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Unit 1
Introduction to the Computer:
Hardware and Software
Unit Goals
1. To appreciate the distinction between micro, mini, and
mainframe computers and to understand our emphasis on the
micro-computer;
2. To gain a lay understanding of selected hardware components
(e.g. cpu, ram, modem, etc);
3. To gain a lay understanding of ways information is stored on
a microcomputer; 4. To become skilled in the use of a window; and
5. To appreciate the importance of organization, backup, and virus
protection.
Many of us have learned about computers and learned to use them
in a very haphazard manner. We pick up tips and shortcuts from
friends and co-workers, learning what we need to know to accomplish
the task at hand. While this approach can keep you functioning,
there are often frustrating moments (or days) when the system isnt
working, or you find yourself with strange results or formatting
that seems out of control.
My goal for this introductory unit is to fill in a few of the
gaps you may have on computer terminology, the function of various
components, and understanding of how information is stored on
micro-computers. This information may help you diagnose a problem
when something does go wrong or at least make it easier for you to
talk with the technician you call for assistance. Shared
terminology can work wonders in communicating your concerns and
understanding the techie.
As a data manager, you may also be responsible for ordering new
computer equipment and you should know what you need so that your
software works efficiently and you have the correct features for
internet access and for ensuring data security and integrity.
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Outline
Section Topic Page
1.
Micro versus Mini versus Mainframe Computers ..
1.3
2.
Hardware Components . 2.1 The CPU . 2.2 The Display (Monitor)
2.3 Printers and Scanners 2.4 Bits How the Computer Stores
Information 2.5 ASCII, Unicode and Hexadecimal Codes 2.6 Computer
Storage Terminology .. 2.7 ROM, RAM, and Read/Write Storage.. 2.8
The Hard Drive 2.9 CDs, Diskettes, and Zip Disks . 2.10 Modem and
Ethernet . 2.11 Ports and Cables 2.12 Care of Computers, Storage
Devices, and
Printers..
1.4 1.5 1.5 1.7 1.9 1.9
1.13 1.13 1.15 1.16 1.18 1.18
1.19
3.
Software .. 3.1 Disk Operating System .. 3.2 Windows 3.3 The
Mouse 3.4 The Anatomy of a Window . 3.5 Managing Files in Windows
.. 3.6 Some General Tips for Working on a PC.
1.20 1.20 1.20 1.21 1.24 1.26 1.29
4.
The Internet and the World Wide Web (WWW) 4.1 Browser Windows
4.2 Uploading and Downloading Files
1.32 1.33 1.34
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1. Micro versus Mini versus Mainframe Computers
In this course we will focus on the use of PC or IBM-compatible
microcomputers.
The three types of computers micro-, mini- and mainframe differ
basically in size and speed. As computers get larger, they usually
get faster and better able to handle large files and programs. The
distinction between micro- mini- and mainframe computers has
blurred over time. More mini-computer type power is available on
micros, often called Work Stations, that are networked together.
Networking of microcomputers (linking of computers through cable
systems) allows for a distributed software environment, formerly
available only on mini and mainframe computers. One computer is
designated as a server that stores distributed software and
licensing, and houses shared network drives for shared access to
files, as well as secure back-up.
The three types of computers differ in maintenance. Maintenance
of mainframe computers usually requires full time staff. Mini
computers usually need a part-time or full time operator.
Microcomputers often have no operator other than the current user,
and the maintenance responsibility falls on the user. A computer
network typically requires part- or full-time staff.
Micro-computers encompass everything from a PDA (personal
digital assistant), a smartphone, or a tablet PC, to laptops,
desktops, and towers that allow for more drives and cables.
There are two common types of microcomputers: MAC and PC type
(or IBM-compatible) computers. MAC computers have had traditional
strengths in ease of use with a graphics interface. MAC computers
popularized the mouse, with point and click instructions, and the
pull-down menu, and more recently the touch screen. MACs were also
the first to run more than one application at the same time known
as multi-tasking. The popularity and ease of use of these features
prompted software manufacturers to develop products that mimic
their features on other computer systems. The ability to do
multi-tasking using the UNIX operating system developed by AT&T
computers and other competitors prompted IBM to develop its own
multi-tasking operating system, OS2. However, none of these
operating systems had the same market share as DOS, the original
operating system for IBM compatible computers.
Although each computer type has strengths and weaknesses, the
same issues may not prevail in the future. The personal computer
industry is competitive, and one brand's advantage is often another
brand's target for future development. Of special note in computing
is the current market share and software usage. MACs are often felt
to have advantages and superior software for music, photo and film
editing as well as fewer problems with viruses; while PCs have the
reputation of stronger computational functioning.
Our focus in this course is use of software on a conventional
laptop, desktop and or networked PC environment.
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2. Hardware Components
A computer consists of hardware and software.
Hardware consists of the physical components of the computer,
including such items as the Central Processing Unit (CPU),
motherboard, disk drives, monitor, and keyboard.
Software consists all of the programs that you and the computer
use to perform tasks. An essential piece of software on all
computers is the Operating System. We will use a WINDOWS operating
system for communication between the computer and the user and a
variety of specialized applications software packages for word
processing, data entry, management and statistical analyses.
The BIOS - Sometimes the boundary between software and hardware
is blurred. The BIOS identifies the Hardware on the computer, and
in early computers was part of the HARDWARE. More recently, some
BIOS are soft and can be programmed, or altered as the HARDWARE is
changed.
There are four (4) types of computer hardware.
Type Examples
1. The Box This is the central box and contains several
components, some optional
- CPU - Hard disk (storage) - RAM (random access memory) - Video
card - Ethernet card
2. Input Devices
- Keyboard - Mouse - Scanner - CD-ROM, DVD-R drives - Microphone
- Touch screen
3. Output Devices
- Monitor - Printer - Plotter - CD or CD/DVD burner - Slide or
overhead projector - Speakers
4. Input / Output Devices
- Disk Drives - CD-Read/Write or DVD-R/W - Modem, Ethernet cable
or Wireless card - LAN (local area network)
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2.1 The CPU
CPU stands for central processing unit and is actually a
microprocessor. Microprocessors have evolved over time with a
tremendous impact on the speed of processing.
