Motherboard/Processors/Memory

10:23:00 PM |


Certification Objectives

CPU Chips
RAM (Random Access Memory)
Motherboards
CMOS (Complementary Metal-Oxide Semiconductor)
The computer industry is one in which technology increases at an exponential rate. Yesterday’s technology has already become outdated as soon as it hits your desk. While it can be overwhelming at times, if you understand the basics behind each current component, you will form the foundation necessary to understand new technologies as they are developed. This chapter focuses on the most important components of every computer: processors, memory, motherboards, and the CMOS.

CPU Chips

The central processing unit (CPU), or simply the processor, is the operations center of a computer. Its job is to provide the devices attached to the computer with directives that retrieve, display, manipulate, and store information. Therefore, the rate at which the CPU can process electronic signals is a determinant factor in the speed of the computer.
CPU chips are integrated circuits that contain thousands to millions of transistors. These transistors are used to process information in the form of electronic signals. The more transistors a CPU has, the faster it can process data. Several evolutions of CPUs have allowed for the chips to hold more transistors than their predecessors, and therefore process information at increasing speeds. As a technician, you will encounter several different types of processors in operation and must familiarize yourself with their various characteristics and features. The following subsections describe each chip in detail.

Popular CPU Chips

As with everything in the computer industry, chip architectures change rapidly. Chip architectures are defined by the number of transistors in the chip and the size of the bus. One of the earliest IBM PCs contained an Intel 8088 chip, which only contained 29,000 transistors and an 8-bit bus. Today’s Intel Pentium II processors contain 7.5 million transistors and supports a 64-bit bus. As discussed in the previous paragraph, the number of transistors inside a chip is one of the determining factors in the rate at which a chip can process information. For example, the 8088 chip only processed data at approximately 4.77 MHz, while the Pentium II is reported to run at speeds of 233 MHz to 400 MHz.

386

The leading processor manufacturer of the time, Intel Corporation, released the 80386 chip in 1985. This chip featured a 32-bit register size, a 32-bit data bus, and a 32-bit address bus and could handle up to 16 MB of memory. However, the 386 did not have an internal math co-processor and users who required heavy calculations had to purchase one separately.
Prior to the 386 chip, Intel would license its technology to its competitors. But the competition found ways to make cheaper, and in some cases faster, processors. Consumers were buying these less expensive chips at an increasing rate, which cut into Intel’s market share and reduced its status as the leading manufacturer. Intel’s competitors came out with their own version of the 386 chip.
The 386 processor was also the first time that there were two versions of the same basic processor, the SX version and the DX version. The 386SX processor came with a 16-bit data bus, a 24-bit address bus, and a 32-bit register size. The 386DX processor’s data bus, address bus, and register size were all 32-bits. Both the SX and DX chips operated at 16 MHz, 20 MHz, 25 MHz, and 33 MHz.

486

The 486 processor is also broken down into four types: 486SX, 486DX, 486DX2, 486DX4. The 486SX chip did not increase the processor speed, which remained at 33 MHz, or enlarge the bus size from 32-bit. It did introduce an on-board cache to the processor, which was an 8-bit cache, along with an on-chip math co-processor. Unfortunately, the math co-processor was disabled at the factory and a secondary chip had to be purchased to obtain the benefits.
When the 486DX was released, it had the same characteristics as the SX version, only the math co-processor was enabled. A later version of the chip, the 486DX2, was still able to run at 33 MHz externally, but doubled the processor speed, or clock speed, internally and brought it up to 66 MHz. Following that, the 486DX4 chip was released, which increased the clock speed even more and brought it up to 133 MHz.

586 or Pentium Class

Intel decided that it wanted to break away from the standard naming convention when it couldn’t trademark the 80x86 name. With the 586 chip, Intel named its chip the Pentium chip and introduced several new features and improvements. The first improvement was in the register size and the data bus size, which was doubled to 64-bit. It also doubled the on-board cache size from 8-bit to 16-bit and increased speeds to a range of 60 MHz up to 200 MHz.
Along with the improvements came a significant change in processor architecture and capabilities. The chip combined two 486DX chips into one, called the Dual Independent Bus Architecture, which allowed each processor inside the chip to execute instructions simultaneously and independently from each other, called parallel processing. The end result was a faster chip, but required a special motherboard that was able to withstand the enormous amount of heat generated by the chip. Heat sinks also had to be employed to help remove the excess heat from the chip or it would burn itself out.

