Glossary

Glossary

Definitions of terms used throughout the documentation and the source code.

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A - E

Bug report A diagnostic document containing environment details, the error message, and exception details, written to error.log and optionally submitted to the developer API. See Services.

CHD A compressed disc-image container (.chd, "Compressed Hunks of Data") read through the CHDSharp library. SimpleXisoDrive decompresses Xbox ISO CHDs hunk-by-hunk on demand; CD and GD-ROM CHDs are rejected, and the decompressed image must contain an XDVDFS filesystem. See Virtual File System.

CISO A compressed ISO container (.cso) that stores the image with block compression. SimpleXisoDrive decompresses it on the fly; split sets use numbered parts (game.1.cso, game.2.cso, …) and are mounted from the first part. See XDVDFS Format.

Dokan A Windows user-mode file system framework and kernel driver that lets applications expose virtual file systems without writing a kernel driver. SimpleXisoDrive uses Dokan 2.x. See https://github.com/dokan-dev/dokany.

DokanNet The .NET wrapper around the Dokan library. The IDokanOperations interface implemented by XboxIsoVfsDokan comes from this library.

Drive letter mount Mapping a volume to a letter such as Z:. Requires a free letter and is most reliable with administrator rights.

Entry size The total number of bytes occupied by a directory entry on disk, including the 14-byte header, the name, and padding to a 4-byte boundary.

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F - L

FILETIME A Windows timestamp format representing 100-nanosecond intervals since 1601-01-01 UTC. The XDVDFS volume descriptor stores the volume creation time as a FILETIME.

FuseSharp The standalone net10.0 FUSE 3 high-level mount library extracted from SimpleXisoDrive and packed as SimpleXisoDrive.FuseSharp. It mounts any read-only volume that implements IFuseVolume and has no dependency on SimpleXisoDrive.Core. See FuseSharp.

FuseVolumeAdapter The internal class in SimpleXisoDrive.Unix that adapts an IVfsVolume (backslash-separated VFS paths) to IFuseVolume (POSIX paths) and wraps each entry so reads can be forwarded to the Xbox volume. See FuseSharp.

Entry (XISO) A file or directory inside an Xbox image, surfaced by XisoVfsVolume as an IVfsEntry. Backed by XISOSharp's ExplorerNode for path-based images or EntryInfo for stream-based images (the legacy name for the concept was FileEntry). See XDVDFS Format.

GLOBAL partition One of the supported disc layout offsets (0x0FD90000) at which the volume descriptor may be found on certain releases.

Hunk The CHD compression unit: a fixed-size block of the decompressed image that is compressed and stored independently. CHDSharp decompresses one hunk at a time and caches the most recent one.

IFuseVolume The read-only POSIX-path volume contract consumed by FuseSharp's FuseFileSystem: volume label, creation time and size, plus entry lookup, directory listing and file reads. The Unix front end supplies an adapter over IVfsVolume. See FuseSharp.

Iteration limit A safety cap that aborts enumeration of corrupted or circular directory trees. ZArchive directory enumeration is capped at 100,000 entries; the XISO directory walk is bounded per table by XISOSharp.

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M - R

Magic ID The signature MICROSOFT*XBOX*MEDIA stored twice in the volume descriptor. Both copies must match for the descriptor to be valid.

Mount point The location where the image becomes visible: a drive letter (Z:) or an NTFS folder path.

NTFS folder mount Mapping a volume into an existing directory on an NTFS volume. Does not consume a drive letter.

Partition offset The byte offset within the image at which the game partition (and therefore the volume descriptor) begins. XISOSharp reports the winning offset as VolumeInfo.DiscLseek and every read adds it.

Read-only volume A volume on which all mutating operations are rejected. SimpleXisoDrive mounts every image this way.

Redump-style image A raw disc dump format that may contain additional/encrypted data and is not directly mountable as XDVDFS until converted to XISO.

Root directory table The sector referenced by the volume descriptor from which the entire directory tree is reachable.

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S - Z

Sector The addressing unit for the image: 2048 bytes. File data and directory tables are sector-aligned.

Serilog The structured logging library used by the application. Console, rolling file, and bug report sinks are configured in LoggingSetup.

Sink A Serilog output target. BugReportSink forwards Warning and higher events to the reporting pipeline.

Subtree index The 16-bit pointer to a child directory entry, expressed as an index that must be multiplied by 4 to obtain a byte offset. The value 0 means "no child"; a first entry with 0xFFFF marks an empty directory table.

Volume descriptor The structure that identifies an XDVDFS volume and points to the root directory table. It occupies one sector and contains two magic IDs. See XDVDFS Format.

Volume offset The global byte offset applied to every stream read so the partition padding before the game partition is ignored. XISOSharp reports it as VolumeInfo.DiscLseek.

VFS (Virtual File System) The abstraction layer that resolves paths, caches entries, and serves file data to the Dokan operation layer. VfsContainer is the facade; the actual storage is an IVfsVolume implementation (XisoVfsVolume for XDVDFS images — including decompressed CHD images — and ZarVfsVolume for ZArchive trees).

XGD1 / XGD3 Xbox Game Disc layout variants. XISOSharp probes their known partition offsets when looking for a volume descriptor.

XISO Common shorthand for an Xbox disc image in XDVDFS format. "Rebuilt XISO" images place the volume descriptor at sector 0.

XisoExplorer The XISOSharp explorer used for path-based mounts. Opened in keep-open mode, it holds one image stream for the lifetime of the mount and serializes metadata operations on an internal lock.

XisoReader The XISOSharp static API used for images embedded in archives: stream-based volume probing, directory listing, entry lookup, and raw data reads.

XDVDFS Xbox Disc Video File System, the file system used on original Xbox game discs. See XDVDFS Format.

ZArchive / ZAR A compressed archive format (.zar, ZArchive 0.1.2) that stores a directory tree with per-block zstd compression. SimpleXisoDrive mounts either the stored game tree or a single embedded XISO image. See Virtual File System.