• Sequential
• Random
• Serial
• Indexed-sequential

• 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 

• it generates and/or allocates an IP address

A computer system refers to computer components that collectively function as a single unit to achieve the desired goal. It can also be defined as a collection of hardware, software, and liveware that work together to receive, process, and manage data

• Real-time OS reads information from input devices and must respond within a short duration of time to ensure correct performance
• Distributed OS distributes computation among several physical processors which do not share memory or clock

The following are some of the possible definitions:

It is system software designed to help the users to analyse, configure, optimize, or maintain a computer

System software that helps maintain the proper and smooth functioning of a computer system

Examples include antivirus software, Disk clean-up tools, disk defragmenters, backup software, etc

1. Virus scanning / Anti-virus. Used to locate and delete viruses / scans and compares files with databases of known viruses.
2. Firewall: checks data packets / examines source address / filters out unexpected packets.
3. Back up. Copies data onto a separate storage device for use if the original data is lost or corrupted.

• Making prosthetic limbs for patients
• Making items which allow precise reconstructive surgery
• Making light-weight plane wings
• Making sculptures

• problem recognition involves the system analyst identifying and accepting the existence of a problem in the current system
• problem definition involves the analyst studying the system to understand its operations and shortcomings

• It ensures that each row has a unique and non-null primary key

CLI

• Commands have to be typed in full with no mistakes
• Requires memorization of commands
• Uses less memory

GUI

• Due to graphics, GUI uses a lot of memory
• GUI is more user friendly
• Cannot operate properly if memory is low

Comparison

• Both carry out file management
• Both are operating systems
• Both control software and hardware

• Registers are small amounts of memory available that hold data fetched from memory or data waiting to be stored in memory. A temporary holding place for the instruction that has been fetched.
• The system clock purpose is to determine the pace of the cycle, each tick of the clock a part of the fetch-execute cycle occurs. Regulates the timing and speed of a computers systems functions.

 A single executable file is produced 

The executable program is portable between machines

The program source code is not available

Code can be optimised/made more efficient 

Entire source code file is converted at once

No special environment is needed to execute the code 

It creates object/machine code

Error report is provided at the end of the compilation

• A barcode is one-dimensional while a QR code is two dimensional
• Barcodes are a set of vertical lines and QR code contains squares
• QR codes can be read from any angle . Barcode is only above or below and lined up horizontally

• 4 (four)

Is an arrangement of people, data, processes, communication and IT that interact to support problem solving

Components of an information system

• Hardware
• Software
• Data - information manipulated by software
• people- all people involved
• Processes - steps to accomplish a goal

• Data Integrity: they provide ways or mechanisms for enforcing data integrity constraints, such as referential integrity. If a record in the parent table is deleted, related records in the child table also get deleted. This ensures accurthe acy and consistency of data stored in the database
• Data Security
• Concurrency control
• Reduces data redundancy
• Data retrieval and querying
• Data indexing
• Data consistency and acid transaction
• Data backup and recovery
• Data sharing and collaboration
• Convenient data maintenance

• Refers to the scrambling of data into unreadable form before transmission over a telecommunication media  OR
• transformation of data from plaintext to ciphertext