Negative Binary Numbers

Test yourself

Negative Binary Numbers

There exist two systems to express negative numbers in binary.

Sign and magnitude

The most significant bit of the binary number is a designated sign bit.
If the number is positive then the MSB is set to 0.
If the number is negative then the MSB is set to 1.

Sign and magnitude

This method allows us to express negative numbers.
However, it is very hard to perform arithmetic using this representation.

Two's compliment

The place value of the MSB is made negative.
This allows us to express negative numbers by subtracting the largest possible place value, and then adding the difference back on.

Two's compliment

This method is much easier to perform calculations with since we can express subtraction as follows:
- a - b = a + (-b)
This means we do not need a separate subtractor circuit in our processor.

1Computer Systems

1.1Data Representation

1.1.1Binary Numbers

1.1.2Negative Binary Numbers

1.1.3Hexadecimal

1.1.4Using Hexadecimal

1.1.5Converting Binary & Hexadecimal

1.1.6Converting Denary & Hexadecimal

1.1.7Capacity

1.1.8Calculating Capacity Requirements

1.1.9Binary in Computer Systems

1.1.10Data Compression

1.1.11Run Length Encoding

1.1.12File Formats

1.2Data Transmission

1.2.1Packet Switching

1.2.2Data Transmission

1.2.3Universal Serial Bus (USB)

1.2.4Parity Check

1.2.5Checksum & Echo Checks

1.2.6Encryption

1.3Hardware

1.4Software

1.4.1Operating Systems

1.4.2Interrupts

1.4.3High-Level Languages

1.4.4Low-Level Languages

1.5The Internet & its Uses

1.5.1The Internet

1.5.2Uniform Resource Locators (URLs)

1.5.3DNS

1.5.4HTML

1.5.5Cookies

1.5.6Web Hosting

1.5.7Digital Currency

1.6Cyber Security

1.6.1Forms of Attack

1.6.2Penetration Testing

1.6.3Types of Malware

1.6.4How Malware Spreads

1.6.5Protecting Against Malware

1.6.6Information Security

1.6.7Structured Query Language (SQL) Injection

1.6.8Firewalls

1.6.9Authentication: User Access Levels

1.6.10Authentication: Passwords

1.6.11Social Engineering

1.6.12Phishing

1.6.13Denial of Service Attacks

1.7Automated & Emerging Technologies

1.7.1Automated Systems

1.7.2Robotics

1.7.3Artificial Intelligence

2Algorithms, Programming & Logic

2.1Algorithm Design & Problem Solving

2.1.1Computational Thinking - Abstraction

2.1.2Computational Thinking - Decomposition

2.1.3Computational Thinking - Algorithmic Thinking

2.1.4Pseudocode

2.1.5Flow Diagrams

2.1.6Interpreting, Correcting & Completing Algorithm

2.1.7Correcting Algorithms

2.1.8Completing Algorithms

2.1.9Testing

2.1.10Types of Testing

2.1.11Test Plans

2.1.12Validation & Sanitation

2.1.13Authentication & Contingencies

2.2Programming

2.2.1Programming Fundamentals - Variables & Constants

2.2.2Programming Fundamentals - Comments

2.2.3Programming Fundamentals - Input & Output

2.2.4Data Types

2.2.5Casting

2.2.6Controlling Program Flow - Sequence

2.2.7Controlling Program Flow - Selection

2.2.8Controlling Program Flow - Iteration

2.2.9Modularity - Subroutines

2.2.10Modularity - Scope

2.2.11Arrays

2.3Databases

2.3.1Structuring Data - Records

2.3.2Structuring Data - Databases

2.3.3SQL

2.4Boolean Logic

2.4.1Binary Systems

2.4.2Logic Circuits

2.4.3Truth Tables

2.4.4Evaluating Expressions

2.4.5Boolean Operators

2.4.6End of Topic Test - Logic

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