will increase signal attenuation or loss and should be minimized. Each antenna type will have a horizontal and vertical beam width specified. The antenna type, gain, cable length, number and mounting is all key to the design. For instance a directional antenna with high gain, no external cable, mounted at proper height will give best performance in an outside deployment with a lot of interference.

The wireless coverage cell on inside deployments can be extended with external antennas that plug into connectors on the access points. Most antennas can be mounted on the ceiling or wall and outside antennas often use a mast to increase height for line of sight.

Effective Isotropic Radiated Power = Transmit Power (dBm) + Gain (dB) – Cable Loss (dB)

Omni-Directional

Omni-directional antenna sends a horizontal radiated pattern of 360 degrees and a vertical pattern of 50 – 70 degrees from its source. From a practical perspective the pattern isn’t circular as much as being elliptical. It is a multi-homing antenna that sends signals to several clients in proximity causing some multipath fading that is minimized with antenna diversity. The gain values with 2.4 GHz antenna range from 2.2 dBi – 12 dBi. The higher gain antenna is deployed outside for the most part. Some Cisco access points have an integrated omni-directional dipole antenna or ” rubber ducky” that is standard with each device.

Directional

The directional antenna sends out a directed radiated pattern connecting with a distant antenna. The antenna purpose is to send traffic between antennas and not used for multi device homing. There are 3 specific directional antennas: Yagi, Patch and Dish. The Dish antenna has highest gain and narrowest radiation angle beam while Patch antenna has lowest gain and widest radiated beam. Gain values with 2.4 GHz antennas range from 6dBi – 21 dBi. Most antenna from this group are implemented in buildings with there is a lot of signal attenuation such as manufacturing, warehouses, and structures with a lot of steel, concrete, angled designs etc.

Diversity 

The diversity antenna implement dual antenna on the access point receiving signals on both. The access point determines what antenna has best gain and transmits on that antenna.  Diversity antennas are designed using either omni-directional, directional or dipole styles. Multipath fading occurs in buildings that have a lot of signal reflection. The signal finds multiple paths from source to destination and signal becomes distorted at receiver. This is minimized or eliminated with diversity antennas. 

External Antenna

Some Cisco access points such as 1200 series have connectors available for an external antenna. This is available with deployments in environments where the access point is at a maximum 300 feet from the wired switch or signal distortion is excessive. The external antenna with a specified coax cable of 3 – 100 feet allow for placement of the antenna at optimal positioning. Minimizing the cable length will decrease signal attenuation before transmission. Implementing the higher gain diversity patch antenna fixes the problem of clients being out of range. The company could have deployed a repeater as an alternative solution with an 1100 series access point that doesn’t support an external antenna.

Building material and structural design will contribute to signal attenuation. The following describes from best to worst building material used with walls, floors and ceilings. Steel and concrete with several feet of construction is most difficult.

• Wood

• Concrete

• Reinforced Concrete   

• Steel

Antenna Mounting

Access points should be ceiling mounted if possible at least 17 – 19 feet in height optimizing horizontal and vertical beam width. In some cases the access points will have to be mounted on the wall. Antenna mounting is important and should be implemented with instructions from the hardware installation guide. The Cisco access points utilize the standard RP-TNC 50 ohm type connector.

Outside Bridge Mounting

Companies have implemented a lot of Cisco wireless bridges that connect buildings in a campus network. The line of sight must be available or use a repeater bridge to extend the network where it isn’t available. Outside antennas deal with environmental issues and longer distances that require higher gain directional antennas. Mounting is usually with a mast or flat against a wall. Distances can extend around 250 – 500 feet or much further with higher wattage bridges, proper mounting of antenna and deploying repeaters. 

Point to point topology is implemented a lot with outside wireless deployments. Point to multipoint topology is implemented both with inside and outside wireless deployments. The root bridge or root access point in a multipoint topology is homed with traffic from several non root bridges or access points. That topology is implemented with several spoke buildings and a hub or core office that must be networked outside. The spoke offices have a point to point connection with the hub office and the hub office has a multipoint connection with all spoke offices. The hub office will implement an omni-directional antenna with a lot of beam width while spoke offices will use a directional antenna.

