Before You Assemble Your PC
The following checklist should be completed when you order PC parts to make sure you have enough components to assemble a working PC:
• ATX Case and power supply Note that both the Pentium 4 and Athlon have special power supply requirements, although many new power supplies provide for both of these.
• ATX Motherboard and CPU Socket 421, 478 or 775 for Pentium 4, depending on CPU model for Athlon or P4, Socket 370, or Slot 1 for Pentium III or Celeron.
• RAM RIMM for Pentium 4, 128MB minimum, DDR for Athlon or Duron (DDR support for Pentium 4 is expected in early 2002), for Pentium III / Celeron, 64MB SD (synchronous dynamic)
• Video 2X / 4X AGP adapter with minimum 8MB video RAM (unless the motherboard has integrated video). Make sure the AGP adapter voltage is universal (3.3V or 1.5V) or matches your motherboard requirement.
• Floppy Drive 1.44MB 3.5" floppy drive.
• Hard Drive 40 GB IDE drive or larger, ATA 100 compatible with 80-conductor cable.
• CD/DVD CD-ROM or CD recorder, DVD-ROM or combination CD-RW / DVD-ROM. Any of these can be used to install the operating system form CD.
• Keyboard Keyboard with PS/2 style connector.
• Mouse Mouse with PS/2 style connector.
• Monitor 15" or larger monitor.
• Operating system Windows or Linux on CD, any version.
Wednesday, October 28, 2009
RAM Details
Memory
We try to avoid giving history lectures in this website, but on the subject of memory, a brief review is essential to understanding the terminology. One of the basic innovations that made digital computers possible, Random Access Memory (RAM) allows the CPU to retrieve information stored at a specific memory address without having to read through all the memory to find it. Contrast this with a tape drive, where the whole tape may have to be wound by the read head to reach the location of the desired information. Even with the relatively fast hard drive, the read head must physically move, as much as tens of millimeters, and wait for the disk to spin until the information is under the head.
The access times of drives are measure in milliseconds, or thousandths of a second; the access time of RAM is measured in nanoseconds, or billionths of a second. When it comes to locating a single byte of data at a random location, memory outperforms other storage media by a factor of hundreds of thousands. If this wasn't the case, the super-fast CPUs would have no purpose, because they would spend all their time waiting for new instructions and data to work on.
There are two basic types of RAM in use: Static RAM (SRAM) and Dynamic RAM (DRAM). Both types of memory forget everything if the power is tuned off, but SRAM doesn't require the constant refreshing the DRAM does, ergo the names, "Static" and "Dynamic." SPRAM requires four or five times as many transistors to implement as DRAM, as it actually traps each bit of information in a structure called a flip-flop. DRAM stores a bit as a temporary charge on the leg of a single transistor, but this decays away so rapidly that it must be reread and refreshed many times per second. SRAM is used as cache memory on CPUs and in other applications, but always in relatively small amounts because of its increased power and real estate demands. DRAM is used for the main PC memory and has been since the original IBM PC was introduced 20 years ago.
Fast Page Memory (FPM) was the first big performance enhancement to DRAM, which had previously treated each new memory transaction like a surprise invitation. FPM made it faster to access data in the same memory "page" although the term "row" offers a better representation of what really goes on. When a new data bit is to come from the same matrix row as the previous bit, the memory controller needs only to increment the column location and the same row address will be used, saving an address transaction.
Extended Data Out (EDO) DRAM shortens the recovery time between sequential DRAM reads, offering about a 20 percent performance boost in overall memory throughput. EDO was backward compatible, meaning it would function in systems that were designed to support FPM RAM, albeit without any performance increase. Burst EDO (BEDO) was the next level of enhancement in which a series, or burst, of bytes from memory could be transferred to the CPU in a single request. If the CPU actually required data from these subsequent locations, an operation has been saved, and if not, nothing has been lost.
Synchronous DRAM (SDRAM) can really boost memory bandwidth through synchronization with the system clock. This eliminates a large number of timing delays, which can result in wait states on the part of the CPU (i.e., idle time). The motherboard must be designed to support SDRAM, which is not backward compatible to EDO or FPM. Early SDRAM modules were 5V devices, but the current modules require 3.3V. Fortunately, memory module designers got together earl on and came up with a standard system of notches in the contact edge of memory modules, which prevents them from being installed in the wrong type of memory socket. SDRAM was originally available at 66 MHz, but 100 MHz (PC100) and 133 MHz (PC133) devices so followed. The current speed champion for SDRAM is PC150 (150MHz) and is popular with overclockers.
