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- theorems
---
# Additive inverse property
**Let $a$ represent any member of $\mathbb{Z}$. Then there is a unique member of
$\mathbb{Z}$ $-a$ such that:**

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tags: [algebra]
---
# Algebra key terms
- **Variable**
- A symbol that stands for a value which may vary
- **Equation**

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- theorems
---
# Axioms of set theory
The basic notions of set theory are defined in
[Basic properties of sets](Basic%20properties%20of%20sets.md). There we
introduced a formal syntax that will be utilised to define the axioms. For easy

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- set-theory
---
# Basic properties of sets
## Set theory
Set theory is a sub-discipline of both mathematics and formal logic. In

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- logic
---
# Conjunction Introduction
If two conjuncts have each been independently derived then they can be
conjoined. Also known more simply as _Conjunction_

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---
id: h7f8
tags:
- disks
- Linux
created: Monday, May 06, 2024
---
# Creating a Linux partition table
## Creating a partition table
To demonstrate the process of partitioning a harddrive I am going to repartition

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@ -3,7 +3,7 @@ tags: [memory, hardware]
created: Friday, July 12, 2024
---
# DRAM_and_SRAM_memory
# DRAM and SRAM memory
There are two types of RAM memory: [SRAM and DRAM](./DRAM_and_SRAM_memory.md).

