28 Mar 2024

feedTalkAndroid

Samsung Finally Gives Us The Specs Of Its Exynos 1480 Chip

Samsung released the Galaxy A55 with the Exynos 1480 as its beating heart, but told us nothing about the chip's technical side, until now.

28 Mar 2024 10:18pm GMT

The Google Pixel 8 Will Be Getting Gemini Nano After All

Google is backtracking on their initial claim that only the Pixel 8 Pro would be getting Gemini Nano, and now telling us that the little Pixel 8 will be welcome too.

28 Mar 2024 8:16pm GMT

Visible’s Unlimited Plans Now Offer More For The Same Money

Visible has announced fresh new benefits for Visible+ members at no extra cost. Check out what all the $45 plan now offers.

28 Mar 2024 6:30pm GMT

25 Mar 2024

feedAndroid Developers Blog

#WeArePlay | Meet the founders changing women's lives: Women’s History Month Stories

Posted by Leticia Lago - Developer Marketing

In celebration of Women's History month, we're celebrating the founders behind groundbreaking apps and games from around the world - made by women or for women. Let's discover four of my favorites in this latest batch of nine #WeArePlay stories.


Múkami Kinoti Kimotho

Royelles Revolution / Royelles Revolution: Gaming For Girls (USA)

Múkami Kinoti Kimotho – Royelles Revolution / Royelles- Gaming For Girls | USA

Múkami's journey began when she noticed the lack of representation for girls in the gaming industry. Determined to change this narrative, she created Royelles, a game designed to inspire girls and non-binary people to pursue careers in STEAM (science, technology, engineering, art, math) fields. The game is anchored in fierce female avatars like the real life NASA scientist Mara who voices a character. Royelles is revolutionizing the gaming landscape and empowering the next generation of innovators. Múkami's excited to release more gamified stories and learning modules, and a range of extended reality and AI-powered avatars based on the game's characters.

"If we're going to effectively educate Gen Z and Gen Alpha, we have to meet them in the metaverse and leverage gamified play as a means of driving education, awareness, inspiration and empowerment."

- Múkami

Leonika Sari Njoto Boedioetomo

Reblood: Blood Services App (Indonesia)

Leonika Sari Njoto Boedioetomo – Reblood / Blood Services App | Indonesia

When her university friend needed an urgent blood transfusion but discovered there was none available in the blood bank, Leonika became aware of the blood donation shortage in Indonesia. Her mission to address this led her to create Reblood, an app connecting blood donors with those in need. With over 140,000 blood donations facilitated to date, Reblood is not only saving lives but also promoting healthier lifestyles with a recently added feature that allows people to find the most affordable medical checkups.

"Our goal is to save more lives by raising awareness of blood donation in Indonesia and promoting healthier lifestyles for blood donors."

- Leonika

Luciane Antunes dos Santos and Renato Hélio Rauber

CARSUL / Car Sul: Urban Mobility App (Brazil)

Luciane Antunes dos Santos and Renato Hélio Rauber – Car Sul: Urban Mobility App | Brazil

Luciane was devastated when she lost her son in a car accident. Her and her husband Renato's loss led them to develop Carsul, an urban mobility app prioritizing safety and security. By providing safe transportation options and partnering with government health programs to chauffeur patients long distances to larger hospitals, Carsul is not only preventing accidents but also saving lives. Luciane and Renato's dedication to protecting others from the pain they've experienced is ongoing and they plan to expand to more cities in Brazil.

"Carsul was born from this story of loss, inspiring me to protect other lives. Redefining myself in this way is very rewarding."

- Luciane

Diariata (Diata) N'Diaye

Resonantes / App-Elles: Safety App for Women (France)

Diariata (Diata) N'Diaye – Resonantes /App-Elles: Safety App for Women | France

After hearing the stories of young people who had experienced abuse that was similar to her own, Spoken word artist Diata developed App-Elles - an app that allows women to send alerts when they're in danger. By connecting users with support networks and professional services, App-Elles is empowering women to reclaim their safety and seek help when needed.Diata also runs writing and recording workshops to help victims overcome their experiences with violence and has plans to expand her app with the introduction of a discreet wearable that sends out alerts.

"I realized from my work on the ground that there were victims of violence who needed help and support systems. This was my inspiration to create App-Elles."

- Diata


Discover more #WeArePlay stories and share your favorites.



How useful did you find this blog post?