Double Data Rate (DDR) SDRAM, simply known as DDR, is the next step after SDRAM. DDR can effectively double the throughput of earlier SDRAM by transferring data on both the rising and falling edges of the bus clock. The Athlon was the first CPU to take advantage of DDR, which it currently supports with a 266 MHz FSB, and the Pentium 4 is expected to follow suit. The Duron supports DDR at 200 MHz. DDR modules are known both by their MHz rating and PC nomenclature similar to the earlier SDRAM modules. 200 MHz DDR is PC1600,266 MHz DDR is PC2100, and 300 MHz DDR is PC2400. The motherboard must explicitly support DDR for it to be used.
We try to avoid giving history lectures in this website, but on the subject of memory, a brief review is essential to understanding the terminology. One of the basic innovations that made digital computers possible, Random Access Memory (RAM) allows the CPU to retrieve information stored at a specific memory address without having to read through all the memory to find it. Contrast this with a tape drive, where the whole tape may have to be wound by the read head to reach the location of the desired information. Even with the relatively fast hard drive, the read head must physically move, as much as tens of millimeters, and wait for the disk to spin until the information is under the head.
The access times of drives are measure in milliseconds, or thousandths of a second; the access time of RAM is measured in nanoseconds, or billionths of a second. When it comes to locating a single byte of data at a random location, memory outperforms other storage media by a factor of hundreds of thousands. If this wasn't the case, the super-fast CPUs would have no purpose, because they would spend all their time waiting for new instructions and data to work on.
There are two basic types of RAM in use: Static RAM (SRAM) and Dynamic RAM (DRAM). Both types of memory forget everything if the power is tuned off, but SRAM doesn't require the constant refreshing the DRAM does, ergo the names, "Static" and "Dynamic." SPRAM requires four or five times as many transistors to implement as DRAM, as it actually traps each bit of information in a structure called a flip-flop. DRAM stores a bit as a temporary charge on the leg of a single transistor, but this decays away so rapidly that it must be reread and refreshed many times per second. SRAM is used as cache memory on CPUs and in other applications, but always in relatively small amounts because of its increased power and real estate demands. DRAM is used for the main PC memory and has been since the original IBM PC was introduced 20 years ago.
Fast Page Memory (FPM) was the first big performance enhancement to DRAM, which had previously treated each new memory transaction like a surprise invitation. FPM made it faster to access data in the same memory "page" although the term "row" offers a better representation of what really goes on. When a new data bit is to come from the same matrix row as the previous bit, the memory controller needs only to increment the column location and the same row address will be used, saving an address transaction.
Extended Data Out (EDO) DRAM shortens the recovery time between sequential DRAM reads, offering about a 20 percent performance boost in overall memory throughput. EDO was backward compatible, meaning it would function in systems that were designed to support FPM RAM, albeit without any performance increase. Burst EDO (BEDO) was the next level of enhancement in which a series, or burst, of bytes from memory could be transferred to the CPU in a single request. If the CPU actually required data from these subsequent locations, an operation has been saved, and if not, nothing has been lost.
Synchronous DRAM (SDRAM) can really boost memory bandwidth through synchronization with the system clock. This eliminates a large number of timing delays, which can result in wait states on the part of the CPU (i.e., idle time). The motherboard must be designed to support SDRAM, which is not backward compatible to EDO or FPM. Early SDRAM modules were 5V devices, but the current modules require 3.3V. Fortunately, memory module designers got together earl on and came up with a standard system of notches in the contact edge of memory modules, which prevents them from being installed in the wrong type of memory socket. SDRAM was originally available at 66 MHz, but 100 MHz (PC100) and 133 MHz (PC133) devices so followed. The current speed champion for SDRAM is PC150 (150MHz) and is popular with overclockers.