The inside standard access point designs won’t have a group of directional antennas. Most will implement omni-directional antennas and use directional antennas where needed as a means of addressing distances. The outside implementations for the most part imply greater distances and environmental concerns making directional antennas an effective selection. 

Cisco Wireless Network Design Guide available at amazon.com and eBookmall.com

Shaun Hummel is an author of various technical books and has a web site focused on information technology job search solutions and certifications.

http://www.networkjobsolutions.com

Htc brand has gained lots of popularity all over the world. Earlier it was not possible for many people to buy handsets of htc but now a days cheap HTC Mobile Phones are available in UK telecom market which anyone can afford. It is now the top selling brand. Along with beautiful design it is equipped with many high end features. HTC Desire hd deals is one of its latest launch fully loaded with multiple features. It is desire of many people to buy this awesome phone. All the leading networks of UK like Virgin, O2, 3, Orange, Vodafone and T Mobile, vodafone etc offers HTC Desire Deals.

The handset weighs 135 g which measures 119 x 60 x 11.9 mm. It has a AMOLED capacitive touchscreen of 3.7 inches which includes Multi-touch input method, Accelerometer sensor for UI auto-rotate, Proximity sensor for auto turn-off, Optical trackpad and HTC Sense UI. It has internal memory of 576 MB RAM and 512 MB ROM which can be extended up to 32GB. Many connectivity are available in it under GSM bands as well as under the HSDPA network. Such connectivity are like GPRS, EDGE, 3G, WI-FI and Blue tooth technologies.

With all these anyone can access easy an fast internet. It offers high defined camera of 5 MP with resolution of 2592 x 1944 pixels. The pictures can be enhanced by autofocus, LED flash, Geo-tagging. It runs on the Android OS, v2.1 (Eclair) which is upgradable to Android 2.2 (Froyo) and has Qualcomm Snapdragon QSD8250 1 GHz processor. It is available in many different colors like Black, Brown, Silver, White . The best part of this phone is that it supports many different formats of audio and video. Some more high end features are Digital compass , Dedicated search key, radio, games, YouTube, Google Talk, Picasa integration etc. You can buy this phone through many deals such as contract deals, pay as you go deals. The best amongst all deals is HTC desire contract deals because these deals offer number of attractive offers and free gifts. Users can choose the best best offer of their choice..

These days, everyone can use a little extra cash. Monthly expenses are like breathing, but a few extra hundred dollars would be like an extra dose of oxygen! There is a way to make extra cash every month from the comfort of your own home. If you want to earn extra money from home, keep reading! A computer and an internet connection is all it takes.

Earn extra money every month by taking online surveys. Did you know taking online surveys pay upwards to seventy-five bucks or more? Some surveys may require only five or ten minutes, but others may take up to an hour. If a survey takes longer to complete, then you will earn more cash.

If you have seen those online surveys promising mucho money, I bet you have wondered how they worked. Let me try to expound on why it is all about increasing profits for big businesses.

Big corporations have to make big profits. Providing better products and services for the consumer will make them more money. As a consumer, your opinion counts! Listening to your input, the company can increase product and service quality. Big businesses are willing to let loose of big bucks for your honest assessment.

Both paid and free online survey sites can be found. You probably wouldn’t think the free and the paid offer the same type, huh? The amount of surveys available is the main difference between paid and free sites. Free sites may offer a choice of ten to fifty surveys while those paid surveys usually list over a hundred.

When you sign up online at a survey site, you’ll be required to give your email address. They need to know who you are. Also, personal information, such as your name and mailing address, may be required. Truthfully give them what they ask for because they need it in order to pay you. An email with a verification link inside will arrive almost immediately after completing the online form.

To verify your address, click the link, then you may log in and see what surveys they offer. If you want payment, review those options and choose the one best for you. I have found PayPal, check, or direct deposit work equally as well.

It is a good idea to create an alternate email address specifically used for taking online surveys. Many free email services are available, such as hotmail, yahoo, or even gmail. The reason why you want a separate address is because they will be sending you email announcements whenever they have a new offer, The inbox at your personal everyday email will be bombarded with their offers, so always setup a free account for taking surveys.

Regardless of your personal interests and hobbies, you can always find a few surveys to make extra money. Free product and service trials are great, too. You use and review what they have and get paid for it. You’ll want to be sure to read the small print before signing up of a free product trial.