Associated with the microprocessor is a clock speed in
mega-Hertz. This represents the number of calculations that can be
processed per second; one mega-Hertz corresponds to the processing
of 1 million calculations in one second. (1 MHz = 1,000,000 = 1 MIP
processes/sec). Clock speeds of early PCs were slow, and have
increased dramatically.
Clock speed does not provide a true measure of processing time.
Benchmarks have been established, consisting of certain tasks
performed by specific software to establish a machines speed.
Different CPUs can be compared with respect to the time taken to
perform the benchmark task.
2.2 The Display (Monitor)
The computer monitor or screen display was also called the CRT,
which stands for "cathode ray tube". LCD or liquid crystal display
monitors are also in more common use, particularly in laptop
computers. LCD monitors are thinner, lighter and use less power
than the traditional CRT monitor. Current software requires color
monitors.
Screen size is measured on the diagonal. For desktop machines
large (wide) sizes are available; laptop screen sizes can be more
limited, though wider screens have become more common.
Screen resolution refers to the number of pixels that can be
displayed. A pixel (a portmanteau word from picture element) is one
of the many tiny dots that make up the representation of a picture
in a computer's memory. Usually the dots are so small and so
numerous that, when printed on paper or displayed on a computer
monitor, they appear to merge into a smooth image. The colour and
intensity of each dot is chosen individually by the computer to
represent a small area of the picture. For example, a resolution of
640 x 640 indicates that the screen can be covered by 640 dots wide
and 640 dots high. Resolution determines the quality of graphic
display on the screen, and also on the printed page.
Graphic image enlarged to show fuzzing of image related to
enlarging pixels.
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Display settings for your monitor, including resolution, can be
controlled through the Control Panel. Your hardware and commonly
used software will determine the optimal settings. Higher
resolution means more pixels in the same area and can be important
for detailed graphic images.
To check or modify your settings, go to
(StartSettingsControl Panel and select Display.
Use the Settings Tab to control screen resolution and color
settings. Recommendations for optimal settings typically come with
the original hardware and operating system setup. Many software
application packages have suggested settings for optimal display of
graphics.
Only limited combinations are available for screen resolution.
Higher resolution often results in smaller icons and print on your
desktop.
Color quality selection depends upon software and hardware.
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2.3 Printers and Scanners
2.3.1 Printers
The most common types of printers in current use are InkJet and
Laser printers.
InkJet Printers Inkjet printers transfer an image via magnetic
charge. High quality graphics and a large variety of fonts are
available. Inkjet printers tend to be relatively inexpensive to
purchase, but more costly to maintain (ink cartridges are pricey!).
High quality color graphics and photo printing are available.
Inkjet printers are often a good choice for home use. Print speeds
are moderate, and color photo printing options are an advantage.
Inexpensive printers that include a scanner/copier are also
available.
Laser Printer On a laser printer, the image is produced by
scanning a laser beam across an electronically charged drum. Toner,
or ink, having an opposite charge and stuck to the drum, is then
transferred to the paper by pressure and heat. High quality
graphics and multiple font printing are readily available. Laser
printers tend to be more expensive to purchase and relatively
expensive to maintain. These are the best choice for high speed and
large volume printing. Color laser printers are also available and
in more common use again, these tend to be costly.
Printer supplies (paper, ink cartridges, toner, etc) are often
considered to be a part of a data management budget. Keep this in
mind!
Some commonly used printing terms:
Buffer Size refers to the size of the storage device inside the
printer. The buffer stores a portion of the document prior to
printing.
PPM (pages per minute) describes print speed for inkjet or laser
printers (8-12 is good).
PCL stands for "printer control language". Developed by
Hewlett-Packard, it is a set of fonts and layout instructions.
Postscript is a set of fonts and layout instructions originally
defined for MacIntosh computers only.
Computers and printers communicate using a set of codes (see
section 2.5). When you purchase a new printer and first attach it
to your machine you may need an accompanying disk to load
information on the printer so that it is available to your software
programs. Printers require PRINT DRIVERs. A PRINT DRIVER consists
of a program that recodes output from the Software Program to
suitable patterns of dots on the paper. Print drivers are written
by the software manufacturers (not Printer manufacturers), since
the software manufacturers determine the coding table for the
output. You typically need to select a default printer to use with
WORD and other software this sets up the correct print drivers.
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2.3.1 Scanners
Scanners have become an important method of transferring printed
information into digital format in recent years. Scanner technology
has been improving rapidly and systems are available everywhere and
used in many ways. The basic principle of a scanner is to analyze
an image and process it in some way. Scanning of images and text
(using Optical Character Recognition or OCR) allow you to save
information to a file on your computer. You can then alter or
enhance the image, or edit text, and incorporate it into a document
or print it out.
Types of Scanners:
Flatbed scanners, also called desktop scanners, are the most
versatile and commonly used home scanners.
Sheet-fed scanners are similar to flatbed scanners except the
document is moved and the scan head is immobile. This model is
useful in situations with large volumes of pages to be scanned.
Handheld scanners rely on the user to move them instead of a
motorized belt. This type of scanner typically does not provide
good image quality. However, it can be useful for quickly capturing
text. These are most commonly seen for scanning bar codes, and can
be useful in research studies for processing of samples.
Drum scanners are used to capture incredibly detailed images,
and are most commonly used in the publishing industry.
Quality of scanned images and text depends upon a combination of
factors:
Sharpness is a function of the quality of the optics used to
make the lens and the brightness of the light source.
Resolution is defined by the number of dots per inch (dpi). The
scanner's dpi is determined by the number of sensors in a single
row (x-direction sampling rate) by the precision of the stepper
motor (y-direction sampling rate).
