Hardware. The physical parts of a computer system

Hardware

Hardware

The physical parts of a computer system

HardwareThe physical parts of a computer system

Computers based on:

1. Vacuum tube based - c1940s2. Transistor based - late 50s; low cost and reliable

transistors available3. Integrated Circuit (IC) based - mid 60s4. Large Scale Integrated (LSI) circuit based - c80s; These

have up to 100,000 transistors on a single chip5. Very Large Scale Integrated (VLSI) circuit based - c90s;

These have >100,000 transistors on a single chip.

Hardware

Types of Computers

Small (Microcomputers or Personal computers) $500 - $7,000

Desktop Computers and Workstations

Laptop Computers Notebook Computers Palmtop Computers

Personal Digital Assistant

• Known as handheld computers

• PDAs are portable computers taken further

• Pocket sized designed for use on the move

• Use a pen as input (write directly to screen)

• Software 'attempts' to translate handwriting by reference to stored prototypes

Types of Computers (contd.) Medium-sized computers (minicomputers)

- $50,000 - $200,000 - 3 - 25 times faster than a PC

- Scaled down mainframe

- Designed to meet the computing needs of a department or small company. Typically 4-100 concurrent users.

- Can support a number of concurrent applications and often uses a time-sharing operation system that aims to keep the users busy.

Types of Computers (contd.)

Large or Mainframe Computers - $100,000 - $2,000,000 - 10 - 100 times faster than a PC

- A multi-user computer designed to meet the computing needs of a large organization

- Generally refers to computers of the 50s and 60s

- Large number of dumb terminals were used for input/output and it had a large number of peripherals attached

- Can process a number of applications concurrently. This is known as multi-processing which aims to keep the CPU as busy as possible

- Usually housed in special rooms.

Types of Computers (contd.)

Superlarge or Supercomputers

-$2 million - $20 million -50 - 50,000 times faster than a PC

- A large number of processors interconnected by a network.

- Break up gigantic scientific problems into manageable parallel tasks

- Used to simulate nuclear explosions, ocean flow, to track the

trajectories of astronomic bodies.

Computer Operations

Input – entering data into the computer; Processing – performing operations on the

data; Output – presenting results; Storage – saving data, programs, or output for

future use; Communications – sending or retrieving data

via the Internet, etc.

Hardware Devices

Data

• Data consists of raw unprocessed facts.• The applications and users handle them to turn into

Information.• Information is structured, ordered and analyzed data

useful for decision making. Data is stored in files of different types (documents, spreadsheets, databases, pictures,…)

Data Representation

Digital data - is a discrete representation, breaking the information up into separate elements (digits, that is 0 and 1)

Bit

Bit is the smallest unit of data, which denotes the binary value of 1 or 0, On/Off, Magnetic/Not

Byte is the ordered collection of bits

(eight bits grouped together) - EBCDIC - Extended Binary Coded Decimal Interchange

Code (8 bits per byte)

- ASCII - American Standard Code for Information Exchange (7 or 8 bits per byte)

Parity bit is the extra bit added to each byte to help detect errors

Example: "HI" = 0100100001001001

(using binary code)

How Information Is Stored

The Computing Systems Store, Present, and Help Us Modify:

Text Audio Images & graphics Video

System Unit

Houses the processing hardware for computer

Contains:

- CPU

- Memory (several types)

- Interfaces to connect external peripheral devices ( such as printer, etc.)

INPUT DEVICES

SECONDARY STORAGE

PRIMARY STORAGE

Computer Components

CPU

OUTPUT DEVICES

COMMUNICATIONS DEVICES

BUSES

Motherboard• The main circuit board, containing computer

chips and other electronic components, inside the system unit to which all computer system components connect

CPU – Central Processing Unit

• The chip located on the motherboard of a computer that performs the processing for a computer

Multi-core CPUs

• Contain the processing components or cores of multiple independent processors on a single CPU (allow computers to work simultaneously on more tha one task at a time)

Types of CPU

• Desktop c. – Intel Core i7

- AMD PhenomII (2-4 cores)

• Workstation, server

– Intel Xeon

- AMD Opteron (2,4,6 cores)

• Notebook, Tablet PC

- Intel Core 2

- AMD Turion X2 (1, 2,4 cores)

Computer Time

Millisecond .001 second thousand 15min 40 sec

Microsecond .001 millisecond million 11.6 days

Nanosecond .001microsecond billion 31.7 years

Picosecond .001 nanosecond trillion 31,700 years

*

NAME LENGTH SECOND TO 1 SECONDNAME LENGTH SECOND TO 1 SECOND

# PER COMPARED# PER COMPARED

Computer Frequency inversely proportional to computer time

Processing Speed

• CPU clock speed – measurement of the processing speed, which is rated in megahertz (MHz) or gigahertz (GHz)

• Highter CPU clock speed more instractions can be processed per second

• Example: Core i7 3.2 Ghz

faster than

Core i7 2.66 GHz

Memory

• Chip-based storage

- primary - amount of the computer's main memory (random access memory or RAM)

- secondary - amount of long-term storage available to a computer (computer's hard drive or removable storage media)

Types of Memory

• Cache memory and register – volatite, means that their content is rased when power to the memory ceases (like RAM)

• Read-only memory (ROM) and flash memory - nonvolatite

MEMORY SIZE

• KILOBYTE (K): 210 bytes... 1024 bytes• MEGABYTE (MB): 210 KB... “million” bytes• GIGABYTE (GB): 210 MB... “billion” bytes• TERABYTE (TB): 210 GB... “trillion” bytes

*

RAM (Random Access Memory)

• Temporary storage for data, programs and the operating system while you are using the PC

• It is volatile, meaning that the contents of memory are lost forever when the computer is shut off.

