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scanning_fixing_levels
Table of Contents
Scanning and Fixing Levels
RomVault defaults to Level 2 scanning and Level 2 fixing. These settings are best for almost all scenarios, however the options and use cases for the other levels are outlined below.
Scanning Level Settings
There are 3 different Scanning Level settings. The level set in the Global Settings controls the default behavior of the “Scan ROMs” button. Its possible to selectively scan with a different level by selecting what you want to scan in the tree then using the “Scan ROMs” top menu item.
| Level 1 | Level 2 - Default | Level 3 | |
|---|---|---|---|
| Description | Cursory Scan | Normal Scan | Complete Rescan |
| Hashing Scope | Modified files since last scan | Modified files since last scan | All files |
| Hashing Method | ZIP: read from header 7Z (non-solid or 1 file): read from header 7Z (solid with 2+ files): decompress and hash CHD: read from header Everything else: hash files | Decompress files and hash | Decompress files and hash |
| - Size | x | x | x |
| - CRC | x | x | x |
| - MD5 | x | x | |
| - SHA1 | x | x | |
| Speed | Fast if files are in archives | Slow for initial scanning Fast for subsequent scans | Slow |
| Use Cases | If you haven't decided on a final place to store your ROMs yet or you just want to do a quick scan to join a torrent | Its recommended to use the default Level 2 scanning in all situations unless you have a specific reason not to | If you suspect data corruption or you previously scanned with Level 1 and want to upgrade to Level 2 by hashing MD5 and SHA1 |
Note: RomVault has built-in header skipping logic that requires checking the first few bytes of a file to see if it has a header. Solid 7z archives with two or more files require decompressing in order to check for headers. For this reason its advised not to use Level 1 scanning for 7z archives, especially large archives. If you are going to need to decompress solid 7z archives anyways, it makes more sense to stick with a Level 2 scan which will also calculate the MD5 and SHA1.
Fixing Level Settings
There are also Level 1, 2 and 3 Fixing, which sort of works the same as Scanning Levels:
| Level 1 | Level 2 - Default | Level 3 | |
|---|---|---|---|
| Description | Cursory Fix | Normal Fix | Complete Rebuild |
| Fixing Method | Fixes ROM sets by comparing the attributes below | ||
| - Size | x | x | x |
| - CRC | x | x | x |
| - MD5 | x | x | |
| - SHA1 | x | x | |
| Raw Copy* | Yes | Yes | No |
| Speed | Fast | Fast | Slow |
| Use Cases | If your ROMs are also Level 1 scanned and you want to do a quick fix before joining a torrent. There is no point in using Level 1 fixing with ROMs scanned with Level 2. | Pretty much always use Level 2 fixing, especially if your ROMs are scanned with Level 2. This will ensure the highest accuracy and prevent hash collisions. | Only useful if for some reason you want to rebuild archives from scratch and completely decompress and recompress all files in the archives every time. |
Note: RomVault has the ability to copy files directly from a source to a destination archive without the need for recompressing as long as the archives are in TorrentZip format. This allows for extremely fast fix operations.
scanning_fixing_levels.txt · Last modified: 2020/12/15 15:30 by johnsanc
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