> For the complete documentation index, see [llms.txt](https://knowledge.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://knowledge.illumina.com/instrumentation/nextseq-1000-2000/instrumentation-nextseq-1000-2000-reference_material-list/000002501.md).
# Viewing NextSeq 1000/2000 runs in Sequencing Analysis Viewer
**Background**
The latest available version of Sequencing Analysis Viewer (SAV) is [v3.0](https://support.illumina.com/sequencing/sequencing_software/sequencing_analysis_viewer_sav.html). SAV v3.0 has Windows, Mac, and Linux versions; however, the current Linux version is only compatible with Enterprise Linux versions (EL8 and above). The NextSeq 1000/2000 currently has two OS versions. The older CentOS 7 (with NCS v1.7.x and older) that is EL7 and is **not compatible**. The newer OS version is Oracle Linux 9 (with NCS 2.x) that is EL9 is **compatible**.
For more information, see Knowledge article [Common Questions Related to Sequencing Analysis Viewer (SAV) software and the NextSeq 1000/2000](/instrumentation/nextseq-1000-2000/instrumentation-nextseq-1000-2000-faq-list/000007863.md). **Note:** for more details on NextSeq1000/2000 data with ealier SAV versions, see section below.
* The %Occupied metric has not been optimized for the reduced nanowell pitch width on the NextSeq 1000/2000. %Occupied is not a reliable indicator of flow cell loading on the NextSeq 1000/2000.
* %Loading Concentration can be used as a gauge for how loaded the flow cell is. For more information on %Loading Concentration see Knowledge Base [Optimizing loading concentration on the NextSeq 1000/2000.](https://github.com/illumina-swi/illumina-knowledge/tree/master/articles/Knowledge/Optimizing-cluster-density-on-the-NextSeq-2000?r=146\&ui-knowledge-components-aura-actions.KnowledgeArticleVersionCreateDraftFromOnlineAction.createDraftFromOnlineArticle=1)
\*\*Schematic of Flow cells with tiles
P1 Flow cell\*\*
|  |  |  |
| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
**P2 Flow cell**
|  |  |  |
| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
**P3 Flow cell (similar for P4 Flow cell)**
|  |  |
| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
* P3 Flow cell have 14 tiles per swaths and 6 swaths per tile.
* P4 Flow cell have 16 tiles per swaths and 6 swaths per tile.
**Tile Naming Convention**
* The tile name is a four-digit number that represents the tile position on the flow cell. For example, tile name 1205 indicates top surface, swath 2, tile 05.
* The first digit represents the surface: 1 for top or 2 for bottom.
* The second digit represents the swath number: 1, 2, 3, 4, 5, or 6.
* The last two digits represent the tile number. For swath numbers 1-4, the numbering starts with 01 at the outlet end of the flow cell through 11 at the inlet end. For swath numbers 5-6, the numbering starts with 01 at the inlet end and 11 at the outlet end.
**Sequencing Analysis Viewer v2.5.12 and below**
* Version 2.5.12 of Sequencing Analysis Viewer is required for reviewing runs generated on NextSeq 1000/2000 control software version 1.5 or later.
* SAV v2.5.12 is only validated for use with NextSeq 1000/2000 and is not required for any other platform.
* The flow cells for the P1 and P2 600 cycle kits have not changed, but the way the RunInfo and ErrorMetrics are loaded in SAV has been updated
* Example of Error displayed when loading run from NextSeq 1000/2000 control software v1.5 into SAV version 2.4.7 or earlier.\
\
\
\
| |
| :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: |
| *For any feedback or questions regarding this article (Illumina Knowledge Article #2501), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000002501%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:
```
GET https://knowledge.illumina.com/instrumentation/nextseq-1000-2000/instrumentation-nextseq-1000-2000-reference_material-list/000002501.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.