686 or Pentium II Class

Intel’s Pentium II chip outpaced the other chips by offering speeds ranging between 233 MHz to 333 MHz. Another improvement was the integration of Intel’s MMX technology, which speeds up the processing of video, audio, and graphical data. MMX does this by employing an enhanced instruction set and the Single Instruction Multiple Data (SIMD) technique. According to Intel, SIMD works by allowing a single instruction to operate on multiple pieces of data when an application is performing a repetitive loop.

Chip Characteristics

Table 4-1 provides an overview of the different varieties of chips and their respective characteristics.
ProcessorPhysical SizeVoltageSpeedHeat SinkCooling FanOn Board CacheSocketsPins
80884.77N
802868-12N
80386SX16-20N
80386DX16-33N
80486SX16-33N
80486DX25-133N
Pentium60-166Y
Pentium Pro233-266Y
Table 1: Characteristics of Different Types of Chips
Exam Watch: Know Table 4-2 cold for the exam, as there are several questions that will test your knowledge of the different processors’ bus size.
Table 4-2 provides an overview of the different varieties of processors along with their bus sizes.
ProcessorRegisterData BusAddress Bus
808816-bit8-bit20-bit
8028616-bit16-bit24-bit
80386SX32-bit16-bit24-bit
80386DX32-bit32-bit32-bit
80486SX32-bit32-bit32-bit
80486DX32-bit32-bit32-bit
Pentium64-bit64-bit32-bit
Table 2: Bus Sizes of Different Processors

RAM (Random Access Memory)

When the processor needs to perform calculations or store data, it needs a temporary storage area to hold the information. As discussed in Chapter 1, memory is your computer’s work area. Memory is composed of integrated circuits that connect to the system board, or to an expansion card, located inside the computer. These circuits can be either on or off, and therefore represent data as a series of 1s and 0s, respectively. This representation is called binary, and is the language that your computer understands.
In order to understand memory, you need to get a feel for some of the terms related to memory, such as that which describes memory sizes. Each individual 0 or 1 is called a bit, and written as a lower case "b." To try and keep track of the millions and billions of bits would prove a laborious task, so bits are grouped into sets of eight called a byte, which is written as an upper case "B". Since computers work with large numbers of bytes, it would still get a bit tedious listing files sizes of 500,000 bytes or 5,000,000 bytes. Instead, we use a form of shorthand that cuts the numbers down to a more manageable size. There are three common denotations that are used to represent computer numbers: a kilobyte (KB) is 1,024 bytes, amegabyte (MB) denotes 1,048,576 bytes, and a gigabyte (GB) means 1,073,741,824 bytes! So, if you had 16 MB of memory on your computer, you actually have 16,777,216 bytes of memory available. If you are wondering why a kilobyte, for example, isn’t equal to 1,000 bytes it is because the computer works on powers of 2 rather than 10. Thus, when we calculate 2^10, we get 1,024 bytes instead of 1,000 bytes. If we were trying to get a megabyte, we would calculate 2^20.
Memory comes in several forms, but generally the processor accesses random access memory (RAM). RAM gets its name from how the memory is physically accessed. Data can be accessed by one of two methods, either sequentially or randomly. When you store data sequentially, you cannot get immediate access to the data that you need. Instead, you must go through all of the information that had been stored before actually getting to the data that you need, which is the way that magnetic tape stores and retrieves data. However, with random access, you can bypass the data that you don’t need and go directly to the location where the information is stored. RAM allows your computer to store and retrieve data in random locations in memory.
There are several forms of RAM available, each with its own method of random access and differing physical characteristics. We discuss each in the following subsections.

