computer system PEOPLEWARE HARDWARE SOFTWARE PEOPLEWARE User Data

�������� (computer system( • PEOPLEWARE • HARDWARE • SOFTWARE

PEOPLEWARE • • User Data Entry Operator Computer Operator Programmer (Application Programmer, System Programmer) • System Analyst • Administrator (System, Network, Database) • EDP Manager

HARDWARE CPU Control Unit Arithmetic/logic Unit Input device Memory Output device

INPUT DEVICE ���� keyboard, mouse, disk drive, tape drive, microphone, joystick

OUTPUT DEVICE ����� , printer, disk drive, tape drive, plotter, speaker

address MEMORY 0 1 2 bit = binary digit byte = 8 bits 1 K = 210 bytes 1 M = 220 bytes 1 G = 230 bytes ���� s= 2 s -1 RAM (Random Access Memory) ROM (Read-Only Memory) ����� bit ����� address ���� s= 3 ���� address 0 -

SOFTWARE • System Software - System Management Programs: Operating Systems - System Development Programs: Compiler, Interpreter, Editor - System Support Programs: utility, performance monitor, security monitor • Application Software - General-purpose Programs: e. g. word processing, spreadsheet - Application-Specific Programs: e. g. airline reservation, banking

COMPUTER LANGUAGE • Low-level Language - Machine language - Assembly Language • High-level Language e. g. C, Pascal, FORTRAN

ASSEMBLER source program assembly language assembler object program machine language COMPILE TIME

COMPILER source program high-level language compiler object program machine language COMPILE TIME

RUN TIME input data machine language output

INTERPRETER source program input data interpreter COMPILE and RUN TIME output

������� C #include <stdio. h> main() { int i, j; scanf(“%d”, &i); j=2*i+5/10 -3; printf(“%d %dn”, i, j); }

�������� assembly. 386. data i dd ? j dd ? . code mov i, 10 mov ax, i add ax, 5 mov j, ax end

MACHINE LANGUAGE • DATA • INSTRUCTION

DATA REPRESENTATION • • CHARACTER INTEGER FLOATING POINT Binary Code Decimal (BCD(

INTEGER • UNSIGNED INTEGER • SIGNED INTEGER

n=1 binary decimal 0 0 1 1

n=2 binary 00 01 10 11 decimal 0 1 2 3

n=3 binary 000 001 010 011 100 101 110 111 decimal 0 1 2 3 4 5 6 7

SIGNED INTEGER • SIGNED MAGNITUDE • ONE COMPLEMENT • TWO COMPLEMENT

n=2 binary 00 01 10 11 decimal +0 +1 -0 -1

n=3 binary 000 001 010 011 100 101 110 111 decimal +0 +1 +2 +3 -0 -1 -2 -3

n=2 binary 00 01 10 11 decimal +0 +1 -1 -0

n=3 binary 000 001 010 011 100 101 110 111 decimal +0 +1 +2 +3 -3 -2 -1 -0

n=2 binary 00 01 10 11 decimal +0 +1 -2 -1

n=3 binary 000 001 010 011 100 101 110 111 decimal +0 +1 +2 +3 -4 -3 -2 -1

���� 10(0. 00173)������ 0. 000173 x 101 , 0. 001730 x 100, 0. 017300 x 10 -1, ���� 0. 173000 x 10 -2 ��������� normalized 10(103. 5)�������

IEEE standard

IEEE standard

IEEE standard

����� biased exponent mantissa all 0 nonzero all 1 all 0 all 1 nonzero special meaning floating point zero denormalized infinity Na. N (Not a Number)

���� decimal 10. 0 ���� binary ��� IEEE standard, short real ������ 0000 0100 0001 1000 0000

Binary Code Decimal (BCD( • Packed BCD • Unpacked BCD

BCD ��� binary 4 ��� decimal ������� BCD 0000 0001 0010 0011 0100 0101 0110 0111 1000 decimal 0 1 2 3 4 5 6 7 8

Unpacked BCD �������� ��� 0000 �������� BCD ���� decimal 1234 ������ Unpacked BCD ������ 0000 0001 0000 0010 0000 0011 0000 0100

���� data representation data character integer floating point BCD ASCII unsigned packed EBCDIC signed unpacked signed magnitude UNICODE one complement two complement

���� if (A = = B) then A=A+1; else B=B-1 ����������� CMPA, B JEQ L 1 SUB B, 1 JMP L 3 L 1: ADD A, 1 L 3:

���� SUM=0; FOR I=1 TO 100 DO SUM=SUM+I; ������������ MOV SUM, 0 MOV I, 1 L 1: CMP I, 100 JGT L 2 ADD SUM, I ADD I, 1 JMP L 1 L 2: