tw inspect¶

Shows the header of a TWRF capture, a TWTI or TWTZ image, or a TWVL volume.

Synopsis¶

tw [GLOBAL OPTIONS] inspect [--json] FILE

Description¶

tw inspect recognises the file by its magic bytes, not its name. It reads only the header, plus an image's segment table for the segment counts, so it returns at once even on a 1.75 GB image. A .twtz file is decompressed only as far as its segment table. It needs no hardware.

By default it prints a readable summary: the drive's report bytes decoded, the geometry, the segment counts and, for a volume, its holes. With --json it prints the JSON header exactly as stored in the file, byte for byte, with the keys in stored order, followed by one line break.

To see what is on a tape rather than how it was captured, use qicsilver identify.

Options¶

Option	Default	Description
`FILE`		A `.twrf`, `.twti`, `.twtz` or `.twvl` file.
`--json`	off	Print the header exactly as stored, instead of the summary.

Output¶

An excerpt of the summary for an image:

Segments
╭───────────────┬─────────────────╮
│ missing       │ 57,431 (97.34%) │
│ clean         │ 1,445 (2.45%)   │
│ corrected     │ 12 (0.02%)      │
│ uncorrectable │ 14 (0.02%)      │
│ bad           │ 98 (0.17%)      │
╰───────────────┴─────────────────╯
...
Drive
╭─────────────────┬──────────────────────────────────────────────────────╮
│ Drive config    │ 0xd8 -> 1,000 kbit/s, QIC-80 mode, extra-length tape │
│ Vendor          │ 0x11c6 -> Colorado Memory Systems (make 71, model 6) │
│ Tape status     │ 0x63 -> QIC3020, variable length 900 Oe              │
╰─────────────────┴──────────────────────────────────────────────────────╯

(From a blank, factory-formatted QIC-Extra tape.) The header fields of each format are defined in TWS-1 TWRF, TWS-2 TWTI/TWTZ and TWS-3 TWVL.

Examples¶

Show the summary for an image:

tw inspect captures/mytape.twtz

Show which drive and rate recorded a capture:

tw inspect captures/mytape/track-00.twrf

Extract the geometry from an image's stored header with jq:

tw inspect --json captures/mytape.twtz | jq .geometry

Exit status¶

0 on success. 1 if the file is not one of the three formats or cannot be read.

Tapewyrm

tw inspect