Software is then used to enhance images. Interpolation is a
software process used to increase the perceived resolution of an
image. Extra pixels are created in between the ones actually
scanned. These extra pixels are an average of the adjacent
pixels.
Once a document is scanned, you need software on your computer,
called a driver, that knows how to communicate with the scanner
analogous to printer drivers. Most scanners speak a common
language, TWAIN, that can be interpreted by standard image editing
software packages. In addition to the driver, most scanners come
with other a scanning utility and some type of image editing
application. Many scanners include Optical Character Recognition
(OCR) software. OCR allows you to scan in words from a document and
convert them into computer-based text. It uses an averaging process
to determine what the shape of a character is and match it to the
correct letter or number. This is a tremendous aid in scan data
entry systems, which we will be discussing later in the course,
though there are issues in recognition of handwritten characters
which must be accounted for.
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2.4 Bits and Bytes How the Computer Stores Information
The mechanics of computer function is an enormous number of
"on/off" switches. In actuality, computers know only ons and
offs.
A single "on/off" switch is called a bit. The term bit comes
from binary digit. The digit 1 is assigned to on, the digit 0 is
assigned to off.
Bits can be combined to obtain representations for numbers,
letters, and special characters.
Base 10 Number Base 2 Number 0 0 (1 bit) 1 1 2=21 10 (2 bits) 3
11 4=22 100 (3 bits) 5 101 6 110 7 111 8=23 1000 (4 bits) 9 1001 10
1010 11 1011 12 1100 13 1101 14 1110 15 1111 16=24 10000 (5 bits)
...
255 11111111 (8 bits = 1 byte)
A byte is a combination of 8 bits. There are 28 = 256
combinations of 8 bits, or 256 characters that can be represented
by 1 byte.
2.5 ASCII, Unicode and Hexadecimal Codes
ASCII stands for American Standard Codes for Information
Interchange. The ASCII codes correspond to assignments of
characters or icons (letters, number and symbols) to the 256 switch
settings in a byte (8-bits). The ASCII code number is the decimal
equivalent of the binary code used for the eight switch settings.
ASCII code derives from bits and bytes.
Bit Binary digit A bit is the smallest unit of information an
on/off switch. Recall - we use 1 to mean on and 0 to mean off.
Byte A set of 8 bits. A byte is the basic unit of information
for microcomputers.
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The number of possible values for a byte =
(2)(2)(2)(2)(2)(2)(2)(2) = 28 = 256. The 256 values are assigned to
represent letters, numbers, and characters.
It is useful to know that some ASCII codes do not have standard
assignments. Although there are 256 distinct ASCII codes, there are
not an equivalent number of standard character or icon assignments
from the keyboard. Software programs may assign some or all of
these codes to specific icons or functions that differ from
assignment in other software packages. Data or text saved in one
program must then be translated, or exported/imported from one
software package to another, to ensure proper translation of these
codes.
ASCII codes translate the 256 numbers 0 to 255 to a standard set
of symbols. The translation depends on the language you are using.
The first 128 codes (0-127) are the standard ASCII codes. The next
128 codes (from 128-255) are called the Extended Standard ASCII
codes.
Examples of ASCII Code Assignments:
Byte representation ASCII Code Assigned Character 01000001 065 A
01011010 090 Z 01100010 097 a 01111010 122 z 00110000 048 0
00110001 049 1 00110010 050 2 00111001 057 9 00001100 012
(page break) 00011001 027 (end of file)
Each ASCII code has its own byte representation; i.e., its own
set of eight 0/1 bit switch settings.
You can enter ASCII codes to get special symbols in your text in
some software programs by setting the NumLock on your keyboard to
on, holding down the ALT key while typing the associated code on
the number pad:
ALT
For example, with Numlock on typing ALT-065 will result in A
appearing; while ALT-012 will move you to a new page.
Unicode
The most common coding system in current use is Unicode. Unicode
is a newer coding scheme, also derived from assigning sets of bytes
to letters, numbers and other characters. It is an international
standard which has a goal of providing the means to encode the text
of every document people want to store in computers. This includes
all scripts in active use
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today, including many scripts known only by scholars, and
symbols which are used in mathematics, linguistics and other
specialized fields. The creation of Unicode is an ambitious project
to replace existing character sets, many of which are too small in
size and problematic in multilingual environments. Despite
technical problems and limitations and criticism on process, today
Unicode is considered the most complete character set and one of
the largest, and has become the dominant encoding scheme in
internationalization of software and multilingual environments.
Many recent standards such as XML, as well as system software such
as operating systems, have adopted Unicode as an underlying scheme
to represent text.
Tables translating between different coding schemes can be
easily found on the web. A list of scripts available can be found
at http://unicode.org/charts/ .
If you look at the CHARACTER MAP on your computer you can see
the Unicode code for special symbols:
(StartProgramsAccessoriesSystems ToolsCharacter Map):
Unicode for the selected character.
Select font, including specialized symbol fonts.
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You can use the character map to select, copy and paste special
characters into text, as needed. Note that the character map will
vary slightly with different versions of Windows.
The character map is one way to include special characters in
your text, in some software programs. Other programs offer their
own set of special symbols.
For example, within MS Word, special symbols can be added
directly to your text from the Insert menu: Insert Symbol
Unicode values are written in hexadeximal code. Hexadecimal
codes are written in Base 16. A set of 4 binary switches (bits)
forms one hexadecimal number. Unicode values are written as 4 digit
values, or requiring 4x4=16 bits, or the equivalent of 2 bytes for
each letter or symbol. As base 10 numbers require 10 distinct
characters (0, 9), Base 16 requires 16 characters. We add A F to
represent values of eleven through fifteen.
Examples of binary, decimal, and hexadecimal code are given
below.
