YAML

The YAML document is a single mapping, whose entry key holds the entry point and whose table key holds the sequence of the structures:

entry:
  smbios-version: '3.4'
table:
- handle: 0x000a
  type: 7
  length: 39
  level: '3.1'
  state: [decoded]
  description: Cache information
  attributes:
    socket-designator: "L1 - Cache"
    level: 1
    socketed: false
    location: "internal"
    mode: "write-back"
    installed-size: 1310720
    supported-sram:
      burst: false
      pipeline-burst: true
    speed: 1
    associativity: "8-way"

A structure which is not decoded holds its raw bytes instead of the attributes:

- handle: 0x0005
  type: 11
  length: 21
  level: '2.0'
  state: [decoded]
  description: OEM strings
  data: !!binary |-
    CwUFAAE=
  strings:
  - "Default string"

1. Scalars

Scalars are written so that a YAML reader resolves each of them to the type it has in the document, and nothing else:

Handles, types, lengths, offsets and the values of the numeric attributes, i.e. integers, fixed-point numbers, sizes, addresses and handles, are plain scalars, which the readers resolve as numbers, the hexadecimal ones included, e.g. 0x000a.
Booleans are plain scalars, true or false, and so are the codes of the states, the ones a boolean attribute gives to its states, and the string unknown.
Versions are single-quoted, so that 2.0 is not read as a number.
Strings of the structures, codes of the enumerations, dates and UUIDs are double-quoted, so that e.g. yes or 2024-11-05 is not read as a boolean or a timestamp.
Values which are not specified are null.
With --pretty, every value of an attribute is a double-quoted string.

A string which is not valid UTF-8, which the firmware may hold, is written as its bytes, in a !!binary scalar, since YAML has no strings of other encodings. The raw bytes of a structure, data, are always written this way. Readers load !!binary scalars as byte strings rather than as text.

2. Structures

The header of a structure gives every key described in Exported documents, and level is null for the structures which have no versions.

properties and overlays are sequences of mappings of the keys the properties and the entries have, which are all present, with null for the ones which have no value. strings is a sequence of the strings.

3. Schema

The document is described by a JSON Schema, https://opendmi.org/schemas/opendmi.yml, which is written in YAML and is applied to the data a reader loads out of the document, e.g. with check-jsonschema:

$ opendmi export -o smbios.yaml
$ check-jsonschema --schemafile opendmi.yml smbios.yaml

The schema expects the plain hexadecimal scalars to be loaded as numbers, which is what readers following YAML 1.1 or the core schema of YAML 1.2 do, and the !!binary scalars to be loaded as byte strings, which JSON Schema knows no type of.