Double Data Rate (DDR) SDRAM, simply known as DDR, is the next step after SDRAM. DDR can effectively double the throughput of earlier SDRAM by transferring data on both the rising and falling edges of the bus clock. The Athlon was the first CPU to take advantage of DDR, which it currently supports with a 266 MHz FSB, and the Pentium 4 is expected to follow suit. The Duron supports DDR at 200 MHz. DDR modules are known both by their MHz rating and PC nomenclature similar to the earlier SDRAM modules. 200 MHz DDR is PC1600,266 MHz DDR is PC2100, and 300 MHz DDR is PC2400. The motherboard must explicitly support DDR for it to be used.
256 MB DDR DIMM
The RAM used in the IBM PC came in the form of one bit-wide chips in Dual Inline packages ,or Dip Chips. As memory chips shrank and capacity grew, they were mounted on small circuit boards called Single Inline Memory Modules (SIMMs), first 8 bits wide (1byte) and then 32 bits wide (4 bytes). As chips continued to shrink and capacity and memory buses continued to grow, the SIMM width was doubled, giving us DIMM. The current DIMM modules are 64 bits wide, the same as the memory bus in PC systems not using RDRAM, so they can be installed singly or in any multiple.
RAMBUS or RDRAM, technology represents a departure from the step-by-step evolution of RAM we have presented to this point. RDRAM Inline Memory Modules (RIMMs) are only 16 bits wide, but they make up in speed what they lack in width. Dual-channel motherboards operate RIMMs in pairs, allowing an effective width of 32 bits at speeds of up to 800 MHz. Not surprisingly, RDRAM modules run awfully hot, and they currently cost about twice as much as DDR modules of the same capacity.
RIMMs must be installed in banks of two, and unused banks must be filled with special dummies called Continuity RIMMs (CRIMMS) for electrical signal continuity. The 800 MHz RIMM is designated PC800; there are also slower versions designated PC700 and PC600, although they are primarily used in mass-market systems.
Both DDR and RIMM modules are available with the Error Correction Code (ECC) enhancement. ECC memory can correct single-bit errors on the fly and catch multiple-bit errors, unlike the earlier parity error checking, which couldn't correct any errors or identify two-bit flips. ECC memory must be supported by the motherboard, unless it used ECC onboard technology; and the price premium for ECC memory has almost disappeared with plummeting memory price.
CD Drive (compact disk)
CD Drives
CDs were first developed by the music industry to complete with, then replace, vinyl records. The CD drives in PCs are all capable of playing music CDs without the aid of any other hardware, and most come with a headphone jack right on the front of the drive. A CD holds a three mile-long spiral of information, where the location of a particular item is measured in minutes and seconds from the beginning, as if it were being played in a stereo. The difference between music CDs, data CDs, and all the various hybrids is strictly a matter of formatting. The speed at which your computer plays a music CD is fixed to be the same speed at which stereos play CDs, and this became known as single speed or 1X. The standard CD drives in use today can read data CDs at peak of 50X or faster.
CD Drives
HDD (hardisk drive)
Hardisk Drives
The most important storage device in your PC is the hard drive. The average hard drive sold today can store as much information as tens of thousands of floppy disks, and it can find and read that information faster than any other storage device, including CDs and DVDs. The majority of the storage space on most people's hard drive is used for programs such as the operating system, word processing and database software, and games. No author, living or dead, could ever fill up a modern hard drive by writing books, but a couple hours of high-quality video would do the job. Although you can always make room on a nearly full hard drive by destroying (deleting) old programs of information, most people prefer to let the clutter build up like old boxes in the attic, simply adding a new hard drive when things get too crowded.
Although the storage provided by the hard drive is certainly permanent in comparison to RAM, it's nowhere near bulletproof. The mean time between failure (MTBF) ratings provided by hard drive manufactures are highly optimistic, and always exceed the useful life of the drive by at least a decade. Anecdotally, I would estimate that one in ten hard drives suffers complete failure within a couple years of being purchased, with an even higher rate in notebook computers. These failures can result from all sorts of environmental issues such as excessive heat, power spikes, or the PC getting thumped at just the wrong moment.
For this reason, anybody who uses a PC for more than games and Internet surfing should get in the habit of making copies of important information, a process known as "creating a backup”. Creating a backup can be as simple as copying your checkbook register or word processing documents to a floppy disk once a week, but never use the floppy disks to exclusively store documents in place of the hard drive because they are far less reliable, not to mention much slower.
