How to Build a Quiet PC

  1. Power Supply – This is the device that produces the power for your computer. Unfortunately, this is almost always the noisiest part your computer includes. It usually contains one or two fans which are used to cool the device down. Fortunately, with today’s technology, you can now buy power supplies which only use their fans when the temperature reaches a set point. This will both reduce noise, and save energy.
  2. Case Fans – The reasons for having case fans are obvious, to create proper airflow. Unfortunately, for some computers, they’re only there to create obnoxious noise. If your computer is mainly used for documents, internet, and e-mail, chances are you don’t need more than one case fan. A system used for the latest computer games on the other hand, will need proper airflow to bring internal temperatures down to a safe operating level.
  3. Disk Drives – If this is your noise issue, there isn’t too much you can do, except invest in a CD or DVD drive known for being a quieter model, or insert acoustic padding around them. If you’re having issues with floppy drive noises, I’ll just tell you now, you’re way behind in technology. A memory card reader is far faster, and is completely silent.
  4. Hard Drives – Hard drive noises are often difficult to suppress as well. The common hard drive noises are heard when the device is in use, opening a program, installing software, etc. Often the noises are the vibrations between your hard drive, and your hard drives mount. Cushioning your device with padding like silica gel can often reduce some of the noise. If you’re hard drive is making unusual and highly noticeable noises while not in use, there’s a chance it could be failing. Please consult a service technician if this is the case.
  5. Computer Case – This is often forgotten about. There are many types of cases engineered in all sorts of ways. You can even purchase a case with sound padding materials included in it. Consider the material of the case itself. An aluminum case can by flimsy, and can increase noise levels from its vibrations. A steel case however, is more solid, and is less prone to creating vibrations. The down side of a steel case would be its weight. Whichever case you decide to use, adding acoustic sound padding, silica gel, and foam blocks, will significantly reduce vibrations.

Building a quiet pc isn’t for everyone. If you own a brand name computer, you’ll likely have a hard time following the tips shown above. Modifications to a brand name computer could potentially void a warranty. I would suggest researching this first before using my tips. You must also remember that your computer must run at safe operating temperature to avoid any device malfunctions, or even failure. Testing and research is always recommended.

About POS Printers

Printers in a POS system are the main output devices and usually have one or two independent cash register ports attached. Such a printer and cash register will share a single port with a PC and leaves other PC ports free for other peripheral devices of the POS system. Traditional electronic cash registers with printers have given way to specialized printers and accessories for point-of-sale functions like labeling and coding products, printing receipts, and printing identity cards. There are many manufacturers in the market who give printers with different features to suit unique needs of vendors.

Printers can be classified according to the printing technology used, their connection compatibility, and the unique features provided by the manufacturers. Dot-matrix, thermal printers, and laser printers are the most common types of printers used in most POS systems. Laser and thermal printers are very quick, but it is the dot-matrix printer that is used by small scale retailers and restaurant owners, due to its low pricing and maintenance costs. For clear printing that is essential for barcodes and labels, the best solution are direct thermal printers and thermal transfer printers with auto cutters. PC and printer compatibility is essential for smooth functioning of the POS system. Computers and printers can be connected directly through a parallel port in both the devices, or they can be connected directly through a serial interface. Some PCs allow printer connection through USB cables or RJ11 adapters as well.

You should be looking at the specific needs of your outlet before choosing a printer with different features like barcode formats, auto cutters, check and credit card receipts, and product labels. Getting the right printer with the right combination of technology, features, and cost-effective system-compatibility will play a part in smooth running of your business.


The SPI Bus was specially designed to exchange data between various IC chips, at very high speeds; say, at 180 MHz or even more. Due to this high-speed aspect, the Bus lines cannot be too long, because their reactance increases too much, and the Bus becomes unusable. However, if you want, you could use the SPI Bus outside the PCB at low speeds, but this is not quite practical–the SPI Bus requires 3 or 4 communications lines, which are a bit too many, when compared to 1 or 2 lines usually needed to communicate, efficiently, with field devices located outside the PCB.

Anyway, on the PCB the SPI Bus is very good, because we can practically attach to the Bus as many ICs (or devices) as we want. Please excuse me for not providing a picture of the SPI Bus, but rest assured you do not need one: the SPI Bus is so simple that you will understand everything in words.

The next question is: “Why is this SPI Bus particularly useful?” Besides from exchanging data between various IC chips, the SPI Bus is a method of multiplying microcontroller’s pins. In other words, if you have a tiny 8 pins microcontroller, you could control with that little monster few hundreds of digital Inputs and Outputs. This is impressive, and I am certain many doubt my words. Let’s explain this.