RAM (contd.)

• Capacity measured in bytes

• Type of RAM that can be installed depends on

- CPU (32-bit CPU – up to 3 GB of RAM,

64-bit – more than 3 GB)

- Operating system (64-bit version of Windows Vista – up to 8 GB, up to 16 or more than 128 GB, depending on the edition)

ROM (Read-Only Memory)

• Consists of non-erasable hardware modules that store program instructions

• It is non-volatile (that is „read only“)

Ports and Connectors

• Connectors located on the exterior of the system unit that are used to connect external hardware devicrs

• Each port attached to the appropriate bus on the motherboard

Storage System

• Storage medium is the hardware where data is actually stored (CD, flash memory card)

• Storage device is the type of drive by which storage media is read

- internal (inside the CPU)

- external (plugged into external port)

- remote (located on another computer)

Access Methods

• Random (direct) access, means that data can be retrieved directly from any location on the storage medium, in any order

• Sequential access, means that the data can be retrieved in the order in which it is physically stored on the medium

Hard Drive

• Primary storage system used to store most programs and data used with a computer

Types of Hard Drives

- Magnetic hard drive – a hard drive, consisting of one or more metal magnetic disks permanently sealed with an access mechanism and read/write heads, inside its drive

• Solid-state drive (SSD) – a hard drive that uses flash memory instead of metal magnetic hard disks.

Types of Hard Drives

Disc Access Time

• The total time that it takes for a hard drive to read/write data

• Include three steps:

- seek time

- rotational delay

- data movement time

• Typically it is around 8.5.milliseconds

Optical Disks

• A type of storage medium read from and written to using a laser beam (Example: CD, DVD)

• Advantages: - large capacity

- durability

• Disadvantages: - fragile

Optical Drive

• A drive used with optical discs (CD disc, DVD disc)

Optical Discs

• Read-Only optical disc (CD-ROM, DVD-ROM, BD-ROM)

• Recordable optical disc (CD-R, DVD-R, DVD+R, BD-R)

• Rewritable optical disc (CD-RW, DVD-RW, DVD+RW, BD-Re)

Optical Disks (contd.)1) CD-ROM - 700 MB (0.7 GB), single layer, red laser,

cheap, outdated. For delivering music, software, storing data.

2) DVD+-R/RW (Digital Vesatile Disk), 4.7 GB (DVD-5) (single-layer), 8.5 GB (DVD-9) (dual-layer), 9.4 GB (double-sided disk), red laser, current, cheap. For software, movies, data.

3) Blu-Ray, 25 GB (single layer), 50 GB (double-layer), may support up to 6-8 layers in the future, blue laser, quite expensive. For high-definition movies, HDTV, data.

4) HVD (Holographic Vesatile Disk) - 3.9 TB, 2 lasers, very expensive, emerging.

Other Types of Storage System

• Flash memory – a chip-based storage medium that store data using electrons

• Flash memory card – a small , rectangular flash memory medium (such as CompactFlash)

• Holographic storage – the type of three dimension (3D) storage system that uses multiple blue laser beams to store data in three dimensions

• Advantages: - speed

- capability

- convenient for rarely changed data

Other Types of Storage System (contd.)

• Magnetic tape – storage media consisting of plastic tape with a magnetizable surface that store data as a series of magnetic spot

• Advantages: - low cost per megabyte

Other Types of Storage System (contd.)

• RAID (redundant arrays of independent disks)

a storage method that uses several hard rives working together

• Purpose: - to increase perfomance

- to protect critical data on storage server (to increase fault tolerance)

• Techniques: - disc stripping

- disc mirroring

Other Types of Storage System (contd.)

RAID

• RAID

Bus

• Electronic path over which data can travel

• Bus width is the number of wires in the bus over which data can travel, affects the number of bits being transmitted at one time

• Throughput or bandwidth is the amount of data that can be transferred via the bus in a given time period

Input Devices

Keyboards

• An input device containing numerous keys that can be used to input letters, numbers, and other symbols

Pointing and Touch Devices

• An input device that moves an on-screen pointer to allow the user to select objects on the screen

• Types: - mouse

- pen/styluses

- touch screens

Scanners• An input device that reads printed text and

graphics and transfers them to a computer in digital form

Speech Recognition System

• Speech recognition systems

• Music input systems

Music Input System

• Used to input music into a computer

Output Devices

Printers

• Quality mesured by dots per inch (dpi)

Speed measured in pages per minute (ppm)

• Types: - laser printers (use toner powder)

- ink-jet printers (use liquid ink)

- special purposes printers (photoprinter, 3D printer)

3D Printing

Display Devices (Monitor, Display Screen)

• CRT monitors

• Flat-panel displays: - liquid crystal displays (LCD)

- plasma displays

• Organic light emmiting diode (OLED) displays

Display Devices (contd.)

• Pixels – the smallest colorable area in an electronic image

• Screen resolution affects the amount of information (in pixels) displayed on the screen

Video Card

• Installed inside computer or directly into the motherboard (in graphic processing unit GPU)

• Detrmins the graphic capabilities of the computer

Audio Output