Chapter 2 Technology

Computer categories Mainframes Minicomputers Microcomputers Traditional categories: small, mid-range and large mainframes and super computers Application categories: host-computers, database servers, transaction systems and central systems Traditional categories: minicomputers, mid-rang systems Application categories : departmental systems, network servers, technical workstations, workgroup systems Traditional categories : portable, desktop and minitower-computers Application categories : personal computers, multi-user systems, netwerk-servers technical, office and professional workstations O’Brien 48

Trends in Computer Characteristics Size Room Closet Desk Dessktop Credit card? Generation Fist Second Third Fourth Fifth Reliability Hours Days weeks Months Years? Instuct/sec Hundreds Thousands Milions Tens of millions Billions? Circuitry Vacuum Tubes Transistors IC’s LSI’s VLSI Memory Thousands 10s Thousands 100s Thousands Millions Billions? Price/M instr $ 10 $ 1.0 $ 0.1 $ $ ? O’Brien p 50

Categories l Microcomputers or personal computers l Midrange computers or minicomputers l Mainframe computers l Supercomputers l Computer Networks ê client/server systems ê network computers O’Brien 51-54

Client/Server Host system super server Client Server types Functionality O’Brien p 55

Multimedia Computersystemen O’Brien p 56

Multimedia l Technologies : Languages HTML, JAVA ê Hypertex ê Hypermedia l Elements ê CDI compact disk interactive ê Compressed audio ê Computer edit systems ê Digital audio ê DVI digital video interactive ê MIDI musical instrument digital interface ê Sound card ê Video capture card O’Brien p 57-58

Design of a computer system Central processing unit CPU Input device inputs data and instructions into the CPU Keyboard mouse touch screen optical scanner light pen speech input barcode.... Control Unit Translates instructions and manages processing Arithmetic/Logical unit (ALU) Executes arithmetic operations and compares Internal storage unit Stores data and instructions during execution Output device video screen printer loudspeaker video... External storage Stores data and programs for the applications O’Brien 60

Peripheral Devices l terminals ê video, hand terminals, intelligent terminals, transaction-terminals (POS),... l Pointing devices ê pictogram, mouse, trackball, joystick, touch-sensitive, light pen, graphical tablet l Terminal input/output ê LCD, plasma, video-output, impact printers, laser printer, inktjet printer l Speech input/output l Optical and magnetic recognition (OCR, MICR) l Storage: tape, magnetic disk, optical disk (ROM, WORM) O’Brien

The “Von Neumann” Computer INTERFACEINTERFACE INTERFACEINTERFACE Data memory Arithmetic unit Control unit Program memory Programmer Interface DATADATA RESULTSRESULTS

Computer Architecture Input and Output Converters translate the external representation into an internal representation or the other way around. eg: keyboards, video screens, printers, barcode readers, magnetic cards, sensors,... Data memory Temporary storage of data. intermediate results ( eg. program variables ). input/output buffers

Computer Architecture 2 Program memory Contains the instructions that go via the program interface to the CPU and that will be executed one by one. Central memory A set of numbered cells that can contain a binary number. Terminology:. word. address Program variables represent an address

Central Memory address contents In most computers, data memory and program memory are only logically separated

Storage Semiconductor memory Magnetic disks Magnetic tape Optical disk Access speed increases Storage capacity decreases Cost/byte increases RAM ROM Primary Secondary Tekst: O’Brien p 74

Computer Architecture 3 Arithmetic and Logical Unit This unit is responsible for the processing of the data read from, and rewritten into the data memory. The unit can compare the contents of memory cells and execute basic operations. The Control Unit This unit reads the instructions one by one from the program memory, decodes them and sends the appropriate signals to the other components.

Peripheral Memory. Uses no electrical energy. Usually stored in blocks of hundreds of words, which are moved as one block into the central memory. Magnetic material in permanent movement - disk memory < 1/10 sec : allows " random access " - Magnetic tapes : sequential memory. Optical material - CD-ROM : to distribute large amounts of data - WORM : archiving

Usage of Memory Registers central memory Mass storage ( disk - tape ) Price per bit Access Time Registers: Very fast memory ( < 100 ns ) in arithmetic and control unit Central memory: ( between 50 and 500 ns ) These types of memory use integrated circuits and use electrical energy. The content is lost with a power supply interruption.

Units Memory capacity l Kilobyte: one thousand bytes l Megabyte: one million bytes l Gigabyte: one billion bytes l Terabyte: one trillion bytes Time l Millisecond: one thousandth of a second l Microsecond: one millionth of a second l Nanosecond: one billionth of a second l Picosecond: one trillionth of a second O’Brien 61

Memory Access Time price access time s I.C. Disk CD-ROM Tape

Coding Data Numerical Data - integer : binary numbers = b = 21 d - real numbers mantissa and exponential part

ASCII computer codes : 058 3A ; 059 3B A B C D E F G H I J 074 4A K 075 4B L 076 4C char dec hex oct binary O’Brien 61

Complex Configuration LAN/WAN Remote Data Base

Hardware Schema Microcomputer System bus... other system management and equipment Central Microprocessor Supporting Microprocessor RAMROM Keyboard Interface Display Interface CD-ROM Interface Serial Interface Diskdrive Interface Parallel Interface Keyboard Video screen CD-ROM Modem Diskette station Printer... Internal memory

Instructions Information processing instructions opc.op.1op.2resnext opc.op.1op.2 next1next2 Control instructions opc. = operation code op.1 = address in memory of the first operand op.2 = address in memory of the second operand next = address in the program memory of the next instruction next1 = address of the next instruction if a condition is true next2 = address of the next instruction if a condition is false

Program Example Data memory Arithmetic unit Control unit Program memory Programmer Interface Computer controlled door

Computer Controlled Door STO EQ? MUL ADD NE? STO 0 KFL D2 D1 D KDA D1 P2 D2 P3 P3 P4 D2 P5 D2 P6 D1 P7 P3 P8 P1 P9 DDA P1 KFL key flag KDA key data DDA door data D1 number of digits read D2 value read

Usage of P-register P - register or ordinal counter Control Unit +1 P-registerI-register Program Memory op c. op. 1 op. 2 res op c. op. 1 op. 2 nex t Control instructions Information processing instructions

Door program with P-register STO EQ? MUL ADD NE? STO JMP 0 KFL D2 D1 D KDA D1 D2 P3 D2 D1 P3 P1 DDA P1

Client server Clients comm. server comm. server DB. server DB. server DB. server O.A. server