Terminology

As we mentioned in the preceding paragraphs, memory stores data as a series of 0s and 1s. These 0s and 1s are stored electronically, but signals on memory chips can degrade unless power is constantly fed to it. To ensure that those signals are correct, memory chips are constantly updated, a process called refresh. The rate at which the chips are refreshed is called therefresh rate and usually occurs around 60 or 70 nanoseconds, or about 60 to 70 thousandths of a second. When your computer loses power, all of the circuits are set back to 0s and anything stored in RAM is wiped.

Static RAM (SRAM)

Static Random Access Memory, or SRAM, does not need to be constantly refreshed, hence it is static. However, while it doesn’t need a constant update, it does require a periodic update and tends to use excessive amounts of power when it does so. SRAM chips were used in the original IBM PC and XT computers and employed transistors to store information, leading to a large chip size. Unfortunately, an SRAM chip can only hold approximately 256Kb of data per chip and are relatively expensive.

Dynamic Random Access Memory (DRAM)

Dynamic Random Access Memory, or DRAM, chips abandoned the idea of using the unwieldy transistors and switches in favor of using the smaller capacitors that could represent 0s and 1s as an electronic charge. This resulted in the ability to store more information on a single chip, but also meant that the chip needed a constant refresh and hence more power.

Windows Accelerator Card RAM (WRAM)

Microsoft Windows has become one of the most popular client operating systems (OS) in use today due to its graphical nature and ease of use. However, in some environments, it can be a slow one. To help speed up the OS without purchasing a new processor, and in some cases a new motherboard to go with it, the Windows Accelerator Card was introduced into the market. This card utilizes memory that resides on the card itself to perform the Windows-specific functions, and therefore speeds up the OS.

Extended Data Output RAM (EDO RAM)

Extended data output RAM (EDO RAM) is a DRAM memory chip designed for processor access speeds of approximately 10 to 15 percent above fast-page mode processors. This requires both a motherboard and processor that is capable of supporting EDO RAM.

RAM Locations and Physical Characteristics

Random access memory (RAM) is the place that your computer temporarily stores the instructions that make up an application, as well as the actual data it manipulates. As mentioned in the previous section, RAM comes in several forms and possesses differing characteristics.

Memory Bank

A memory bank is the actual slot that memory goes into. The original memory chips were installed individually in sockets designed to hold only one chip at a time. Newer memory components are installed in special slots designed to hold one card that contains multiple memory chips. With both types of memory, the socket or slot is located on the motherboard and uses the system board’s circuitry to communicate directly with the processor. In cases where a device uses a DMA channel, such as with sound cards, the component itself can communicate directly with RAM.

Parity Versus Non-Parity Chips

Parity is an error-checking mechanism that enables the device to recognize single-bit errors. Parity comes in two forms: even parity and odd parity. With odd parity, the number of 1s in a byte are added up and checked to see if it is an odd number. If it is, an extra bit set to zero (0) is added to the byte, thus ensuring that the total number of ones result in an odd number. However, if the number of ones add up to an even number, the extra bit added on is set to one , thus ensuring that the total number of ones results in an odd number.
Even parity works in the same manner, except that the total number of ones must add up to an even number. Therefore, if the sum of ones equals an even number, the extra bit is set to zero. However, if the sum of ones equals an odd number, the extra bit is set to one. Should one of the data bits switch, say from a one to a zero, the total number of ones will not result in the correct odd number (for odd parity) or even number (for even parity). The problem with this is that if two of the bits were switched, the data would still pass the parity test.
Parity is not just used with memory, but is utilized in hard drives and communications. While it is not a 100-percent guaranteed method of ensuring that your data is intact, it is still better than having no parity at all. With a non-parity chip, you have no guarantee that the data that is stored on the chip is what was truly sent.

Memory Chips (8-bit, 16-bit, and 32-bit)

Memory chips communicate with the processor or peripherals through the bus. As stated in Chapter 1, the bus is the actual pathway used to transmit electronic signals from one device to another. The number of bits that can be transmitted or received simultaneously is one of the determining factors of bus architecture. Bus configurations come in 8-bit, 16-bit, 32-bit, and 64-bit.

