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Appendix 2.5 to ETSO-C153a - Integrated Modular Avionics (IMA) Platform and Module Minimum Performance Standard (MPS

Available versions for ERULES-1963177438-18128

ED Decision 2020/011/R found in: CS-ETSO Amdt 17 - European Technical Standard Orders (Oct 2026)

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**Appendix
2.5 to ETSO-C153a – Integrated Modular Avionics (IMA) Platform and
Module Minimum Performance Standard (MPS**

*ED
Decision
2020/011/R*

**CLASS DS: Data Storage (DS)**

**1. Purpose
and scope**

1.1. Introduction

This Appendix contains the Minimum Performance Standard (MPS) for the
CLASS DS Intended Function: Data Storage.

These standards specify characteristics that should be useful to
designers, manufacturers, installers and users of the IMA module.

1.2. Definitions

For ETSO-C153a CLASS DS, the IMA module provides shared resources in
terms of data storage between hosted applications, modules and/or
components.

Data Storage refers to the storage of data in a continuing and
machine-readable mode. A Data Storage module that records data may
access both the separate portable (removable) recording component
and/or a permanent component to store and retrieve data.

The following definitions are used:

—
Storage Unit: a set of physical
components (hardware and/or software) in charge of supplying and
managing recorded data resources (e.g. memory components and the
associated interfaces, etc.)

—
Data Storage Element: a completely
defined set of data storage which is a primary form of recorded data
and for which a level of isolation would be guaranteed by the IMA
module.

In the context of DS class, the ‘concurrent item’ defined in
Appendix 2.1, paragraph 1 means ‘Data Storage Element’.

1.3. Intended Function

For ETSO-C153a CLASS DS, the intended function is to provide the
capability to share recorded data or data storage space supplied by
one or several storage unit(s).

**2. Requirements**

2.1. Functional requirements for ETSO-C153a CLASS DS

DS.a) The IMA module shall provide to hosted applications, modules
and/or components, a Data Storage Resource which has the capacity to
record or to retrieve a set of data on/from a storage unit by
performing data-retaining operations.

DS.b) The IMA module shall provide to hosted applications, modules
and/or components, the capacity to use shared recorded data resources
thanks to data storage elements accessible through (a) logical and/or
physical interface(s).

![](/static/files/file_jytjXw2lpRK/image133.png)

***Figure 19:
CLASS DS — the relationship between the data storage elements***

2.2. Characterisation requirements

DS.c) All aspects of the Data Storage performance of the shared
Storage Unit of the IMA module shall be characterised, including but
not limited to the following:

1. performances of Memory Management functionality, including the
cache and Memory Management Unit (e.g. storage capacity, cache
performance, etc.);

2. performance of (a) User Interface Mechanism(s), Protocol(s) and
Service(s) (e.g. access timings and throughputs, etc.); and

3. performance of a supported Data Storage Element Type (e.g.
namespace, address scheme, arbitrary principles for multiple access,
throughputs, timings, data space, etc.).

Note: These performance requirements are additional to those
applicable in Appendix 2.1 — COMMON.

**3. Verification
procedures**

The following table gives the verification method for each MPS;
nevertheless, an alternative method may be proposed to the
certification authority:

<table bgcolor="#d9d9d9" cellpadding="7" cellspacing="0">
<col/>
<col/>
<col/>
<col/>
<col/>
<tr valign="top">
<td bgcolor="#808080">
Requirement
				identifier
</td>
<td bgcolor="#808080">
Verification
				method
</td>
<td bgcolor="#808080">
Test
				under normal conditions
</td>
<td bgcolor="#808080">
Test
				under 

environmental
				conditions
</td>
<td bgcolor="#808080">
Comment
</td>
</tr>
<tr valign="top">
<td bgcolor="#d9d9d9">
DS.a)
</td>
<td bgcolor="#d9d9d9">
T
</td>
<td bgcolor="#d9d9d9">
Y
</td>
<td bgcolor="#d9d9d9">
Y
</td>
<td bgcolor="#d9d9d9">
 

</td>
</tr>
<tr valign="top">
<td bgcolor="#d9d9d9">
DS.b)
</td>
<td bgcolor="#d9d9d9">
T
</td>
<td bgcolor="#d9d9d9">
Y
</td>
<td bgcolor="#d9d9d9">
Y
</td>
<td bgcolor="#d9d9d9">
 

</td>
</tr>
<tr valign="top">
<td bgcolor="#d9d9d9">
DS.c)
</td>
<td bgcolor="#d9d9d9">
T(A*)
</td>
<td bgcolor="#d9d9d9">
Y
</td>
<td bgcolor="#d9d9d9">
Y(1)
</td>
<td bgcolor="#d9d9d9">
 

</td>
</tr>
</table>

***Table 5:
Verification Acceptance Criteria***

(A\*) means that verification by the Analysis method is possible for
the item that cannot be tested.

Note (1): applicable for a functional subset 
cf. CO.gg).

[Amdt ETSO/10]

[Amdt ETSO/16]