[LMG S5] Issue 63: Limitations of Meltdown and Spectre
Previously: To snoop the cache, we: Flush the cache corresponding to the 256 memory addresses (to get a cache miss when attempting to load the data from...
[LMG S5] Issue 62: Cache snooping
Apologies for the delay in Issue 62, it took longer than expected to work out how to laymanise it enough to be easily understood. Much thanks to Alex for his...
[LMG S5] Issue 61: Mapping the cache
Previously: Speculative execution is a feature that lets the CPU speed up execution if it correctly predicts a decision point. The CPU carries out the...
[LMG S5] Issue 60: CPU Optimisation Part 2 – Speculative Execution and Spectre
Previously: A set of instructions can trick a CPU into reordering load instructions so that the data is temporarily loaded into the cache before the...
[LMG S5] Issue 59: Meltdown
Previously: The CPU comprises different types of execution units. All the execution units can run at the same time, but they may execute instructions over...
[LMG S5] Issue 58: CPU Optimisation Part 1 – Out-of-Order Processing
Previously: The CPU stores data for ready access in the CPU cache. Accessing data from the CPU cache is much faster than accessing data from main memory....
[LMG S5] Issue 57: Cache, the CPU’s working space
Previously: The operating system is responsible for listing and managing the computer’s resources, making them available to programs running on the computer,...
[LMG S5] Issue 56: Operating Systems and resource management
Previously: The CPU just executes instruction after instruction after instruction. Each instruction may consist of loading data from a memory location,...
[LMG S5] Issue 55: Addressing memory
Previously: To get useful output from a CPU, we must translate the operations we want it to perform into CPU instructions, in a process known as compiling....
[LMG S5] Issue 54: Compiling programming code into CPU instructions
Previously: CPUs are unconscious slaves that simply execute instruction after instruction, at a very fast rate. Last issue, I introduced the idea of the CPU...
[LMG S5] Issue 53: The CPU is an instruction-obeying slave
Previously: PDF’s markup language is more concerned with how things appear on the page than with what they were originally. Once the PDF is generated, it is...
[LMG S4] Issue 52: PDFs part 2 – Text and images
Previously: PDF is the gold standard for universal compatibility (supported by most software and platforms) and visual fidelity (displays exactly the same...
![[LMG S4] Issue 51: PDFs part 1 – Compatibility and fidelity](https://raw.githubusercontent.com/ngjunsiang/laymansguide/release/season4/issue051/issue051_01.png)
[LMG S4] Issue 51: PDFs part 1 – Compatibility and fidelity
Previously: An HTML file contains markup tags that tell the browser how to interpret and format the text within the tags. Other document formats usually use...
![[LMG S4] Issue 50: Complex file formats and the Document](https://raw.githubusercontent.com/ngjunsiang/laymansguide/release/season4/issue050/issue050_01.png)
[LMG S4] Issue 50: Complex file formats and the Document
Previously: A file consists of data, preceded by a file header which describes the data. Software (including operating systems) detect the kind of data...
![[LMG S4] Issue 49: What is a File?](https://raw.githubusercontent.com/ngjunsiang/laymansguide/release/season4/issue049/issue049_01.png)
[LMG S4] Issue 49: What is a File?
Previously: A video container can hold one or more audio, video, or text data streams. To encode or decode a data stream, you need to have the necessary...
![[LMG S4] Issue 48: Of containers and codecs](https://raw.githubusercontent.com/ngjunsiang/laymansguide/release/season4/issue048/issue048_01.png)
[LMG S4] Issue 48: Of containers and codecs
Previously: Data cannot be compressed beyond its predictability limit in a lossless fashion. Lossless compression does not discard any information. It spots...
![[LMG S4] Issue 47: Lossless compression](https://raw.githubusercontent.com/ngjunsiang/laymansguide/release/season4/issue047/issue047_01.png)
[LMG S4] Issue 47: Lossless compression
Previously: Computers compress image and audio data through a process similar to summarising: it analyses the data using algorithms that use brightness and...
![[LMG S4] Issue 46: Lossy compression](https://github.com/ngjunsiang/laymansguide/blob/release/season4/issue046/issue046_01.jpg?raw=true)
[LMG S4] Issue 46: Lossy compression
Previously: Humans can distinguish 120 dB of loudness, which means the loudest perceivable sound is a million times louder than the softest perceivable...
![[LMG S4] Issue 45: Audio, a sampling of values](https://raw.githubusercontent.com/ngjunsiang/laymansguide/release/season4/issue045/issue045_01.png)
[LMG S4] Issue 45: Audio, a sampling of values
Previously: An image’s resolution describes its dimensions. Its pixel resolution gives an indication of its physical size (if printed or displayed on a...
[LMG S4] Issue 44: Image resolution
Previously: Colour is stored as a combination of red, green, and blue. In a computer system, each colour is stored as one byte (8 bits), allowing for 256...