fundamentals of computer hardware and software
most computers come with
512 Mb to 2Gb of RAM
a magnetic strip can hold a maximum of
60 characters of magnetically stored information; it is usually encoded and never changed
examples of hybrid memory
EEPROM flash
sensors
MII
barcode readers
a barcode is a group of vertical bars of different widths found on a lot of products with numbers printed above or below the barcode. they are read into a computer using a fixed scanner.
turnaround document
a document which has some unique info printed on it by a computer but other information needs to be added to it by a human being
touch pad
a flat rectangular surface which also senses movement of a finger on its surface.
what does a monitor contain
a matrix of luminescent dots of RGB
scanner
a scanner allows you to transfer pictures, graphics and text to your computer.
touch screen
a specially mounted screen that is sensitive to touch so that you do not need a keyboard or mouse
without software, the computer hardware would do _____________ as there would be ____ _______________
absolutely nothing no instructions
what info is located on a cheque
acc number cheque number branch code
swiping of a card transfers...
account information the cost of the goods
hard copy
aka permanent output; it is printed for you to review away from the computer
a computer is
an electronic device operating under the control of instructions stored in it's memory
mouse
as you move it along a flat surface, the pointer on the screen moves in the same direction; the left is used to select text and the right is used to access menus
CRT
cathode ray tube
hybrid memory
combines the features of both RAM and ROM in the sense that they can be read and written as desired but maintain their contents without electrical power
digitizer
convert drawings and photographs into data for architects and makers of maps.
when sending data, a modem
converts digital data to analogue signals by varying the frequency of a carrier wave
microphone
data can be entered into a computer through a microphone and the computer responds to this data by carrying out instructions
address
data stored at a specific memory location
resolution
determines how clear and detailed the output on the screen is
printers
devices which produce an output of your work
non impact printers
do not involve actually striking the paper; instead ink spray or toner powder is used and characters are fixed onto the paper by heating
how do we erase information from EEPROMS
electrically
this is known as
electronic funds transfer at point of sale
electronic point of sale
enable large amounts of data to be input very quickly and accurately
modem
enables a computer to send data to and receive data from another computer over a telephone line
memory
enables a computer to temporarily store instructions and data
types of plotters
flatbed drum pinch rollers
output devices
get processed information out of a computer
keyboard
has a set of alphabet keys, a set of digit keys and various function keys so the data entered is in the form of individual letters, words or numbers; when you press a key on the keyboard, a code is sent to the computer to tell it which key you have pressed
programmable ROM
if the code or data stored here must be changed, the device must be discarded
computer programs
instructions produced by programmers to create system and application software
a telephone system is analog device that
is designed to transmit the human voice
light pen
is similar to a mouse but you can move it over the screen and point at items on the screen to input data
major disadvantage of RAM
it is volatile; data held in RAM is lost when a computer is turned off or malfunctions
LED
light emitting diode
LCD
liquid crystal display
main memory
located directly on the computer's main circuit board so that data can travel quickly to and from the CPU
peripheral devices
located outside the CPU but are controlled by it; they can be added to computer system
central processing unit
made up of the control unit (carries out instructions in the software and directs the flow of data through the computer) and the arithmetic logic unit (performs the calculations and logic operations)
what is a bitmap
mapping the location and colour information of each bit of data
RGB can be blended to produce
millions of colours
disadvantages of impact printers
noisy do not usually print acceptable graphics
soft copy
not a permanent copy; includes output from a computer monitor, audio from speakers and electric signals from modems, and output from one computer to another.
PROMs are also known as
one time programmable devices
the optical mouse uses an ___________________________ to track its movements
optical
bitmaps are made of
pixels
magnetic ink character reader
reads the information on cheques along with the amount on the cheque, into the banks info systems so they can be cashed
optical mark recognition
relies on precisely positioned marks on a form being read by a special scanner
the features of a computer screen
size resolution colour cursor scrolling
application software
software that instructs a computer to carry out a specific task
a computer is a digital device that...
switches on and off millions of signals
advantage of RAM
the computer can access data held in RAM almost immediately
size
the dimension of the screen which shows the output
to gather information from a card, it is swiped through a machine which quickly and accurately reads the magnetic pattern. if the magnetic area on the card is scratched or soiled then....
the information stored on the card can be destroyed
word
the largest amount of data which can be accessed together
software
the name given to computer programs that tell the hardware how to work.
word size
the number of bits which can be transferred in a word
microfilm
the output is printed on a roll of film or microfiche rather than paper; its faster and condenses large stacks of paper into small amounts with no special programming
hardware
the physical parts of a computer
what information does a barcode not give
the price
optical character recognition
the scanned text is turned into a file that can be edited, reformatted and reprinted by a word processor
bit
the smallest chunk of information or piece of data that a computer can work with
kilobits per secon
the speed at which a modem transfers data
everything that the computer does results from ...
the turning on and off of different combinations of microelectronic switches knon as bistable devices or transistors
erasable programmable ROM
these can be erased and reprogrammed repeatedly
random access memory
these hold the temporary operating instructions for the computer, its programs and the data; this is where the CPU receives the instructions and data it needs to do its job
ROM
these instructions can be read but not changed (non-volatile) and are available every time the computer is switched on
biometric systems
these systems used some part of a person's body to uniquely identify them example- fingerprints and voice or signature
impact printer
this printer strikes through a carbon or inked ribbon
input means...
to enter data, programs, commands and user responses into the memory of a computer
input devices
transfer data into a computer
direct data entry devices
transfers info automatically and are used when large amounts of data must be entered quickly.
advantage of impact printers
useful for printing multiple copies using carbon paper and printing payroll or financial reports
plotter
uses coloured pens or toner to draw an image on paper
system software
usually called an operating system since it controls the hardware and how all other software works
VDT
video display terminal
VDU
visual display unit
The most common opp system is
windows by microsoft
manual input devices
you must transfer data into the computer by hand
how do you erase an EPROM
you simply expose the device to a strong source of UV light. By doing this you reset the entire chip to its initial un-programmed state.
