---
license: other
task_categories:
- text-generation
language:
- en
- multilingual
tags:
- openeurollm
- long-context
- megatron-lm
- tokenized
- 128k
- 256k
pretty_name: OELLM Natural Long-Context Tokenized 128K/256K Expanded Pilot
---

# OELLM Natural Long-Context Tokenized 128K/256K Expanded Pilot

This dataset contains Megatron-LM tokenized continuation-training artifacts for natural long-context extension experiments at 128K and 256K sequence scales.

This public revision expands the original pilot from 128 to 512 packed examples per source/tier, for 3,072 packed examples total. The raw pack manifest reports approximately 586M source-side estimated tokens across all six source/tier shards.

Accessible source streams used for this revision:

- `edward-io/starcoderdata-repo` as repo-packed code fallback
- `sedthh/gutenberg_multilang` for long multilingual book text
- `allenai/olmo-mix-1124` / `arxiv` for full paper text

The intended final code source is Stack v2 repository hydration, but that is not included here because gated Stack v2/SWH access was not available on the GPU host at build time.

## Contents

The artifact layout follows `openeuro-longctx-megatron-v1`:

- `bin/`: Megatron `.bin` / `.idx` files plus tokenization summary
- `mix/`: weighted Megatron `--data-path` files
- `manifests/`: build metadata, SHA256 checksums, raw pack manifest, and the 512-example recipe

The staged training mix is:

- `natural_code_repo_pack_128k`: 25%
- `natural_code_repo_pack_256k`: 25%
- `natural_books_concat_128k`: 15%
- `natural_books_concat_256k`: 15%
- `natural_arxiv_full_concat_128k`: 10%
- `natural_arxiv_full_concat_256k`: 10%

Each source/tier contains 512 packed examples.

## Usage

Download the dataset and use the generated Megatron data path:

```bash
python -m longctx.cli artifacts download \
  --repo-id birgermoell/oellm-longctx-tokenized-natural-128k-256k-pilot-v1 \
  --output-dir ./data/oellm-natural-128k-256k-pilot

export DATA_PATH="$(cat ./data/oellm-natural-128k-256k-pilot/mix/data_path.args)"
```

Pass `$DATA_PATH` to Megatron with `--data-path`.

## Tokenizer

Built with:

- tokenizer type: `HuggingFaceTokenizer`
- tokenizer model: `/home/ubuntu/birger/Megatron-Bridge-utils/tokenizers/openeurollm/tokenizer-256k`
- vocab size: `262144`

## Source and license note

This is a derived tokenized artifact. Rights and usage constraints follow the upstream datasets and their source documents; this dataset card does not grant additional rights beyond those upstream terms.