Beginner's Guide to Computer Hardware http://beginnersguide.com/computer-hardware/ Computer Hardware en Copyright 2007 Wed, 11 Oct 2006 09:55:00 +0000 http://www.sixapart.com/movabletype/?v=3.35 http://blogs.law.harvard.edu/tech/rss Dynamic Random Access Memory (DRAM) Dynamic Random Access Memory (or DRAM) stores information using one transistor and one capacitor for each bit of information. This leads to reduced cost and improved density, compared to Static RAM, since each bit of data can be stored with less hardware.

A problem with using capacitors to store data is that the electrical charge they store fades with time. To keep from losing information, the bits need to be refreshed periodically. The term “dynamic” is used to differentiate this type of RAM from Static Random Access Memory (SRAM), which will retain information (without the need for capacitor refresh) for as long as power is applied. (There is an implementation of DRAM that includes built-in refresh circuitry to imitate the simplicity of Static RAM, which is called PSRAM).

DRAM is also available in ECC form, which has extra Error Correcting Code (ECC) for detecting when hardware errors have corrupted data. When possible, the ECC DRAM unit will repair the corrupted data automatically. ECC DRAM is mainly used in server systems where losing a single bit of data could be disastrous (banking or medical systems, for example). Hardware memory errors are caused by high-energy radiation from outer space, and can generally be expected to affect one bit of data per month, per gigabyte of DRAM. Compared to the amount of data loss from viruses, worms, and shoddy software, the average PC user probably won’t notice the damage from a stray cosmic ray every now and then. If your life depends on it, however, it’s nice to know there’s a way to detect and repair these errors.

]]> http://beginnersguide.com/computer-hardware/computer-memory/dynamic-random-access-memory-dram.php http://beginnersguide.com/computer-hardware/computer-memory/dynamic-random-access-memory-dram.php Computer Memory Thu, 04 May 2006 16:24:44 +0000 EDO Random Access Memory Extended Data Out (EDO) DRAM is a now-obsolete type of RAM that could keep an area of memory “open,” allowing faster reads or writes when all of the memory accessed was clustered together in a group. It also allowed the previously read data to remain available when a new memory location was read from or written to. This allowed a bit of pipelining of memory access, improving performance further.

EDO DRAM was introduced in the early 1990’s, and began to replace the previous DRAM technology (Fast Page Mode or FPM DRAM) by the mid 1990’s. In addition to finding common use in personal computers as main memory, EDO RAM was also used as cache memory on some systems and as video RAM on some graphics cards (although generally, the term “Video RAM” usually implies a dual-ported access scheme, which didn’t exist in EDO).

EDO was sold in Single In-Line Memory Modules (as opposed to Dual In-Line Memory Modules), which meant that most systems required them to be installed in pairs.

If you’re looking for EDO Ram to update an older computer, prices on the Internet can range from 7 to 17 cents per megabyte.



Sources:
http://ftp.columbia.edu/acis/history/core.html
http://en.wikipedia.org/wiki/DDR_SDRAM
http://en.wikipedia.org/wiki/DIMM
http://www.oempcworld.com/support/Install_168pin_DIMM.htm
http://en.wikipedia.org/wiki/Delay_line_memory
http://en.wikipedia.org/wiki/Core_memory

]]> http://beginnersguide.com/computer-hardware/computer-memory/edo-random-access-memory.php http://beginnersguide.com/computer-hardware/computer-memory/edo-random-access-memory.php Computer Memory Thu, 04 May 2006 16:25:26 +0000 Sound Cards and Computer Speakers Overview You are sitting at your computer at home playing a video game – or maybe you are letting music play through I-tunes or another MP3 music program in your study and the music reaches the climax. You can’t wait for that amazing guitar solo or movie scene from the game and then suddenly you hear a mix between terrible static and “finger nails on the chalk board.” Is there something wrong with the song or the video game? Probably not. Does your computer not enough memory to run this program adequately? Once again, the answer is probably no. The real reason can be attributed to two pieces of equipment with your computer, or possibly the lack of one or the other.

