IT Chapter 1 Flashcards
information technology
what is data
raw data has no meaning , has no context, isnt pocessed yet
what is information
it is data that has been given meaning, has context and is processed
how is data stored
in binary digits 1=8bites
what is direct data
data that is collected for a purpose and used for that purpose only
what is indirect data
data collected from a third party and used for a different purpose from what it was collected for
what are the direct data sources
questionnaire, interview ,data logging , observation
describe questionnaires
consists of questions on a specific issue
questions could be closed end or open ended
easy to distribute
complete
easy familiar process
describe interviews
It’s a formal meeting usually between 2 people, done face to face
observation
data collectors watch what is happening in a given situation
data logging
the use of sensors to collect data
Data is collected over a period of time
faster and more accurate than humans
could be put in dangerous areas
the data is directly sent to the computer automatically
what are the factors that affect the quality of the information?
Accuracy, Age of data, completeness, relevance & level of detail
Describe the accuracy of information
it depends on the accuracy of the data and how it was collected
transposed errors and transcript error could affect the data accuracy
validation & verification is used to reduce errors and increase accuracy
what is transposed error
when data copied there was an error in coping down the information in the correct way
ex.26 was copied as 62
what is transcript error?
when transfering data from one medium to another an error happens.
Relevance of information.
data must meet requirements
relevance Matters if data collected was irrelevent then there was a waste of time & money
Age of data/ info
Data needs to be updated inorder not to cause inaccuracy
the data needs to be updated regularly
old info causes wrong decision making
Level of detail
the details should be in the right amount not too much nor too less.
completeness
the data needs to be complete to avoid gaps collecting more data could be a great decision to avoid these gaps
need of encryption
- to avoid fraud
- to avoid identity theft
- to avoid black Mailing
- to avoid ransom
describe encryption
it is away of scrambling data in a way that only authorised people can understand the information
it is a process of converting info. to a code that is imposible to understand without a decryption key
it is used when storing data or when transmitting data across the internet.
Doesnt prevent hackers from intercepting the data it only stops them from understanding it
it is a Process of converting plaintext to cipher text
where the “authorised” people
they’re people who have the decryption key
encrypting the data
to encrypt the data we need encryption key and encryption algorithm
to decrypt the data
we need decryption key and decryption algorithm.
what is encryption algorithm
it is a program that converts plain text to cipher text
what is decryption algorithm
it is a program that converts cipher text to plain text
what are the 2 types of encryption
symmetric & asymmetric
what is symmetric encryption
the sender & reciever have the same key to encrypt & decrypt the data
it is mostly used when storing On a harddisk
key private key
what is asymmetric encryption
an encryption that uses I different keys
1. public key to encrypt data
2. private key to decrypt the data
used mostly for encrypting emails
it is more secure yet slow process
2 other names for symmetric encryption
secret key encryption
private key encryption
what happens in an SSL / TLS handshake
- client sends a message to the server to set connection & to agree on the rules of communication and on what ss L/ TLS version should be used
2, server shows digital certificate to the Client - client checks if certificate is valid and authentic
- client obtains servers public key to encrypt a new random secret key (session key) . to be used throughout the session
- the server decrypts the session key by the private key
encrypting a hard disk
- backup the data before the encryption process
- choose the encryption software that meets the security needs and is compatable with your os
- select if you want to encrypt the whole hard disk or specific partitions only
- set a strong password (private key)
- Begin the encryption process& wait till complete
- store the recovery key.
Adv of encryption
avoid ransom ,identity theft, fraud
company secrets wont be hacked & sold to competitors
DISADV of encryption
it takes time to load the encrypted data & requires additional processing power
uses more valuable memory for both client& sever
if private key is lost it is difficult to recover the data(may be cost perminantly)
SSL /TLS VS Ipsec
digital certificate only needed in sst ItIs for sever only while both certificates are needed in ipsec
so ipsec is more secure
VPN is Only for lP sec
SSL /TLS saves Money because Client doesnt need digital Certificate
the purpose of SSL/ TL S
enable protection/ encryption
make sure that the businesses say who they say they are
ensures data integrity
what information does a digital certificate hold?