You will run across lots of general-question surveys, too. Being quick and easy to finish easily make them the favorites. It only takes three or four minutes to finish these. Multiple-choice questions make them really simple. Whether quick and short or long and lengthy, always give honest answers. Remember, they need your input to improve their product quality!

So there’s nothing to be frightened of, right? Get going and start making extra cash! Getting paid for computer time? What a great gig!

Ever felt that your wireless network is not performing at its maximum capacity? Does your signal strength indicate that your connection is not as fast and reliable as it should be? There are some basic steps you can take to instantly improve your wireless experience…

You do not always need to go as far as replacing your antenna. Many people have found that by simply relocating the access point provides extremely satisfactory results. The location of your antenna is extremely important – you should move it to avoid obstacles and to give a clear “shot” to the rest of your network. You can even try raising the antenna. Additionally, there are a few basic steps you can take to ensure maximum network performance…

Use a Repeater

Using a wireless repeater is as simple as placing the device halfway between your access point and your computer. Make sure that you place the repeater a fair distance away from your access point. If they are too close together, a feedback loop can be created and damage the repeater.

Reduce Interference

Devices such as mobile phones, cordless phones or anything that transmits a radio frequency can possibly cause interference with your wireless network. Devices that use the 2.4GHz frequency range usually cause a problem. You should check if any of these devices are causing interference by disabling them and then assessing the performance of your network.

Upgrade Drivers and Firmware

Keeping up to date with the <a rel=”nofollow” onclick=”javascript:_gaq.push(['_trackPageview', '/outgoing/article_exit_link']);” href=”http://www.pcdriverhelper.com/Wireless+Devices.html”>latest drivers</a> and firmware is extremely important to maintain maximum performance. You should check for updates on your manufacturers website for your PCI, USB or PCMCIA wireless device. If you have a wireless router, manufacturers occasionally provide updates for the firmware of these devices. These updates are usually free and may increase performance.

You should aim for as much LOS (Line of Sight) between your antenna and computer as possible. Take note that the more walls and objects that are in between these devices will degrade the signal strength profusely.

If there has ever been a growth field, it is computer security certification. With a good computer security certificate from a reputable college, you can go anywhere. Even if you go to one of those IT training schools the you see advertised on daytime television, your certification computer security will probably open doors for you. There are all kinds of jobs for computer security experts, from Homeland security to private industry. You can help prevent data theft, write computer security software, or investigate hackers for law enforcement. For a security certified network professional, the sky is the limit.

I had never expected to get into computer security certification when I was growing up. If anything, I was on the other side of the law. Many of the experts in computer security certification were hackers when they were kids. I used to try to break into all kinds of things just to see if I could do it. It wasn’t a matter of malicious intent. I just wanted to test the boundaries and see what holes computer security systems had in them. To me, it was more of a game or an intellectual exercise than an act of vandalism. Unfortunately, law enforcement did not see it that way. I was caught when I was 16 years old, breaking into the offices of a major multinational corporation. Because of my age I got off with probation, but I realized that I had to turn my life around.

I got my computer security certification training after a few years of soul-searching. To be honest, I was tempted to give up computer hacking altogether, but finally I realized that this was not the course for me. I was just too fascinated by computer networking and the security issues that it involved. I knew that, if I did not go into computer security, it was only a matter of time before I would get into trouble again. Temptation would overwhelm me, and I would suddenly found myself hacking into something or other. Although a I could get away with it for years this time (I had learned from my mistakes) is still didn’t seem to be worth the risk. In the long run, I would get caught. That is why I got my computer security certification. As a certified information security auditor, I can make my hobby into my life and stay on the right side of the law.

Barebones Computer Kits

Barebones computer kits the most simple of all the computer kits.  The take the most basic computer hardware, assemble it into a simple computer case, and will run the most basic level tasks and processes.  There is nothing flashy or exciting about these kits, they are just the barebone essentials, hence the name barebones computer kits.

Uses

Because of the system limitations with barebones computer kits, they are uses are going to be very limited as well.  The reason for purchasing a barebones computer kits, or building  one is because a computer is more of a convenience, and less of a necessity.  For those users, dumping excessive amounts of money into their computers is pointless because the computer kit will not be used enough to justify the large expenditure that a gaming computer kit or home computer kits may tend to cause.