SIMMS (Single In-line Memory Module)

Before the Single In-Line Memory Module, or SIMM, memory chips were purchased individually and placed on the motherboard in separate sockets. With SIMMs, you get a card that has several DIP chips embedded on one side of the card. Each SIMM module is given a pin designation, such as a 30-pin SIMM card, and is called the SIMM type. The "30-pin" refers to the number of fingers, or pins, that are on the connector.
SIMMs come as either 30-pin or 72-pin cards, but each card has a different format. The format is broken down as follows:
Capacity of the Chip x Data Bits
The capacity is the amount of data the card can hold, usually denoted in megabytes. However, the data bits determines if the SIMM utilizes parity. If the data bits equals 8 or 32, the SIMM does not use a parity bit, but a 9 or 36 will indicate that parity is in use (8 + 1 parity bit or 32 + 4 parity bits).

DIMMS (Dual In-line Memory Module)

Dual In-Line Memory Modules (DIMMs) are very similar to SIMMs except that they have memory chips embedded in both sides of the chip. Thus, the memory card can hold twice as many chips and twice as much memory as a SIMM. DIMMs come in 32-bit or 64-bit configurations, as well as a variety of pin types. However, as 64-bit motherboards are more common, the DIMM is becoming the memory type of choice.

Motherboards

The most important component of any computer is the motherboard. The motherboard is made of a fiber-glass sheet that has miniature electronic circuitry embedded in it. This circuitry provides the pathways for electronic signals to flow between devices. However, not every motherboard is created equal. In the next sections, we will discuss different types of motherboards, their components, and give you some basic compatibility guidelines.

Types of Motherboards

Motherboards come in various shapes and sizes, but there are two basic types of motherboards: AT and ATX. Both motherboards provide the same basic services to the computer, but they are not interchangeable. In the next sections, we take a brief look at both forms of system boards.

AT (Full and Baby)

The AT motherboard actually comes in two different types: Full and Baby. The primary difference between the two types is a matter of size, with the Full form at approximately 12" wide and the Baby at about 8.5" wide. The Full form is usually found with 386 or earlier computers and fits in a wider case. However, most AT-type motherboards in today’s computer systems are usually Baby ATs.
Regardless of which type of AT motherboard you are working with, the characteristics are basically the same. The processor is normally located in the front of the board, which has been an annoyance to many technicians attempting to install a new expansion card. The serial and parallel ports are actually located on the back of the case, and attach to the motherboard by headers.

ATX

The ATX motherboard specification was introduced by Intel and has become an industry-accepted standard. While the ATX system board is smaller than a Full AT, it is approximately the same size as the Baby AT. However, the processor has been moved to the back of the board and out of the way of expansion cards. In addition, the ATX form integrates the serial and parallel ports on the motherboard.

Components

A motherboard is composed of several components that work together as a unit. As a service technician, you should familiarize yourself with each of these components and know what their function is. By understanding each component’s job and how it works, you will be able to troubleshoot problems with these components much quicker. The following paragraphs discuss each component and what it does.

Communication ports

A computer lives to process information of all kinds, but in order to receive that data, it has to have a method of communicating with peripheral devices. Internal components attach directly to the motherboard through expansion slots. However, for external devices to connect to the motherboard in this fashion would require the computer’s case to be left off. Instead, the communication ports on the system board allow external devices to attach directly to the processor without having to remove the case.
There are two types of communication ports found on a motherboard: serial and parallel. Serial ports transmit data sequentially, bit by bit over a single conductor. This type of communication is usually found with modems and mice. However, a parallel port allows transmission of data over eight conductors at one time. An example of a device that utilizes a parallel port is a printer.

CMOS

The Complementary Metallic-Oxide Semiconductor (CMOS) stores the settings used by the Basic Input-Output System (BIOS). When the computer is rebooted or has lost power, the BIOS is incapable of retaining its settings. To avoid having to reenter these settings, a task that can prove tedious to say the least, the CMOS uses a battery to store the settings and then provide them to the computer’s BIOS upon reboot.

SIMM AND DIMM

Single In-Line Memory Modules (SIMM) and Dual In-Line Memory Modules (DIMM) are the memory types that are used on the motherboard. These types of memory were discussed in-depth earlier in the chapter.

