Учебно-методическое пособие infotech hardware москва 2009




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Overclocking

To overclock - to run a microprocessor faster than the speed for which it has been tested and approved.

Factors that favor your ability to successfully "upgrade by resetting" include (in addition to having an Intel microprocessor): having a well-designed motherboard with a fast enough bus and having a fan or other cooling device that will keep your system cool enough.

What Is CPU Overclocking?

While the words CPU and microprocessor are used interchangeably, in the world of personal computers (PC), a microprocessor is actually a silicon chip that contains a CPU. The three basic characteristics that differentiate microprocessors are the following:


  • Instruction set: The set of instructions that the microprocessor can execute.

  • Bandwidth: The number of bits processed in a single instruction.

  • Clock speed: Given in megahertz (MHz), the clock speed determines how many instructions per second the processor can execute.

Basically overclocking means to run a microprocessor faster than the clock speed for which it has been tested and approved. Overclocking is a popular technique for getting a little performance boost from your system, without purchasing any additional hardware. Because of the performance boost overclocking, is very popular among hardcore 3D gamers

Most times overclocking will result in a performance boost of 10 percent or less.

An overclocked CPU will have an increased heat output, which means you have to look at additional cooling methods to ensure proper cooling of an overclocked CPU. Standard heat sinks and fans will generally not support an overclocked system. Additionally, you also have to have some understanding of the different types of system memory. Even though your CPU can be overclocked, it doesn't mean your RAM modules will support the higher speeds.

The most common methods of overclocking your CPU is to either raise the multiplier or raise the FSB (frontside bus). To understand overclocking, you have to understand the basics of CPU speeds. The speed of a CPU is measured in Megahertz (MHz) or Gigahertz (GHz). This represents the number of clock cycles that can be performed per second. The more clock cycles your CPU can do, the faster it processes information.

The formula for processor speed is:  frontside bus x multiplier = processor speed.

The frontside bus connects the CPU to the main memory on the motherboard — basically, it's the conduit used by your entire system to communicate with your CPU.

One caution with raising the FBS is that is can affect other system components. When you change the multiplier on a CPU, it will change only the CPU speed. If you change the FSB you are changing the speed at which all components of your system communicate with the CPU.

Overclocking comes with many risks, such as overheating, so you should become familiar with all the pros and cons before you attempt it. Additionally, overclocking isn't supported by the major chip manufacturers which means overclocking your CPU will void your warranty. Overclocking can also decrease the lifespan of the CPU, cause failure in critical components and may even result in some data corruption. You  may also notice an increase in unexplainable crashes and freezes.


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Speech Recognition
Today, when we call most large companies, a person doesn't usually answer the phone. Instead, an automated voice recording answers and instructs you to press buttons to move through option menus. Many companies have moved beyond requiring you to press buttons, though. Often you can just speak certain words (again, as instructed by a recording) to get what you need. The system that makes this possible is a type of speech recognition program -- an automated phone system.

You can also use speech recognition software in homes and businesses. A range of software products allows users to dictate to their computer and have their words converted to text in a word processing or e-mail document. You can access function commands, such as opening files and accessing menus, with voice instructions. Some programs are for specific business settings, such as medical or legal transcription.

Current programs fall into two categories:

Small-vocabularies/many users. These systems are ideal for automated telephone answering. The users can speak with a great deal of variation in accent and speech patterns, and the system will still understand them most of the time. However, usage is limited to a small number of predetermined commands and inputs, such as basic menu options or numbers.

Large-vocabularies/limited users. These systems work best in a business environment where a small number of users will work with the program. While these systems work with a good degree of accuracy (85 percent or higher with an expert user) and have vocabularies in the tens of thousands, you must train them to work best with a small number of primary users. The accuracy rate will fall drastically with any other user.

Speech recognition systems made more than 10 years ago also faced a choice between discrete and continuous speech. It is much easier for the program to understand words when we speak them separately, with a distinct pause between each one. However, most users prefer to speak in a normal, conversational speed. Almost all modern systems are capable of understanding continuous speech.



Speech to Data

To convert speech to on-screen text or a computer command, a computer has to go through several complex steps. When you speak, you create vibrations in the air. The analog-to-digital converter (ADC) translates this analog wave into digital data that the computer can understand. To do this, it samples, or digitizes, the sound by taking precise measurements of the wave at frequent intervals. The system filters the digitized sound to remove unwanted noise, and sometimes to separate it into different bands of frequency. It also normalizes the sound, or adjusts it to a constant volume level. It may also have to be temporally aligned. People don't always speak at the same speed, so the sound must be adjusted to match the speed of the template sound samples already stored in the system's memory.