A barebones computer kits are used for the most basic of operations, and are usually bought to to perform the following functions:

internet surfing
email
social media networking
word documents, and office and business applications

Since barebones computer kits are meant to do nothing more than the more basic functions, there is no need to dump a great deal of money into something so simplistic.

If you look at barebones computer kits from a different perspective, say laptops for example, you are looking at what is called a netbook. Netbooks are very small, very simple, and very inexpensive and are only meant for a few functions.  A barebones computer kit would be the same concept as a netbook but in desktop format.

Specs

A barebones computer kit should carry a minimum of the following:

2GB-3GB RAM
80GB Hard Drive
Intel Pentium or AMD Athlon Processor
128MB Graphics Card

The system specs do not have to be intense.  The goal is for a bare minimum because the computer is not used often enough to justify that.

When you look for RAM keep in mind that it takes around 1GB of RAM to run most of the newer operating systems.  So you still want to make sure that you have enough RAM to run the other functions that you are intending to use your computer for.

Your hard drive does not need to be huge unless you have a lot of games, photos, movies, and other media type files.  Word documents, no matter what form they are saved as take up very little space.  An 80GB hard drive would leave you with roughly 68GB of storage space.  Part of the hard drive is allocated for the operating system and BIOS for your computer.  68GB is plenty of space for most people.

As far as your processor goes, I would recommend nothing less than a pentium or AMD athlon processor.  A dual-core can be easily added for very little cost, and if you have a little bit of swing room, I would definately recommend the dual core.  It wil help speed up your processes, and make the general speed of the computer much faster.

Your graphics card is highly dependant on your other system hardware.  You can not support a 1GB graphics card on the barebones computer kits.  This is why I recommended a 128MG graphics card as opposed to something higher.  The downside to a graphics card of this capacity is that it will not render graphics well on the screen.

A higher end graphics card would show much more detail and color in pictures, play games better, and show movies more clearly.  With a barebones computer kit few if any of those operation are being done, so it is not necessary to pay extra for a higher caliber graphics card.  Also, a barebones computer kit would not liekly support a higher end graphics card.  Nothing more than a 128MG is necessary.

Conclusion

This article gives the information as to differentiate a home computer kit from a barebones computer kit.  Home computer carry a little more versatility than a barebones computer kit, however, on the most basic level of functions they can handle them both on the same level.  Barebones computer kits are intended for the users who sparingly use their computer kits, and a home computer kit is intended for a little more use, so the specs on home computer kits will be slightly higher than barebones computer kits.

Have you ever asked yourself how does wireless networking work? The main principle that is involved in wireless networking is the usage of radio waves to our convenience. In fact, radio waves constitute the main medium through which information is transferred and received.

The transmission of data in computers happens through binary ones and zeros i.e. in simpler words in the digital format. The same communication mechanism is application to the movement of radio waves too. We are often not aware that these radio waves are all around us and we can hardly feel them or hear those transmitting data to that mobile phone or a wireless laptop that is beside you.

It is through a mechanism that is similar to Morse code which transmits information in the form of dots and dashes over a radio. The radio links come with a transmitter and a receiver. While the transmitter transmits the radio signals, the receiver in the range of the transmitter will grasp the signal and output what it has to. This is similar to something like infrared but for one small difference that infrared requires a line of sight to be maintained between the transmitter and the receiver and also the data transfer is in the form of IR radiation.

Also, a wireless network makes use of something called as frequency hopping technique which helps in transmitting different frequencies by simply switching between them. Also, each device has signals received in its own allotted spectrum. This is the reason why wireless networks are immune to the interfering radio signals from any other wireless device. The information in case of wireless networking is sent in very high frequencies, almost in the range of 2.4 GHz. This brief concept answers the question “How does wireless networking work?”

One of the most irritating problems when surfing on the web is having an IE 8 with no internet connection; not only that you can’t work properly, you’re at a loss to know where to turn to repair whatever’s at fault. If you are hoping to learn a simple and straightforward method to use to resolve these annoying errors, don’t stop reading – the answer is coming right up.

