libretro/wiki/glossary.md

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Glossary

The first part holds the words anyone meets when setting up BIOS files. The second part holds the words this project uses in its reference pages.

Words you will meet

BIOS, or firmware

A small program built into a console. Many emulators need a copy of it to start games. What BIOS files are says more.

Emulator

A program that lets a computer, a phone or a handheld act like an older console.

Core

One emulator inside RetroArch. RetroArch loads a different core for each console.

Frontend

The menu you pick and start games from, such as EmulationStation, MinUI or the RetroArch menu. It starts the emulator for you.

Setup, or platform

The software you play with: RetroArch, Batocera, EmuDeck, KNULLI and the others. Each one keeps its BIOS files in a folder of its own.

BIOS folder

The folder where your setup looks for BIOS files. Its place depends on the setup, and the page of each setup gives it.

Pack

One ZIP file with every BIOS file a setup uses. A pack over 2 GB comes in several parts, and every part is needed.

Installer

A small program started by one line pasted into a terminal. It finds your BIOS folder and downloads only the files that are missing.

Terminal, or command line

A window where you type commands. On Windows it is PowerShell, on a Mac it is Terminal, on a Steam Deck it is Konsole.

Hash, or checksum (MD5, SHA1)

A fingerprint of a file's contents. Two files with the same hash hold the same bytes. Some setups use it to refuse a file that is not the expected version.

Region

The market a console was sold in, such as Japan, North America or Europe. Some emulators pick the BIOS of the same region as the game.

Required and optional

Required: the emulator does not start games without the file. Optional: games start without it, with small differences such as a missing start-up screen.

HLE

High-level emulation: code in the emulator that stands in for the BIOS. Many games work with it, some glitch or do not start.

Game data

Files of a game that a game engine reads, such as the data of Doom or Diablo. They come from your own copy of the game, and their absence does not affect any console.

Project terms

Profile

A YAML file in emulators/ that documents what one emulator loads, read from its source code.

Ground truth

The emulator's source code, the reference every profile is checked against.

System

A console or computer being emulated, named by an id such as sony-playstation or nintendo-gba.

Verification mode

How a setup checks a file: by its name only (existence), by MD5 or by SHA1. Reference: How each platform checks files.

Status

The outcome of one file check: ok, untested (present, but not the expected hash) or missing.

Severity

How much a check result matters: OK, INFO (negligible), WARNING (degraded), CRITICAL (the emulator cannot start games).

Discrepancy

A file that passes the setup's own check but fails the emulator's size or hash check.

hle_fallback

A flag on a profile entry: the emulator has HLE for this file, so its absence is reported at INFO.

Variant

Another version of a BIOS file (a revision, a region or another dump), kept in .variants/ in the repository.

Cross-reference

The comparison of emulator profiles with a setup's own list, which finds the files the setup's emulators load and its list does not name.

Shared group

A group of files in _shared.yml that several setups include, with the folder an emulator expects.

Data directory

A whole folder an emulator needs, such as Dolphin's Sys/ or the PPSSPP assets, kept in data/ and not indexed in the database.

Storage tier

Where a file comes from: embedded (in bios/), external (downloaded at build time) or user_provided.

Target

A hardware architecture a setup runs on, such as switch, rpi4 or x86_64.

Manifest

The JSON list of files per setup in install/, which the installer reads.

Scraper

A script that reads a setup's own BIOS list (System.dat, es_bios.xml and others) into this project's format.

Exporter

A script that writes the project's data back in a setup's own format.

Truth

A setup's file list generated from the emulator profiles, compared with the list the setup publishes.

Dump catalog

A preservation project (Redump, No-Intro, TOSEC) that publishes lists of verified hardware dumps.

Provenance

The catalogs that list a file, joined to the database by hash. It informs, it never overrides the emulator code.

!!! tip "Next"

- [What BIOS files are](what-are-bios-files.md)
- [Get your files](../which-pack.md)