Chapter 1-1 Computers and Software in Networks.pptx

What Is a Computer?
● A computer is an
electronic device that
accepts information and
instructions from a user,
manipulates the
information according to
the instructions, displays
the information in some
way, and stores the
information for retrieval
later

Types of Computers
● Personal computers (PCs)
● Desktop computers
● Notebook (laptop) computers
● Tablet PCs
● Handheld computers
● PDA (personal digital assistant)
● MP3 players
● Mainframe computers
● Supercomputers

● Includes computer hardware and software
● Hardware refers to the physical components of a
computer
● Software refers to the intangible components of a
computer system, particularly the programs, or
lists of instructions, the computer needs to perform
a specific task
● The design and construction of the hardware of a
particular computer is referred to as its architecture
or configuration
● The technical details about each component are
called specifications.
Computer Systems

Processing Hardware
● The motherboard is the
main electronic
component of the
computer
● Circuit board
● The microprocessor is
one of the most
important pieces of
processing hardware on
the motherboard
● Cards are removable
circuit boards

Input and Output
● The data or instructions you type into the
computer are called input.
● The result of the computer processing
your input is referred to as output.
● Peripheral devices accomplish input and
output functions.

Input Devices
● You use an input device, such as a keyboard or a mouse, to input
data and issue commands
● Keyboard
● Ergonomic
● Pointing device
● Controls the pointer
● Mouse
● Scroll wheel
● Trackball
● Touch pad
● Pointing stick
● Scanner

Output Devices
● Output devices
show you the results
of processing data
● Monitor
● Flat panel
● LCD
● CRT
● Printer
● Laser
● Inkjet
● Dot matrix

Primary Storage
● Primary storage is a category of computer storage,
often called main memory.
● Has three functions:
● Stores all or part of the program that is being executed.
● Stores the operating system programs that manage the
operation of the computer.
● Holds data that the program is using.
● Data and program are placed in primary storage
before processing, between processing steps and
after processing has ended prior to being returned to
secondary storage or released as output.

Memory
● How is memory measured?
● By number of bytes available for storage
Term Abbreviation Approximate Size
Kilobyte KB or K 1
thousand bytes
Megabyte MB 1 million
bytes
Gigabyte GB 1 billion
bytes

● Modern primary storage devices include:
● Random access memory (RAM)
● is used for short-term storage of data or program
instructions. RAM is volatile. Its contents will be lost
when the computer’s electric supply is disrupted by a
power outage or when the computer turned off.
● Read-only memory (ROM)
● can only be read from. It cannot be written to. ROM
chips come from the manufacturer with programs
already burned in, or stored. ROM is used in general-
purpose computers to store important or frequently
used programs, such as computing routine for
calculating the square roots of numbers.

Memory
● What is random access memory (RAM)?
The more RAM a
computer has, the
faster it responds
Also called
main memory
or primary
storage
Most RAM is
volatile, it is lost
when computer’s
power is
turned off
Memory chips that can be
read from and written
to by processor

Dongles
RJ45 BNC
LC
Coaxial
Fiber optic
Wired netcard
Network Interface Cards -
Types

How the NIC transfers data
● The app you are using generates the data
you would like to send to another computer.
● Your NIC accepts the data from your
motherboard and transfers it to a small
buffer on the card.
● The NIC adds its address (set by the
manufacturer) plus the destination address
and the type of data to the buffer.
● Your NIC calculates the checksum, or CRC,
for the data in the buffer.

How the NIC transfers data
● The information is arranged into a frame.
● The NIC “listens” to the network for other
transmissions. If a transmission is heard, it will wait
until the transmission is complete.
● The NIC begins to serially transmit the frame over
the network.
● The receiving NIC calculates the checksum for the
received frame, then compares it to the checksum it
received.
● If there are no errors, the receiving station
acknowledges the received data.

Translated into 5 steps
● The network application retrieves the data
being sent.
● The NIC puts the address of the other
computer onto the data.
● The NIC calculates for errors.
● The data is arranged into a packet and sent
over the network.
● The receiving card checks for errors, if there
are none, it acknowledges the data.

System Software
● System software
manages the
fundamental
operations of your
computer
● Operating system
● System resource
● Multitasking
● Utilities
● Programming
Languages

Application Software
● Application software enables you to
perform specific computer tasks, such as
document production, spreadsheet
calculations, and database management
● Document production software

● Web site creation and management software
● Spreadsheet software
● Database management software

● Presentation software

● Photo editing software
● Multimedia authoring software
● Accounting software
● Information management software

What is an Operating System (1)?
● A modern computer consists of:
● One or more processors
● Main memory
● Disks
● Printers
● Various input/output devices.
● Managing all these varied components
requires a layer of software – the
Operating System (OS).

What is an Operating System (2)?
● An Operating System is a program that acts
as an intermediary/interface between a user
of a computer and the computer hardware.
● OS goals:
● Control/execute user/application programs.
● Make the computer system convenient to use.
● Ease the solving of user problems.
● Use the computer hardware in an efficient
manner.

What is an operating system (OS)?
Operating System Software
Software which manages the overall operation of the computer system
including:
● hardware (CPU, RAM, I/O)
● security
● system interface
● application interface

What is an operating system (OS)?

Services provided by an OS
● Facilities for program creation
● editors, compilers, linkers, debuggers, etc.
● Program execution
● loading in memory, I/O and file initialization.
● Access to I/O and files
● deals with the specifics of I/O and file formats.
● System access
● resolves conflicts for resource contention.
● protection in access to resources and data.

Why are Operating Systems Important?
● Important to understand and know how to correctly use
when writing user applications.
● Large and complex systems that have a high economic
impact and result in interesting problems of management.
● Few actually involved in OS design and implementation
but nevertheless many general techniques to be learned
and applied.
● Combines concepts from many other areas of Computer
Science: Architecture, Languages,
Data Structures, Algorithms.

Chapter 1-1 Computers and Software in Networks.pptx

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