chapter 1.9

user backup

write protect (keep files from being overwritten) and make copies

data processing

the transformation of data into a form that is useful for specific purposes

data processing can be achieved by

batch processing on-line processing real time time-sharing

batch processing

this system is one where data is collected together in a batch before processing starts

batch processing is most suitable...

when large amounts of data have to be processed on a regular basis

advantages of batch processing

once the data is submitted it may be left running with human interaction
the computer is only used for a certain period of time
jobs can be scheduled for a time

disadvantages

there's a delay and usually involves expensive computers

time sharing

this system allows users to share time on a single computer
multitasking
multiprocessing
multi programming
multi user
security

on line processing

when devices are connected to a main processor and turn on so that the operator can interact with them

real time processing

this system processes data without significant delay, making it always up to date

real time processing advantages

no significant delay

information always up-to-date

input can be adjusted by output

real time processing disadvantages

the computer must be solely dedicated to the task

computers must be continually on-line

data transfer

the movement of information from one place to another: within the computer, between 2 or more computers and a computer and external device