PC Fundamentals
The Inel Family
Objectives:
To introduce the components of a modern desktop PC and examine the advances in processor technology identify the components of a modern desktop PC
outline the role of the central processing unit (CPU) and printed circuit cards
identify the built-in connectors and input/output (I/O) slots on a typical motherboard
describe the function of the power supply unit
list the members of Intel's processor family
distinguish between the Pentium, Pentium II, Celeron, Pentium III, and Pentium 4 processors
identify the other CPU manufacturers in the PC market
Lesson:
In order to understand recent developments in processor technology, it's useful to be familiar with PC history.
PC history really began when Intel introduced the 8086 CPU chip in 1979.
Intel followed this with the hugely successful 8088 CPU chip in 1980.
The original IBM PC that dominated the computer market was built around the Intel 8088 chip.
Over the next 20 years, Intel went on to develop a collection of chips related to the original 8088.
They named this collection of Intel processors the x86 family.
The reason Intel refers to a "family" of processors is because they reflect a common approach to CPU manufacture.
Although the basic architecture has evolved over time, Intel processors share a common inheritance.
For example, the way in which an Intel processor addresses system memory is still fundamentally unchanged.
Similarly, the basic set of instructions understood by all Intel processors remains the same - although later models accept a much greater range of instructions.
Backward compatibility is another reason for the continuity of Intel's product over the years.
With such a huge share of the processor market worldwide, Intel had to ensure that all new microprocessor designs were acceptable to their existing customer base.
Intel continued to develop and improve their original 16-bit 8086 CPU.
Subsequent members of the Intel processor family began to appear on the market,
including:• 80186
• 80286
• 80386
Building on the common features of these products, the Intel marketing team decided to call the whole family of chips its x86 family.
They also dropped the "80" from the naming system - so that the "80386" became the "386".
And they encouraged customers to look for the "Intel Inside" logo on their system units.
The 386 model marked a significant increase in performance over its predecessors.
It worked faster and possessed a larger set of CPU instructions than any of its previous family members.
Perhaps the greatest advance in CPU technology associated with the 386 was the innovation in memory access.
The 286 CPU could access just over 16MB of RAM.
The 386, however, pushed the memory access level up to 4GB (4,096MB).
The 386 also introduced a new memory mechanism called "paging".
Paging is used to implement virtual memory - this allows your computer's hard drive to function as an extension of the random access memory (RAM).
The result of these improvements was to encourage a whole new generation of software products that required at least a 386 CPU to run.
This is why the 386 is still considered the greatest innovation in CPU technology to date.
Intel followed the 386 with a 486 CPU in 1989.
The 486 included some advances in integrated circuit manufacturing, bringing all the math processing power onto the motherboard.
Previously, such functionality was restricted to a secondary floating-point coprocessor chip.
The 486 also introduced a small amount of level-one (L1) cache memory.
This is a RAM component that stores information briefly on its way to or from the CPU.
The L1 cache is contained within the CPU chip itself.
L1 cache data is available with minimal delay and it allows the processor to run at full speed.
The L1 cache was introduced because the CPU must deliver its data at a very high speed, and regular RAM can not maintain that speed.
Therefore, a special RAM type called a cache is used as a buffer or temporary storage area.
To get top performance from the CPU, the number of outgoing transactions must be minimized.
The more data transmissions that can be contained inside the CPU, the better the performance.
This is why the 486 was equipped with the following features:
• mathematicalcoprocessor
• floating point unit
• 8KB L1 cache RAM
Due to a copyright dispute over the names of the 386 and 486 processors, Intel decided to call the next member of its x86 family a Pentium.
Intel introduced the Pentium processor in 1993.
One of the most significant features of the Pentium processor was its ability to support 64 I/O pins.
This allowed the Pentium processor to move information on and off the chip in 8-byte segments.
The Pentium processor also doubled the amount of L1 cache memory available on the processor to 16KB.
This 16KB capacity is divided into two 8KB caches - one cache is reserved for data and the other for instructions.
The dual L1 cache system served its purpose by storing important system information in a readily accessible location.
This effectively reduces the number of times the main memory is accessed and increases processor performance.
Each time you access the main memory location, the CPU must wait until that information has been retrieved.
Reducing the number of access hits to the Pentium processor has significant system performance benefits.