The SPI Bus contains three lines, and they can be on any general I/O controller pins. These Bus lines are: Clock, Data-In, and Data-Out. In addition, each IC connected to the SPI Bus needs an individual Enable line. Things work like this: suppose we have four devices, A, B, C, and D; all of them are wired to the SPI Bus lines, and the Bus itself is wired to seven controller pins–this is 3 Bus lines plus the 4 Enable ones. When we want to send a message to device C, we enable its Enable line first, then we send the message serially, one bit at a time. In the same time devices A, B, and D do exactly nothing, because they are not enabled.

The beauty with the SPI Bus is, it is Synchronous, meaning, when the controller sends the message to one IC, it is also able to receive data from that IC, in the same time. This particular aspect of the SPI protocol is particularly well suited for microcontroller-to-microcontroller communications.

Now, we have seen a small 8 pins microcontroller can control 4 devices (ICs) using 7 pins. Taking into account one device of type A, B, C, or D could have eight or even sixteen I/O ports, this is still far from the hundreds Inputs and Outputs I promised to you. The next beautiful thing about the SPI Bus is: one device IC can be serialized with many more of the same type! For example, we could have B1, B2, B3, B4, B5, and so on. All ICs of type B# are serialized together, and they require only 4 microcontroller pins to make them work; the Enable line is common to all of them. Next, we can use each device of type A, B, C, and D as a group of tens similar ICs.

The enabling speed of each I/O port on the SPI Bus it is slower, when multiplying microcontroller’s pins, but always take into account I/O field devices don’t necessarily need speeds of, say 1000 ON/OFF activations per second each, simply because most of them cannot handle that speed. However, there are few, very smart firmware techniques like the “barrel-shift” type of functions, which allows us to maintain high-speed messaging on the SPI Bus, even if we have hundreds of I/Os. In the same time, the “barrel-shift” functions allow for better time management inside microcontroller, so that it has more time to execute other tasks–makes sense to me! To conclude, I believe it is clear now we can, indeed, build hundreds of efficient I/O lines on a small 8 pins controller.

Further from this general presentation of the SPI Bus, you should be aware almost all ICs implement the SPI protocol in a particular way. For detailed and practical applications I suggest you visit my home site at Corollary Theorems. There you are going to discover a good tutorial book about working with hardware, firmware–including the “barrel-shift” type of functions–and software design, in general, and about few nice and practical implementations of the SPI Bus in particular.

Rundown of Barcode Scanners

The Barcode Scanners Classified on the Basis of Technology Used

  • Omnidirectional Barcode Scanners: The omnidirectional barcode scanner makes use of a series of curved or straight scanning lines of different directions in starburst form. These scanners generate beam patterns in different orientations permitted them to read the barcodes to these readers at various angles. Many use the polygonal single rotating mirror and a medley of differently fixed mirrors for generating complicated scan patterns.
  • Laser Scanners: The laser barcode reader work in the same way as the pen type barcode readers except that they make use of the ‘laser beam’ for the light source. They make use of the rotating prism or the reciprocating mirror for scanning the laser beam forth and back across barcode reader.
  • Pen-Type Scanners: The pen-type barcode readers comprise the photodiode or the light source which is placed side by side on the pen tip or wand. The photodiodes measure the light intensity that is reflected back from the light source as pen tip crosses space and each bar in printed code. The photodiode produces the waveform which is used for measuring the space and bar width in the barcode.

Barcode Readers Based on the Housing Design

  • Handheld Scanner: This type of scanner is available with the handle as well as the trigger button for turning on ‘light source’.
  • Stationary Scanner: The stationary scanners are table or wall-mounted. These barcode readers are widely used at ‘checkout counters’ of the supermarkets as well as the other retailers.
  • Fixed-Position Scanner: The fixed-position scanner is the industrial barcode scanners that are used for identifying products during logistics or manufacture. These barcode readers are used on the conveyor tracks for identifying pallets or cartons needed for routing to a different shipping location or process. The holographic scanners are joined by another application to the check weigher for reading the ‘barcodes’ of any placement or orientation and then weighs the specific package. Such systems are widely used in farm automation or factories for shipping and quality management.
  • PDA scanner: The Auto-ID PDA or the PDA scanner are basically built-in barcode readers or are attached barcode scanners.
  • Automatic reader: The automatic barcode reader is the back office tool used for reading the barcode documents at a speed of 50,000/hour.
  • Wireless or Cordless Scanner: The wireless barcode scanner is battery-operated and is not connected to the main electricity. It is used for transferring data to a connected device such as the PC.