Almost all computers these days are coming with a sound card internally built in. Maybe 10 years ago you would have to worry about not having a sound card, but now they are pretty common among personal home computers, as well as laptops. The quality that is factory installed may not be the best sound cards, but they do have them in them. Moving onto your speakers. A lot of monitors will have speakers, and some personal home computers may come with 2- small speakers to amplify the sound a little more. Laptops usually have two small speakers on the front of the keyboard platform. Any of these speaker options are usually low in sound quality, and they also probably can put out that much sound. But through all this you may be asking yourself whether you really need to move on to a more advanced system at all – you may not need to. You will also need to know what makes one sound card better than the next and what are some of the basic components of a computer speaker. And finally there are lots of different kinds and brands of computer sound systems – you need to know which ones are out there and what makes them different from each other.

]]> http://beginnersguide.com/computer-hardware/sound-cards-and-computer-speakers/sound-cards-and-computer-speakers-overview.php http://beginnersguide.com/computer-hardware/sound-cards-and-computer-speakers/sound-cards-and-computer-speakers-overview.php Sound Cards and Computer Speakers Tue, 27 Jun 2006 20:18:57 +0000 Why do I need to get a better sound system other than the factory system that came with my computer? Do you play video games? Then you probably need a better sound system. Do you listen to a lot of music through your computer and don’t have it hooked through your home entertainment system? Then you probably need a better sound system hooked up to your computer. Do you watch movies, edit movies, chat live vocally through the Internet, record your own music, edit your or others music onto a CD, or just like to listen to sounds a little more crisp? Than you need a new sound system past your factory system that came with your computer.

Dell computers, one of the largest suppliers of home and office computers, does not supply speakers free with their computers but does allow the customer to buy a basic set of speakers for only 16 dollars. While these speakers will provide better sound than out of their monitors – they rate these speakers as “Basic” for music listening, gaming, and movie watching. “Basic” level is actually below they’re good level which means to many people that these will be sub-par level speakers. For additional amounts of money, the customers can upgrade to other speakers, which is heavily advised by the Dell Corporation. This is just one example of a company presenting opportunities to have a better sound to their computer experience. While not necessary to move up in level of sound quality – for anyone above the level of hearing the “ding” of new mail or some basic sound applications, it may be a good idea to spend some extra money on a better sound system.

]]> http://beginnersguide.com/computer-hardware/sound-cards-and-computer-speakers/why-do-i-need-to-get-a-better-sound-system-other-than-the-factory-system-that-came-with-my-computer.php http://beginnersguide.com/computer-hardware/sound-cards-and-computer-speakers/why-do-i-need-to-get-a-better-sound-system-other-than-the-factory-system-that-came-with-my-computer.php Sound Cards and Computer Speakers Tue, 27 Jun 2006 20:20:18 +0000 What makes one sound card better than another sound card? There are three major areas that make one sound card better than another. The first is the capability that it gives your speakers that are connected to it. Many times, simply buying better speakers will make your computer sound better. However, because Dolby sound is such a big deal right now – especially when watching movies or playing video games – some of the sound cards are moving to this sound expertise. So if you have speakers that allow for Dolby Surround Sound, but your sound card will not work that high, then you might want to invest in a new sound card that will allow for this increased output of sound. Also certain sound cards only are able to handle certain speak configurations. A low-level factory sound card might be able to go left-right stereo, and perhaps a low level output of a powered sub-woofer, while a higher-level sound card will allow a 7 speaker system to have a different sound coming out of each speaker for a more full sound.

The second consideration in getting a sound card is simultaneous speech. Many higher-level games use this new sound technique. It simply allows for a different sound wave to come across for each voice, rather than smashing them into a single sound. This may not seem like a huge deal, but the ability to break apart the sound rather than grouping it together makes music, and different audio effects crisper. The third thing to look for, and listen for when trying out a sound car, is the ability to make a not as good sound into a better one. When you put in a movie like Top Gun or an older MP3 you will notice a sound difference from newer movies and music, however some sound cards will actually increase the quality of these older files.