25 Mar 2024 4:00pm GMT

21 Mar 2024

feedAndroid Developers Blog

The Second Developer Preview of Android 15

Posted by Dave Burke, VP of Engineering


Android 14 logo


Today marks the second chapter of the Android 15 story with the release of Android 15 Developer Preview 2!

Android 15 continues our work to build a platform that helps improve your productivity while giving you new capabilities to produce superior media and AI experiences, take advantage of device form factors, minimize battery impact, maximize smooth app performance, and protect user privacy and security, all on the most diverse lineup of devices out there.

Android continues to add features enabling your apps to take advantage of premium device hardware, including the latest telecommunications features, high-end media capabilities, dazzling displays, foldable/filppable form factors, and AI processing.

Your feedback on the Android 15 Developer Preview and Beta program plays a key role in helping Android continuously improve. The Android 15 developer site has more information about the preview, including downloads for Pixel and detailed documentation about changes. This preview is just the beginning, and we'll have lots more to share as we move through the release cycle. Thank you in advance for your help in making Android a platform that works for everyone.

Updating Android communications

Android 15 updates the platform to give your app access to the latest advances in communication.

Satellite support

Android 15 continues to extend platform support for satellite connectivity and includes some UI elements to ensure a consistent user experience across the satellite connectivity landscape.

screen schot of a mobile Android device showing notification when device connects to satellite
Notification when device connects to satellite

Apps can use ServiceState.isUsingNonTerrestrialNetwork() to detect when a device is connected to a satellite, giving them more awareness of why full network services may be unavailable. Additionally, Android 15 provides support for SMS/ MMS applications as well as preloaded RCS applications to use satellite connectivity for sending and receiving messages.

Smoother NFC experiences

Android 15 is working to make the tap to pay experience more seamless and reliable while continuing to support Android's robust NFC app ecosystem. On supported devices, apps can request the NfcAdapter enter observe mode, where the device will listen but not respond to NFC readers, sending the app's NFC service PollingFrame objects to process. The PollingFrame objects

can be used to auth ahead of the first communication to the NFC reader, allowing for a one tap transaction in many cases.

Developer productivity

While most of our work to improve your productivity centers around tools like Android Studio, Jetpack Compose, and the Android Jetpack libraries, we always look for ways in the platform to help you more easily realize your vision.

PDF Improvements

screen schot of a mobile Android device showing search enabled for PDF files
Enable searching embedded PDF files with updates to PdfRenderer


Android 15 Developer Preview 2 includes an early preview of substantial improvements to the PdfRenderer APIs, giving apps capabilities to incorporate advanced features such as rendering password-protected files, annotations, form editing, searching, and selection with copy. Linearized PDF optimizations are supported to speed local PDF viewing and reduce resource use.

The PdfRenderer has been moved to a module that can be updated using Google Play system updates independent of the platform release, and we're supporting these changes back to Android R by creating a compatible pre-Android 15 version of the API surface, called PdfRendererPreV.

We value your feedback on the enhancements we've made to the PdfRenderer API surface, and we plan to make it much easier to incorporate these APIs into your app with an upcoming Android Jetpack library. Stay tuned.

Automatic language switching refinements

Android 14 added on-device multi-language audio recognition with automatic switching between languages, but this can cause words to get dropped, especially when languages switch with less of a pause between the two utterances. Android 15 has added additional controls to allow apps to help tune this switching for their use case. EXTRA_LANGUAGE_SWITCH_INITIAL_ACTIVE_DURATION_TIME_MILLIS confines the automatic switching to the beginning of the audio session, while EXTRA_LANGUAGE_SWITCH_MATCH_SWITCHES deactivates the language switching after a defined number of switches. This can be a useful refinement, particularly if the expectation is that there will be a single language spoken during the session that should be autodetected.

Granular line break controls

Starting in Android 15, the TextView and the underlying line breaker can preserve the given portion of text in the same line to improve readability. You can take advantage of this line break customization by using the <nobreak> tag in string resources or createNoBreakSpan. Similarly, you can preserve words from hyphenation by using the <nohyphen> tag or createNoHyphenationSpan.

Examples and screenshots:

<resources>
    <string name="pixel8pro">The power and brains behind Pixel 8 Pro.</string>
</resources>
text reads: The power and brains behind Pixel 8 Pro.
<resources>
    <string name="pixel8pro">The power and brains behind <nobreak>Pixel 8 Pro.</nobreak></string>
</resources>
text reads: The power and brains behind Pixel 8 Pro.