Examples of Binary, Decimal, and Hexadecimal Codes
Binary Code Decimal Equivalent Hexadecimal Codes 00000000 0 0000
00000011 3 0003 00000101 5 0005 10000000 128 0080 10101000 168 00A8
11111111 255 00FF
Select font, including specialized symbol fonts.
Note the convenient recently used symbols feature.
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2.6 Computer Storage Terminology
We consider next how units of bits and bytes of information are
used to define storage space on a computer.
One bit represents one "0/1" switch.
One byte represents 23 bits = 8 bits.
After that, we increment bytes by powers of 10.
One Kilobyte (KB) = 210 Bytes = 1024 Bytes = 213 Bits = 8192
Bits
One Megabyte (MB) = 210 Kilobytes = 1024 Kilobytes = 220 Bytes =
1048576 Bytes = 223 Bits = 8388608 Bits
One Gigabyte (GB) = 210 Megabytes = 1024 Megabytes = 220
Kilobytes = 1048576 Kilobytes = 230 Bytes = 1073741824 Bytes = 233
Bits = 8589934592 Bits
The amount of storage space available on a disk is usually
described in terms of bits, bytes, KB, MB, or GB.
2.7 RAM, ROM, and Read/Write Storage
A major component of the microcomputer is the storage device(s).
All microcomputers have systems for getting data into the computer,
saving information on the computer, and getting data back out of
the computer. Data are stored on disks that may be removable or
fixed in the computer.
There are different kinds of storage:
(1) Random Access Memory (RAM) (2) Read Only Memory (ROM) (3)
Read/Write storage: Hard Disk, Floppy Disk, CD, DVD, Zip disk,
plug-in
drives
Random Access Memory (RAM) is a major component of personal
computers. RAM is the fastest storage device, and is accessed at
the speed of the microprocessor. Most software has a minimum RAM
requirement.
Random Access Memory can be installed on the motherboard (the
motherboard is the CPU), or installed in expansion slots in a
computer.
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Special software is needed to access RAM. WINDOWS serves this
purpose, allowing access to as much RAM as is available. Most
WINDOWS programs require 16 or more MB of RAM. SAS 9.x recommends
minimally 32 MB of RAM for operation. WINDOWS XP suggests that it
be operated with at least 128 MB of RAM and 1.5 GB of hard drive
space and a computer speed of minimally 300 MHz.
To check on your system:
Start Settings Control Panel Performance and Maintenance
System
Physically, RAM is a chip installed on a circuit board inside
the computer box. You can purchase additional RAM for your computer
if required for newer software you are using, or to improve
operating speed and multi-tasking.
A major limitation of RAM is that it is temporary. When the
computer is turned off, the information stored in RAM is lost.
Every time you run an application (e.g., MSWord or SAS), the CPU
uses RAM for retrieval and storage of information as the
application is running. This is efficient because RAM is accessed
at a high clock speed, usually close to the same clock speed as the
CPU. However, until you hit SAVE, any work that is only current in
RAM will be lost if you lose power or have some other glitch or
malfunction.
Consider using the autosave feature of your software programs,
so that you are at less risk of losing your work. An autosave
feature automatically saves current work in a temporary
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file at regular intervals, which can be recovered after a power
loss. You can set the frequency with which automatic saves
occur:
Example using the autosave feature in MS Word 2010
File Options Save
Too frequent auto saves can interfere with smooth workflow, but
too infrequent (e.g., set at 1 hour) can mean drastic loss of work.
When you do lose power or a program shuts down on you, as you
restart the software application, the auto-saved version of the
file with most of your recent work can be accessed.
2.8 The Hard Drive
In contrast to RAM, information can be stored permanently on a
hard disk. Physically, a hard disk is a magnetic medium and can be
either:
a device inside the computer box (most common) a card in an
expansion slot an external device
You will find an option to set the frequency of auto saves,
under:
Save AutoRecovery info every:
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The amount of information that can be stored on a hard disk has
increased substantially over time:
Machine (Year) Storage Capacity of Hard Drive 80286 (1982) 10-20
MB 80486 (1990) 200-540 MB P5 (1995) Gigabyte+ Current PCs Many
many GB
Note that I say permanently in quotes disks can be broken or
destroyed; data can be destroyed or rendered inaccessible by
viruses or worms; additionally magnetic storage may deteriorate
over time.
2.9 CDs, Diskettes, and Zip Disks
CD-ROM stands for "Compact Disk-Read Only Memory. CD-ROM is a
storage medium based on laser technology. The storage capacity is
large, on the order of one or more gigabytes. Read only means that
the hardware to write, or save, to a CD is not included. It is not
possible to write to a CD without special hardware, a CD writer,
popularly known as a CD burner.
CD-R/W stands for Compact Disk-Read/Write. However, once you
have written to a CD, it cannot be erased and overwritten like a
diskette, unless you buy CDs designed for re-writing. Even
re-writable CDs are not designed for continual saving and
overwriting
Use My Computer
To look at total, used and free storage on your local hard
drive.
(Right-click on C: and select Properties from the menu).
This computer has 74.4 GB total storage for software and other
files.
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as you are in the process of editing and updating files. They
are more suited to saving final copies of data files and reports,
especially those you dont want re-edited.
DVD (Digital Video Display) drives are a common option on
computers. They are commonly read only drives, often in combination
with a CD-R/W drive; DVD-R/W drives are also available. More and
more software, especially with complex graphics (particularly
games) is distributed on DVD.
Other removable storage devices are known as diskettes or floppy
disks have been pretty much phased out.
5- " Floppy Diskette (Pretty much phased out) An electronic
medium storage device. Reading from and writing to are both
possible. Storage capacity 360K - 1.2 MB.
3.5" Diskette (Typically referred to as the a: drive) also
pretty much phased out. An electronic medium storage device.
Reading from and writing to are both possible. Storage capacity
720K - 1.44 MB. Less easily damaged than 5.25" floppy diskette.