Apple Mac Mini

Now this is power packed into a small package – Apple has outdone themselves! Under the sleek anodized aluminum styling of the Mac mini is a G4 processor, room for up to 1GB PC2700 main memory, a Radeon 9200 graphics chip, and a large enough hard drive, up to 80 GB, to store today’s digital media.

With the mini connections you can hook-up your digital devices like cameras, iPod, printer, camcorder, and your keyboard. There is even a audio/headphone jack. You can customize this Mac with some great extra options after you select your Mac mini.

You have the choice to use your own keyboard and mouse or choose the Apple Wireless keyboard and mouse and free yourself from the clutter of cables. You will need the Bluetooth module and with it you will also be able to have wireless access to printers, cell phones, PDAs, input devices and other peripherals. Or add a AirPort Extreme Card and have the freedom of wireless networking from anywhere in your home. Although you must have these features added when ordering your Mac or they will have to be added by an authorized service provider because they are not user-installable.

Hard Drive Selection

Rotational frequency has become a large selling point (5400/7200/10000/15000RPM) recently, so you shouldn’t have too much difficulty finding out what the rotational frequency of your HDD is when you go to buy it. Now of course the faster it spins, the faster it can read from the disk (there are other advantages also), but be aware that the faster it spins, the more wear is put on the drive, and the more likely it is to encounter errors and malfunctions later in life. Hard drives are pretty much the only systems within your computer that have moving parts (CD-ROM, floppy disk drives, and fans also have moving parts, but they’re all cheap and if they break you won’t lose all the data you’ve accumulated over the course of owning your computer, be sure to back up your data regularly!).

If you know anything about physics or engineering, then you know that moving parts produce friction and wear, and a faster spinning platter (the part that holds the data and spins) means more friction, and therefore more wear on your drive. Of course the faster it spins the faster it can read data from the platter. So what can you do? well again you backup your data as much as possible and you get the fastest spinning drive money can buy (which is 7200RPM for ATA devices (the sort you are buying) and 15000RPM for SCSI and some Serial ATA devices (you might get Serial ATA, that depends on your motherboard)). So look for a “7200RPM” label on the drive you’re thinking of getting, it’s important!

The “buffer” I’m referring to is the transfer buffer that temporarily stores data to read from or write to the hard drive. The reason for this is that the bus (data channel between the hard drive and the motherboard) can only handle so much information at a time, and it takes a long time for the data to be found and retrieved from a platter (random seek time), so it takes a big chunk of the requested data and stores it in a very fast data buffer to be sent at the bus’s convenience. So with a larger buffer you can queue more data for transfer over the bus without having to keep sending requests to slowly find more data from the platters. Some newer drives come with as much as 8MB of buffer capacity, but it is more common to see 2 or 4MB. Usually a drive with a large amount will use that as a selling point and print it on the box/website, otherwise you can assume it has a 2/4MB buffer. My advice is to find one with as much as you can afford.

Now for the transfer rates you’re going to need to do some searching, the best way to find these numbers is to go to the manufacturer’s website and look at specification sheet for the model you’re looking to buy (actually this is the best way to get all the information I’ve talked about so far). One thing to look out for is that you may read something that says 133MB/s or ATA/133 or SATA150 or 150MB/s, and these are not the numbers you are looking for, those numbers describe the bus connecting the hard drive to the motherboard, and are theoretical peak numbers, which tell us virtually nothing. Also, if you are buying a Maxtor, don’t bother looking up actual transfer rates, as Maxtor is apparently afraid to release such information. Not to say Maxtor’s are bad drives, actually Maxtor has risen to the top in terms of technical support and they are much more willing to replace broken drives than some other companies, which is important since some ridiculously large amount (something like 10 or 15%) of hard drives are either dead on arrival or die within the first few weeks of use. As with the last two points, when looking at transfer speeds (if you can find them) always try to pick the one with the highest numbers you can afford.

Notice that the first three of the 4 major aspects were all speed related? That was done intentionally to give you a sense of the importance of speed in the hard drive, because they are very very slow creatures, and for your gaming experience you don’t need an enormous hard drive so much as a fast one. To increase speed substantially more you can set up a RAID, which is a network of hard drives which (in RAID0 mode) share portions of the same data, such that accessing data takes 1/n time (n = number of hard drives attached) compared to 1 hard drive. To do this you really need a hardware RAID chipset, which are commonly included on higher-end mainboards.

