---
title: "vfs-snapbench — Mova code model"
description: "Mova code model of vfs/examples/snapbench.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/vfs/examples/snapbench.rs.groupant/"
---
Elamur: [Mova](https://md.mova.elamur.ai/free/en/) · [Dictionary](https://md.dictionary.elamur.ai/free/en/) · [Research](https://md.research.elamur.ai/free/en/) · **Groupants**

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# vfs-snapbench

The groupant beside vfs/examples/snapbench.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.

## Facts

- **kind:** groupant
- **status:** partial source bound model
- **source:** [`vfs/examples/snapbench.rs`](https://github.com/ElamurAI/mova-free/blob/main/vfs/examples/snapbench.rs)
- **source SHA-256:** `df7ed460def06537…`
- **repository folder:** [`vfs/examples/snapbench.rs.groupant`](https://github.com/ElamurAI/mova-free/tree/main/vfs/examples/snapbench.rs.groupant)
- **repository commit:** `855da7bd4a7b`

> **Implementation material.** A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.

## Components

| component | label | where |
|---|---|---|
| **approximant** | partial | [approximant](#approximant) |
| **ast** | partial | `syntax.json` |
| **composition** | partial | [composition](#composition) |
| **cost** | partial | [Cost](#cost) |
| **descriptant** | present | [descriptant](#descriptant) |
| **invariant** | partial | [Invariant](#invariant) |
| **tests** | executed bounded checks | [tests](#tests) |

## Obernants

The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.

| id | type | label | where |
|---|---|---|---|
| `behavior_complement` | behavior_complement | partial source derived model | [behavior_complement](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial source derived model | [reverse_reconstruction](#reverse-reconstruction) |
| `iteration_count` | iteration_count | partial source derived model | [iteration_count](#iteration-count) |
| `format_partition` | format_partition | partial source derived model | [format_partition](#format-partition) |
| `benchmark_scope` | benchmark_scope | partial source derived model | [benchmark_scope](#benchmark-scope) |
| `allocation_domain` | allocation_domain | partial source derived model | [allocation_domain](#allocation-domain) |

## Model text


### descriptant

#### vfs-snapbench

Timing helpers and unexecuted snapshot workload.

##### Prospective epoch

2026-10-31: source reviewed before edits; prospective review retained under $MOVA_DATA/runs/octopus-wave31-vfs-2026-10-31/prospective.md. Predicted order/cost: per_op O(n*closure cost), main allocation O(N*1024+64MiB), repeated shared-buffer edits copy64MiB; main intentionally not executed.

##### Observation epoch

Bounded actual calls and compiled negative controls are recorded in tests.md. Production behavior bytes unchanged; only focused test blocks added. Snapshot constant-time wording is conditional on cwd and destruction; recursive operations may partially commit.

##### Unsupported approximants

No executable percentage surrogate is claimed for these categorical/state/effect observations. Future 1%,2%,5%,10% require a useful metric, explicit domain and exact reference.

### approximant

#### Forward relation

Timing helpers and unexecuted snapshot workload.

per_op(n,f) invokes f exactly n times then divides elapsed seconds by n; fmt chooses ns if s<1e-6, microseconds if s<1e-3 else ms. Main scales1000/10000/100000 files plus64MiB and compares snapshot,restore,write,dump timings.

Domain: bounded inputs with available allocation and nonoverflowing counters unless checked explicitly. The relation is partial and source-derived.

### composition

#### Composition

Timing helpers and unexecuted snapshot workload. Shared state and order: per_op(n,f) invokes f exactly n times then divides elapsed seconds by n; fmt chooses ns if s<1e-6, microseconds if s<1e-3 else ms. Main scales1000/10000/100000 files plus64MiB and compares snapshot,restore,write,dump timings.

Scoped children project this same source. Their domains and effects remain conditional; source execution connects these clauses rather than independently proving their wiring. For n>0 bounded helper elapsed is finite nonnegative; timing is nondeterministic. fmt boundaries use strict less-than. n0 remains undefined useful average (infinite/NaN possible).

### models

## Typed source models

Source-bound partial relations; no universal finite-test proof.

### behavior_complement

Subject: vfs-snapbench. Domain: Timing helpers and unexecuted snapshot workload. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: At exactly1e-6 output cannot be ns, at1e-3 cannot be microseconds. Helper tests do not validate benchmark speed claims.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### reverse_reconstruction

Subject: vfs-snapbench. Domain: Timing helpers and unexecuted snapshot workload. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: Formatted rounded duration admits intervals and cannot reconstruct raw clock or workload timing distribution. Per-op mean admits many individual duration sequences.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### iteration_count

Subject: vfs-snapbench. Domain: Timing helpers and unexecuted snapshot workload. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: n3 calls closure3 times; n0 invokes none but divides by0, outside useful timing domain.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### format_partition

Subject: vfs-snapbench. Domain: Timing helpers and unexecuted snapshot workload. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: Strict thresholds at1e-6 and1e-3; rounding precision differs by branch.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### benchmark_scope

Subject: vfs-snapbench. Domain: Timing helpers and unexecuted snapshot workload. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: black_box prevents easy elimination but timings include closure/drop effects; no portable complexity measurement follows.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### allocation_domain

Subject: vfs-snapbench. Domain: Timing helpers and unexecuted snapshot workload. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: Largest main fixture and million iterations skipped; only three no-allocation closure invocations tested.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### tests

#### Checks and limitations

Exact named observations: wave31::bounded_helpers.

Fresh receipts: $MOVA_DATA/runs/octopus-wave31-vfs-2026-10-31; run.sh retains four profile/repetition sets with raw logs and numeric statuses. native-commands.json and source-test-map.json disambiguate targets. Compiled mutations and exact restoration are separately retained in mutation-summary.json.

These finite observations are not semantic completeness. Source syntax generated twice and compared byte-for-byte. Host effects are limited to owned TMPDIR fixtures. Existing absolute_paths_never_reach_the_host and open_modes are skipped; snapbench main is skipped. Standalone helpers/reexports are only observed through named callers or representation checks; RealFs effect methods unexecuted.

### invariant-and-cost

## Invariant and cost

### Invariant

For n>0 bounded helper elapsed is finite nonnegative; timing is nondeterministic. fmt boundaries use strict less-than. n0 remains undefined useful average (infinite/NaN possible).

### Cost

per_op O(n*closure cost), main allocation O(N*1024+64MiB), repeated shared-buffer edits copy64MiB; main intentionally not executed.

No timing or numerical error guarantee is inferred from finite tests.