- Domain name
- which org was the certificate issued for
- expiery date
- public key
what is the purpose of a digital certificate?
to verify the ownership of the website to avoid fraud
what are the types of data
1- Numeric
2. Boolean
3- Alphanumeric
4. Date/ time
5. currency
what is validation?
the process to ensure the data being entered is sensible , meets certain criteria or standards
what is verification
the process of confirming the accuracy& consistancy & integrity of the data When it is entered into the computer or transfered from 1 medium to another to ensure it is reliable & free of error
What are the validation methods
presence check
Range check
Type/ character check
length checks
format / picture check
limit check
Lookup check
consistancy check
check digit
presence check
Data must not be skipped or left out
applied on any datatype
Range check
checks if the data is within a specified range of values/2 boundaries
on numeric & Date/ time
Type/ character check
ensures that the data entered is of a particular type
numeric & Date/ time
length check
ensures that the data has the correct number of characters
Alphanumeric
format or Picture check
ensures a specific combination of characters that must be followed
Alphanumeric & Date /time
Limit check
checks that the date is greater than or less than a preset valve One boundary, One boundary
numiric& date/ time
Lookup check
compares data that has been entered witha limited set of valid entries. if it matches one of these then it is allowed if it doesnt then an error isge will be displayed
any data type
consistancy check
when the valve of 2 different lds depend on each other it checks that the data across the two field is consistant
Any datatype
digit check
a single digit added to a numerical value or alphanumeric code to verify the accuracy of the code to detect to check errors
numeric/ alphanumeric
differance between validation & verification
validation checks if data is sensible or not- verification checks if the dat has been copied or entered correctly
validation caried out by computer- verification done by computer/ human
validation doesnt tell if the data has been copied correctly or not verification could alert the user if an error occurs
what are the methods of verification.
visual checking
double data entry
parity check
checksum
Hash total
control total
visual checking
the user checks visually if the data entered Matches the original source
weakness for visual check
it doesnt ensure if data entered is correct
Double data entry (DDE)
inputting the data into the system twice
the data will be compared by the system if they match then it. verified
weakness of DDE
the data could be entered incorrectly twice
parity check
used to find errors during data transmission
what are the 2 types of parity check
- even parity : a bit is added to parity making even numbers of 1’s at the endat the end
- odd parity: bit added to the end ofthe byte making an odd number of 1 ‘s
weakness of parity check
an error will not apear if the data is transposed
check sum
calculation result of entire file to check it has been transmitted Or copied correctly
weakness of checksum
wouldn’t notice if2 or more bytes were swapped.
what are the types of algorithm in checksum
- MD5
- SHA-1
- SHA-2
- SHA-3
Hash total
A calculation calculated bll adding together values from an input field for all the correct records that need to be input
control total
same as hash total but only carried on numeric fields.
weakness of hash & control total
if 2 numbers are transposed an error will occur but will not be picked up by them (controls)
Data processing
an activity that manipulates or carries out operation on data (delete, add, change)
the 3 types of data processing
- Batch processing
- online processing
- real time processing
what is batch processing
transactions that need to be preformed on the data are collected together into a batch , the system automatically carries out all the transactions & uplates the data file
ADV’s of batch processing
- effective for processing large volumes of data
- data is processed all together & not one by one
- Requires very little /no human interaction
Examples of batch
- automated backups
2- employee wages - customer order & stock control
4.customer billing(bills at end of month) - processing checks
what’s a master file
a file that stores data that doesnt change often
what’s a transaction file?
a file that usually stores data that changes every day or week
Algorithm example⇒ Batch
a. validate
b. sort according to master file
C. read records
d. compare
e. if match do calculation
if don’t match copy as is
f.read next until EOF
g. copy any of data remaining in old master file to new.
another name for online processing
interactive processing
online processing
user inputs data the computer responds until the user saves the data (almost immediately)
one transaction at a time.
Differance between batch & online processing
Data searching:
Batch: sequential access
online: direct access
when does the process begin:
Batch: gathering data and process it all together in batches
online: process is done almost immediately
amount of data:
batch: huge amount of data
online: one transaction at a time
Example of online processing
- online booking
- EFT (electronic funds transfer)
3.online stores - Automatic stock control
- electronic data exchange
- B2B buying & selling
Real-time- processing
system processes data as soon as it has been input
used when immediacy of data is vital
usually found in systems that use sensors
Examples of real time processing
- Air traffic control
- online computer games
- Rocket guidance systems
ADV of real time p
no delay
information always upto date
instant data collection
Dis ADV of real time P
needs expensive & complex computer systems
continuously occupies cpu⇒ very expensive