Processor Sockets

The processor socket is the actual socket used to attach the processor to the motherboard. In earlier computers, the processor was actually soldered onto the motherboard. When it came time for an upgrade, you would usually have to purchase a new motherboard. With today’s computers, the processor is not soldered onto the motherboard and can be removed when necessary.

External Cache Memory (Level 2)

Cache memory is used to store frequently used instructions and data so that they can be accessed quickly by the computer. While many processors offer an integrated cache, it is useful to increase the capacity of the cache memory to speed up the computer’s performance. The motherboard contains cache memory slots, or external cache memory slots, that allow you to put additional cache memory onboard the system board.

ROM

Read-Only Memory (ROM) is a form of memory that is only read from, rather than written to. This is because the memory chips were permanently written to by the manufacturer. Types of ROM include the Basic Input-Output System (BIOS) chip, and Complementary Metal-Oxide Semiconductor (CMOS).

Bus Architecture

The bus allows a device to communicate with the motherboard and its underlying circuitry. It is defined by how many data bits can be transmitted at any given instant, such as an 8-bit or 16-bit bus. In general, motherboards only have one or two types of bus architecture on any given board. This is due to the fact that the processor’s data bus determines what types of architecture can utilize it. There are several architectures available on the market.
Industry Standard Architecture (ISA) was introduced after the IBM AT computers were released. AT computers allowed for a 16-bit data bus, but the peripherals at the time were still stuck on the 8-bit bus. To improve the communication speed of the devices, and to provide for an industry standard, several of the larger companies got together and developed ISA technology. This now allows for peripherals to utilize the 16-bit data bus that is available with 286 and 386 processors.
Extended Industry Standard Architecture (EISA) was introduced to compete against IBM’s Micro-Channel Architecture (MCA) devices, which increased their peripheral’s bus size from a 16-bit bus to a 32-bit bus. Because MCA was expensive and proprietary, the original companies that developed ISA got together and created a 32-bit card that was not only cheaper, but retained backward compatibility with the 16-bit ISA cards. This type of bus architecture is used in conjunction with 386 and 486 processors.
Peripheral Component Interconnect (PCI) was designed in response to the Pentium class processor’s utilization of a 64-bit bus. Until the development of the PCI bus, peripherals were tied to the processor architecture as well as the processor data bus. However, PCI buses are designed to be processor independent. They are able to accomplish this feat by utilizing a special bridge circuit along with a processor-dependent configuration program.
The VESA Local Bus (VL-Bus) was originally created to address performance issues. One of the problems with earlier bus designs was that they could only handle a maximum clock speed of only 8 MHz, while processors could run at much higher clock speeds. The idea was to create a bus that would have the same clock speed as the processor, known as a local bus. Components that utilized the local bus increased their performance, and thus several types of components were designed to take advantage of the faster speed.
Of the kinds of components that used the new bus architecture—hard drive cards, memory cards, cache cards – video cards became the most prevalent. However, compatibility issues arose as vendors used proprietary local bus slots and cards. This meant that you had to purchase the vendor’s card in order for it to work in the vendor’s slot. The Video Electronics Standards Association (VESA) was formed to address this compatibility problem.
VESA created the standards for the local bus architecture that were incorporated into the manufacturer’s products. This ensured that a card from one vendor would work in another manufacturer’s computer. The VL-Bus used a 32-bit slot and was built upon ISA bus architecture. This meant that the bus was backward-compatible with ISA and that configuration would require the old jumper and/or DIP switch configuration methods.
The Personal Computer Memory Card International Association (PCMCIA), or the less hard to remember PC Card, bus was first created to expand the memory capabilities in small, hand-held computers. The bus itself is about the size of a credit card and is only 16-bit. While some computers utilize the PC Card bus, the 16-bit size is somewhat restricting in computers that are capable of handling 64-bits. Therefore, a new standard is currently under construction to increase the PC Card to a 32-bit standard.
Exam Watch: Make sure that you know the differences between each type of bus and what each acronym stands for. While most of the acronyms seem intuitive, the exam will throw in a few that will seem to be just as plausible.