]]> http://beginnersguide.com/computer-hardware/sound-cards-and-computer-speakers/what-makes-one-sound-card-better-than-another-sound-card.php http://beginnersguide.com/computer-hardware/sound-cards-and-computer-speakers/what-makes-one-sound-card-better-than-another-sound-card.php Sound Cards and Computer Speakers Tue, 27 Jun 2006 20:20:50 +0000 What are the basic components of computer speakers? Once again there are some simple things that you can look at for your computer speakers to see which ones are better. The first thing that will be easily spotted is the number of speakers. Some sound systems that are now coming out are actually just one speaker with a wide spectrum of sound within that one speaker, but more often are the speaker systems that have at least two speakers. If you only have space for two speakers, then you may want to look for a sound system that allows for that – with a higher quality of sound just coming from those speakers. The second bit of information is directly linked to the number of speakers and that is a little number that looks like, “2:1” or “5:1” or maybe even “7:1.” This tells the number of separate sounds that your speakers are running to. If you are getting a sound system with 10 speakers and the specifications say “2:1” that means that the sound will be split into 2 different sounds, not 10. So it might be a better idea to just get a system with two speakers when the specifications say “2:1.”

A third way to look at the speakers is to look at the larger speaker that may come with the system – the sub-woofer. This allows for a much deeper sound and places a much more full sound with your computer system. Most of the sub-woofers will be powered independently from the rest of the speakers because of the need for extra power. And this is the fourth important thing and that is the power that is being given to the subwoofer and to the satellite speakers. If you have 10 speakers and only 30 watts of power going to them that means that at the max, each speaker is only getting 3 watts of power. But if you have 2 speakers and the same 30 watts that means that each speaker will get 15 watts. The more watts that you have going through the satellite speakers, the larger the sound that the speakers will probably put out.

]]> http://beginnersguide.com/computer-hardware/sound-cards-and-computer-speakers/what-are-the-basic-components-of-computer-speakers.php http://beginnersguide.com/computer-hardware/sound-cards-and-computer-speakers/what-are-the-basic-components-of-computer-speakers.php Sound Cards and Computer Speakers Tue, 27 Jun 2006 20:21:25 +0000 What are the different kinds of computer sound systems? If you look through the other questions much of this will be explained also, but this will be a short-listing of kinds and brands of computer sound systems. Speaker systems come in sets of anywhere from 1 speaker to 7 speakers in most instances. The one-speaker systems are usually expensive because of the branding that goes along with them – as well as the ability to place all the components into one single instrument. 2 speaker systems will usually consist of a left and a right channel speaker. And then from there it usually consists of a sub-woofer and the rest of the speakers being satellites.

There are also some sound systems that include center channels. The center channel gives a unified sound with the satellites attributing to the ambience of sound. Some of these sound systems are simply just plugged into the sound jack in the computer, while others require to be also plugged into the wall. The ones that require an additional power source usually have more wattage going to the speakers.

Some of the most common sound speaker systems are:
Altec Lansing, Bose, Cyber Acoustics, Klipsch, Logitech, Panasonic, Sony, and Toshiba. In addition to these each retailer will probably have cheaper product line that is sometimes a much better deal, but just a little less quality than the big names.

]]> http://beginnersguide.com/computer-hardware/sound-cards-and-computer-speakers/what-are-the-different-kinds-of-computer-sound-systems.php http://beginnersguide.com/computer-hardware/sound-cards-and-computer-speakers/what-are-the-different-kinds-of-computer-sound-systems.php Sound Cards and Computer Speakers Tue, 27 Jun 2006 20:21:57 +0000 Computer Memory compmem.jpg

Random Access Memory

Read Only Memory

SIMM

Static Random Access Memory

]]> http://beginnersguide.com/computer-hardware/newbies-picks/computer-memory.php http://beginnersguide.com/computer-hardware/newbies-picks/computer-memory.php Newbie's Picks Fri, 21 Jul 2006 17:32:36 +0000 Computer Monitors compmon.jpg

Computer Monitors Overview

Flat Panel Monitors

Touch Screen Monitors

CRT Monitors

]]> http://beginnersguide.com/computer-hardware/newbies-picks/computer-monitors.php http://beginnersguide.com/computer-hardware/newbies-picks/computer-monitors.php Newbie's Picks Fri, 21 Jul 2006 17:34:23 +0000 Laser Printers laserprint.jpg

Laser Printers Overview

How Laser Printers Work

Advantages of Owning a Laser Printer

Characteristics of Laser Printers

]]> http://beginnersguide.com/computer-hardware/newbies-picks/laser-printers.php http://beginnersguide.com/computer-hardware/newbies-picks/laser-printers.php Newbie's Picks Fri, 21 Jul 2006 17:35:59 +0000 Sound Cards and Computer Speakers soundcard.jpg

Sound Cards and Computer Speakers Overview

Why do I need to get a better sound system other than the factory system that came with my computer?