The Pentium processor is designed to process and distribute data through the system in 32-bit chunks.
But the most significant enhancement of the Pentium processor is its ability to run faster than any earlier members of the x86 family.
This speed increase is largely due to a faster clock frequency that executes more instructions per second.
The Pentium is also able to process two instructions simultaneously - this is known as a "super-scalar" performance increase.
Rather than simply making the Pentium faster than its predecessors, major performance improvements can be attributed to the doubling up of execution units.
After the Pentium, Intel introduced the Pentium Pro as the next member of the x86 family.
The Pentium Pro is a pure RISC processor.
RISC stands for Reduced Instruction Set Computer.
In a RISC-based design, the complexity of the processor instruction set is only minimally greater than the instructions used by the computer's functional parts.
It has been optimized for Windows NT, UNIX, and other genuine 32-bit environments.
The Pentium Pro incorporates two integrated circuit chips.
It has all the functionality of the Pentium, including a 16KB L1 cache, in the first chip.
It also contains a level-two (L2) cache in the second chip.
The L2 cache is an addition to the standard cache that comes built into the Pentium chip.
It adds 256KB more RAM to the system and increases its speed.
The L2 cache chip is connected to the CPU itself, so it runs synchronously with the CPU speed.
In line with consumer demand, Intel decided to extend the Pentium instruction set.
They developed a class of processor instructions called multimedia extensions (MMX).
MMX technology consists of 57 integer instructions and a collection of datatypes that expands the capabilities of the CPU.
These instructions are designed for improved execution of multimedia programs.
With MMX, a developer can send multiple data items in a single 64-bit package.
Any operation specified by the MMX instructions can then be performed on the data package.
The Pentium MMX has performance advantages over the original Pentium processor.
Its L1 cache has been doubled in size to 32KB, thereby increasing the speed of certain
programs.MMX is primarily used by people who develop or use games and video presentations.
It's particularly effective for multimedia applications that incorporate full-motion video, enhanced sound, and elaborate graphics.
But it's also useful in more standard desktop applications.
The Pentium II uses a SEC cartridge that fits into a slot on the motherboard known as Slot 1.
It was designed for high-performance desktops, workstations, and servers.
The table shown here, lists the features of various processors.
Intel released the Pentium III processor in 1999.
The Pentium III is based on the Pentium Pro and Pentium II processor architectures.
The Pentium III is designed for high-performance desktop PCs, workstations, and
servers.It is ideally suited to 32-bit applications running on the following operating systems:
• Windows 2000
• Windows NT
• UNIX
The Pentium III processor provides desktop PC users with dual processing (DP) capability commonly used in server and high-end workstation environments.
The DP support is “glueless” because no additional circuitry is required on the motherboard to support the two processors.
The system bus supports multiple outstanding transactions by increasing the available
bandwidth.This enables low-cost, two-way symmetric multiprocessing (SMP).
SMP significantly boosts performance for multitasking operating systems and multithreaded applications.
Pentium III makes use of the full functionality of MMX technology.
It utilizes a fast video connector, called the Accelerated Graphics Port (AGP).
AGP enhances multimedia application performance by providing a dedicated bus between the graphics adapter and system memory.
The Pentium III processor contains two separate cache levels - a 32KB L1 cache, and a 512KB L2 cache.
The 32KB L1 cache incorporates two separate 16KB caches.
One 16KB cache is reserved for instructions and the other 16KB cache is reserved for data.
The Pentium III processor is available with two different second level (L2) cache implementations.
In the "discrete" cache version, the L2 cache is composed of an external (to processor silicon) TagRAM and burst pipelined synchronous static RAM(BSRAM).
The Advanced Transfer Cache version has the L2 cache entirely within the processor silicon.
Pentium III processors are offered on Single Edge Contact Cartridge (S.E.C.C.), Single Edge Contact Cartridge 2 (S.E.C.C. 2), and the PGA370 socket.
The SEC cartridge contains a printed circuit board unit - both the CPU and L2 cache chips are mounted on it.
It looks like a large rectangular plastic box, which sits on the motherboard.
The SEC cartridge is encapsulated, so that it looks like a single chip.
It plugs into a separate socket, called slot 1 (SC242 or 242-contact slot connector), on the motherboard.
With the Pentium III processor for the SC242 connector, there is Pentium III processor for the PGA370 socket.