Computer Confluence 7/e Chapter 2 Performance 2.The architecture and word size of the processor  Architecture : the design that determines how the individual components of the CPU are put together on the chip.  Newer chips can manipulate more bits simultaneously than older chips can.  more efficient  more faster.  The number of bits a CPU can process at one time is called the CPU ’ s word size  High-end workstations and servers use 64-bit processors  Most PCs and Macintoshes use 32-bit processors  Some embedded and special-purpose computers still use 8- and 16-bit processors

Computer Confluence 7/e Chapter 2 Performance (continued) Techniques for speeding up a computer ’ s ability to manipulate and move bits:  Parallel processing (symmetric multiprocessing or multiprocessing ): using multiple processors to divide jobs into pieces and work simultaneously on the pieces.  Many PC have specialized subsidiary processors. Ex : math, graphic display.  Used in servers, workstations. © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 2 Performance (continued Techniques for speeding up a computer ’ s ability to manipulate and move bits:  server clusters : a grouping of servers to improve rendering speed in computer graphics and increase reliability.

How the CPU works

1- In most cases the actual execution of an instruction is performed by the CPU’s arithmetic logic unit (ALU). The ALU includes registers, each usually 32 or 64 bits in size. 2- Program instructions are stored in primary storage (memory), which is usually on chips outside the CPU. The CPU’s first task is to read an instruction from memory. The bus unit handles all communication between the CPU and primary storage.

How the CPU works 3- The prefetch unit, or prefetcher, instructs the bus unit to read the instruction stored at a particular memory address. This unit not only fetches the next instruction to execute, but it also fetches several subsequent instructions to ensure that an instruction is always ready to be executed. 4-The decode unit takes the instruction read by the prefetcher and translates it into a form suitable for the CPU’s internal processing. It does this by looking up the steps required to complete an instruction in the control unit.

How the CPU works 5 - If an instruction requires that information be sent out from the CPU—for example, written into memory—then the final phase of execution is writeback, in which the bus unit writes the results of the instruction back into memory or some other device. 6 - Microprocessor manufacturers use many techniques to eliminate bottlenecks and speed up processing. For example, in the same way it prefetches the next likely instructions to be read, the CPU prereads the next likely data to be used into a cache in memory (called a Level 2 cache (L2 cache) or, for faster access, in the CPU itself (a Level 1 cache).

Computer Confluence 7/e Chapter 2 The Computer ’ s Memory RAM (random access memory)  Used to store program instructions and data temporarily  Divided into locations with unique addresses.  data can be stored in any RAM location  Can quickly retrieve information  Will not remain if power goes off (volatile) © 2006 Prentice-Hall, Inc.

memory

Computer Confluence 7/e Chapter 2 The Computer ’ s Memory (continued) ROM (read-only memory)  Information is stored permanently on a chip (nonvolatile)  Contains startup instructions and other permanent data CMOS (complementary metal oxide semiconductor)  Special low-energy kind of RAM  Store small amounts of data for long periods of time on battery power. (date, time, calendar in a PC) Flash memory  Can be written and erased rapidly and repeatedly and it is nonvolatile.  Used for phones, pagers, portable computers, handheld computers, PDAs © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 2 The Computer ’ s Memory (continued) Memory access time is another factor that affects the computer ’ s overall speed and is measured in nanoseconds (ns). Memory access time: the amount of time it takes for a CPU to retrieve a unit of data from memory.

Memory 1 - When you turn on the computer, the CPU automatically begins executing instructions stored in read-only memory (ROM). On most computer systems, ROM also contains parts of the operating system. The firmware programs in ROM are sometimes called the BIOS (basic input/output system). 2 - The executing instructions help the system start up and tell it how to load the operating system—copy it from disk into memory. 3 - Once executing instructions for O.S. are loaded into memory, the CPU is able to execute them.

Memory 1 2 3

Computer Confluence 7/e Chapter 2 Buses, Ports, and Peripherals Information travels between components on the motherboard through groups of wires called system buses, or just buses © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 2 Buses, Ports, and Peripherals (continued) Buses  Typically have 32 or 64 wires or data paths.  Connect to storage devices in bays- open areas in the system box for disk drives and other devices.  Connect to expansion slots- you can insert expansion cards into these slots.  Connect to external buses and ports- sockets on the outside of computer chassis. © 2006 Prentice-Hall, Inc.

Standard Computer Ports mouse keyboard USB serial Parallel

Expansion slots an expansion board being inserted into an expansion slot

Computer Confluence 7/e Chapter 2 Buses, Ports, and Peripherals (continued) PC Card : Used on laptops, Devices are the size of a credit card contain memory, peripheral, addition ports. Slots and ports Make it easy to add external devices, called peripherals to the computer system so the CPU can communicate with the outside world and store information.

Computer Confluence 7/e Chapter 2 Inventing the Future New laser etching technology called extreme ultraviolet lithography (EUVL) could reduce chip size and increase performance radically Superconductors that transmit electricity without heat could increase computer speed a hundredfold The optical computer transmits information in light waves rather than electrical pulses © 2006 Prentice-Hall, Inc. The only thing that has consistently grown faster than hardware in the last 40 years is human expectation. —Bjarne Stroustrup, AT&T Bell Labs, designer of the C++ programming language

Computer Confluence 7/e Chapter 2 Lesson Summary A computer manipulates patterns of bits — binary digits of information The CPU follows software instructions, reduced to strings of bits, to perform the calculations and logical manipulations that transform input data into output Not all CPUs are compatible with each other © 2006 Prentice-Hall, Inc. The great Information Age is really an explosion of non-information; it is an explosion of data. To deal with the increasing onslaught of data, it is imperative to distinguish between the two; information is that which leads to understanding. —Richard Saul Wurman, in Information Anxiety

Computer Confluence 7/e Chapter 2 Lesson Summary (continued) The CPU uses:  RAM (random access memory) as a temporary storage area — a scratch pad — for instructions and data  ROM (read-only memory), which contains unchangeable information that serves as reference material for the CPU as it executes program instructions The CPU and main memory are housed in silicon chips on the motherboard © 2006 Prentice-Hall, Inc.