System analyst

Web designers

Network administrators

Database administrators

Programmers

Computer technicians

• Main memory is transitory/temporary/volatile, secondary storage is (semi-)permanent
• The processor can only use data/instructions that are in the main memory
• Main memory is directly accessible to the processor, secondary storage is not directly accessible to the processor 

• Broadcast Radio
• Infrared
• Bluetooth
• Microwaves
• Satellite

• 4 (four)

(a) byte

• fixed number of bits, 8 bits
• represents a character

(b) compiler  program

• converts/changes/translates high-level language into machine code/machine language/low-level language/object code
• changes each high-level language instruction into machine code instructions
• produces an independent program capable of being executed by itself
• all (syntax errors) listed
• converts the whole program before execution/in one go
• converts source code to object code

(c) handshaking

• exchanging of signals to establish communication between two devices/computers e.g. printer and computer, modem and computer

(d) technical documentation

• documentation to ensure that the system can be maintained/updated/altered/developed/upgraded
• trouble shooting/correcting errors/correcting faults
• explanation of what the program does/how the system works
• contains file structures
• algorithms/flow charts/pseudo code
• program listings
• hierarchical chart

(e) simulation

• studying the behavior of a system by using a model/represents real-life/mathematical representation
  e.g. flight simulator (or others), hazardous applications results can be predicted

download speed :
– speed at which information/data is transferred FROM server/Internet
– speed at which information/data is transferred TO the user’s computer
upload speed :
– speed at which information/data is transferred FROM user’s computer
– speed at which information/data is transferred TO the Internet/server

• A laser printer makes use of powdered ink and static electricity to print
• Unlike inkjet printers which print line-by-line, laser printers print the whole page in one go

Steps

• The data from the  file to be printed is sent to a printer driver
• The printer driver checks that the data is in an understandable format
• The printer driver checks if the printer is able to carry out the print job
• The data is sent to the printer and is stored in a printer buffer
• A printing drum in the printer is given a positve charge. A laser beam removes the positive charge in some areas. This leaves negatively charged areas which matches the characters/images to be printed
•  

• novice can use the system right away
• user-friendly/easy to select
• click on icons/picture to select
• easier to input/words are replaced with icons
• no need to know command language to use the system/remember
• command language
• selecting item using mouse is faster than entering commands
• avoids typing errors
• no need to type
• no need to remember commands
• no need know the different commands for the different software
• multitasking (several programs open at the same time therefore easier
• /faster to switch
• easier/faster switching between files, folders etc.

Without a primary key, a table in a database may have duplicate rows, making data not uniquely identifiable. This can lead to issues with data integrity and challenges in maintaining relationships between tables. Retrieving and updating specific records becomes problematic, and setting referential integrity constraints is impossible, potentially leading to loss of data.

Dual input of data

• Two inputs are compared by the system and any discrepancies are reported (and not stored.)
• Data input once, either printed out or checked on the screen and  errors corrected

 Rules are given to the processor

• Only accept A, B, C, D, E, F, G i.e Any other input rejected.

Drop-down list/radio buttons

• Provides only valid inputs, so no other validation is required

•  map IP addresses to names and criteria
• To map directory services
• Maintain directory of domain names
• To map URL (web address) to IP address

• It covers many aspects that will be used to decide whether to go ahead with the project or not.
• The main components are technical, operational, economic, legal and scheduling.

The user is not allowed to access the source code so, they cannot tailor the software to their needs and  they cannot fix any bugs in it

The software is still covered by copyright

The user must get the owner’s permission to do anything beyond using it

Manages memory (RAM) 

• Allocates memory to programs currently executing •

Ensures programs/data do not corrupt each other: Ensures all programs and data including itself is stored in correct memory locations

Manages processes: Ensures different processes can utilise the CPU and do not interfere with each other or crash •

Allows a user to run programs : On a multi-tasking O/S ensure that all tasks appear to run simultaneously

• Allocates time slices 
• Scheduling of programs
• Handles interrupt
• Allows a user to configure hardware

• Phased means that only one part of the system is implemented at a time

• Object code refers to a program in machine language while source code to a program in a high level language that must be translated to object code for it to be machine readable

• data must be up to date
•  data can only be read/used for the purpose for which it was collected
• data must be adequate, relevant and not excessive
• data must be accurate
• data must be destroyed when no longer needed/don’t keep longer than necessary
• data user must register what data stored
• data must be used/collected fairly and lawfully
• data must be held securely
• data must be protected from accidental damage
• only authorised personnel can have access to the data
• fines are imposed for data mis-use
• data should not be passed on to a third party without permission
• a person can view data and have it changed/removed if incorrect

ROM stores BIOS / bootstrap / start-up 

RAM stores currently executing programs and data

- Passwords
- Hierarchy
- Only allow some staff to access student files
- Only some machines able to access
- Physical location of these machines
- Physical lock on machines
- Encrypted data in files
- Firewall if connected to the Internet

• an attribute/combination of attributes chosen to ensure that the records in a table are unique