Information Technology - Introduction to Computersseas3.elte.hu/itcourse-2009/computer_intro.pdf ·...

Introduction History General architecture Main types The PC: hardware The PC: software Summary

Information TechnologyIntroduction to Computers

László Kálmán1 Csaba Oravecz1 Péter Szigetvári2

1Research Institute for LinguisticsHungarian Academy of Sciences

2Department of English LinguisticsEötvös Loránd University

Lecture 1. / 9 Sep, 2009

Oravecz, Szigetvári Introduction to Computers


Outline1 Introduction2 Short history3 General architecture

The stored program architecture (von Neumann)4 Main types

Mainframes, mini- and microcomputers5 The PC: hardware

MotherboardThe CPUStorageMemoryMass storage devicesInput devicesOutput devicesExpansion slotsPorts and protocolsNotebooks

6 The PC: softwareThe BIOSThe operating systemThe boot process



Trust The Computer. The Computer is your friend.

A computer lets you make more mistakes faster than anyother invention, with the possible exceptions of handguns

and Tequilla.Mitch Ratcliffe



The usual useless definitions

A computer is

• an electronic device for the storage and processing ofinformation.

• a machine for manipulating data according to a list ofinstructions known as a program.

• a machine for performing operations on numeric orsymbolic data.



The beginnings

• computer: a person who performed numerical calculations



The beginnings


• ancestors: abacus, Antikythera mechanism



The beginnings



• 1801: Jacquard loom with punch cards



The beginnings

Figure: Jacquard loom with punch cards.



The beginnings






The beginnings




• late 19th c.: large-scale automated data processing withP(unch) C(ard)s



The beginnings





• first half of 20th c.: sophisticated special-purpose analogcomputers



The beginnings





• first half of 20th c.: sophisticated special-purpose analogcomputers

• direct mechanical or electrical model of the problem as abasis for computation



The middle

• 1940s: several “first digital electronic computers”



The middle


• ENIAC (1946): first based on the von Neumannarchitecture



The middle

Figure: ENIAC.



The middle





The middle



• 1950s: valve (tube) driven computers



The middle




• 1960s: transistor-based computers



The middle





• 1970s–: integrated circuit technology → low enough cost→ personal computers



The middle





• 1970s–: integrated circuit technology → low enough cost→ personal computers

• today’s computers are exponentially more capable thanpreceding ones (c.f. Moore’s Law)



The end

Figure: A Sentinel.



Stored program architecture

• four main sections:




• four main sections:1 arithmetic and logic unit (ALU)




• four main sections:1 arithmetic and logic unit (ALU)2 control system




• four main sections:1 arithmetic and logic unit (ALU)2 control system3 memory




• four main sections:1 arithmetic and logic unit (ALU)2 control system3 memory4 I/O devices




• four main sections:1 arithmetic and logic unit (ALU)2 control system3 memory4 I/O devices

• connected by bundles of wires (buses) and driven by atimer or clock



Task of components

• ALU: heart and/or brain of computer, performs basicoperations



Task of components


• memory: stores information; data or instructions



Task of components



• I/O system: communicates with the outside world



Task of components



• I/O system: communicates with the outside world• control system:

• reads instructions and data from memory or I/O• provides the ALU with the correct inputs acc. to the

instructions• tells the ALU what operation to perform on inputs• sends the results back to the memory or to I/O



Task of components



• I/O system: communicates with the outside world• control system:

• reads instructions and data from memory or I/O• provides the ALU with the correct inputs acc. to the

instructions• tells the ALU what operation to perform on inputs• sends the results back to the memory or to I/O

1980s–: ALU + control unit = CPU (central processing unit)



How the computer works

Operation

On each clock cycle, the computer fetches instructions anddata from its memory. The instructions are executed, theresults are stored, and the next instruction is fetched. Thisprocedure repeats until a halt instruction is encountered.



How the computer works

Operation

On each clock cycle, the computer fetches instructions anddata from its memory. The instructions are executed, theresults are stored, and the next instruction is fetched. Thisprocedure repeats until a halt instruction is encountered.