Basic Compatibility Guidelines

Whenever you have to determine if an expansion card is compatible with an expansion slot, you should always first refer to the manufacturer’s documentation. A good rule of thumb is to remember that an expansion card must be of the same type as the expansion slot (i.e., a VL-Bus card can only go into a VL-Bus expansion slot). However, ISA cards are an exception to the rule and can go into an ISA slot, an EISA slot, and a VL-Bus slot.

CMOS (Complementary Metal-Oxide Semiconductor)

The Basic Input-Output System (BIOS) can only hold its settings as long as the power is kept on. Once it loses power, it loses the settings and has to get them from somewhere. The Complementary Metal-Oxide Semiconductor (CMOS) was designed to store these settings and therefore drastically cut down on the number of times that the user would have to input them. However, the CMOS utilizes a battery that does not have an infinite life, and it is always prudent for you to note them down in a safe location in the event that the battery begins to fail.

From the Field

BIOS Fears

Improper handling of the BIOS can cause big headaches and much wasted time. The good news is that the BIOS are improving over the years. They now auto-detect most hardware and set themselves without too much user intervention. The bad new is that most of the BIOS that you will work with will be old.
Over time, batteries become depleted and this resets the bios. The clock is turned back to 1904. This causes you to have to replace the battery and reset the settings. You need to choose between all the types of hard drives, or worse, fill in the blank for the cylinder numbers, heads, and so forth. Well, if you have a good hard drive, you can usually find this labeled on the drive. If not, you can always look up this information in a book if you have the manufacturer and the serial number. You will in time find some of these that have none of this information on them. I’ve seen techs reboot 79 times only to find out that the drive is not one of those preset in the CMOS. Only third-party software and much time can be the answer to this dilemma.
Get a good idea of when these batteries often die. If you find out that a certain model of computers are losing their batteries after a certain amount of time, make sure you replace the other computers that were bought at about the same time. If the clock starts losing time, you can bet that the battery is to blame. Your best defense, however, is to keep track of the BIOS settings. There are some software programs out there that will save this data and let you print it. Do so, and keep this information with the log for the computer. Not only are hard drives tough to set in the BIOS, but some BIOS have settings that are very difficult to decipher. With your list ,you will never have to guess if you should have a setting activated or not.
— By Ted Hamilton, MCP, A+ Certified

Basic CMOS Settings

There are several basic CMOS settings that you should familiarize yourself with, as at some point you will have to reconfigure these settings as a result of a dead battery or a system upgrade. While we discuss these items in the following sections, it is always recommended to consult with the manufacturer’s documentation in case these settings are slightly different.

Printer Parallel Port

Unidirectional A single directional mode for the parallel port. Data travels only from the computer to the printer in this mode.
Bi-directional A two directional mode for the parallel port. Data travels both from the computer to the printer and vice versa.
Disable/enable Enables or disables the parallel port.
ECP–Extended Capability Port ECP mode offers the same features as bi-directional in addition to the use of a DMA channel for data transfer. This speeds up data transfer rates by bypassing the processor and writing the data directly to memory.
EPP–Enhanced Parallel Port EPP mode offers the same features as bi-directional and offers an extended control code set.
Exam Watch: Know the different types of parallel ports for the exam, as many people get stuck on these types of questions.

Com/Serial port

Memory address All serial ports require a memory address. The memory address is used to receive commands from the processor that are destined for the device attached to the COM port. Each device must have a unique memory address in order for it to function.
Interrupt request Every COM port must have a unique interrupt. It is through this interrupt that the peripheral attached to the COM port notifies the CPU that there is data available to be retrieved from the peripheral. An example is when the modem receives data. The modem will fire an interrupt on the COM port, which in turn triggers the CPU to pick up data from the modem.
The standard COM1 interrupt address is 4 and the memory address is 03F8. With COM2, the interrupt address is 3 and the memory address is 02F8. This has a tendency to seem counterintuitive, as COM1 would be listed before COM2.
Exam Watch: Remember the interrupt and memory addresses for both COM1 and COM2 for the A+ Certification Exam.
Enable/disable The enable/disable either enables or disables the COM port for use.
Size The size of the drive is automatically calculated from the number of cylinders, sectors, and heads on the drive. If you need to calculate the size of a drive, you would use the following formula:
(# of cylinders) * (# of sectors) * (# of heads) * 0.5 KB
The 0.5 KB constant is due to the fact that most hard drives have 512 bytes per sector.

