TAR - Large UID/GID (GNU base-256)
The uid and gid fields hold 7 octal digits, so they top out at 2097151. This member is owned by uid 3000000, which needs GNU base-256 encoding: the field's high bit is set and the remaining bytes are a big-endian integer. Its group sibling encodes the same ownership the other way, so a reader can be checked against both without a second variable.
- README.txt
- owned.txt
Specifications
- Seed
- 20260807
- Tar Format
- GNU tar
- Members
- 2
- Uid
- 3000000
- Gid
- 3000001
- Octal Field Capacity
- 2097151
- Mechanism
- GNU base-256 encoding: the field's high bit is set and the remaining bytes are a big-endian integer
Testing contract
Expected to pass- Scenario
- List the archive with numeric owner IDs shown and compare against the group sibling.
- Expected result
- ids/owned.txt reports uid 3000000 and gid 3000001 exactly, matching the sibling archive; a reader that parses the classic octal field alone reports 2097151 or fails.
What is a .tar file?
TAR (Tape Archive) is a Unix archive format that concatenates files with their metadata into a single uncompressed stream of fixed-size blocks. It preserves permissions, ownership, and directory structure but applies no compression itself. It is usually paired with a compressor such as gzip or xz.
How to use this file
Use an example TAR to test archive extraction, metadata and permission preservation, streaming block parsing, and pipelines that combine tar with external compression.
How to use this file for testing
“TAR - Large UID/GID (GNU base-256)” is a deterministic Novus Examples fixture for Conversion testing, Metadata testing, Error handling. The same content exported across many formats and linked as a group, so you can convert one and diff against the expected twin.
Documented properties for this file: seed 20260807. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Archive fixtures are documented down to their member list (shown on this page) and are deliberately safe — no zip bombs, executables, or hidden payloads. Test extractors against nested, unicode, empty, and encrypted variants.
Code examples
tar -tf large-ids-gnu.tar # list
tar -xf large-ids-gnu.tar -C out/ # extractRelated files
- tarTAR - FIFO and Device Node RecordsA FIFO, a character device and a block device, each a header with no data blocks and with the device numbers in the devmajor/devminor fields. Unprivileged extraction cannot create the two device nodes, so the correct behaviour is to skip them with a warning rather than to abort the whole archive or to create empty regular files in their place.
- zipZIP - Unknown Extra Field IDAn extra field with header ID 0x9901, which is assigned to nothing, sits alongside a recognised extended-timestamp field in a different order in each header. The extra-field area is a length-prefixed chain, so the only correct behaviour is to skip unknown IDs by their declared length and keep walking.
- ttfTTF — Correct Checksums (integrity reference)The clean control for the checksum pair: a small, valid font whose head.checkSumAdjustment and every table-directory checksum are correct. Diff it against its damaged twin to see exactly which four bytes a validator is complaining about. Original typeface, free to use.
- ttfTTF — Intentionally Corrupt: Wrong glyf Table-Directory ChecksumAn intentionally corrupt font whose glyf table data is perfectly fine but whose recorded checksum in the table directory is wrong. The complement to the head fixture: this one catches tools that verify per-table checksums, and its glyphs still draw, so the damage is invisible without a real integrity check.
- ttfTTF — Intentionally Corrupt: Wrong head.checkSumAdjustmentAn intentionally corrupt font: four bytes of head.checkSumAdjustment overwritten with 0xDEADBEEF and nothing else touched. It still renders, because browsers and operating systems do not verify the field — which is precisely why this is a useful fixture for validators, signing tools, and font-integrity checks that claim they do.
- ttfTTF — Overlapping Contours with OVERLAP_SIMPLE and OVERLAP_COMPOUNDThis whole family is drawn as overlapping strokes rather than merged outlines, and this cut sets the two flags that tell a rasteriser so: OVERLAP_SIMPLE on simple glyphs and OVERLAP_COMPOUND on composites. For testing rasterisers that need the hint to avoid seams, and tools that must preserve the flags through a round trip. Original typeface, free to use.
Generated by generation/archives_p7.py. Free for any use, no attribution required — license.