qicsilver identify¶

Reports what is on a tape: the cartridge, the factory stamp, dates, bad sectors and the volume table.

Synopsis¶

qicsilver identify [OPTIONS] IMAGE

Description¶

identify reads the header segment and the volume table of a TWTI or TWTZ tape image and prints them. Run it first on every tape: it tells you how many backup volumes the tape holds, what number each one has, and which volume profile and file-set parser the other commands will use to read them.

Both structures sit at the start of track 0, so an image converted from a short capture of track 0 is enough. identify does not read raw captures; run tw convert on them first.

identify reads the volume table through the volume profile that fits best. Every built-in profile whose fingerprint matches the tape is scored; the others are eliminated. Use --volume-profile to force one. See Cartridge and volume profiles for how the choice is made.

The report names the chosen profile, the file-set parser it implies, and any warnings on the reading (generic, low-confidence, untested, manual and others). The parser is named, not run: identify does not build the volumes, so the line says per the profile (not probed). extract, inspect and tar probe the parser against the volume's bytes.

Options¶

Option	Default	Description
`--json`	off	Print the report as JSON instead of text.
`--raw`	off	Also print the raw format parameter record, every raw VTBL record as a hex dump, and every profile's checks with their points. Fingerprint checks are marked `[fingerprint]`.
`--volume-profile NAME\\|PATH`	`guess`	The volume profile to read the volume table with: a built-in name, a path to a TOML file, or `guess` to score them all. See profiles.
`--fileset-parser NAME`	the profile's	Read the volumes with this file-set parser. See overrides.
`--fileset-param KEY=VALUE`	none	A parameter of the file-set parser. Repeatable. See overrides.
`--extent-offset-bytes 4\\|8`	the profile's	Width of the uncompressed-offset field at the head of each QIC-122 extent. See overrides.
`--extent-frame-size-bytes 2\\|4`	the profile's	Width of each compression frame's size field. See overrides.
`--vtbl-field NAME=OFFSET,LENGTH`	the profile's	Place one VTBL field (bytes 57-127) by hand. Repeatable. See overrides.

--raw is not -v: -v is the global log-level option and goes before the command name.

Output¶

Illustrative output for a tape with one compressed volume:

tape name     EXAMPLE  (named 1998-12-20 10:00:00)
manufacturer  -  (lot -)
              no factory stamp
cartridge     QIC-80, 425 ft x 0.250 in ...
format        code 5, ...
geometry      28 tracks x 207 segments = 5796 segments; ...
data area     segments 2-5795
formatted     1998-12-20 10:00:00  (first 1998-12-20 10:00:00, 1 times)
last written  1998-12-23 05:13:20
bad sectors   0 sectors + 0 whole segments in the map
header        segment 0 (clean); copies at 0 and 1
volume table  segment 2 (clean); 1 volume(s)
volume profile  cms-qic113 (score 14); others: qic113-rev-g (12), qic80-rev-n (3), mtn (-2, eliminated)
file set      qic113-extended parser, per the profile (not probed)

   #  segments     date                       size  compression  description
   0  3-120        1998-12-23 05:13:20     3.3 MB  QIC-122      EXAMPLE BACKUP  [EXAMPLE-PC]

The fields you will use most:

Line	Meaning
`cartridge`	The cartridge type, from the cartridge profile that fits the header's track and segment counts.
`drive saw`	What the drive reported while dumping, from the TWRF headers. Present when the image was converted from captures that recorded it.
`bad sectors`	The bad-sector map written at format time. Those sectors were never used, so they are not losses.
`header`, `volume table`	The segment each was found in, and whether it was recovered `clean`, `corrected`, or not at all.
`volume profile`	The chosen profile and its score, then every other profile's score. `eliminated` means that profile's fingerprint did not match.
`file set`	The file-set parser the chosen profile names.
`warnings`	Caveats on the reading, when there are any.
volume rows	One row per volume: its number (`#`), segment range, date, size, compression (`no`, `QIC-122`, `code N` or `?`) and description. A source label follows in brackets. A size with `~` is the on-tape span, used when the profile does not know the section sizes.
`note:`	Anything the reader wants you to know, for example that no profile's fingerprint matched, or that two profiles tied.

The volume number in the # column is the number extract --volumes, inspect --volume and tar --volume take.

JSON¶

--json prints one object. Its main members are header, header_raw_hex, bad_sectors, bad_segments, header_seg, header_state, vtbl_seg, vtbl_state, cartridge, drive, volume_profile (the chosen profile's name), volume_profile_scores (name to score), volume_profiles (every profile's full reading), fileset_parser, warnings, volumes (each with its decoded fields and raw_hex) and notes.

Examples¶

Identify a tape image:

qicsilver identify captures/NAME.twtz

Show every profile's score and checks, to see why one won:

qicsilver identify --raw captures/NAME.twtz

Force the Colorado backup layout:

qicsilver identify --volume-profile cms-qic113 captures/NAME.twtz

Read the volume table with a profile you wrote:

qicsilver identify --volume-profile ./my-backup.toml captures/NAME.twtz

Print the report as JSON and pull out the chosen profile with jq:

qicsilver identify --json captures/NAME.twtz | jq -r .volume_profile

Tapewyrm

qicsilver identify