What makes one sound card better than another sound card?

What are the basic components of computer speakers?

]]> http://beginnersguide.com/computer-hardware/newbies-picks/sound-cards-and-computer-speakers.php http://beginnersguide.com/computer-hardware/newbies-picks/sound-cards-and-computer-speakers.php Newbie's Picks Fri, 21 Jul 2006 17:37:31 +0000 Uninterruptible Power Supply Overview The fundamental purpose of a UPS is to provide an uninterruptible source of power for the equipment it protects. An electric device plugged into the wall or into a surge suppressor plugged into the wall, has only one source of power. If there is a blackout, the electricity is cut and the device obviously goes off immediately. A UPS changes this equation by providing its equipment two sources of power.

UPSs are designed so that there is one source of power that is normally used, called the primary power source, and another source that kicks in if the primary is disrupted, called the secondary power source. The power from the wall is always one of these sources, and the battery contained within the UPS is the other. A switch is used to control which of these sources powers the equipment at any given time. The switch changes from the primary source to the secondary when it detects that the primary power has gone out. It switches back from the secondary power source to the primary when it detects that the primary power source has returned.

]]> http://beginnersguide.com/computer-hardware/uninterruptible-power-supply-ups/uninterruptible-power-supply-overview.php http://beginnersguide.com/computer-hardware/uninterruptible-power-supply-ups/uninterruptible-power-supply-overview.php Uninterruptible Power Supply (UPS) Wed, 11 Oct 2006 09:50:54 +0000 Are Uninterruptible Power Supplies The Same Size And Shapes? The size of the UPS is primarily dictated by the size of the battery; the larger the battery, the more time your equipment can run on battery power before shutting down. Larger units not only can power equipment for more time, they can also handle a larger total demand for power. Different UPS have various other additional features, including warning signals, PC control software, and conditioning circuitry for the AC power source. Most of the newer UPS also include a feature to shut down your PC in the event that both of its power sources fail, to avoid possible operating system problems caused by the power going out suddenly to the PC.

]]> http://beginnersguide.com/computer-hardware/uninterruptible-power-supply-ups/are-uninterruptible-power-supplies-the-same-size-and-shapes.php http://beginnersguide.com/computer-hardware/uninterruptible-power-supply-ups/are-uninterruptible-power-supplies-the-same-size-and-shapes.php Uninterruptible Power Supply (UPS) Wed, 11 Oct 2006 09:54:10 +0000 What Are The Different Uninterruptible Power Supply Types? The standby UPS is the simplest and least expensive UPS design. In fact, some don't even consider a standby UPS to really be a UPS, calling it instead a standby power supply (SPS). However, many of the most common consumer-grade devices marketed as UPS, particularly on the lower end of the budget scale, in fact use this general design. They are sometimes also called offline UPS to distinguish them from online UPS.

In this type of UPS, the primary power source is line power from the utility, and the secondary power source is the battery. It is called a standby UPS because the battery and inverter are normally not supplying power to the equipment. The battery charger is using line power to charge the battery, and the battery and inverter are waiting on standby until they are needed. When the AC power goes out, the transfer switch changes to the secondary power source. When line power is restored, the UPS switches back.

While the least desirable type of UPS, a standby unit is still a UPS and will serve well for most users. For a very critical function, however, such as an important server, they are not generally used. The issue with a standby UPS is that when the line power goes out, the switch to battery power happens very quickly, but not instantly. There is a delay of a fraction of a second while the switch occurs, which is called the switch time or transfer time of the UPS. While rare, it is possible for the UPS to not make the switch fast enough for the PC's power supply to continue operation uninterrupted. Standby UPS are usually available in a size range of up to about 1000 VA.

A ferroresonant standby UPS is an improvement on the design of the standby UPS. As with a standby UPS, the primary power source is line power from the utility, and the secondary power source is the battery. The battery and inverter are still waiting on standby until needed. The big difference is that the standby UPS's transfer switch that selects between power sources has been replaced by a ferroresonant transformer.

