AS (H046) Computer Science

1.1 Characteristics of contemporary processors, input, output and storage devices

1.1.1

Architecture

Main Parts of a CPU

• Control Unit
• ALU
• Registers

Registers within the CPU

• Accumulator
• Memory Data Register
• Memory Address Register
• Program Counter
• Current Instruction Register

Fetch-Decode-Execute cycle

CPU performance factors

• Clock speed
• Multi-core
• Cache
• RAM size
• GPU
• Pipelining

System performance factors

• Faster CPU
• Improved RAM
• Graphics card
• Upgraded Drive
• Upgraded OS

Von Neumann and Harvard

1.1.2

Types of Processor

CISC and RISC

Multicore and Parallel processing

• Pipelining
• Array processor
• Multi-core
• GPU

1.1.3

Input Output and Storage

Selecting Devices

Type of storage

• Magnetic
• Optical
• Solid State

RAM and ROM and virtual memory

1.2 Types of software and software development

1.2.1

Operating System

Purpose of an operating system

• Kernel
• Device Drivers
• Utilities
• User Interface

Memory Management

• Segmentation
• Pagination
• Virtual memory
• Memory issues

Interrupts and Polling

Scheduling

• Round Robin
• First Come First Serve
• Shortest Job
• Shortest time
• Multi-level

Types of operating systems

• Multi Tasking
• Multi User
• Distributed
• Real Time

BIOS

Device Drivers

Virtual Machines

1.2.2

Applications Generation

Types of applications and utilities

• Applications
• Utilities
• Generic software
• Bespoke & Custom software
• Closed source
• Open source

Applications generation/ program creation

• Translators
• Interpreters
• Compilers
• Assemblers

1.2.3

Introduction to Programming

Procedural language techniques

• What is a procedural language
• Procedures
• Subroutines
• Functions
• Program flow
• Variables and Scope
• Constants
• String Handling
• File Handling
• Operators

Assembly language and LMC

• LMC Model
• Instruction Set
• Labels
• Calculation
• Branching
• Input-Output
• Loops

1.3 Exchanging data

1.3.1

Databases

Databases

• Flat file databases
• Relational databases
• Primary key
• Foreign key
• Secondary key

E-R Diagrams

• Entities
• One-to-One
• One-to-Many
• Many-Many
• E-R Formats

1.3.2

Network Characteristics

Networks

• Network Characteristics
• Protocols and Standards Importance

TCP/IP Stack

• TCP/IP
• Ports and Sockets

Packet Switching

• Circuit switching
• Datagrams
• Packet Switching

IP Addressing

• IP Format
• Subnet Mask
• IANA and ICANN
• IPv4 and IPv6
• DNS and Domain Name
• MAC address

Models and Protocol Layering

• Internet 4 Layer Model
• Protocol Layering
• Physical & Logical layers
• OSI

Internet Protocols

• Global standards
• UDP
• HTTP(s)
• FTP
• POP,LDAP,SMTP
• Ethernet

LANs, WANs, PANs, SANs, MANS

• PAN
• LAN
• WAN
• SAN and MAN

Network configuration

• Client Server
• Peer to peer

1.4 Representing Data

1.4.1

Data Types

Primitive

• Integer
• Real
• Character
• String
• Boolean

Integer

• Range
• Unsigned
• Signed
• Sign & Magnitude
• Two's compliment

Real

• Fixed point
• Floating point
• Mantissa, Exponent
• Placing binary point

Normalising

• Floating point limits
• Normalising floating point
• Examples

1.5 Legal, moral, cultural and ethical issues

1.5.1

Computing related legislation

1.5.2

Ethical, moral and cultural issues

Artificial Intelligence

Automated Decision Making

Censorship and the internet

Computers in the workforce

2.2 Problem solving and programming

2.2.2

Software development

Software Development

• Waterfall
• Rapid Application Development
• Spiral
• Agile
• Extreme Programming
• Merits of different software methods