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INFORMATION

TECHNOLOGY

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code of course: BU01

Department of Computer Science

Faculty of Civil Engineering, Brno University of Technology

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Content of course

• Introduction - 4 lectures•how computers work•how PCs work•peripheral devices•computer networks•algorithm, program, data

• Operational systems - 2 lectures•classification and global properties•standard OS: file system, processes, policies•using Unix, Windows

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Content of course - cont.

• Text processing - typography•Principles of computer typography - 1 lecture•WYSIWYG text processing and DTP (MS Office)

- 6 practices•Markup languages (HTML) – 5 practices

• Computer graphics and image processing• Databases and spreadsheets

•Principles of data modeling and database systems

- 1 lecture•Calculations in spreadsheet environment

- 5 practices

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Basic Information

• http://www.fce.vutbr.cz

•student server http://study.fce.vutbr.cz )

• computer classrooms – in winter change one's shoes!

• Lectures: classroom B432, typically Tuesday 16:00

• Practices: B427, typically Monday 16:00

• Tests and credit:

•Simple calculation in MS Excel

•Knowledge testing of information technology

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How do the computers work Goal: unification of knowledge of technologies used in computer scienceApproach: great simplificationContent:

• CPU and operational memory - main parts of computer• instruction processing in computer• main computer architectures• CPU and memory communication• peripheral devices and their controllers• permanent and external memory• program and machine code

Department of Computer Science

Faculty of Civil Engineering, Brno University of Technology

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Main parts of computer

CPU

01001011

10000010

01001111

10101011

00001000

00000001

00000010

00000011

00000100

00000000

Address Content

RAM

Bi-directionalcommunication

Byte (59Hex = 89Dec)

0 1 0 1 1 0 0 1

7. 6. 5. 4. 3. 2. 1. 0.

5 9

Basic information structure

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Instruction cycle

CPU

01001011

10000010

01001111

10101011

00001000

00000001

00000010

00000011

00000100

00000000

Address Content

RAM

Phases of cycle• Instruction fetching• Instruction decoding• Instruction performing

Instruction table of CPU

Content What to do00000000 No operation00000001 Jump over next address00000010 ...

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Input-Output devices

CPU

RAM

controllerPeripheraldevice

• Each device has its own controller that transforms the other type of information into binary one

• Controller accesses to the partial part of RAM• Device types:

• Write only to the memory - input device (e.g. keyboard)• Read only from the memory - output device (e.g. monitor)• Read/write - input-output device (e.g. disk memory)

• Direct communication between CPU and controller - I/O ports

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Architecture according to Von Neumann

• Computer consists of processing unit, memory and I/O devices

• Computer structure is not depended on the solved problem

• Memory is divided into the same cells. Access to the cells is enabled through their addresses

• Cells of memory contain both instructions and data distinguishable only by context

• Program is composed of sequence of instructions executed step by step excluding jumps

• Addresses, instructions and data are represented in binary form

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Central processing unit

Controlling unit Arithmetic-logic

unit

Registers

RAM

CPU

Instructions Data

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Instructions

• transfer - moving data between registers of CPUand cells of RAM

• arithmetic - adding, subtracting, multiplying, … typically operate with data in registers

• logic - log. conjunction, disjunction, rotation, shift, … typically operate with data in registers

• jumps - condit. commands, calling subroutines, …

• input-output - moving data between registers of CPUand I/O ports of controllers of peripheral devices

• others - controlling, …

CISC (Complex Instruction Set Computer)

RISC (Reduced Instruction Set Computer)

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Memory

• Device for storing the information (binary encoded data and instructions)

• Capacity of memory (amount of storable information) is measured in bytes

• Memory is divided into the same cells - minimal addressable units

• Two types of memory:

• operational (internal) - main part of computer realized by integrated circuits. Depends on the source of el. energy.

• peripheral (external) - stores data permanently, information is not accessible directly by CPU. Cheaper, slow (disks, CD-ROM, floppy, ZIP, …)

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Memory hierarchy

Magn. tape, (optical disk)

Magn. disk

Operational memory

Caches

Registers

Cost

of

bit

in

crease

s Cap

aity

ince

rase

s

Acce

ss time in

crease

s

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Units for capacity of memory

Prefixes used for multiply coefficients slightly differ from the ones in SI standard:

1 KB = 210 B = 1 024 B,

1 MB = 220 B = 1 048 576 B = 1 024 KB,

1 GB = 230 B = 1 073 741 824 B,

1 TB = 240 B = 1 099 511 627 780 B.

64 KB = 65 536 B, 512 KB = 0,5 MB, …

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CPU - RAM communication

data

control

address

CPU RAM I/O control.

Inte

rnal bu

s

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Internal (system) bus

• Set of conductors with el. signals• Three parts of bus with signals of the same meaning

•Data part - transfer of data between CPU and RAM, 16, 32, 64 bits wide corresponding to the type of processor•Address part - transfer of addresses from CPU to RAM,

16-64 bits wide determines limit capacity of memory•Controlling part - controls the flow of information through the

bus• Asynchronous commun. (handshaking on contr. part):

•CPU: I have the address for you on the address part of bus•RAM: I have the data (content of address) for you on the data part of bus

• Synchronous communication (preferred):• Independent bus clock determines the phases above

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Generation of computers

Possible classification according to the used components

<109VLSI1981 4.

<1.000.000LSI1972 3½.

<100.000Integ. circuits1964 3.

<10.000Transistors1958 2.

<1.000Electron tube1950 1.

<10Relay1940 0.

Speed(Instr./s)

Basic componentYearGener.

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Bugs in computer software

Grace Murray Hopper, working in a temporary WorldWar I building at Harvard University on the Mark IIcomputer, found the first computer bug beaten todeath in the jaws of a relay. She glued it into thelogbook of the computer and thereafter when themachine stops (frequently) they tell Howard Aikenthat they are "debugging" the computer. The very firstbug still exists in the National Museum of AmericanHistory of the Smithsonian Institution. The word bugand the concept of debugging had been usedpreviously, perhaps by Edison, but this was probablythe first verification that the concept applied tocomputers.

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Bugs in computer software

„First actual case of bug being found.“ September 9th, 1945

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Beginning of computers

Electr. computerENIAC (1945)

• 17 648 elect. tubes• mass 30 t• supply 140 kW• cooled by two aircraft motors

• programmable through jumpers on the spec. desk panel• till 1946 top secret• Electronic Numerator, Integrator, Analyzer and Computer

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Program and subprogram

Procedural languages (Algol, Fortran, Pascal, C, C++, …)

Nonprocedural languages (Prolog, Lisp, query languages, …)

Interpreted languages(Basic, Java, Pearl, …)

Nativelanguage

Instructionsfor CPU

(machine code)

Programming language

compilerprogrammer

Realization of subprogram in machine code - stackAdvantages of using subprogram

•memory saving•well arranged programming•mechanisms of interrupt

Disadvantages•slightly slower

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• http://www.maxmon.com/history.htm

• http://www.cs.virginia.edu/brochure/museum.html

Literature