Next the signal is divided into small segments as short as a few hundredths of a second, or even thousandths. The program then matches these segments to known phonemes in the appropriate language. A phoneme is the smallest element of a language -- a representation of the sounds we make and put together to form meaningful expressions. There are roughly 40 phonemes in the English language (different linguists have different opinions on the exact number), while other languages have more or fewer phonemes.

The next step seems simple, but it is actually the most difficult to accomplish and is the focus of most speech recognition research. The program examines phonemes in the context of the other phonemes around them and compares them to a large library of known words, phrases and sentences. The program then determines what the user was probably saying and either outputs it as text or issues a computer command.



Speech Recognition: Weaknesses and Flaws

No speech recognition system is 100 percent perfect; several factors can reduce accuracy. Some of these factors are issues that continue to improve as the technology improves. Others can be lessened -- if not completely corrected -- by the user.

The program needs to "hear" the words spoken distinctly, and any extra noise introduced into the sound will interfere with this. The noise can come from a number of sources, including loud background noise in an office environment. Users should work in a quiet room with a quality microphone positioned as close to their mouths as possible. Low-quality sound cards, which provide the input for the microphone to send the signal to the computer, often do not have enough shielding from the electrical signals produced by other computer components. They can introduce hum or hiss into the signal.

Overlapping speech. Current systems have difficulty separating simultaneous speech from multiple users. If you try to employ recognition technology in conversations or meetings where people frequently interrupt each other or talk over one another, you're likely to get extremely poor results.

Intensive use of computer power. Running the statistical models needed for speech recognition requires the computer's processor to do a lot of heavy work. One reason for this is the need to remember each stage of the word-recognition search in case the system needs to backtrack to come up with the right word. The fastest personal computers in use today can still have difficulties with complicated commands or phrases, slowing down the response time significantly. The vocabularies needed by the programs also take up a large amount of hard drive space. Fortunately, disk storage and processor speed are areas of rapid advancement -- the computers in use 10 years from now will benefit from an exponential increase in both factors.

The potential problems with using speech recognition were on public display recently in a Windows Vista demonstration. While the system performed flawlessly at opening programs and accessing documents, when it came to transcribing text, it wasn't very accurate. The problems likely stemmed from the background noise and echo present in the large auditorium with an audience where the demo took place. A video of the incident soon spread across the Internet, hurting the reputations of Windows Vista and speech recognition in general.


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SSD - Solid State Drive

A Hard Drive Alternative Based on Flash Memory

One of the big items in the world of computers from the 2007 CES show in Las Vegas is the SSD or Solid State Drive. This is actually technology that has been around for many years, but only now is it actually set to become something that consumer may actually get to use within the next year. This article takes a look at exactly what is a solid state drive and how it may benefit consumers, especially with their portable computing.

Solid state is an electrical term that refers to electronic circuitry that is built entirely out of semiconductors. The term was originally used to define those electronics such as a transistor radio that used semiconductors rather than vacuum tubes in its construction. Most all electronics that we have today are built around semiconductors and chips. In terms of a SSD, it refers to the fact that the primary storage medium is through semiconductors rather than a magnetic media such as a hard drive.

Now, you might say that this type of storage already exists in the form of flash memory drives that plug into the USB port. This is partially true as solid state drives and USB flash drives both use the same type of non-volatile memory chips that retain their information even when they have no power. The difference is in the form factor and capacity of the drives. While a flash drive is designed to be external to the computer system, an SSD is designed to reside inside the computer in place of a more traditional hard drive.

So how exactly do they do this? Well, an SSD on the outside looks almost no different than a traditional hard drive. This design is to allow the SSD drive to put in a notebook or desktop computer in place of a hard drive. To do this, it needs to have the standard dimension as a 1.8, 2.5 or 3.5-inch hard drive. It also will use either the ATA or SATA drive interfaces so that there is a compatible interface.

Solid state drives have several advantages over the magnetic hard drives. The majority of this comes from the fact that the drive does not have any moving parts. While a traditional drive has drive motors to spin up the magnetic platters and the drive heads, all the storage on a solid state drive is handled by flash memory chips. This provides three distinct advantages:



  • Less Power Usage

  • Faster Data Access

  • Higher Reliability

The power usage is a key role for the use of solid state drives in portable computers. Because there is no power draw for the motors, the drive uses far less energy than the regular hard drive. Now, the industry has taken steps to address this with drive spin downs and the development of hybrid hard drives, but both of these still use more power. The solid state drive will consistently draw less power then the traditional and hybrid hard drive.

