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59 lines
2.6 KiB
Markdown
59 lines
2.6 KiB
Markdown
# FAQ: Emulation
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## What is a ROM File Used by Emulators?
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A ROM file is a digital copy of the data from a read-only memory (ROM) chip, typically from a computer or video game cartridge. These files are created by copying the data from the physical hardware to a digital file. For arcade games, you'll need data from several different chips, grouped together to form a ROM set for that game.
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ROM files are used by emulators to mimic the hardware of old gaming systems on modern devices, allowing you to play classic games on your computer, phone, or other devices.
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## What are the types of Arcade ROM Sets?
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- **Non-Merged Sets**: Contains everything needed for a game in one ZIP file. It's space-inefficient but keeps everything self-contained.
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- **Split Sets**: The parent set has all the normal data, and clone sets contain only the changes compared to the parent set. This saves space.
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- **Merged Sets**: Combines the parent and clone sets into one ZIP file, which is space-efficient but more complex to manage.
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## What are CD Image Formats and Disc Images?
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Disc images are exact copies of physical discs. They allow you to play games without using the original discs, which helps preserve them.
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Here we list some common file formats for disc images.
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### .iso (Optical Disc Image)
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- The most common disc image format.
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- Used for uncompressed disc images.
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### .nrg (Nero CD/DVD Image File)
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- Created with Nero disc authoring software.
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- Used for CD or DVD disc images.
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### .bin and .cue (Binary file and Cue sheet)
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- .bin file contains the data or audio track.
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- .cue file contains the structure details of the disc (you always load the .cue file).
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### .mdf and .mds (Media disk Image File and Media Descriptor File)
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- .mdf file contains the CD or DVD data.
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- .mds file contains the header and track information.
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### .chd (Compressed Hunks of Data)
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- A lossless compression format originally developed for MAME.
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- Compresses the contents of a disc image into a single .chd file.
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- Supported by many systems and recommended for 3DO, Dreamcast, Sega CD, Neo Geo CD, PC Engine CD, PSX, PS2, and Saturn.
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## Why Are All Emulation Games Called ROMs?
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Even if they are disc images, emulation games are often called ROMs because:
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- **Historical Reason**: Originally, ROMs were copies of data from game cartridges.
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- **General Term**: Over time, "ROM" became a general term for any game file used in emulation.
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- **Disc Images**: Disc-based games are often called ISOs, but in emulation, they are still referred to as ROMs.
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So, "ROM" is used as a catch-all term for game files in emulation, even if they come from discs.
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