Four main functions• processing

• storage

• input

• output



Representing information: binary notation

• computer data (and instructions) are coded, manipulatedand stored by use of an exclusive two-state condition





• in the computer this means that "there is electricity passingthrough the circuit" or "there is no electricity passingthrough the circuit"






• represented in binary notation by the use of 1s and 0s







• copy : 10110000







• copy : 10110000

• machine language: instruction set that a specific computersupports



Units

Bit

A binary digit. 0/1



Units

Bit

A binary digit. 0/1

Byte

8 bits. 01010101. The standard unit of measurement ofcomputer data.



Units

SI prefix Binary prefix

Name Popularvalue

SI value Name Value

kilobyte (kB) 210 103 kibibyte (KiB) 210

megabyte (MB) 220 106 mebibyte (MiB) 220

gigabyte (GB) 230 109 gibibyte (GiB) 230

terabyte (TB) 240 1012 tebibyte (TiB) 240

petabyte (PB) 250 1015 pebibyte (PiB) 250

exabyte (EB) 260 1018 exbibyte (EiB) 260

zettabyte (ZB) 270 1021 zebibyte (ZiB) 270

yottabyte (YB) 280 1024 yobibyte (YiB) 280

Table: Quantities



From Mainframes to the PC

Mainframes (Big Iron)

• RAS: reliability, availability,serviceability

Personal computer (PC)

Minis (workstations)






• thousands of users









• multiple virtual machines











• for personal use











• user friendly software












• standardized, userupgradeable














• originally in between the above two














• multi-user, multitasking














• multi-user, multitasking

• today mostly taken over by PCs (c.f. midrange servers)




Figure: IBM Z890 mainframe




Figure: IBM Z890 mainframe Figure: IBM PC




Figure: IBM Z890 mainframe Figure: IBM PC

Figure: IBM iSeries server



The PC

There is no reason to suppose the average boy or girlcannot be master of a personal computer.

John W. Mauchly – 1962



The PC

Figure: An exploded view of a PC



The PC


1 display (monitor)



The PC


1 display (monitor)2 motherboard



The PC


1 display (monitor)2 motherboard3 CPU (microprocessor)



The PC


1 display (monitor)2 motherboard3 CPU (microprocessor)4 RAM (Random Acces

Memory)



The PC



Memory)5 expansion cards



The PC



Memory)5 expansion cards6 power supply



The PC



Memory)5 expansion cards6 power supply7 optical disk drive



The PC



Memory)5 expansion cards6 power supply7 optical disk drive8 hard disk



The PC



Memory)5 expansion cards6 power supply7 optical disk drive8 hard disk9 keyboard



The PC



Memory)5 expansion cards6 power supply7 optical disk drive8 hard disk9 keyboard

10 mouse



The motherboard



The motherboard

Houses all basic hardware devices. Provides attachment points for theCPU, memory, storage and I/O devices (peripherals), expansion cards.



The motherboard

Houses all basic hardware devices. Provides attachment points for theCPU, memory, storage and I/O devices (peripherals), expansion cards.

Standardised but still has many forms acc. to CPU sockets andphysical form (size and power supply).



The CPU – from 30MHz to 4–. . . GHz




FunctionInterprets instructions and processes datacontained in computer programs,executing a sequence of basic steps on aclock signal.





Architecture

The design and implementation of a CPU can vary to a large extentdepending on use. Today’s PCs predominantly use the x86 (Intel/AMD)architecture.





Architecture

The design and implementation of a CPU can vary to a large extentdepending on use. Today’s PCs predominantly use the x86 (Intel/AMD)architecture. (From 2005 the Macintosh is no longer an exception.)



Information: how fast do we need it?

Figure: Storage types w.r.t. CPU"distance"

Storage

• primary: short terminformation with quick access





Storage


• secondary: long-term storageof persistent information; usingI/O channels → slower





Storage



• off-line: storage medium canbe easily removed from thestorage device (approachesspeed of sec. storage devices)





Storage



• off-line: storage medium canbe easily removed from thestorage device (approachesspeed of sec. storage devices)

• all long-term devices havesome standard structure tostore data in accessible format(file system → next week)



Primary storage: RAM – from 64 kB to 2–. . . GB

Figure: RAMs galore

Random Access Memory

• holds the program code anddata during computation




Figure: RAMs galore



• all memory locations can beaccessed at almost the samespeed




Figure: RAMs galore




• much faster than mass storagedevices (hard disk) but cannotretain data without power(volatile); more expensive




Figure: RAMs galore




• much faster than mass storagedevices (hard disk) but cannotretain data without power(volatile); more expensive

• memory wall: current memoryspeed lags behind CPUspeed. . .