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created: Saturday, March 30, 2024
---
# Docker_CLI
# Docker CLI
```sh
# List images

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- shell
---
# Environmental and shell variables
## Important!
To understand the difference between environmental and shell variables know
@ -43,8 +45,7 @@ spawned instances? Is this even possible or do they die on `exit` .
- The environment is an area that the shell builds every time that it starts a
session. It contains variables that define system properties.
- Every time a
[shell session](Shell-sessions-e6dd743dec1d4fe3b1ee672c8f9731f6)
- Every time a [shell session](Shell-sessions-e6dd743dec1d4fe3b1ee672c8f9731f6)
spawns, a process takes place to gather and compile information that should be
available to the shell process and its child processes. It obtains the data
for these settings from a variety of different files and settings on the

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tags: [algebra]
---
## Equivalent equations
# Equivalent equations
> Two equations are equivalent if they have the same
> [solution](Algebra%20key%20terms.md#678811) set.
@ -30,11 +30,16 @@ of the $=$ symbol). Adding or subtracting the same quantity from both sides
### Demonstration with addition
$$ x - 4 = 3
$$
x - 4 = 3
$$
The [solution](Algebra%20key%20terms.md#678811) to this equation is $7$
$$ x -
4 (+4) = 3 (+ 4) $$
$$
x -
4 (+4) = 3 (+ 4)
$$
Here we have added $4$ to each side of the equation. If $x = 7$ then:
@ -46,11 +51,16 @@ $$ 3 + 4 = 7 $$
### Demonstration with subtraction
$$ x + 4 = 9
$$
x + 4 = 9
$$
The [solution](Algebra%20key%20terms.md#678811) to this equation is $5$.
$$ x +
4 (-4) = 9(-4) $$
$$
x +
4 (-4) = 9(-4)
$$
Here we have subtracted $4$ from each side of the equation. If $x = 5$ then:
@ -62,8 +72,9 @@ $$ 9 - 4 = 5 $$
### Demonstration with multiplication
$$x \cdot 2 = 10 $$
The [solution](Algebra%20key%20terms.md#678811) to this equation is $5$.
$$x \cdot 2 = 10 $$ The [solution](Algebra%20key%20terms.md#678811) to this
equation is $5$.
$$
(x \cdot 2) \cdot 3 = 10 \cdot 3 $$ Here we have multiplied each side of the
equation by $3$. If $x =5$ then
@ -78,7 +89,12 @@ The [solution](Algebra%20key%20terms.md#678811) to this equation is $6$.
$$\frac{x
\cdot 3}{3} = \frac{18}{3}
$$
Here we have divided each side of the equation by $3$. If $x$ is 6, then
$$\frac{6
\cdot 3}{3} = 6$$
$$
\frac{6
\cdot 3}{3} = 6
$$
$$\frac{18}{3} = 6 $$

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- fractions
---
# Equivalent fractions
Two fractions are equivalent if they represent the same value. To begin with we
can represent this visually:

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- fractions
---
# Expressing whole numbers as fractions
Being asked to express a natural number as a fraction seems confusing at first
but you need to just know that for any whole number $n$, you express it as a
fraction with $\frac{n}{1}$.

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@ -3,7 +3,7 @@ tags:
- prealgebra
---
## Factors and divisors
# Factors and divisors
The terms **factor** and **divisor** are used interchangeably. They are
different ways of expressing the same mathematical truth and this is because of

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- prealgebra
---
# Formal conventions
## Grouping symbols
We use parentheses to delimit the part of an expression we want evaluated first.
@ -14,8 +16,10 @@ grouping symbols first,
We only write one equals sign per line. For example, if we are resolving
parentheses:
$$ \begin{equation} \begin{split} 2 + \[3 + (4+5)\] = 2 + \[3 +9\] \\ = 2 + 12
\\ = 14 \end{split} \end{equation} $$
$$
\begin{equation} \begin{split} 2 + \[3 + (4+5)\] = 2 + \[3 +9\] \\ = 2 + 12
\\ = 14 \end{split} \end{equation}
$$
We call parentheses (`()`), brackets (`[]`) and braces `{}`) grouping symbols.
When groupings (say parentheses) are used, the expression inside any pair of

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- theorems
---
# Fundamental Theorem of Arithmetic
> Every integer greater than one is either a prime number itself or is product
> of a unique combination of primes.

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- REST
---
# HTTP request types
## GET
- Get data

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- fractions
---
# Increasing fractions to their highest terms
Given the equivalence between factors and divisors we can increase fractions to
higher terms in a very similar way to when we reduce fractions. In the latter
case we are dividing by divisors to reduce. In the former, we are multiplying by

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- shell
---
# Introduction to the Unix shell
## Unix based systems
Many operating systems are based on the UNIX software architecture. macOS/OSX

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- prealgebra
---
# Inversion of operators
## Addition, subtraction
Addition is the inverse of subtraction: $$(x - a) + a = x$$ $$ (6 - 2) + 2 = 6
$$
Subtraction is the inverse of addition: $$(x + a) - a = x$$ $$ (3 + 2) - 2 = 3$$
Division is the inverse of multiplication $$ \frac{a \cdot x}{a} = x$$
$$ \frac{6
\cdot 3}{6} = 3$$
\cdot 3}{6} = 3
$$
Multiplication is the inverse of division $$ a \cdot \frac{x}{a} = x$$
$$ 2 \cdot
\frac{8}{2} = 8$$
$$
2 \cdot
\frac{8}{2} = 8
$$

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@ -4,7 +4,7 @@ tags: [python, shell]
created: Monday, April 29, 2024
---
# Invoking the shell_in_Python
# Invoking the shell in Python
```py
import subprocess

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- procedural
---
# Killing processes
## Kill a process running on a port
For example a local server.

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- shell
---
# Listing and navigating directories in the shell
## Listing options
Obviously we know that in order to list the files and sub-directories in our

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@ -3,7 +3,7 @@ tags: [computer-history, memory]
created: Friday, September 27, 2024
---
# Magnetic_core_memory
# Magnetic core memory
![](../img/magnetic-core-memory.jpg)

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created: Friday, September 27, 2024
---
# Mainframe_computers
# Mainframe computers
A mainframe computer, also known as a "big iron" is a high performance computer
used for resource-intensive tasks that require greater security and availability

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@ -3,7 +3,7 @@ tags: ["question"]
created: Thursday, August 01, 2024
---
# Memory_versus_processor
# Memory versus processor
> Would a more powerful processor with average or reduced memory capacity
> perform better than, equal to, or less than a less powerful processor with

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- node-js
---
# Module wrapping at runtime in NodeJS
## The Module Wrapper Function
When Node runs each of our module files are wrapped within an

