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Computer ???
Adhi Harmoko S, M.Komp
What is a computer?A computer is a machine that stores data (numbers, words, pictures), interacts with devices (the monitor screen, the sound system, the printer), and executes programs.A computer program is a sequence of instructions and decisions that the computer carries out to achieve a task.Programs describe specific actions.A computer executes very simple instructions.A computer executes instructions very rapidly.A computer is a general purpose machine
What is a computer?A computer must be programmed to perform tasks. Different tasks require different programs.A computer program consists of a finite sequence of very basic operations.A typical operation may be one of the following:
put a red dot onto a certain screen positionsend the letter B to the printerget a number from a certain location in memoryadd up two numbersif this value is negative, stop the programrepeat this instruction ten times
What is a computer?Hardware
Physical devices of computer systemSoftware
Programs that run on computers
"Buses" allow components to pass data to each other
Hardware Components of a Typical Computer
PeripheralDevices
Central ProcessingUnit (CPU)
Memory
Hardware Components of a Typical Computer -- CPU
Central Processing Unit (CPU)performs the basic operationsconsists of two parts:
Arithmetic / Logic Unit (ALU) - data manipulationControl Unit - coordinate machine’s activities
MemoryPeripheralDevices
Central ProcessingUnit (CPU)
PeripheralDevices
Central ProcessingUnit (CPU)
Memory
Hardware Components of a Typical Computer -- Memory
Main Memoryholds programs and datastores bits in fixed-sized chunks: “word” (8, 16, 32, or 64 bits)each word is stored in a cell, which has a unique addressthe cells can be accessed in any order =>random-access memory or “RAM”
Hardware Components of a Typical Computer -- Memory
A bit: 0 or 1A word: chunk of bits (8, 16, 32 or 64 bits)
a byte = 8 bitsa kilobyte = 210 bytes = 1024 bytes a megabyte = 1024 KB = 220 bytes = 1,048,576 bytesa gigabyte = 1024 MB = 230 bytesa terabyte = 1024 GB = 240 bytes
PeripheralDevices
Central ProcessingUnit (CPU)
Memory
Hardware Components of a Typical Computer -- Peripherals
Peripheral devices –communicate with the outside worldstore data long term
PeripheralDevices
Central ProcessingUnit (CPU)
Memory
Input/Output (I/O)Input: keyboard, mouse, microphone, scanner, sensors (camera, infra-red), punch-cardsOutput: video, printer, audio speakers, etc
Communicationmodem, ethernet card
Hardware Components of a Typical Computer –Peripheral Devices that Communicate with the Outside World
Hardware Components of a Typical Computer –Peripheral Devices that Store Data Long Term
Secondary (mass) storageStores information for long periods of time as filesExamples: hard drive, floppy disk, tape, CD-ROM (Compact Disk Read-Only Memory)
Features of Computers – SpeedCPU Speed
One cycle Example Clock
CPU clock speed: in cycles per second ("hertz")Example: 700MHz Pentium III, 3.2GHz P4
but different CPU designs do different amounts of work in one clock cycle (e.g. P4 vs G5)“flops” (floating-point operations per second)“mips” (million instructions per second)
communication between CPU, memory and peripheral devices depends on main board (a.k.a. "motherboard") design
Examples: Intel 3.60GHz Pentium-4 works on a 200MHz bus speed50MHz, 60MHz, 66MHz, 100Mhz, 133MHz, 200MHz, 266MHz, and risingQuad-pumped multiplies by 4
Features of Computers – SpeedSystem-Clock/Bus Speed
Features of Computers – SpeedMemory-Access Speed
RAMabout 50ns (1 nanosecond = a billionth of a second), and getting fastermay be rated with respect to “bus speed’’ (e.g., PC-100, PC-133, etc)
Cache memoryfaster than main memory (less than 20ns access speed), but more expensivecontains data which the CPU is likely to use next
Features of Computers – Speed Peripheral-Device Speed
Mass storageExamples:
3.5in 1.4MB floppy disk: about 500kb/sec at 300 rpm (revolutions per minute)3.5in hard disk: average seek time about 8.5 microseconds, and 7,200 rpm
CommunicationsExamples: modems at 56 kilobits per second, and network cards at 10 or 100 megabits per second
I/OExamples: ISA, PCI, IDE, SCSI, ATA, USB, etc....
Most system failures are due to software flaws rather than hardware
Features of Computers -- ReliabilityFactors that affect reliability:
heat, ventilation, “over-clocking”, power surges
10110001
Modes of communicationParallel communication:
all the bits are transferred at the same time each bit on a separate line
Serial communication: one bit at a time
Modems (MOdulator-DEModulator)
Remote Computer
ModemHome
Computer
ModemDigitalData
DigitalData
Audio signalphone lines
TypesLocal Area Networks (LAN)
Computers in an organizationExample: the PCs in the lab
Long Haul Networks Separated by hundreds or thousands of milesPhysical wires, telephone lines, satellites, etc
Example: Internet “backbone”
Computer Networks
Computer Networks – Method of Communication
Each computer has an addressExample: IP address of www.fisika.ui.ac.id is 152.118.167.2
A sender computer transmits data through the network in packets; each packet is tagged with the destination and return address
When data is too big to fit in one packet, the sender computer can split the data into several packets, labeled in sequence
Computer Networks – Method of Communication (cont)
The packets are sent via links from computer to computer (“routing”) Each intermediate computer receives and retransmits the message (“hops”)
The packets do not necessarily arrive in the order in which they were sent
The recipient computer puts the packets in correct sequence and retrieves the data
Computer and SupportJaringan Komputer LAN / WLAN
Computer and SupportSistem Input Data
Computer and SupportSistem Pemroses Data
Computer and SupportSistem Output Data
Computer and SupportSistem Penyimpan Data
Computer and SupportFiber Optic Communication
Technology Information Todaywireless communication
What is programming?A computer program tells a computer, in very detail, the sequence of steps that are needed to fulfill a task.The act of designing and implementing these programs is called computer programming.Programmers develop computer programs to make computers perform new tasks.A professional computer scientist or software engineer does a great deal of programming.The activity of programming is an important part of science
What is Algorithm?
AlgorithmAlgorithm: A set of instructions describing how to do a task (or process)
eureka!
ProgramProgram: : C++C++
Programming LanguagesMachine language
“Natural language” of computer componentMachine dependent
Assembly languageEnglish-like abbreviations represent computer operationsAssembler converts it to machine language
High-level languageAllows for writing more “English-like” instructions
Contains commonly used mathematical operationsCompiler converts it to machine language
InterpreterExecute high-level language programs without compilation
Computer and SupportSoftware: Operating System
Computer and SupportSoftware: Aplikasi
Computer and SupportSoftware: Development
Computer ProductMultimedia
Computer Productsms, w@p, gprs communication
Computer ProductSistem Control berbasis Web