Hardisk DriveIn critical business applications, a special technology called RAID (Redundant Array of Inexpensive Drives) provides a means to duplicate data across several hard drives to increase performance and protect against the failure of any individual drive. RAID solutions usually provide automatic fail over, so you won't experience any down time if a single drive fails in the middle of the business day. We will give an example of a simple RAID sub-system in our Pentium 4 build.
RAID provides no protection against fire, theft, data management errors, or computer viruses. Tape backups are the dominant devices for backing up large amounts of data, although DVD recorders and new high-capacity cartridge drives from Iomega might pick up some of the load. CD recorders, also know as burners, provide an excellent option for data backup if you organize your files on the hard drive so you know what to copy to the CD.
RAM (random access memory)
System Memory or RAM
Random Access Memory (RAM) provides the fast, temporary storage from which your CPU draws the data it needs to operate. The storage capacity of RAM is measured in megabytes (millions of bytes). You'll want to build your new PC with an absolute minimum of 64 MB of RAM. If you are running very demanding applications or high data throughput jobs like video editing, you might want to install as much memory as you can afford. Currently, 256 MB is a pretty healthy amount, and is more than is included in most PCs sold in stores.
There are three basic families of RAM in use today, and we give an example of each with our three builds. The Dynamic RAM (DRAM) that makes up the system memory actually starts to forget everything many times a second, but a dedicated memory controller endlessly reads and writes this information to keep it fresh. Memory, amusingly enough, does forget everything the moment the PC is turned off, which is why we have hard drives, CDS, and floppies to provide storage. The fastest way to tip off a showroom vulture that you are a little hazy about computer terminology is to refer to "the memory in the hard drive."
Random Access Memory (RAM) provides the fast, temporary storage from which your CPU draws the data it needs to operate. The storage capacity of RAM is measured in megabytes (millions of bytes). You'll want to build your new PC with an absolute minimum of 64 MB of RAM. If you are running very demanding applications or high data throughput jobs like video editing, you might want to install as much memory as you can afford. Currently, 256 MB is a pretty healthy amount, and is more than is included in most PCs sold in stores.
There are three basic families of RAM in use today, and we give an example of each with our three builds. The Dynamic RAM (DRAM) that makes up the system memory actually starts to forget everything many times a second, but a dedicated memory controller endlessly reads and writes this information to keep it fresh. Memory, amusingly enough, does forget everything the moment the PC is turned off, which is why we have hard drives, CDS, and floppies to provide storage. The fastest way to tip off a showroom vulture that you are a little hazy about computer terminology is to refer to "the memory in the hard drive."
CPU (central processing unit)
Central Processing Unit (CPU)
The CPU is the brain of your PC, executing the instructions of the software programs you run, such as Windows XP, Linux, Word, and Quicken. Most PCs are referred to by their CPU and speed, such as a "2GHz Pentium 4" or a "1.4GHz Athlon." Currently, all CPUs being manufactured for use in PCs run at speeds from a minimum of 500 megahertz (MHz) to more than 2 gigahertz (GHz), where hertz (Hz) expresses the number clock cycles the CPU steps through in one second.
If you should as, "What can a CPU do in a single step?" the answer is "It depends on the CPU." All CPUs can actually do several things at the same time, and the designers squeeze every drop of performance they can out of a clock cycle. Although it's no longer true that equivalent speed ratings for Intel and AMD CPUs express equivalent performance, the numbers are valid for comparing performance within a family of CPUs. Thus, a 2 GHz Pentium 4 can execute 33 percent more instructions/second than a 1.5 GHz Pentium 4. We'll talk more about how the speed of the CPU impacts the overall performance of the PC in the next chapter.
The CPU is the brain of your PC, executing the instructions of the software programs you run, such as Windows XP, Linux, Word, and Quicken. Most PCs are referred to by their CPU and speed, such as a "2GHz Pentium 4" or a "1.4GHz Athlon." Currently, all CPUs being manufactured for use in PCs run at speeds from a minimum of 500 megahertz (MHz) to more than 2 gigahertz (GHz), where hertz (Hz) expresses the number clock cycles the CPU steps through in one second.