Zip Disks 100 or 250 MB ZIP disks, designed for use in 100 or
250 MB ZIP drives, which can be an external drive, or part of the
box. Note that the device size (100 or 250 MB) and disk size (100
or 250 MB) must be compatible.
Other Options
Compact Flash (USB drives), memory sticks and other compact
media (e.g., micro SD cards) are increasing versatile and vary in
capacity. They are very useful to have and can fit in your wallet
or on a keychain. These attach through USB or special drives.
Prices vary with the capacity (amount of storage space); you can
get a relatively inexpensive one that can hold a lot of data.
Infra-red communication and wireless interfaces are increasingly
valuable and available.
(Tip: I recommend using USB flash drives you can fit most of
your coursework on a single, inexpensive flash drive, and back-up
your work to the U: drive.)
Access Time is the time required by the CPU of the computer to
access one byte of information on a device. It is good to have fast
access time. The access time is measured in milliseconds.
Early machines (e.g., 80286) had access times of 88 msec. Today,
hard disk drives have access times of 14 msec or less. In general,
the higher the storage device, the faster the access time.
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2.10 Modem and Ethernet
"Modem" is shorthand for Modulate and Demodulate. It enables two
computers to exchange data over standard telephone lines. Use of a
modem requires communications software, which performs several
functions, among them:
Dialing and redialing Logging on (connecting) to system being
called Transmission of information.
The transmission speed of a modem is expressed as the baud rate.
Baud rate = # bits that can be transferred in 1 second. The
standard for a good, high-speed modem is 56K.
An Ethernet connection is a cable connection to a system, rather
than a phone line.
MIPS = Million Instructions per Second. Ethernet wiring
connection through a hardwire or cable system, transmits at 10
MIPS. The backbone fiber optics network at UMASS transmits at 100
MIPS.
Wireless connection is increasingly available, and requires the
appropriate card in your computer, as well as working within a
wireless environment. Many buildings and areas on campus have been
established as wireless zones, which means that if your laptop has
the capability, you can establish an internet connection when in
those areas. Check on the OIT website for wireless zones on
campus.
2.11 Ports and Cables
Port. A port is a physical location through which the computer
exchanges information with an external device (e.g., printer or
modem).
A port has an address so that the computer knows where to send
or receive information.
There are three types of ports and associated cables: parallel
and serial ports, and USB ports.
1. Parallel 8 bits are simultaneously transmitted over 8 wires
(or transmitted in parallel). Most commonly used for printers. Also
commonly used for external disk drives.
2. Serial Each bit is transmitted one after the other (in
serial) over a single wire. Most commonly used for modems.
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3. USB Universal Serial Bus Port Currently most common method of
attaching peripheral hardware; these are
the standard method for most current laptop computers, and
increasingly on newer desktop computers, also.
Ports are typically available on rear and front (for easy
access) of box, as well as on the side of monitors.
USB supplies power to the peripherals, reducing the need for
additional power sources.
Full speed devices communicate with the PC at 12Mbps. Mice and
keyboards etc. can communicate at a lower 1.5Mbps rate.
PlugNPlay - The PC recognizes each device that is plugged in and
loads the appropriate driver. If it's a new device for which it has
no driver, and doesn't run with a generic driver, it prompts for a
driver to be loaded.
No confusing special cables required for USB connections no null
modem cables, handshaking lines to mess with etc.
Supports 4 different data transfer types:- Isochronous, Control,
Interrupt, Bulk
Attaching Peripheral Hardware
When you first attach new hardware (a modem, printer, disk
drive, ) to your computer, you need to set up the communications
systems for the new hardware component. While much of this has been
automated a disk which steps you through the process is typically
included with new hardware you are occasionally asked to make
choices, and unless you are using a USB port, you will need to know
which port you are using.
When you attach hardware to a serial or parallel port, or
hook-up your computer cable or modem connection, you typically need
to restart the computer until you restart, the newly attached
component is not recognized or not found. However hardware that can
be attached through a USB port does not require restarting the
computer; it will be recognized without a reboot. Note that it is
recommended that you take time to Safely Remove Hardware that is
connected through a USB port, before switching to another piece of
equipment on the USB drive. There is a chance for lost or
non-readable files; or your computer may not appropriately
recognize another drive or piece of hardware that you subsequently
attach to that port.
2.12 Care of Computers, Storage Devices, and Printers
Micro computer and storage disks (both hard disks and floppy
disks) will perform better, require less maintenance, and last
longer if several simple rules are followed.
First, computers must be kept clean. This means insisting on no
food or drink near the computer, and regular cleaning of dust and
debris.
Second, computers should be kept at moderate temperature
(between 45 and 85 degrees F). High or low temperatures may damage
motherboard memory and disk drive memory.
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Third, computers and disks must be kept clear of static. Since
information is stored via magnetic fields, static electricity can
destroy stored information. Similarly, static electricity can
destroy RAM prior to installation in a computer. Computer memory,
when shipped, comes packed in static proof wrap. Special care and
grounding will minimize the chance that memory will be destroyed
during installation. Low static carpeting may be a good
investment.
Finally, all computers should be connected to surge protectors.
The surge protector will prevent voltage surges from damaging the
system.
3. Software
3.1 Disk Operating System
The CPU, storage devices, and other devices in a personal
computer communicate with each other via an operating system.
Examples of IBM compatible operating systems include UNIX, DOS, and
OS2.
The DOS operating system was basic for most IBM compatible
computers. In the past, as recently as 1996, learning DOS commands
to manage files and access to application software was
important.
Originally, WINDOWS functioned as a layer above the disk
operating system, though in new versions Windows serves as the
operating system.
3.2 Windows
Windows is a Graphical User Interface (GUI) a more intuitive way
to interact with a computer. Instead of typing a command in DOS,
tasks can be performed in an intuitive, visual manner via point and
click, with the help of a mouse or other input device.
Tasks such as copying a file from one disk to another can be
accomplished by dragging an icon representing the file from the
icon representing one disk to the icon of another.