A transformer is a core of metal around which are normally wrapped two coils of wire. When current is applied to one coil, it is magnetically coupled to the other coil and a current is induced in the second coil. Transformers are normally used to change one AC voltage into another. However, the other effect of a transformer is that it tends to smooth out power problems in its input, and not pass them on to the output. This makes them well suited for use as a line-filtering component in a UPS.

The transformer used in this type of UPS is not a regular transformer however, because it has three windings. Two of the windings are input, from the primary and secondary power sources, and the third is the output. This allows the transformer itself to act as a sort of switch, because whichever input source is operating, the output will take its energy.

Ferroresonant standby UPS are usually available in a size range of up to about 15,000 VA, making them suitable for even the largest servers. Once one of the most common designs, the ferroresonant UPS is still made by some manufacturers, while others have abandoned this design, claiming that it is inefficient, in favor of the online UPS for models in the range of 1,000 VA or higher.

The line-interactive UPS uses a totally different design than any type of standby UPS. In this type of unit, the separate battery charger, inverter and source selection switch have all been replaced by a combination inverter/converter, which both charges the battery and converts its energy to AC for the output as required. AC line power is still the primary power source, and the battery is the secondary. When the line power is operating, the inverter/converter charges the battery; when the power fails, it operates in reverse.

The main advantage of this design is that the inverter/converter unit is always connected to the output, powering the equipment. This design allows for faster response to a power failure than a standby UPS. The inverter/converter is also normally fitted with circuitry to filter out noise and spikes, and to regulate the power output, providing additional power during brownouts and curtailing output during surges.

The line-interactive UPS is an improved design that is commonly used in units for home and business use, available in sizes up to 3,000 VA or so. It is superior to the standby UPS, but it still has a transfer time, and thus does not provide protection as good as the
Online UPS.

The online UPS, sometimes called a true UPS, is the best type you can buy. Paradoxically, it is both very similar to, and totally opposite to, the least-expensive type, the standby UPS. It is very similar to it in that it has the same two power sources, and a transfer switch that selects between them. It is the exact opposite from the standby UPS because it has reversed its sources: in the online UPS the primary power source is the UPS battery, and utility power is the secondary power source.

Under normal operation the online UPS is always running off the battery, using its inverter, while the line power runs the battery charger. For this reason, this type of UPS is sometimes also called a double-conversion or double-conversion online UPS. This design means that there is no transfer time in the event of a power failure. A computer powered by an online UPS responds to a power failure in the same way that a plugged-in laptop PC does: it keeps running without interruption, and all that happens is that the battery starts to run down because there is no line power to charge it.

]]> http://beginnersguide.com/computer-hardware/uninterruptible-power-supply-ups/what-are-the-different-uninterruptible-power-supply-types.php http://beginnersguide.com/computer-hardware/uninterruptible-power-supply-ups/what-are-the-different-uninterruptible-power-supply-types.php Uninterruptible Power Supply (UPS) Wed, 11 Oct 2006 09:54:32 +0000 What Is The Run Time Of Uninterruptible Power Supply? One of the most important features of a UPS is its capacity. Another is its run time. While these two concepts are related, they are not the same. It's important to understand the difference between them, as these numbers play a critical role in UPS sizing.

The run time that a UPS provides is the number of minutes that the UPS will be able to provide power from the battery for a given load level. Since driving more equipment requires more power to be taken from the battery, driving more load will result in shorter run time. A UPS with a larger battery, or with an add-on battery pack, will provide longer run time for a given load size. Run time is critically important because it tells you how long a power outage the UPS can handle before the battery runs out. Most UPS manufacturers will provide tables that show the typical run times for a model based on the loads it has to handle.


Resources:

WWW.JETCAFE.ORG
WWW.PCGUIDE.COM
WWW.COMPUTER.HOWSTUFFWORKS.COM

]]> http://beginnersguide.com/computer-hardware/uninterruptible-power-supply-ups/what-is-the-run-time-of-uninterruptible-power-supply.php http://beginnersguide.com/computer-hardware/uninterruptible-power-supply-ups/what-is-the-run-time-of-uninterruptible-power-supply.php Uninterruptible Power Supply (UPS) Wed, 11 Oct 2006 09:55:00 +0000