If you should as, "What can a CPU do in a single step?" the answer is "It depends on the CPU." All CPUs can actually do several things at the same time, and the designers squeeze every drop of performance they can out of a clock cycle. Although it's no longer true that equivalent speed ratings for Intel and AMD CPUs express equivalent performance, the numbers are valid for comparing performance within a family of CPUs. Thus, a 2 GHz Pentium 4 can execute 33 percent more instructions/second than a 1.5 GHz Pentium 4. We'll talk more about how the speed of the CPU impacts the overall performance of the PC in the next chapter.
Intel Pentium CPUOne of the biggest bottlenecks to CPU performance is memory speed. These huge numbers for CPU speed we are casually throwing around don't mean much of anything unless the CPU can be supplied with instructions to carry out and data to operate on. To minimize the amount of time CPUs spend waiting for memory, small amounts of super-fast memory called cache are included in the CPU package. The Athlon has the biggest cache at 384 KB, followed by the Pentium 4, the Pentium III, the Duron, and the Celeron. Depending on the type of work the CPU is doing, it might find as much as 90 percent of the data it is looking for in cache. Considering that the CPU cache is likely to amount to less than 1 percent of the total system memory, that's pretty good hit rate.
Tuesday, October 27, 2009
SMPS
S.M.P.S (Switch Mode Power Supply)
The case is almost universally sold with the power supply installed and included in the price. You can build a PC on a workbench without a case (technicians often do this when testing parts), but it takes up a lot of space, interferes with the radio, and is awfully hard to pick up and move in one trip. The function of the case is to house all the parts that make up your PC, provide ventilation for the heat they generate, and protect the local environment from radio frequency interference.
The case is almost universally sold with the power supply installed and included in the price. You can build a PC on a workbench without a case (technicians often do this when testing parts), but it takes up a lot of space, interferes with the radio, and is awfully hard to pick up and move in one trip. The function of the case is to house all the parts that make up your PC, provide ventilation for the heat they generate, and protect the local environment from radio frequency interference.
All electrical devices that produce radio frequency emissions are required by law to be certified by the Federal Communications Commission (FCC) as no interfering with assigned broadcast frequencies. Computers produce a lot of radio frequency "noise" in the FM radio band and higher, but at very low power levels. Normally, if a computer in your home interferes with a radio or television, moving it to another room or even just changing its position by a couple feet will fix the problem.
Computer parts are sold as being FCC Class A or B approved. Class A is for business use, the Class B rating meets more stringent limits for residential use. Assembling a collection of approved parts is no guarantee that the completed computer would pass an FCC test suite for one rating or the other, but as a home hobbyist, you aren't required to have your computer tested. However, if you decide you love building PCs so much that you want to go into business selling thousands of them, you'll want to buy partially assembled or packaged systems that come with an FCC approval sticker.
Power supplies are equipped with a 115V/230V switch, so they can be set to 230 volts for Europe and most other regions of the world that don't use the U.S. standard 115 VAC distribution system. Just a few years ago, this 115 or 230 volts was wired directly to the switch on the front of the PC, like the switch on a lamp or a toaster oven. However, in all new PCs, the high voltage never leaves the power supply. The switch on the front panel is really just a logic switch that closes a circuit on the motherboard, which tells the power supply to come on at full power. The power supply is always providing a trickle of current to the motherboard to enable this "wake up" logic, whether the signal is generated by the power switch or by incoming traffic to the modem or network card.
ATX Power SupplyThe second function of the power supply is to generate a cooling airflow for both itself and the other parts in the case. This fan in the power supply is thermion source of noise coming from most PCs. The manufacturers of the newest high-speed components often recommend that you include additional fans in the case of increase the cooling airflow. The most common location of a single additional fan is at the bottom of the front of the case, to draw in air. A second fan can be added under the power supply at the back of the PC to exhaust more hot air. The goal is always to increase the airflow through the case, not just to blow hot air in a circle, so don't install several fans to draw air into the case and none to exhaust it, or vice versa.
Motherboard
Motherboard
The motherboard, or main board, is normally the first component to be installed in the case. All additional adapters will be installed directly on the motherboard, and storage device (drives) will be attached to it by wide ribbon cables. There are a dozen well-known motherboard manufacturers and hundreds of lesser-known brands. PCs are not named for their motherboards, but by their CPUs, such as Pentium 4 or Athlon. The CPU and the memory (RAM) require no connections to anything else in the case other than the motherboard, and can therefore be mounted on the motherboard before it is installed in the case. Not surprisingly, the motherboard is the largest component you will install in the case, and is often the most expensive.