Storage without power – HD/SSD

Figure: Old IBM HD

Figure: New laptop HD

Hard disk




Figure: Old IBM HD


Hard disk• non-volatile storage device• stores data on the magnetic surfaces of hard disk

platters• Capacity (SI prefixed): ≤ 1.5TB (average PC: ≥

100GB)• Access/Interface type (connected to motherboard with

appropriate cable): IDE/ATA/SATA; SCSI• Speed: rotation (10000 rpm); data transfer (125 MB/s)• Size: 3.5" (PC) or 2.5" (laptop)




Figure: Old IBM HD


Hard disk• non-volatile storage device• stores data on the magnetic surfaces of hard disk

platters• Capacity (SI prefixed): ≤ 1.5TB (average PC: ≥

100GB)• Access/Interface type (connected to motherboard with

appropriate cable): IDE/ATA/SATA; SCSI• Speed: rotation (10000 rpm); data transfer (125 MB/s)• Size: 3.5" (PC) or 2.5" (laptop)

Solid-state drive (SSD)

• with no moving parts, uses solid-state memory to storepersistent data

• fast access of data (r/w speed up to 250MB/s)• completely silent, low power consumption• (less and less) expensive, have already appeared in

laptops



Off-line storage – CD/DVD

Figure: CD-RW drive

Compact Disc Read-Only Memory




Figure: CD-RW drive


• non-volatile storage device, R, RW,




Figure: CD-RW drive


• non-volatile storage device, R, RW,• stores data as a series of microscopic

indentations (pits and lands, read bya laser beam)




Figure: CD-RW drive




• up to 700MB; transfer speed up to ≈7MB/s




Figure: CD-RW drive

Figure: DVD








Figure: CD-RW drive

Figure: DVD





Digital Video Disc

• like the CD but different format,higher density




Figure: CD-RW drive

Figure: DVD





Digital Video Disc


• capacity: single layer 4.7 GB, dual 8.5GB




Figure: CD-RW drive

Figure: DVD





Digital Video Disc


• capacity: single layer 4.7 GB, dual 8.5GB

• to be continued on week ≈12



Peripherals – Keyboard

Figure: PC keyboard

Computer keyboard




Figure: PC keyboard

Computer keyboard

• device to control the operation of acomputer through pressing keys




Figure: PC keyboard

Computer keyboard


• keys produce text (characters),actions or modify other keys (modifierkey)




Figure: PC keyboard

Figure: US 104 key QWERTYlayout

Computer keyboard



Standards• several types from 83 to 130 keys




Figure: PC keyboard


Computer keyboard



Standards• several types from 83 to 130 keys• most common: PC keyboard with

QWERTY arrangement




Figure: PC keyboard


Computer keyboard



Standards• several types from 83 to 130 keys• most common: PC keyboard with

QWERTY arrangement• connection to motherboard: PS/2,

USB



Peripherals – Mouse

Figure: The first mouse (1970)

Operation





Operation

• its motion typically translates into themotion of a pointer on a display





Figure: Wireless mice withscroll wheel

Operation


Types

• movement detection: mechanical("ball mouse")/optical/laser






Operation


Types


• limbs: 1–3 buttons, scroll wheel(s)






Operation


Types


• limbs: 1–3 buttons, scroll wheel(s)• connection: serial, PS/2, USB

(wireless)



Peripherals – Display

Today’s dominant type: Liquid Crystal Display





• display signals as images on a screen




Figure: DEC VT100 (1978)


• display signals as images on a screen• Cathode Ray Tube monitors – outdated





Figure: Dual 30" Apple Cinemadisplay


• display signals as images on a screen• Cathode Ray Tube monitors – outdated• resolution: number of pixels

(160x200–1024x768–3840x2400)• size: diagonal in inches• refresh rate: number of times/sec that a

display is illuminated (in LCDs it is fixed tousually 60 or 75Hz)










• response time: minimum time necessary tochange a pixel’s color or brightness











• native resolution: single fixed resolution forthe LCD; using other value → loss ofimage quality.











• native resolution: single fixed resolution forthe LCD; using other value → loss ofimage quality.