Finally, capacity is an unnecessary nicety. The smallest hard drives you can buy today that are still within those higher speed classes are all about 30GB, which is more than enough for your games. But since games are not everything, and if you happen to be an iTunes member or like to download anime then you will really want some extra space. So I would recommend getting something between 60 and 120GB, any more and you’re going to be paying through your teeth, any less and you might be looking to buy a supplementary hard drive in a couple years. And, oh yeah, 300GB hard drives from Maxtor are out, but they are comparatively slow, so I wouldn’t recommend getting one for gaming, I like to stick to single platter drives (40-100GB usually), as they produce less heat and are less likely to break down on me.

Info of Router Firewalls

A typical and very common threat that a router firewall will automatically block is a port scan to your system. If an external user (that is, he doesn’t belong to the network or he is not recognized by the firewall as a valid user) tries to port scan one of the computers in the network, the router firewall will automatically block him. This will prevent him from discovering potential vulnerabilities; generally, he will be unable to achieve any type of background communication with the computer that the firewall protects.

Routers utilizing the NAT (Network Address Translation) protocol are also known as NAT Firewalls. NAT protocol allows multiple computers to access the Internet with only one Internet connection and thus, only one IP address. All computers that belong to the NAT network (those computers that belong to the intranet) are assigned special IP addresses (that are not valid, real-world IP addresses) in order for every computer to have a specific, unique reference name. The hardware router translates the requests from each computer into requests from the single IP address. Normally, the router doesn’t encode requests originating from the outside of the network, and it doesn’t pass them on to the local network. This way, the hardware router, by default, acts as a basic firewall system.

All in all, router firewalls provide a basic, yet effective protection that comes as a bonus to connection sharing. Of course, all features depend on the concrete router that you choose to use. For those who have high expectations, there are many sophisticated router firewalls available.

Laptop Compare

Do you remember when you quickly compared laptops at an electronic store for the last time? I admit I am a computer nut, so it is a no surprise that I did it yesterday. The technology is changing so fast that I frequently find new and upgraded versions and accessories. What I really want to say is that I cannot imagine that there might be a single person who would refuse a new computer. Yesterday while searching the Internet I came across some hot offers on Best Buy, there were some amazing deals on Sony laptops and notebooks. I regret not having one of these as not only are they upper-scale but they also have a reasonable price. There isn’t anything better than that. After I ended browsing in Best Buy, I started a laptop compare in Circuit City. They also offer a good choice of computers.

After all, the only laptops compare and search I do is online. The World-Wide-Web is the best place for it. Furthermore, in cyberspace you can find such great deals that you can only dream of. I did a full background research before buying my Mac Ibook G4. I did a thorough laptop compare in different review sites and I got much information. It was also interesting to read so many reviews regarding different computers.

In case you’d like to compare some laptops, I’d offer you to try the Internet first. Don’t get enchanted by the guy at the Dell booth, or Mac store. All he wants is to do is sell his product and get the commission. He is not interested in your needs. Consequently, if you are considering buying a computer, then you’d better did some research on your own. What is a must is to decide whether you’d like to purchase the PC or Mac. And the rest is so simple – log online and do a laptop compare just in a few seconds.

Choose a Sound Card

First thing to consider here is your intended usage of the sound card. If all you want is basic sound support and not spectacular 3D surround sound, I’d say go buy a cheap, simple card like the Sabrent 6-Channel or even rely on your motherboard’s on-board sound. If you want great surround sound and better speaker connectivity options, then you’ll want to consider a dedicated sound card like the TurtleBeach Montego or Sound Blaster Audigy 2.

As always, cost is an important issue to consider. A basic, no-frills sound card these days costs about $10, while the latest heavy-duty sound card with surround sound support can cost about $250. If you only need simple sound support, don’t waste money buying a high-end product with features you don’t need.

Surround Sound

A critical factor to consider is to take a look at what sound standards your sound card supports. Most high-end sound cards in the market today have EAX and 5.1 surround sound support. You can connect up to five speakers to these cards to enjoy a surreal, 3D audio effects. Some cards even starting to provide 7.1 surround sound support.

Special Needs

Do you have any special needs that you need to cater for? For example, if you’re into professional, multi-track music recording, you’ll want to get a proper multi-channel sound card. If you’re into things like MIDI, you’ll want a card that supports provides good MIDI support.

If you want to take advantage of the latest features in the new sound cards out there, you’ll usually need to ensure you have a powerful CPU to go along with it. No point having the latest super-duper audio card if you’re installing it into an old Pentium 3 computer.

Bundled Software

It’s also useful to look at what software comes with the sound card package. Cards like the Creative Labs Sound Blaster Audigy 2 ZS are wonderful because they throw in great music and audio software. This will save you money, especially if the software you’ve always wanted is found in the package.

Recommended Sound Cards

Now let’s take a look at some of the sound cards I’d recommend to prospective buyers.

