---
title: "Prism Launcher Glossary — mrpack, Loader, JVM Arguments, G1GC & MSA Terms | Prism Launcher for Windows"
description: "Clear definitions of Minecraft modding and launcher terms: `.mrpack`, Fabric vs NeoForge, JVM heap flags, G1GC/ZGC, and Exit Code 1. Open-source Minecraft launcher for Windows 10 and 11. Download at /download."
canonical: https://prismlauncher.ink/words
updated: 2026-10-17
---

# Prism Launcher Technical Glossary

Clear definitions of Minecraft modding and launcher terms: `.mrpack`, Fabric vs NeoForge, JVM heap flags, G1GC/ZGC, and Exit Code 1.

## Facts (2026-10-17)

- **Section:** Glossary
- **Platform:** Windows 10 & Windows 11 (x64 / ARM64)
- **Mod Platforms:** Modrinth, CurseForge, FTB, Technic, ATLauncher
- **Installer:** Available at /download

## How Prism Launcher Technical Glossary works on Windows

Clear definitions of Minecraft modding and launcher terms: `.mrpack`, Fabric vs NeoForge, JVM heap flags, G1GC/ZGC, and Exit Code 1. Understanding how Prism Launcher structures instances, resolves mod dependencies, and launches the JVM on Windows.

Prism Launcher is a fast, lightweight C++/Qt launcher that keeps every Minecraft profile in its own isolated instance folder, with zero ads and no background bloatware.

Get the Windows installer or portable ZIP from [/download](https://prismlauncher.ink/download), or dive into the guides linked below.

## Key advantages for modded Minecraft

- **One-Click Mod Loaders:** Switch between [Fabric, NeoForge, Forge, and Quilt](https://prismlauncher.ink/loaders) inside any instance's Version tab.
- **Built-in Mod & Modpack Browser:** Search and update [Modrinth and CurseForge modpacks](https://prismlauncher.ink/modpacks), shaders, and resource packs directly inside the app.
- **Automatic Java Management:** Pair [Java 21, Java 17, and Java 8](https://prismlauncher.ink/java) per instance so modern 1.21 packs and classic 1.12.2 packs both launch cleanly.

## Pages in Prism Launcher Technical Glossary

- [Instance (Isolated Minecraft Environment)](https://prismlauncher.ink/words/minecraft-instance) — A self-contained folder holding its own Minecraft version, mod loader, `mods/`, `config/`, `saves/`, and Java settings.
- [.mrpack (Modrinth Modpack Archive)](https://prismlauncher.ink/words/mrpack-modrinth-format) — Open modpack package format containing a `modrinth.index.json` manifest and `overrides/` config folder.
- [CurseForge Third-Party Download Restriction](https://prismlauncher.ink/words/curseforge-blocked-mods-workaround) — Some CurseForge authors opt out of direct third-party API downloads, prompting Prism Launcher to open the exact download link in your browser.
- [Minecraft Exit Code 1 & Exit Code -1](https://prismlauncher.ink/words/exit-code-1-and-minus-1) — Generic JVM termination codes indicating a Java version mismatch, missing mod dependency, or broken mixin.
- [Fabric Loader vs Fabric API](https://prismlauncher.ink/words/fabric-api-vs-fabric-loader) — Fabric Loader is the base runtime installed in the Version tab; Fabric API is the standard library JAR placed in the Mods tab.
- [JVM Heap Memory (-Xms and -Xmx)](https://prismlauncher.ink/words/jvm-heap-xmx-xms) — The minimum (`-Xms`) and maximum (`-Xmx`) system RAM in MiB that Java is allowed to allocate for Minecraft.
- [Offline Account Profile](https://prismlauncher.ink/words/offline-mode-account-profile) — Local player profile in Prism Launcher for playing single-player worlds or LAN test servers without an active internet connection.
- [mclo.gs One-Click Log Upload](https://prismlauncher.ink/words/mclogs-crash-log-upload) — Privacy-safe crash log sharing built into Prism Launcher that strips your Windows username and session tokens automatically.
- [Pre-Launch, Wrapper & Post-Exit Commands](https://prismlauncher.ink/words/pre-launch-and-post-exit-commands) — Custom shell scripts or executables that Prism Launcher runs before starting Minecraft and after the game closes.
- [Sodium & Iris Shaders](https://prismlauncher.ink/words/sodium-and-iris-shaders) — The modern open-source rendering engine and shader loader for Fabric and NeoForge that replaces legacy OptiFine.

## FAQ

### Where do I download Prism Launcher for Windows?

Download the Windows installer or portable package directly from [/download](https://prismlauncher.ink/download) on this host.

### Does Prism Launcher work with both Modrinth and CurseForge?

Yes. You can install complete modpacks or mix individual mods from both Modrinth and CurseForge inside the same instance.

## Related

- [Instance (Isolated Minecraft Environment)](https://prismlauncher.ink/words/minecraft-instance)
- [.mrpack (Modrinth Modpack Archive)](https://prismlauncher.ink/words/mrpack-modrinth-format)
- [CurseForge Third-Party Download Restriction](https://prismlauncher.ink/words/curseforge-blocked-mods-workaround)
- [Minecraft Exit Code 1 & Exit Code -1](https://prismlauncher.ink/words/exit-code-1-and-minus-1)
- [Fabric Loader vs Fabric API](https://prismlauncher.ink/words/fabric-api-vs-fabric-loader)

## Download

Free and open source: [Download Prism Launcher](https://prismlauncher.ink/download)

Markdown mirror: https://prismlauncher.ink/words.md