• different standard w.r.t. resolution(([WS]?VGA)|(W?[QUS]XGA))



Peripherals – Printer

Figure: Laser printer for home

Types





Types

• local(ly connected): directly attachedto the PC; USB or parallel





Types


• network printer: available through thenetwork





Types



Technology





Types



Technology

• dot-matrix printer: slow, poor quality, cheap, outdated





Types



Technology

• dot-matrix printer: slow, poor quality, cheap, outdated• inkjet printer: slow, medium quality. BEWARE: printer is low price

but ink cartridge is very expensive.





Types



Technology

• dot-matrix printer: slow, poor quality, cheap, outdated• inkjet printer: slow, medium quality. BEWARE: printer is low price

but ink cartridge is very expensive.• laser printer: high quality prints, good print speed, low per-copy

cost. Printer is (was?) very expensive.



Expansion slots

Figure: Installing a PCI card

Function and standards



Expansion slots


Function and standards• allow peripheral devices and cards to be

inserted and attached to the PC



Expansion slots



inserted and attached to the PC• PCI (Peripheral Component

Interconnect): most common (white)• AGP (Accelerated Graphics Port):

high-speed channel for attaching agraphics card (brown)



Expansion slots


Figure: AGP graphics card





• PCI Express (PCI[eE]): new high speedreplacement for the above two



Expansion slots








Common expansion cards

• graphics card



Expansion slots









• graphics card• network (ethernet) card (more on week 6)



Expansion slots









• graphics card• network (ethernet) card (more on week 6)• sound, tv tuner, wifi card (week 6/12)



Ports and protocols

Protocol

Communication standard (the common language) between hardwaredevices.



Ports and protocols

Protocol


Ports (hardware)

Physical interface between hardware devices. (Here: PC and peripherals.)



Ports and protocols

Protocol


Ports (hardware)

Physical interface between hardware devices. (Here: PC and peripherals.)

Figure: Serial (mouse) Figure: SVGA (display) Figure: DVI (display)



Ports and protocols

Figure: PS/2

IBM Personal System/2



Ports and protocols

Figure: PS/2


• keyboard (purple), mouse (green)



Ports and protocols

Figure: PS/2


• keyboard (purple), mouse (green)• not designed to be hot swappable: not to be

(dis)connected while power is on



Ports and protocols

Figure: PS/2

Figure: USB




Universal Serial Bus



Ports and protocols

Figure: PS/2

Figure: USB




Universal Serial Bus• allows peripherals to be connected without the

need to plug expansion cards



Ports and protocols

Figure: PS/2

Figure: USB





need to plug expansion cards• allows devices to be hot-swapped



Ports and protocols

Figure: PS/2

Figure: USB





need to plug expansion cards• allows devices to be hot-swapped• becoming the (only) standard connection

method for almost all peripheral devices



Ports and protocols

Figure: PS/2

Figure: USB






method for almost all peripheral devices• Standards: 1.[01] (slow, outdated); 2.0:

high-speed; 3.0: superspeed (from 2010)



Ports and protocols

Figure: PS/2

Figure: USB






method for almost all peripheral devices• Standards: 1.[01] (slow, outdated); 2.0:

high-speed; 3.0: superspeed (from 2010)• USB flash drive (128MB–16GB)



Laptops – small mobile computers

Desktop replacement

Subnotebook




Figure: MacBook Pro notebook

Desktop replacement

• full capabilities of a desktop computerwhile remaining portable

• large, bulky, heavy or very expensive ifgood quality

Subnotebook




Figure: MacBook Pro notebook

Figure: The ASUS Eee PCsubnotebook

Desktop replacement

• full capabilities of a desktop computerwhile remaining portable

• large, bulky, heavy or very expensive ifgood quality

Subnotebook• small, light, with a screen of 6.4 to 13.3

inches• some reduced capability (weaker

graphics/CPU performance, ports omitted,removable media; c.f. docking station)

• new wave: low cost ultra-small devices




Properties to be concerned with




Figure: Thinkpad intimacy

Properties to be concerned with

• all peripherals squeezed into oneplace (keyboard, display, touchpad→ ergonomy problems (c.f. RSI)

• battery performance/life (3–9 cells,2440–7800mAh, 1–6 hours)

• durability problems• less powerful for the same price as

desktop PCs



Basic Input/Output System

Figure: Bios

Function and properties




Figure: Bios


• software code run by acomputer when first poweredon




Figure: Bios



• initializes the machine so thatthe operating system (OS) canload




Figure: Bios




• coded in some non-volatilememory chip




Figure: Bios




• coded in some non-volatilememory chip

• user customizable (for basichardware settings) but there issome read-only default forsafety



Computers are like air conditioners. Both stop working, ifyou open windows.

