Hardware
Hardware
The physical parts of a
computer system
Hardware
The physical parts of a computer system
Hardware
Computers based on:
1.
2.
3.
4.
5.
Vacuum tube based - c1940s
Transistor based - late 50s; low cost and reliable
transistors available
Integrated Circuit (IC) based - mid 60s
Large Scale Integrated (LSI) circuit based - c80s; These
have up to 100,000 transistors on a single chip
Very Large Scale Integrated (VLSI) circuit based - c90s;
These have >100,000 transistors on a single chip.
Types of Computers
Small (Microcomputers or Personal computers)
$500 - $7,000
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Desktop Computers and Workstations
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Laptop Computers
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Notebook Computers
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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.)
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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
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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
How Information Is Stored
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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)
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The Computing Systems
Store, Present, and Help Us Modify:

Text
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Audio
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Images & graphics
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Video
System Unit
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Houses the processing hardware for computer
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Contains:
- CPU
- Memory (several types)
- Interfaces to connect external peripheral
devices ( such as printer, etc.)
Computer Components
CPU
INPUT
DEVICES
SECONDARY
STORAGE
BUSES
OUTPUT
DEVICES
COMMUNICATIONS
DEVICES
PRIMARY
STORAGE
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
# PER
COMPARED
LENGTH
SECOND
TO 1 SECOND
.001 second
thousand
15min 40 sec
Microsecond .001 millisecond
million
11.6 days
Nanosecond .001microsecond
billion
31.7 years
Picosecond
trillion
31,700 years
NAME
Millisecond
.001 nanosecond
*
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
Types of Hard Drives
• Solid-state drive (SSD) – a hard drive that uses
flash memory instead of metal magnetic hard
disks.
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)
Other Types of Storage System
(contd.)
• 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
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