A GUI acts as a translator allowing the user and the computer to
communicate with each other in a way that is easy for both to
understand.
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3.3 The Mouse
The mouse is a pointing and selecting device. It plays a major
role in a graphical user interface. Everything that can be done
with the mouse can also be done with the keyboard, although this
defeats the purpose of the GUI.
Common terms used with mouse directions:
Point: placing the cursor (arrow) on top of a screen object by
moving the mouse.
Click: pointing at an object and quickly clicking/pressing the
(left) mouse button; then letting go.
Double Click: pointing at an object and (left) clicking twice
rapidly.
Drag: pointing at an object pressing and holding down the mouse
button; moving the mouse to drag the object and releasing the
button when the object is in a new place.
Select: pulling down a menu by clicking on the menu name; moving
the pointer down to the command you want and then releasing.
Rollover: Move the pointer over an object without clicking. This
allows rollover text if available, which describes the function of
the object or give additional information, to appear.
Most current models of the PC mouse have left and right buttons.
Different menus become available if you left-click or right-click
on a file or pull-down menu. The user has options to set which menu
appears with a left or right click, as well as the appearance of
the pointer on the screen, the speed of scrolling, etc.
The cursor typically takes the shape of an arrow when you use it
to point and click, and an hourglass to indicate a program is
loading or operating. The cursor returns to an arrow when you can
take the next step. Again, the user has the option of resetting the
shape of the mouse pointer.
Mouse properties, including speed of action, type of movement
and screen appearance can be reset using:
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Start Control Panel Appearance and Themes and selecting Mouse
Properties.
Everything that can be done with the mouse can also be done with
the keyboard.
For example, while there are many ways to select text, cut, copy
and paste using the mouse, these can also be accomplished with
keyboard strokes. A few of the more useful ones to know are:
Function Keyboard Strokes Select all Ctrl-A (this means hold
Ctrl Key and tap the A) Cut Ctrl-X Copy Ctrl-C Paste Ctrl-V
If you are ever having trouble copying/pasting between different
software applications (e.g., from a webpage to a word processor),
try using keyboard strokes in place of menu choices and mouse
actions.
Excessive mouse use can cause fatigue and repetitive strain
injury and it is valuable to learn to do some frequently performed
tasks on the keyboard. Some examples are copy, cut, paste, select
all, as shown above. Other common actions include use of
ctrl or F10 to save F12 to save as etc.
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Within a software program you can often customize these commands
by creating MACROS, or programs to assign functions to keyboard
strokes.
Many operations are faster and sometimes more precise with the
keyboard than with a mouse. You can also use mouse actions and
keyboard controls together some examples:
Selecting a section of a document to copy can be done with the
Shift key and the mouse. Use the mouse to position the cursor at
the start of the section you wish to copy. Hold down the shift key,
and use the mouse to move the cursor to the point in the document
that marks the end of the section you wish to copy and click on
it.
Select columns of text to cut or copy by positioning the cursor
at the start of the columns to be selected; holding down the Alt
key, and dragging the mouse over the section of text you wish to
select. This is particularly useful when editing computer output
into Word documents.
Special electronic pads and pens are available for those with
wrist or other problems making a mouse difficult to use; in
addition voice recognition systems are in use and further
development to give commands and enter information orally.
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3.4 The Anatomy of a Window
Windows uses a desktop metaphor:
Computer Screen == Electronic Desktop
Graphical objects on the screen are like objects on your desk
they can be moved around to get something out of the way, or they
can be covered up by a file you are currently working on.
Keeping the desktop metaphor in mind will help make the concepts
and techniques about using windows easier to grasp. Just as you
shift papers around on your desk, cover papers allowing only the
important parts to show, stack papers on top of one another and
file papers, etc. all this can be accomplished with different
windows and information within them.
Each application program on your computer can run its own window
or, more commonly, its own set of windows. Each window operates in
a similar manner, although the tasks performed may be very
different.
While the type of window seen at any given time depends upon the
individual application in use many of these features are common to
all windows.
Title Bar
Menu Bar
Minimize Button Maximize
Button
Close Button
Workspace
Vertical Scroll Bar
Horizontal Scroll Bar Window Corner
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Title Bar at the top of the window, this shows the name of the
program and type of window or software.
o This is highlighted in color (usually in blue with white text)
when the window is active.
o The title bar appears in gray (or a gray-blue) when the window
is inactive when another document or program window is currently in
front, and active.
Menu Bar the horizontal bar below the title bar listing the
available categories of commands or actions which can be performed
in this window.
Scroll Bars vertical and horizontal bars along the right hand
and bottom edge of a window: buttons on the scroll bar move you
quickly through a window.
Minimize Button The leftmost of 3 boxes in the upper right-hand
corner of a window. The Minimize button effectively hides the
window the window appears only on the task bar at the bottom of the
screen when minimized. Note this does not close the window the
program and/or document are still open and held in active memory,
just folded up, out of the way.
Maximize/Restore Button the middle of the 3 buttons in the upper
right-hand corner of a window. This shifts between maximizing a
window (filling the whole screen) and shrinking the window to fill
only part of the screen so that other open windows or the desktop
may be viewed.
Close Button the button with the X used to close a window. This
actually closes the document and/or application program, and
removes it from active memory (from RAM).
Window Corner can be used to resize/reshape a window by dragging
to the desired size/shape.
The TASKBAR at the bottom of the screen indicates which windows
are currently open. The highlighted window is currently active.
At the left of the taskbar the Start button can be used to
access all the software.
At the right-hand side of the taskbar, icons for features
running in the background are displayed. These vary with your
computer setup. Typically if you roll the cursor over the icon,
information about its function will appear.
Software and files that are currently open in RAM (active
memory) show on the taskbar.
You can switch between active windows by clicking on the item
you wish to have active in the taskbar.
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3.5 Managing Files in Windows
Two key programs for file management are available with
windows:
(1) My Computer (2) The Windows Explorer.