Hard Drive

Size The size of the drive is automatically detected by the computer.
Primary master/secondary slave Each hard drive has a controller built into the drive itself that actually controls the drive. When you have more than one hard drive attached to an adapter card, the adapter could get confused as to which controller was in charge. In order to distinguish which controller is actually being used, one of the drives is designated as a master drive and its controller is used to control the other drives, which are called slaves. When you look at the CMOS configuration screen, you will note that you have to fill in the primary master section for the master drive, and the secondary slave section for the slave drive.
Tracks A hard drive is made up of several disks mounted on a spindle. Each disk can be broken down into rings of concentric circles, where each ring is called a track. The number of tracks that a hard drive has is usually printed on the outside case of the drive itself.
Sectors As you can break down a disk into tracks, you can further subdivide the disk into sectors. This is done by "slicing" the disk up as you would a pie. Each piece of that pie is called a sector. The number of sectors on a hard drive is usually printed on the outside case of the drive itself.
Cylinder When you combine the same tracks on each of the disks in a hard drive, you have what is known as a cylinder. The number of cylinders in a hard drive is also printed on the outside case of the drive itself.
Drive type With the older CMOS configuration utilities, you would have to manually input all of the preceding information plus the type–MFM, IDE, SCSI–drive it was. However, today’s version of the CMOS configuration utility can auto-detect the drive type and all of the preceding information. To do this, you simply set the drive to AUTO and it does the work for you. Although, you should know how to modify these settings yourself in the event that the CMOS does not recognize the drive you have.

Floppy Drive

Enable/disable drive When installing a floppy drive, you do have the option to disable it. To do this, you must set Drive A to None.
Density Drive types are usually defined by the capacity and size of the media. There are five standard types available. They are:
5.25" 360 KB
5.25" 1.2 MB
3.5" 720 KB
3.5" 1.44 MB
3.5" 2.88 MB
5.25" drives are a rarity in today’s computers as they are the original floppy drive technology, and purchasing a replacement drive is almost an impossibility. Most computers today utilize the 3.5" 1.44 MB drive even though the 3.5" 2.88 MB can hold twice the amount of data. There are several factors that have kept the 3.5" 2.88 MB drive from becoming commonplace, but you should familiarize yourself with them for environments that do utilize them.

Boot Sequence

When your computer boots, it has to look for the location of the files and settings that are needed during the boot process. The boot sequence tells the computer where to start looking for these files and in what order to search the various storage devices. For example, if you have the boot sequence set up for floppy drive, hard drive, and CD-ROM, the computer first goes to the floppy drive. If it can’t find what it needs on the floppy drive, it then proceeds to the hard drive, and so on.
While most people have this set up to search for a floppy drive first, you may want to set the machine to look to the hard drive first. Many customers have a tendency to leave their data disk in the drive when they turn their computers off. When they boot, the computer can’t find an operating system to load and it produces an error message. You can cut down on the number of calls by setting the boot sequence to check for the hard drive first, and the floppy drive second. However, the drawback to this is that if you do need to boot from a floppy, you will have to reconfigure this setting.

Memory

As mentioned earlier in the "RAM (Random Access Memory)" section of this chapter, memory is the workplace of the computer. When it comes to configuring memory in the CMOS, there is really nothing that you need to be concerned about because memory is automatically detected and configured. However, there are some cases when you may get a memory error after installing new memory that requires you to enter the CMOS. If this does happen to you, all you need to do is select the EXIT AND SAVE option from the menu and the computer will begin to reboot.

Network Interface Card

Unless you are using a motherboard that has an integrated network interface card (NIC), there is no CMOS setting for this component. If you do work with a computer with an integrated NIC, you must consult with the manufacturer’s documentation for the correct settings. Integrated NICs are not a common component found in computers.

Date/Time

The system date and time is stored in the CMOS. This ensures that the user does not have to reenter the date/time every time they boot their computer. This feature is not only utilized by the user, but is used by the operating system and by application software for certain routines that require timing components.