The modern ATX (AT extension) motherboard provides many basic function: It passes power from the power supply to the installed adapters, CPU, and memory modules; provides connection ports for the keyboard, mouse and printer; and integrates all the supporting function necessary to make the CPU into a computer. Most jobs handled by the motherboard go on entirely in the background, transparent to the user and remarked on only if there is a problem. The motherboard function that you should always keep in mind when building your PC is that it acts as the communications infrastructure for the entire computer. The motherboard is crisscrossed by information superhighways, some as wide as 64 lanes, which move information and instructions from one component to another.
The motherboard, or main board, is normally the first component to be installed in the case. All additional adapters will be installed directly on the motherboard, and storage device (drives) will be attached to it by wide ribbon cables. There are a dozen well-known motherboard manufacturers and hundreds of lesser-known brands. PCs are not named for their motherboards, but by their CPUs, such as Pentium 4 or Athlon. The CPU and the memory (RAM) require no connections to anything else in the case other than the motherboard, and can therefore be mounted on the motherboard before it is installed in the case. Not surprisingly, the motherboard is the largest component you will install in the case, and is often the most expensive.
The modern ATX (AT extension) motherboard provides many basic function: It passes power from the power supply to the installed adapters, CPU, and memory modules; provides connection ports for the keyboard, mouse and printer; and integrates all the supporting function necessary to make the CPU into a computer. Most jobs handled by the motherboard go on entirely in the background, transparent to the user and remarked on only if there is a problem. The motherboard function that you should always keep in mind when building your PC is that it acts as the communications infrastructure for the entire computer. The motherboard is crisscrossed by information superhighways, some as wide as 64 lanes, which move information and instructions from one component to another.
MotherboardFor example, to display a checkbook ledger stored on your system last week, the CPU (which does most of the decision making) asks the hard drive, via a motherboard superhighway, to send this information to immediate memory for use. The requested information is moved from the hard drive to the memory (RAM) via a motherboard superhighway, where the CPU operates on it via a special expressway and formats it for presentation. The information is then sent via another superhighway to the video adapter, which translates it into television-type signals for the monitor. You don't have to keep track of which superhighway, called a bus, is involved in every operation, but it is important to understand that the various push-together connections you will make to the motherboard form vital bridges for the information flow.
Manufacturers in a “reinventing the wheel” process do not design motherboards. The design of the motherboard is largely controlled by the choice of the chipset-the one or two highly integrated chips that support the CPU. Although the CPU can be seen as the decision maker, it doesn't actually carry out the policing of all the motherboard superhighways (and back roads) by itself. The chipset handles all the support functions for the motherboard largely in automatic mode, just like nervous system of the human body maintains our vital function even while we sleep. The level of support offered by the chipset defines the capabilities that can be built into the motherboard, including what speeds will be possible for the CPU and memory. There are far fewer chipset manufacturers than motherboard manufacturers, and CPU manufacturers always design a companion chipset of their own to go with their CPUs.
Sunday, October 11, 2009
The devices is require to assemble a P.C
The basic parts in a computer are all dependant on each other to carry out their functions. For example, all the parts depend on the power supply for electrical current at the required voltage levels, and some parts, like the central processing unit and memory, are dependant on the motherboard (main circuit board) ot further refine that power for them. This makes it difficult to explain the funcitons of these parts without referring to others, os we will tackle them in an order that minimizes cunfusion.
All in all, there are somewhere between 10 and 15 distinct parts involved in a PC build, including the monitor, keyboard, and mouse. By distinct parts, we mean components you pick off a store shelf or order over the phone or internet. Assembling all these parts to creat a working PC will require you to make a bout 10 push-together connections and secrew in 20 or 30 screws, four here, six there, nothing complicated.
All in all, there are somewhere between 10 and 15 distinct parts involved in a PC build, including the monitor, keyboard, and mouse. By distinct parts, we mean components you pick off a store shelf or order over the phone or internet. Assembling all these parts to creat a working PC will require you to make a bout 10 push-together connections and secrew in 20 or 30 screws, four here, six there, nothing complicated.
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