Each of these programs gives a picture of the files documents,
data and program files that are stored on the various computer
disks. You have a choice of VIEWS or ways of displaying the
information, using large or small icons, with or without
details.
Either program can be used to copy, move, delete and open
programs and documents.
My Computer looks at a particular location on the computer and
displays all the folders and files.
Windows Explorer provides, in addition, a tree diagram structure
to indicate the storage relationships among files and folders.
Windows HELP and Support can be accessed from the Start Menu on
the Task Bar. It provides a tutorial with exercises for practice on
use of Windows as well as help on specified tasks, such as copying
and moving files, and creating shortcuts to programs and files.
TIP - You can learn to use both My Computer and Windows Explorer
through the HELP tutorials. I suggest you pick one or the other and
get comfortable with it.
My Computer:
Views button
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In this example of My Computer, the disks and folders are
displayed as large icons. You can switch the type of display using
the VIEWS button on the menu bar.
By right-clicking on a drive and selecting Properties you get
the following:
Take advantage of the feature that allows you to name a disk or
flash drive. This name will appear next to the drive designation in
My Computer or the Windows Explorer a great advantage when you
leave your flash drive in the computer lab!
This screen allows you to:
label or name your disk
look at the amount of free and used space on the disk
perform disk clean-up.
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The Windows Explorer:
The left-hand side of the explorer window displays a
tree-diagram of the disk drives, with folders displayed.
Clicking on the + beside a folder or disk drive will display all
subfolders.
An open folder on the left indicates the folder whose contents
are displayed on the right-hand side of the screen.
The right-hand side of the explorer lists the files and
sub-folders in the selected drive\directory.
In this example, the VIEW has been set on Details. A small icon
to represent the file application type is followed by the full file
name. The file size, type and date/time saved are also listed.
By clicking a column heading bar (Name, Size, Type or Modified)
you can sort the file listing alphabetically (Name), by Size, by
type of file, or by date/time last saved. A second click reverses
the order. This feature makes it easy to find files!
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3.6 Some General Tips for Working on a PC
Naming Files
Filenames have 2 levels in DOS and Windows, separated by a dot
(.) or period.
The first level before the dot can be a long descriptive title
including most of the keyboard characters (exceptions include / * ?
> < and perhaps others).
The 3+ letter extension after the dot is determined by the file
type. For example MS Word files all have the extension .doc, while
MS Excel files use the extension .xls and text files have the
extension .txt.
Each software package has one or more extensions used to
indicate the type of file.
The type of file is also indicated by the icon. For example:
is used for Word files, for Excel, and for text files.
Other icons and extensions are used for other software packages,
many packages having different icons for each type of file the
package recognizes. These icons are recognized by the computer once
that software is installed on your machine. On rare occasion you
will have a conflict 2 software packages use the same extension
with different meaning. Youll have to choose a default.
Be careful when you rename a file; do NOT change the file
extension (the part of the name after the dot). If you rename a
file and change the extension, then the software package will not
recognize the file type, and you will not be able to access the
file properly.
If the 3 letter extension does not show in My Computer or the
Windows Explorer, its a good idea to turn this on: Tools Folder
Options and selecting the View tab:
Uncheck Hide extensions for known file types to make sure that
extensions are visible.
I recommend having this Apply to All Folders by clicking the
appropriate button.
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The first part of a file name is up to you, as the user. I
recommend keeping it short and simple. Occasionally part of a long
name is lost when you send a file as an email attachment it depends
on both your email system and the recipients system. This was a
greater problem a few years ago, but you may still run into it.
Take care when naming files that you will be posting to the
Web:
Web file names are CASE SENSITIVE (UPPER vs. lower case). While
capitalization is ignored in filenames in Windows, UPPER and lower
case letters are read as different characters in Web-file
names.
This means that CASE and Case and case would all be read as
different file names in a web environment; on a PC they are
equivalent.
In naming files to be posted on the web, use only letters,
numbers, the underscore (_), and NO SPACES. Once a space is
encountered in a name on a file posted to the web, the rest of the
name is lost (so use an underscore in place of a space). For
example in place of Personal Page.html which contains a space
(allowed in Windows!) use the name Personal_Page.html when creating
a personal webpage.
Deleting Files
When you delete files or folders from the hard drive (by
dragging to the Recycle Bin or using the delete button on the
keyboard or on a menu), the file (all the bits of info) is not
deleted from the disk, but information on its physical location is
moved to the Recycle Bin. This gives you the chance to retrieve the
file if you have deleted it in error. Until you empty the recycle
bin, files are retrievable simply click to open the recycle bin and
drag the file icon back to another location. Note: files deleted
from a removable disk, USB drive or network drive are deleted from
the list of files, and location information is NOT moved to the
recycle bin and therefore these files are not readily
retrievable.
However, even when a file has been deleted and the recycle bin
emptied, it may still be retrievable. Deleting a file merely
removes its name from the directory, and indicates that the space
is available for re-use, but the information is still stored on
disk until it is over-written by another file. Programs such as
Norton Utilities can be used to recover deleted files, as long as
new files havent overwritten the old files.
This is both good and bad news:
Good news for the day you make that awful mistake and delete
something important you may be able to find and retrieve it;
Bad news when you think you have deleted confidential
information from a computer. You must take some other action, such
as reformatting an empty disk, or cleaning up a hard disk, so
deleted data is no longer accessible, even by specialized
software.
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Opening Application Programs and Files
Application programs can be opened by using the Start Menu,
e.g.,
Start Programs Microsoft Office Microsoft Word 2010
This opens the program to a blank document or empty file. You
can then open a stored file from within the software package from
the File menu or a toolbar icon, or create a new file.
An alternative way to open both a particular file and a software
application simultaneously is to double click on a previously saved
file in either Windows Explorer or My Computer. Additional files
can be opened from within the software package using the menu or
toolbar options; or additional files can be opened from the Windows
Explorer or My Computer.