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- prealgebra
---
# Natural numbers
## The set of natural numbers
$$ \mathbb{N} = {1, 2, 3, ...} $$

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tags: [algebra, exponents]
---
# Negative exponents
When calculating the exponents of a negative number the answer will always will
be positive:

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@ -3,7 +3,7 @@ tags: [networks, hardware]
created: Tuesday, August 06, 2024
---
# Network_card
# Network card
The network card (technically know as the Network Interface Card (NIC)) or
_network adapter_ is the hardware device that allows a computer to connect to a

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@ -3,7 +3,7 @@ tags: [networks]
created: Saturday, August 03, 2024
---
# Network_hosts
# Network hosts
A network **host** or **node** is a single computing device attached to a
![network](Network_fundamentals.md)

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---
id: 5043
tags: [node-js]
created: Friday, April 26, 2024
---
# NodeJS_scripts
# NodeJS scripts
If we want to use NodeJS as a scripting language without going to the trouble of
setting up an NPM-based development environment, we can use the following

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@ -3,6 +3,8 @@ tags:
- prealgebra
---
# Order of operations
1. Evaluate expressions in **parentheses**
1. Evaluate **exponents**
1. Evaluate **multiplications and divisions** from left to right in the order

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- number-theory
---
### Prime factorisation
# Prime factorisation
Prime factorisation is the activity of expressing a composite number as the
unique product of [prime numbers](Primes%20and%20composites.md). There are two
@ -17,8 +17,8 @@ main approaches to this:
> $n$. We then repeat this process with the resulting factors working
> recursively until the numbers we are left with are primes.
![Untitled Diagram-Page-1.drawio.png](Untitled%20Diagram-Page-1.drawio.png)
_The prime factors of 27 are 2, 3, 3_
![Untitled Diagram-Page-1.drawio.png](Untitled%20Diagram-Page-1.drawio.png) _The
prime factors of 27 are 2, 3, 3_
it doesn't matter which products we choose as the interim factors, we should
always reach the same outcome:

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- number-theory
---
## Prime and composite numbers
# Prime and composite numbers
Definition of a **prime number**:

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---
id: rmvm
tags: [computer-architecture, memory]
created: Monday, June 24, 2024
---
# ROM versus disk loading
I will explore the concept via the practical examples of cartridge-based and
disk-based video games console.
When you insert a disk into an Xbox, the game data is typically read from the
disk and transferred into the console's memory by the OS. If the game is
installed to the hard drive, this initially involves transferring substantial
amounts of data to speed up future access. When you insert a cartridge into a
console like the SNES, the data is not transferred in the same way. Instead, the
cartridge contains a ROM chip that, when inserted, integrates directly with the
motherboard. From the operating systems point of view, this ROM chip behaves as
an extension of the systems memory architecture.
The primary advantage of a ROM-based game is significantly reduced latency. The
game data can be accessed as rapidly as any other data moving along the buses of
the motherboard. With a disk, the data must first be read into a buffer and then
transferred to a memory address where it can be accessed by the CPU.
With a ROM, while the console CPU still uses its own RAM to run the game
(similar to disk-based systems), the game data on the ROM can be loaded into
this RAM more quickly because it is directly attached to the motherboard. This
makes the ROM cartridge effectively a fast, directly connected storage device.
However, despite its speed, the limitation of a ROM cartridge is its storage
capacity—it can hold only as much data as the chip can accommodate. In contrast,
a disk can store much more data. This larger storage capacity allows not just
for bigger and more complex games but also for the possibility of expanding the
game through additional data downloaded to the console's hard drive. Such
expansions or patches represent additional data from the consoles storage that,
combined with the original disk data, are synthesized in memory at runtime for
enhanced or updated gameplay experiences.
(Note however that modern cartridge-based consoles like the Nintendo Switch can
also combine ROM-data with expanded data from the console HDD, sourced from the
internet.)
Both disks and ROMs are forms of static storage in the context of a game
console. While disks can technically be overwritten with new data, in practice,
manufacturers implement various locks and protections to prevent this. Any
changes or additions to the game, such as patches or expansions, are not written
back to the original disk. Instead, these updates are stored on the console's
hard drive.
Therefore, if you download an expansion for a game on your Xbox, the original
disk remains unchanged as when you first purchased it. Consequently, if you were
to take that disk and load it on another Xbox, it would not include any of the
expansions or updates. The game would function in its original form, as the
additional content and updates reside solely on the hard drive of the first
console where they were downloaded.
## Related notes