Faster data access will make a number of people happy. Since the drive doesn't have to spin up the drive platter or move drive heads, the data can be read from the drive near instantly. In a recent demo of two similar equipped notebook computers, Fujitsu was able to demonstrate a roughly 20% speed increase in the booting of Windows XP on a SSD over a standard hard drive.

Reliability is also a key factor for portable drives. Hard drive platters are very fragile and sensitive materials. Even small jarring movements from an impact can cause the drive to be completely unreadable. Since the SSD stores all its data in memory chips, there are fewer moving parts to be damaged in any sort of impact.

As with most computer technologies, the primary limiting factor of using the solid state drives in notebook and desktop computers is cost. These drives have actually been available for some time now, but the cost of the drives is roughly the same as the entire notebook they could be installed into. This is gradually changing as the number of companies producing the drives and the capacity for producing the flash memory chips grows. Drives announced at the 2007 CES were priced at less than half of the drives of the same capacity from the previous year.

The other problem affecting the adoption of the solid state drives is capacity. Current hard drive technology can allow for over 200GB of data in a small 2.5-inch notebook hard drive. Most SSD drives announced at the 2007 CES show are of the 64GB capacity. This means that not only are the drives much more expensive than a traditional hard drive, they only hold a fraction of the data.
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USB Flash Drive
All of this is set to change soon though. Several companies that specialize in flash memory have announced upcoming products that look to push the capacities of the solid state drives to be closer to that of a normal hard drive but at even lower prices than the current SSDs. This will have a huge impact for notebook data storage.

A Universal Serial Bus (USB) flash drive is a portable memory chip and circuit board contained in a small plastic case about the size of a thumb, giving rise to the name ThumbDrive®. Also called a memory stick, the tiny drive sports a removable cap under which is a USB connector. The chip inside the USB flash drive does not require power to retain data, so batteries are not needed. The drive gets power from the computer, making the USB flash drive a popular choice for transferring files between computers.

Flash drives hit the market in 2000 with capacities of eight Megabytes (MB), several times greater than the 1.44 MB floppy disks still used at the time. Today the USB flash dive has become so popular and ubiquitous that models with modest capacities of 128–256 MBs are often given away in sales promotions, imprinted for advertising and branding purposes. A four Gigabyte (GB) USB flash drive can cost as little as $10 US Dollars (USD).

Models with the highest storage capacity at any given time are more expensive than buying an equivalent hard drive. As of winter 2008, a 64 GB USB flash drive sells for just under $200 USD, while an internal 1.5 Terabyte (TB) hard drive can cost under $150 USD. One Terabyte is equal to 1,000 Gigabytes, so that’s a 1,500 GB hard drive versus a 64 GB memory stick.

However, the draw of the USB flash drive isn’t capacity alone, but convenience and portability. All modern computers feature one or more USB ports and on-board device drivers for recognizing memory sticks, making the USB flash drive universally accepted. It is also formatted in FAT or FAT32, understood by all modern operating systems from Microsoft® Windows® to Apple® Macintosh® and Linux®. Since USB is a plug-and-play standard, the USB flash drive can be plugged into a booted computer and recognized, then removed without need of a reboot.

In some cases, it might be convenient to boot from the memory stick itself. BIOS settings on modern motherboards will allow booting from a USB device. You can make a thumb drive bootable by installing appropriate software on it, freely available online. You can also install a portable version of an operating system (OS) on a USB flash drive and boot into it, trying it out without having to install it on your computer. A bootable memory stick is termed a Live USB drive.

Special software programs can also be installed on and run from thumb drives. These programs will not store program information in system files on the hard drive like regular software does, making the programs totally portable. Carry an email client with you on a USB flash drive to use from anyone’s computer, a Web browser with your bookmarks, or a favorite game.

Chips used in memory sticks have a discrete number of read/write cycles after which the chip will fail. People who use a USB flash drive to archive copies of important files or to occasionally transfer files probably don't have to worry. If the memory stick is used frequently for running software or is otherwise engaged in regular duty, you could see failure within ten years.

Part of what makes the USB flash drive so convenient is also a security risk: the drive is so tiny it is easily lost or misplaced. Information Technology (IT) techs might carry a USB flash drive loaded with networking tools on a lanyard or wrist strap to keep it handy. If security is a concern, consider an encryption program to encode the data on your memory stick. You can buy a USB flash drive with pre-installed security software, or use one of many encryption tools available online.