The web-browser you use for the internet is among the busiest of all your programs; you visit new sites, activate various online applications, and download various applications and information to your computer. As you probably already understand, there is a continuous stream of data sent from/to your internet browser and your computer’s operating system; the windows ‘area’ which enables this “conversation” is known as the registry.

Whenever there is a ‘hole’ in your system’s registry, at that time you’ll begin having to deal with nuisances like an IE 8 with no internet connection, freezes, pop up errors and many other problems. The registry has the job of managing all the software and hardware you install or deinstall; an improper installation of downloaded software, for example, may generate a ‘broken’ registry, among other problems. The biggest problem is determining exactly what the trouble is and being able to find the corrupted area of the registry and restore it. Well, just what is a person supposed to do? We can choose to handle it on our own or call in the pros.

If you come upon an IE 8 with no internet connection and are about to pay for technical assistance – not so fast! You don’t need to take that step – there’s no need to spend money on this one – this is something you can handle yourself, even if you’ve always looked for outside help in the past. It’s easy to find a number of registry repairing utilities designed to do a scan of your computer, finding and repairing the trouble spots in almost no time at all. It’s normal for these applications to offer free scans as well as fixes, although there’s a limit on these. I strongly recommend that you get yourself one of these programs; these annoying troubles can be stopped with just a few minutes of your time.

Rapid changes in computing will continue for the foreseeable future.

The field of computing has always changed rapidly, and it is still doing so. The changes are driven, more than anything else, by Moore’s law. Many people think the pace of change is slowing, or even that because we already have the Internet and Google, there is not much left to do. I hope these papers will convince you that this view is entirely wrong.

For the last 50 years, new applications of computers have followed a pattern, as one manual activity after another has become automated. In the 1940s, it became possible to automate the calculation of ballistic trajectories and in the 1950s of payrolls and nuclear weapon simulations. By the 1970s, it was possible to create reasonably faithful representations of paper documents on computer screens. In the 1990s, we had the equivalent of a telephone system for data, in the form of the Internet. In the next two decades we will have embodied computers, machines that can interact with the physical world.

Hardware and Software
The factor that determines whether or not an activity can be automated is whether the hardware is up to it. According to Moore’s law, the cost performance of computers improves by a factor of 2 every 18 months, or a factor of 100 every 10 years; this applies to processing, storage, and communication. Moore’s law is not a law of physics, but it has held roughly true for several decades and seems likely to continue to hold true for at least another decade. Indeed, today some things are developing much faster than that. Storage capacity, for example, is doubling every 9 months, not every 18 months. Wide-area communication bandwidth is also improving faster than Moore’s law. Sometimes, with speech recognition and web search engines, for example, the cheaper cycles or bytes can be applied directly. Often, however, by spending more hardware resources, we can minimize programming effort; this is true for applications that use web browsers or database systems.

Hardware is the raw material of computing, but software gives it form. Our ability to write software is limited by complexity. People have been complaining about the “software crisis” at least since the early 1960s, and many people predicted in the 1960s and 1970s that software development would grind to a halt because of our inability to handle the increasing complexity of software. Needless to say, this has not happened. The software “crisis” will always be with us, however (so it isn’t really a crisis). There are three reasons for this:

As computing hardware becomes more powerful (at the rate of Moore’s law), new applications quickly become feasible, and they require new software. In other branches of engineering the pace of change is much slower.
Although it is difficult to handle complexity in software, it is much easier to handle it there than elsewhere in a system. Therefore, it is good engineering to move as much complexity as possible into software, and engineers are busily doing so.
External forces, such as physical laws, impose few limits on the application of computers. Usually the only limit is our inability to write programs. Because we have no theory of software complexity, the only way to find this limit is by trial and error, so we are bound to overreach fairly often.

A lot of software today is built from truly gigantic components: the operating system (Windows or Linux), the database (Oracle or DB2), and the browser (Netscape or Internet Explorer). These programs have 5 million to 40 million lines of code. By combining them with a little bit of new code, we can build complex applications very quickly. These new applications may use a hundred or a thousand times the hardware resources custom-built programs would use, but they can be available in three months instead of five years. Because we have plenty of hardware resources, this is a good way to use them. It is programmers and time to market that are in short supply, and customers care much more about flexibility and total cost of ownership than about the costs of raw hardware.