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@ -9,22 +9,50 @@ created: Monday, June 24, 2024
I will explore the concept via the practical examples of cartridge-based and
disk-based video games console.
When you insert a disk into an XBox, the game data is transferred from the disk
into the console's memory by the OS. When you insert a cartridge into a SNES,
there is no transferral of data. The game data is stored on a chip and this chip
is attached to the motherboard. From the point of view of the OS, it is just
another chip along with the others that comprise the motherboard.
When you insert a disk into an Xbox, the game data is typically read from the
disk and transferred into the console's memory by the OS. If the game is
installed to the hard drive, this initially involves transferring substantial
amounts of data to speed up future access. When you insert a cartridge into a
console like the SNES, the data is not transferred in the same way. Instead, the
cartridge contains a ROM chip that, when inserted, integrates directly with the
motherboard. From the operating systems point of view, this ROM chip behaves as
an extension of the systems memory architecture.
The chief advantage with a ROM game is that the latency is greatly reduced. The
game data can be accessed as rapidly as any other data travelling along the
busses of the motherboard. With a disk, the bytes have to be transferred in a
buffer from the disk into a memory address and from there, accessed by the CPU.
The primary advantage of a ROM-based game is significantly reduced latency. The
game data can be accessed as rapidly as any other data moving along the buses of
the motherboard. With a disk, the data must first be read into a buffer and then
transferred to a memory address where it can be accessed by the CPU.
With a ROM, the console CPU still uses its own memory to run the game (as with
disk-based consoles), it is just that the game data on the ROM can be loaded
into memory quicker because it is attached to the motherboard.
With a ROM, while the console CPU still uses its own RAM to run the game
(similar to disk-based systems), the game data on the ROM can be loaded into
this RAM more quickly because it is directly attached to the motherboard. This
makes the ROM cartridge effectively a fast, directly connected storage device.
becomes part of the motherboard just like the other chips that comprise the
motherboard.
However, despite its speed, the limitation of a ROM cartridge is its storage
capacity—it can hold only as much data as the chip can accommodate. In contrast,
a disk can store much more data. This larger storage capacity allows not just
for bigger and more complex games but also for the possibility of expanding the
game through additional data downloaded to the console's hard drive. Such
expansions or patches represent additional data from the consoles storage that,
combined with the original disk data, are synthesized in memory at runtime for
enhanced or updated gameplay experiences.
(Note however that modern cartridge-based consoles like the Nintendo Switch can
also combine ROM-data with expanded data from the console HDD, sourced from the
internet.)
Both disks and ROMs are forms of static storage in the context of a game
console. While disks can technically be overwritten with new data, in practice,
manufacturers implement various locks and protections to prevent this. Any
changes or additions to the game, such as patches or expansions, are not written
back to the original disk. Instead, these updates are stored on the console's
hard drive.
Therefore, if you download an expansion for a game on your Xbox, the original
disk remains unchanged as when you first purchased it. Consequently, if you were
to take that disk and load it on another Xbox, it would not include any of the
expansions or updates. The game would function in its original form, as the
additional content and updates reside solely on the hard drive of the first
console where they were downloaded.
## Related notes

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@ -4,7 +4,7 @@ tags:
- fractions
---
## Reducing fractions to their lowest terms
# Reducing fractions to their lowest terms
> A fraction is said to be _reduced to its lowest terms_ if the
> [greatest common divisor](Factors%20and%20divisors.md#greatest-common-divisor)