Adam Heath

The less you know about computers the more you wantMicrosoft!

Microsoft ad campaign, ≈1996



The Operating System

Services




Services• OS is the software which takes over the operation of the

computer from BIOS





computer from BIOS

• controls all input and output to and from the peripherals aswell as the operation of other programs





computer from BIOS


• allows the user to work with and manage files withoutknowing how the data is stored and retrieved





computer from BIOS



• manage user access to the processor and peripherals andschedule jobs (processes/programs)





computer from BIOS



• manage user access to the processor and peripherals andschedule jobs (processes/programs)

• in the broad sense it contains many applications (systemsoftware) in the narrow sense it refers only to the




Figure: Kernel in the computer

• kernel: central part of an OS,manages the system’sresources and thecommunication betweenhardware and software






Common OSs for the PC or Macintosh






Common OSs for the PC or Macintosh• Windows eXPerience/Vista: dominant OS for the PC (Mac?)






Common OSs for the PC or Macintosh• Windows eXPerience/Vista: dominant OS for the PC (Mac?)• Mac OS X: OS for the Mac






Common OSs for the PC or Macintosh• Windows eXPerience/Vista: dominant OS for the PC (Mac?)• Mac OS X: OS for the Mac• Linux: open source OS for PC and Mac






Common OSs for the PC or Macintosh• Windows eXPerience/Vista: dominant OS for the PC (Mac?)• Mac OS X: OS for the Mac• Linux: open source OS for PC and Mac• by default they are not compatible with each other



Important concepts I.



Important concepts I.

Live CD (DVD)

Contains a bootable computer operating system and can runon a computer without mutable secondary storage, such as ahard disk drive. The content of the disk is static, i.e. cannot bemodified.

Live USB flash drive

Similar to live CDs, but modifiable: you can automatically andtransparently write changes back to the bootable drive.



The boot process

PC startup



The boot process

PC startup

1 power on →

BIOS: checksand initializesboot devices



The boot process

PC startup

1 power on →


• keyboard• display• initial program load device: a (bootable) storage

device that contains the boot loader



The boot process

PC startup

1 power on →



device that contains the boot loader• boot interface is user selectable in BIOS (floppy,

HD, CD, USB drive, network)



The boot process

PC startup

1 power on →




HD, CD, USB drive, network)• bootable devices have a special area where the

primary boot loader resides: boot sector (in HD→ Master Boot Record/MBR)



The boot process

PC startup

1 power on →


2 BIOS loads andexecutes the bootloader







The boot process

PC startup

1 power on →







• small program residing in the boot sector



The boot process

PC startup

1 power on →



3 boot loader loadsthe kernel








The boot process

PC startup

1 power on →




4 kernel loadsdevice drivers,starts programsto make PC readyfor user input








The boot process

PC startup

1 power on →









• small program residing in the boot sector• several OSs can coexist in a PC, selectable in

the boot loader



The boot process

PC startup

1 power on →









• small program residing in the boot sector• several OSs can coexist in a PC, selectable in

the boot loader• "reverse" process: shutdown 6= switch off!!!



Summary

After this talk we know . . .• the basic building blocks of a personal computer and their

functions



Summary


functions

• the four main operations of a computer system(processing, storage, input, output)



Summary


functions


• what kind of software runs first after the computer ispowered on



Summary


functions



• the role of this software i.e. how the PC starts up



Summary


functions



• the role of this software i.e. how the PC starts up

• the basic functions of the operating system



Future

Next time (and after) we will explore . . .

• the Matrix . . .



Future


• the Matrix . . . the virtual world of the computer



Future


• the Matrix . . . the virtual world of the computer

• how we can solve a lump of useful tasks (very) efficientlywith the help of the computer



Useful information

Course websitehttp://seas3.elte.hu/itcourse


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