Index


General PC hardware information

    Environmental effects

    Computers can have many different kind of effects to our environment where we are. Computers generate noise. Even though we grow accustomed to the constant noise, it can still be distracting. Most of the noise from a PC comes from fans. In addition to this the hard disks and other drives can generate noise in a normal PC. Fans play a vital role in cooling the components that give PCs their performance. There is a challenge to provide even higher-cooling capacity to deal with increasing power dissipation from new processors, graphics and memory products. With suitable arrangements, the noise can be reduced. If the PC cooling system is to undergo changes in reducing fan noise it must be done carefully so as not to throw the cooling out with the noise. Yes, one way to reduce fan noise is to slow the fan down. If fan speed (RPM) could be controlled in such a way that an adequate level of cooling is provided, even as conditions vary, it may be possible to minimize acoustic noise by slowing down RPM when a lower cooling level is OK: And increase RPM and cooling capacity only when needed -- i.e. worst-case conditions. Many quiet PCs use this technology in addition to special case constructions. The heat was mentioned on the last chapter. When a PC system operates, generally most (almost all) the power it takes from the mains outlet is converted eventually to heat. When a normal typical PC system with a large monitor can consume something like 200-400 watts of power, thus means that the PC system can heat your room. In cold enviroments where room heating is neeeded this is not usually a problem, because the PC generated heat can substitute other heating. But on hotter places, the introduction of PCs have generally increased the need for an air condition system. A typical office in many countries needs to be cooled more than heated because the amount of heat generated the PCs and people using them. Cooling systems are vital parts of any large computer server rooms, because the large amounts of heats generared in them. PCs consume a considerable amount of power that costs money and generate it's own enviromental problems (generating electricity has it's own environmental side-effects). The equipment power ratings should be written on the manufacturers labels at the back of your PC andmonitor/screen. The power drawn (W) will be approximately the voltage (V) x Current (I) in typical fixed load like a kettle. But not as accurate for a PC. What you will be reading is the maximum rating, probably of the power supply.If the goal is to size a supply circuit or UPS, then the nameplaterating is OK to use. If one is trying to determine actual consumption toestimate relative power costs of various units (for example) more detail may be needed.The actual consumption will depend on usage patterns, the type of motherboard, processor and peripherals and power management settings in the BIOS and software.Power management of personal computers (PCs) and monitors has the potential to save significant amounts of electricity as well as deliver other economic and environmental benefits. The Environmental Protection Agency's Energy Star program has transformed the PC market so that equipment capable of power management is now widely available. However, previous studies have found that many Energy Star compliant computer systems are not accomplishing energy savings. Computers can cause interference to radio and TV reception. Nearly any computer system has the potential for causing interference. Computers are classified as unintentional radiators under Part 15 of FCC regulations. Part 15 limits the amount of interference that will be caused by a computer system, but the regulations protect a neighboring home from having television interference when you operate your computer, for example. They are not usually sufficient to ensure that your computer will not interfere with sensitive reception in the same room. This same applies to European countries where the European EMC regulations apply to computers. In USA FCC has two classes of computing devices: Class B for home use and Class A for industrial environments. The Class B devices are quite a bit less noisy than their industrial counterparts. Make sure you use only Class B devices at home. Computer systems and monitors generate electric and magnetic fields around them. The PC system CRT monitor is generally considered as the largest source of those. In the late 1980s concern over possible health issues related to monitor use were raised. In Sweden this resulted a standard MPR1 to be developed. This was amended in 1990 to the internationally adopted MPR2 standard, which called for the reduction of electrostatic emissions with a conductive coating on the monitor screen. In 1992 a further stricter standard, entitled TCO (TCO92), was introduced by the Swedish Confederation of Professional Employees. Other relevant monitor safety standards include: ISO 9241 part 3 (the international standard for monitor ergonomics), EN60950 (the European standard for the electrical safety of IT equipment) and the German TUV/EG mark (monitor has been tested to ISO 9241 part 3, EN60950, MPR2 and German standard for basic ergonomics ZH/618). With electronics it is very difficult to be green. We leave our computer waste in the recyle bin lest dangerous chemicals like lead and mercury seep into our landfills. The more dedicated environmentalists make a trip to the local recyling center where they may be asked around to pay around $15-$30 to recycle their old PCs. Using too much computer can cause healtjh problems to the user. Computing can sometimes be a real "pain-in-the-neck" ... but more particularly in the hands, wrists, and arms! From the heavy-duty professional user at work, to the happy "gamer" at home, constant, repetitive use of a computer keyboard can lead directly to a severe case of "RSI", or Repetitive Strain Injury. Many of us work for hours each day in front of displays. It is very important to establish viewing conditions that minimize stress to our eyes.

    Computer room design

    Here are few tips to build a good computer room:

    • Have enough elecricity to power everything reliably. Have multiple circuits coming to the room. Maybe not one for every socket, but at least two for a small room and more on larger room. If there is a short electrical outa, there is a huge demand surge as all the computers try to turn back on at the same time. Be sure that your computer room has grounded elecrical outlets.
    • UPSes are great so that short electrical power problems will not crash your computers.
    • Be prepared that you computer room will need air-conditioning because the computers generate lots of heat. Be sure that your computer has it's own air conditioner, because the needs for computer room air conditioning are different than in normal office or home room.
    • A KVM (keyboard, video and mouse) is an useful accesory that allows you to easily manage many computers using just one set of monitor, keyboard and mouse. Nothing like being able to sit in one place and control multiple PC's. This will greatly reduce the amount of space needed also.
    • Have good enough telecom and LAN wirign to your computer room.
    • Take out the carpet. Carpet and linoleum create static that can damage computer when you touch them. Use material that does not generate lots of static electricity.
    • If you have computer repair place on your room, get a grounded workbench pad (a rubbery pad that covers the workbench). Get also a grounded wrist strap as well.
    KVM (keyboard video mouse) switches are used to connect multiple computers to a single set of monitor, keyboard, and mouse. There are two basic types: mechanical and electrical. Mechanical switches are less expensive but have some limitations. In order to start up the computer, you need to be switched to that computer so it will see the mouse and keyboard during startup. Using mechanical switch is almost like unplugging the mouse and keyboard from one computer and hooking it up to another. Usually this wont cause problems but sometimes removing the mouse while the system is on can cause crashes. So mechanical switch is an inexpensive solution what works if the demands are not very high (test if one works for you). A typical mechanical switch works aaround this way: Mechanical changeover switches/relays to select between two input signal sources. For VGA connection geneally pins 1,2,3,6,7,8,13,14, and 10 of the monitor connector are switched (usually also 12 and 15 so that DCC for plyg&play monitor connection works). There are some variations what pins are switched (some implementations do not switch the ground lines, they keep then always connected. some other switch also those lines). The keyboard and mouse will use similar relays/switches. Generally a simple light switch will work for only two monitors well. Electronic switches comprise a video switch that switches analog video and sync pulses between shared monitors and computers and a microprocessor controlled system that sends and receives keyboard and mouse data and emulates the presence of keyboards and mice when they are not connected directly to the computer. There are also swtiches that are built as a conbination of electronic and mechanical switches. Some KVM switches use mechanical switching for video signals and electronic switchign for keyboard/mouse, thus having the benfits of keyboard/mouse emulation combines with cheap mechanical switch construction. One important thing to consider when looking at KVM switches is the maximum supported screen resolution. Make sure you get one that supports the resolution you use. Good switches list the maximum supported resolution.

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