Passwords

Most customers do not implement the password feature of CMOS, as they have enough passwords and codes to remember as it is. However, if you work at any high-security sites, they may have the CMOS password feature enabled. To enable it, you will have to type in a password twice, once for the initial setting and a second time for verification. Then, whenever the computer boots, the CMOS will require that password to be entered in order for the computer to complete the boot sequence.

Certification Summary

In this chapter, you have learned about the various types of processors that have been used in the computer industry. These chips defined the types of memory and peripherals that could be used by the motherboard itself. We have also discussed the motherboard and its various components, such as memory, communications ports, and CMOS settings. Armed with this knowledge, you should have a good grasp of how these components work together.

Two-Minute Drill

The CPU’s job is to provide the devices attached to the computer with directives that retrieve, display, manipulate, and store information.
Today’s Intel Pentium II processors contain 7.5 million transistors and supports a 64-bit bus.
SIMM stands for Single In-Line Memory Module, which is a type of RAM chip.
The Intel 586 (Pentium) chip combined two 486DX chips into one, called the Dual Independent Bus Architecture. This allowed each processor inside the chip to execute instructions simultaneously and independently from each other, which is called parallel processing.
The PCI (Peripheral Component Interconnect) was designed in response to the Pentium class processor’s utilization of a 64-bit bus. PCI buses are designed to be processor-independent
Review Table 4-2, which provides an overview of the different varieties of processors along with their bus sizes.
As a service technician, you should familiarize yourself with each of the motherboard’s components and know what their function is.
There are three common denotations that are used to represent computer numbers: a kilobyte (KB) is 1,024 bytes, a megabyte (MB) denotes 1,048,576 bytes, and a gigabyte (GB)means 1,073,741,824 bytes!
DIMM stands for Dual In-Line Module, which is a type of RAM chip.
To ensure that the signals on memory chips are correct, they are constantly updated, a process called refresh.
WRAM, which was design specifically for the Microsoft Windows operating system, utilizes memory that resides on the card itself to perform the Windows-specific functions, and therefore speeds up the OS.
The number of transistors inside a chip is one of the determining factors in the rate at which a chip can process information.
A memory bank is the actual slot that memory goes into.
There are two basic types of motherboards: AT and ATX.
ISA (Industry Standard Architecture) is an industry standard bus architecture that allows for peripherals to utilize the 16-bit data bus that is available with 286 and 386 processors.
On the AT motherboard, the processor is normally located in the front of the board, which has been an annoyance to many technicians attempting to install a new expansion card.
The communication ports on the system board allow external devices to attach directly to the processor without having to remove the case.
While SRAM doesn’t need a constant update, it does require a periodic update and tends to use excessive amounts of power when it does so.
A serial port transmits data sequentially, bit by bit, over a single conductor and is most commonly used with modems and mice.
A parallel port transmits data over eight conductors at one time and is most commonly used with printers.
The processor socket is the actual socket used to attach the processor to the motherboard.
Cache memory is used to store frequently used instructions and data so that they can be accessed quickly by the computer.
EISA (Extended Industry Standard Architecture) is an industry standard bus architecture that allows for peripherals to utilize the 32-bit data bus that is available with 386 and 486 processors.
Originally created to address performance issues, the VL-Bus was meant to enable earlier bus designs to handle a maximum clock speed equivalent to that of processors.
The Personal Computer Memory Card International Association (PCMCIA), or the less hard to remember PC Card, bus was first created to expand the memory capabilities in small, hand-held computers.
Make sure that you know the differences between each type of bus and what each acronym stands for. While most of the acronyms seem intuitive, the exam will throw in a few that will seem to be just as plausible.
Know the different types of parallel ports for the exam, as many people get stuck on these types of questions.
The memory address is used to receive commands from the processor that are destined for the device attached to the COM port. Each device must have a unique memory address in order for it to function.
The standard COM1 interrupt address is 4 and the memory address is 03F8.
With COM2, the interrupt address is 3 and the memory address is 02F8.
Each hard drive has a controller built into the drive itself that actually controls the drive.
The number of tracks, sectors, and cylinders on a hard drive is usually printed on the outside case of the drive itself.
Integrated NICs are not a common component found in computers.