  • Sabrent 6-Channel. You’ve probably not heard of the brand Powmax – but the Sabrent 6-Channel 5.1 3D Surround Sound PCI Card is one solid, reliable sound card. It is sold for a very low price (about $10) but provides up to 6 channels of stereo sound to any computer. Great for basic multimedia usage like playing games or watching DVDs.
  • TurtleBeach Montego. The TurtleBeach Montego provides 7.1 channel surround sound for a complete home theater experience. The 24-bit audio quality is excellent, whilst the wealth of connectivity options to external audio devices is a big plus for fans of high fidelity audio.
  • Creative Labs Sound Blaster Audigy 2 ZS. If you have the cash, this is one of the best sound cards in the market today. It can do almost anything imaginable with your computer’s audio. Among others, it incorporates support for DVD-Audio, Dolby Digital EX, wavetable synthesis, EAX and hard-disk recording. The moment my current sound card breaks down, I’m rushing out to get one!

Install an AGP Graphics Card

Power Down Your System

To install video card components correctly in your computer you will have to begin by powering your system down first. This is a matter of safety and precaution.

Always make sure your computer is completely shut down before you install video card components or any other internal part for that matter. After you shut down your computer you also need to cut off the juice to the power supply. If you’ve never done this before, take a look at the back of your computer. You will see a switch where the power supply is. Flip that switch into the off position. Finally, pull the AC power cord.

It may have never occurred to you that you would need to do all of this, but it’s important that we show you how to install computer components the right way. Rule 1 is to make sure there is absolutely no power going into the system. Any latent surges will fry your system in a heartbeat and could injure you in the process.

Opening Up the Computer Case

Next we will have to open up the case. Since we are learning how to install an AGP graphics card, and that card goes inside your computer, we will have to remove the case.

Don’t worry about this procedure though. Perhaps you have experience in knowing how to install computer components like external hard drives, but said you would never poke around inside your computer. Really, it’s not that hard.

Before you can open your case however you need to find out what kind of case you have. That will determine how your particular case is to be opened. If you have something like a mini-tower, you can open this case by removing one of the side panels. Be sure to remove the side that’s above the motherboard. Simply remove the screws in the back of the computer that hold the panel onto the chassis and then lift it off.

Some older style cases, however, require that you remove the whole back cover off and slide the chassis out. Check your particular model and see how it’s designed.

Remove PC Slot Cover

Before you can install video card components like the AGP graphics card, you will need to remove the PC slot cover in the back of the computer.

Look at the back of your computer and you’ll see what we mean. There are a series of several metal latches facing the slots where you can insert internal computer components. Most of these metal latches are secured by one or two screws. When it comes times to insert a component, like a modem, for example, you will need to first remove the metal latch in front of the slot before you insert the component.

With the AGP graphics card the process is the same. First locate the AGP graphics card slot. There is only one slot that will correctly match your card, so you’re in luck. Then unscrew the metal latch in front of the AGP graphics card slot, slide the latch out, and set the screws in a safe place.

Installing the AGP Card into its Slot

Now comes the part you’ve been waiting for, knowing how to install an AGP graphics card into its slot. Again, there is only one card on the motherboard that matches your AGP card, so don’t worry about putting it into the wrong slot.

If you’re not sure, look at the bottom of the AGP card to match it up with possible slots on you. The AGP card slot stands out from all of the other slots on your motherboard, kind of in its own little corner.

When you’re ready, align the AGP graphics card above its slot. Hold the card with your fingers from both ends and press it down into the slot until it seats firmly. Make sure that it’s firmly pressed into the slot. If anyone part of the card is sticking out, push it back in. Then secure the card into the motherboard by screwing the retaining screw into the motherboard.

Plugging In the Monitor, Closing Up and Powering Up

With your card properly installed, it’s time to plug in your monitor. That wasn’t so bad, was it? Little by little, you’re learning how to install computer components until you become a real pro! Find your monitor cable and plug it into the AGP card monitor connector.

If your card has more than one connector, this means that your card can support more than one monitor. Check your documentation to determine which is the appropriate connector for your monitor. Plug it in, and you’ll be good to go!

Not it’s time to close up and power up. Place the computer cover back onto your computer. Screw it back on using the screws that (hopefully) you remembered to set in a safe place earlier. Now it’s time to power up.

Flip your power supply’s power switch back on, and then plug the AC cord into wall outlet. Then, reboot your computer. To correctly install video card components, as with other components, you also need to install software drivers. Locate the CD that came with your card and insert into your computer when it reboots. Follow the instructions to install the appropriate software drivers.