A USB flash drive weighs next to nothing and is all but impervious to the standard kinds of abuses that might befall a small item like this. It isn’t likely to be effected by being dropped or exposed to extreme temperatures. There are even reports of thumb drives surviving the washer and dryer with no apparent harm done and no data lost. While not wise to count on this, it does speak to the product’s general durability.

Memory sticks are available everywhere electronics are sold. Buying a USB flash drive with pre-loaded software typically costs more than purchasing a blank drive and dressing it up yourself.
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Different Types of Memory Cards
Memory cards are a popular storage medium for many of today's consumer electronics devices, including digital cameras, cellphones, handheld computers and other small electronic devices. Flash memory is nonvolatile, that is the memory card will not lose its data when removed from the device, and the cards can also be erased or reformatted and reused.

NAND Flash architecture is one of two flash technologies (the other being NOR) used in memory cards such as the CompactFlash cards. It is also used in USB Flash drives, MP3 players, and provides the image storage for digital cameras.


There are a few major types of memory cards that can be used in common electronics, such as a digital camera. Each of these types of memory cards are different sizes and, as the technology progresses further, we see that over time the cards have become smaller in physical size but grow larger in logical size.

Common Types of Memory Cards

PCMCIA (Personal Computer Memory Card International Association)


CompactFlash (CF), Secure Digital Card (SD card)
MiniSD Card
MicroSD
MultiMediaCard (MMC)
Sony Memory Sticks

Memory cards are quite sturdy and you can expect cards to be capable of working through more than one million data write/read/erase cycles. The card itself has its weakest point at its socket connectors, which are used when you remove and reinsert the memory card into a device. You can expect a memory card to be capable of withstanding around 10,000 insertions. These numbers, of course, will differ slightly between manufacturers.

Like with any consumer electronic or device, proper care is required by the users to meet the lifespan of the device. You should avoid applying too much pressure on your memory cards, and never drop or bend the card either. When the correct memory card is being used in a device, it will fit into the slot only in one direction and it will easily slide and click into place. You should never have to apply any amount of pressure to make the card fit. Memory cards should also be kept away from electrostatic sources and should never be introduced to direct sunlight or extreme ranges of temperatures.

What is a 'smart card'?

A small electronic device about the size of a credit card that contains electronic memory, and possibly an embedded integrated circuit (IC). Smart cards containing an IC are sometimes called Integrated Circuit Cards (ICCs).

A smart card resembles a credit card in size and shape, but inside it is completely different. First of all, it has an inside -- a normal credit card is a simple piece of plastic. The inside of a smart card usually contains an embedded microprocessor. The microprocessor is under a gold contact pad on one side of the card. Think of the microprocessor as replacing the usual magnetic stripe on a credit card or debit card.

Smart cards are much more popular in Europe than in the United States. In Europe, the health insurance and banking industries use smart cards extensively. Every German citizen has a smart card for health insurance.

Magnetic stripe technology remains in wide use in the United States. However, the data on the stripe can easily be read, written, deleted or changed with off-the-shelf equipment. Therefore, the stripe is really not the best place to store sensitive information. To protect the consumer, businesses in the U.S. have invested in extensive online mainframe-based computer networks for verification and processing. In Europe, such an infrastructure did not develop -- instead, the card carries the intelligence.

The microprocessor on the smart card is there for security. The host computer and card reader actually "talk" to the microprocessor. The microprocessor enforces access to the data on the card. If the host computer read and wrote the smart card's random access memory (RAM), it would be no different than a diskette.

Smarts cards may have up to 8 kilobytes of RAM, 346 kilobytes of ROM, 256 kilobytes of programmable ROM, and a 16-bit microprocessor. The smart card uses a serial interface and receives its power from external sources like a card reader. The processor uses a limited instruction set for applications such as cryptography.

The most common smart card applications are:



  • Credit cards

  • Electronic cash

  • Computer security systems

  • Wireless communication

  • Loyalty systems (like frequent flyer points)

  • Banking

  • Satellite TV

  • Government identification

Smart cards can be used with a smart-card reader attachment to a personal computer to authenticate a user. Web browsers also can use smart card technology to supplement Secure Sockets Layer (SSL) for improved security of Internet transactions. Visa's Smart Card FAQ shows how online purchases work using a smart card and a PC equipped with a smart-card reader. Smart-card readers can also be found in mobile phones and vending machines.


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