File Management
It is always a good idea to have some organized structure to
storing files, otherwise you can end up with endless lists of files
to look through to find the one you want.
You can and should create FOLDERS on your disks, analogous to
file folders for storing actual papers that you are filing.
Depending upon the scope of your project you may want to organize
folders by file type, date, user, or topic and various combinations
of the above.
While you are allowed by the system to give folders and files
long, descriptive multi-word titles in Windows, it is a good idea
to be brief. Some applications have limits internally to file name
lengths, so part of a name can get lost.
If you will be sharing a file with other users, think about
using a name that clearly identifies you and/or the project. E.g.,
rather than a using name like draft1.doc a name such as
Pekow_691f_v1.doc is much more informative, and less likely to be
overwritten by another document with an identical name.
Shutting Down the Computer
Microcomputers should not be turned off without first shutting
down the computer. This is a process that closes down shared files
and programs that are running in the background before the computer
is turned off. Failing to shut down will leave unnecessary
temporary files on your computer that can hamper effective
operation over the long term. In addition, if you fail to shut-down
and simply turn off the power, the start-up will take longer when
you next turn on the machine, as the system works through a scan
for disk errors.
It is a good idea to shut down your computer at least
occasionally so that this clean-up of temporary files will take
place.
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Virus Protection
A computer virus or worm is a file or segment of computer code
that is designed to infect files or systems by destroying required
system files, copying endlessly and clogging up systems or various
other methods.
Virus protection software is particularly important in an
environment where files are shared through the web, email, and use
of common computers in a lab. McAfee Virus protection software is
available to the UMass community once you have an OIT account. This
is distributed by CD when you obtain your account, or can be
downloaded from the OIT website.
PLEASE TAKE ADVANTAGE of the availability of the software, and
update regularly.
4. The Internet and the World Wide Web
The Internet is the vast collection of inter-connected computer
networks that use a specified set of protocols for transmission
known as the TCP/IP (Transmission Control Protocol/Internet
Protocol).
Any set of computers connected together form an internet, also
known as a network. We typically speak of a local area network
(LAN) for a set of computers connected within a company or
organization. Such an intranet may also be connected to The
Internet.
The World Wide Web is a system of Internet servers that support
specially formatted documents. A Web Server is a computer connected
to the Internet that has a specified IP (Internet Protocol)
address, so that it can be located to provide documents via the
Web. Web documents are formatted in HyperText Markup Language
(HTML). HTML is a standardized language of computer code that lies
behind all Web documents, containing the text you see, images,
links to other documents, as well as formatting instructions for
display on the screen. If you copy or save material from a web
page, and try to edit it in a word processing package such as MS
Word, you might find strange things happening with formats and
spacing, and also find occasional unusual characters in the
document. These are remnants from the HTML coding. While Word has
features that allow you to create an HTML version of a document you
are writing, there are specialized software packages designed for
creating and managing web pages and websites.
In addition to the World Wide Web, there are other systems using
the Internet. Email is one example of another type of connection
made through the Internet that allows you to send messages and
files. Another example is FTP or File Transfer Protocols for moving
files from one computer to another without an email connection.
To connect your PC to the Internet, you need a either a modem
(for a phone line connection), an Ethernet card (for a cable
connection), or wireless capability, along with software to make
the connection, an ISP (Internet Service Provider), and a web
browser.
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A browser is a software program that lets you view web
documents. Browsers translate HTML-encoded files into the features
(text, images, sound, motion) that you see on your screen. Commonly
used browsers are Netscape and MS Internet Explorer and Firefox.
Some ISPs (e.g., AOL) provide their own browser.
4.1 Browser Windows
Once you connect to the Web, and open your browser, you see a
Window similar to the Windows you usually work with.
Example Webpage Window:
Note icon in Title Bar indicates an Internet Explorer
window.
Special Menu bars allow you to navigate, or use other special
web features.
Address box indicates the URL or web address of the page you are
viewing.
As you move the cursor (arrow) over a link the URL appears in
this lower left bar of the browser window.
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Each web page is a single document on the World Wide Web. This
means it is an HTML document stored on a web server, with an
address. Every Web page address is identified by a unique URL
(Uniform Resource Locator). This provides the unique address of the
web page. You may type a URL into the address box and hit the enter
key to access a page. Or, more often, you will click on a Link
provided in another web page. A link is a URL imbedded in another
document that allows you move directly to the new page.
A website is a set of interconnected web pages.
4.2 Uploading and Downloading Files
Each time you access a new page (identified by a new URL) this
page must be read and transferred to your local PC through your
connection by phone line or cable or wireless transmission. A web
page can take from a fraction of a second to many, many minutes to
be read. Images or graphics tend to use many bytes and make pages
load much more slowly. The time of transfer depends upon both the
size of the file, and the speed of your connection. A cable
connection seems instantaneous, while a slow modem (phone
connection) can seem interminable.
You will often want to download information from the web. This
is the process of copying a file or part of a file from an online
server to your own computer. When you have downloaded a file you
have saved it, and made it available to use on your own computer,
without taking the time to connect to the web to locate and read
the file again. You can also edit and cut and paste from your saved
file into reports or other documents you are creating.
You will also want to upload files to the web. This is the
process of taking a file or part of a file that you have stored on
your own computer, and loading it onto a server or bulletin board,
so that it becomes available to other users of The Internet.
Using the UMass U: drive
Once you activate your UMass email account, in addition to email
access you have space available for use on a webserver for storing
files, referred to as the U: drive. Information for using this
space is available at http://www.oit.umass.edu/udrive/index.html
.
A few words of caution on use of the U: drive: Do not try to
open files directly from the U: drive, do not edit/save files while
working from the U: drive. Errors related to brief loss of
connections can render files unusable; some file types (such as
.mdb database files) are not directly usable and will give you an
error message. Always download files to your local computer; work,
edit, save then close the file and upload to the U: drive for use
at another time, another computer.