Another way to look at this is that today’s PC is about 10,000 times bigger and faster than the 1973 Xerox Alto, which it otherwise closely resembles (Thacker, 1988). A PC certainly doesn’t do 10,000 times as much, or do it 10,000 times faster. Where did these cycles go? Most of them went into delivering lots of features quickly, which means that first-class design had to be sacrificed. Software developers traded reductions in hardware resources for shorter time to market. A lot of cycles also went into integration (for example, universal character sets and typography, drag and drop functions, spreadsheets embedded in text documents) and compatibility with lots of different hardware and lots of old systems. Only a factor of 10 went into faster responses.

Applications
There have been three broad waves of applications for computers, about 25 years apart. Currently, the communication wave is in full flood, and the first signs of embodiment (relatively unrestrained interactions with the physical world) are starting to appear. Of course the earlier waves do not disappear, simulation continues to be an important class of applications.

Usually a computer application begins as a fairly close simulation of a manual function. After 10 or 20 years, people begin to explore how the computer can do the job in a radically different way. In business, this is called “business process reengineering.” The computer no longer does the same things as a bookkeeper; instead, it makes it possible to close a company’s books two days after a quarter ends. Boeing builds airplanes in a very different way because computers can model every mechanical detail.

The earliest computers in the 1950s were used for simulation. Simulations of nuclear weapons, astrophysics, protein folding, payrolls, project scheduling, games, and virtual realities all fall comfortably into this category.

The communication wave became apparent outside of research laboratories around 1980, and we are now in the middle of it. Today, we have e-mail, search engines, and the ability to buy airline tickets, books, movie tickets, and almost anything else online. TerraServer, gives us access to publicly available satellite telemetry of the world. The Library of Congress’ catalog is online, and you can buy any one of a million and a half books on Amazon.com. Conduct a search on Google today, and in half a second you can research a database of about 3 billion pages that is updated every two weeks – and will soon be updated in real time.

The next great wave, which is just beginning, is embodiment. Of course, computers have been used in process-control systems for a long time, but that is comparatively uninteresting (albeit of considerable economic importance). We are now seeing the first computer systems that can function effectively in the real world – computerized cars, robots, smart dust. They are still in their infancy, but the most interesting developments in computing in the next 30 years will be in this domain.

A Boston company called iRobot has just introduced what seems to be the first plausible domestic robot, a vacuum cleaner that crawls around a room in a vaguely spiral pattern, bouncing off of things (see it at www.roombavac.com). The price is 9. In fact, with only 14k bytes of ROM and 256 bytes (not kilobytes) of RAM, it’s barely a computer.

What’s Next?
In a recent paper, Jim Gray (2003) countered the widely held perception that most of the important developments in computing have already happened and that the future holds little more than refinements and cost reductions. Gray predicted that the next 50 years would be much more exciting than the last 50, both intellectually and in practical applications. Here are some of the challenges he raises.

Win the impersonation game. The classic Turing test asks whether a person sitting at a keyboard and display can distinguish between a conversation with a computer and a conversation with another person. To win, roughly speaking, a computer must able to read, write, think, and understand as well as a person. The computer will need some facility with natural language and a good deal of common sense. Anyone who has tried using natural language to interact with a computer knows that we still have a long way to go; and we don’t even know how far.

Hear, speak, and see as well as a person. Meeting this challenge will be much more difficult. Today’s best text-to-speech systems, given enough data, can do a pretty good job of simulating a person’s voice, although they still have trouble with intonation. In a quiet room, you can dictate to a computer a little faster than a person can type, at least if, like me, the person types fairly fast but makes a lot of errors. If there is any background noise, however, the computer does much worse than a person. To see as well as a person is even more difficult. People first learned to parse two-dimensional images on the retina and construct a model of a three-dimensional world so they could detect tigers in the jungle and swing from tree to tree. Today’s best systems do a fair job of recognizing buildings on a city street, but not in real time.

Answer questions about a text corpus as well as a human expert. Then add sounds and images. A computer can’t yet read and absorb Google’s 3 billion web pages and then answer questions about them in a sensible way. It can find documents where words occur or documents with a lot of other documents pointing to them, but it can’t understand content.

Be somewhere else as observer (tele-past), participant (tele-present).Videoconferencing Read the rest of this entry »