Expanded IntentFilter Functionality

Android 15 builds-in support for more precise Intent resolution through UriRelativeFilterGroup, which contain a set of UriRelativeFilter objects that form a set of Intent matching rules that must each be satisfied, including URL query parameters, URL fragments, and blocking/exclusion rules. This helps applications better keep up with the dynamic demands of web-hosted deep links.

These rules can be defined in the AndroidManifest with the new <uri-relative-filter-group> tag which can optionally include an android:allow tag. These tags can contain tags that use existing data tag attributes as well as the new android:query and android:fragment attributes.

An example of the AndroidManifest syntax that will be supported:

<intent-filter>
  <action android:name="android.intent.action.VIEW" />
  <category android:name="android.intent.category.BROWSABLE" />
  <data android:scheme="http" />
  <data android:scheme="https" />
  <data android:domain="astore.com" />
  <uri-relative-filter-group>
    <data android:pathPrefix="/auth" />
    <data android:query="region=na" />
  </uri-relative-filter-group>
  <uri-relative-filter-group android:allow="false">
    <data android:pathPrefix="/auth" />
    <data android:query="mobileoptout=true" />
  </uri-relative-filter-group>
  <uri-relative-filter-group android:allow="false">
    <data android:pathPrefix="/auth" />
    <data android:fragmentPrefix="faq" />
  </uri-relative-filter-group>
</intent-filter>

More OpenJDK API support

Android 15 continues to add OpenJDK APIs. Developer Preview 2 includes support for additional math/strictmath methods, lots of util updates including sequenced collection/map/set, ByteBuffer support in Deflater, and security key updates. These APIs are updated on over a billion devices running Android 12+ through Android 15 through Google Play System updates so you can target the latest programming features.

Giving your app more flexibility on more screens

Android 15 gives your apps the support to get the most out of Android's form factors, including large screens, flippables, and foldables.

Cover screen support

Your app can declare a property that Android 15 uses to allow your Application or Activity to be presented on the small cover screens of supported flippable devices. These screens are too small to be considered as compatible targets for Android apps to run on, but your app can opt-in to supporting them, making your app available in more places.

A more private, secure Android

We're always looking to give users more transparency and control over their data while enhancing the core security features of the platform.

Screen record detection

Android 15 adds support for apps to detect that they are being recorded. A callback is invoked whenever the app transitions between being visible or invisible within a screen recording. (An app is considered visible if activities owned by the registering process's UID are being recorded.) This way, if your app is performing a sensitive operation, you can inform the user that they're being recorded.

val mCallback = Consumer<Int> { state ->
  if (state == SCREEN_RECORDING_STATE_VISIBLE) {
    // we're being recorded
  } else {
    // we're not being recorded
  }
}

override fun onStart() {
   super.onStart()
   val initialState =
      windowManager.addScreenRecordingCallback(mainExecutor, mCallback)
   mCallback.accept(initialState)
}

override fun onStop() {
    super.onStop()
    windowManager.removeScreenRecordingCallback(mCallback)
}

Making Android more efficient

We are introducing new APIs that can help you gather insights about your apps, continuing to optimize the way background applications work, and providing APIs to help make tasks in your app more efficient to execute.

ApplicationStartInfo API

App startup on Android has always been a bit of a mystery. There was no easy way to know within your app whether it started from a cold, warm, or hot state. It was difficult to know how long your app spent during the various launch phases: forking the process, calling onCreate, drawing the first frame, and more. When your application class was instantiated, you had no way of knowing whether the app started from a broadcast, a content provider, a job, a backup, boot complete, an alarm, or an Activity.

The ApplicationStartInfo API on Android 15 gives you all of this and more. You can even choose to add your own timestamps into the flow to make it easy to collect timing data in one place. In addition to collecting metrics, you can use ApplicationStartInfo to help directly optimize app startup; for example, you can eliminate the costly instantiation of UI-related libraries within your Application class when your app is starting up due to a broadcast.

Changes to package stopped state

Android 15 includes several improvements to the PackageManager's Stopped State. Apps that are in a Stopped State should only be leaving this state through direct user action. Furthermore, apps entering the Stopped State will have their PendingIntents removed. To help developers re-register their pending intents, apps will now receive the BOOT_COMPLETED broadcast once they are removed from the Stopped State. Lastly, the new ApplicationStartInfo will also include the ApplicationStartInfo.wasForceStopped() to let developers know that their app was put into the Stopped State.

Detailed app size information

Android has offered an API, StorageStats.getAppBytes(), that summarizes the installed size of an app as a single number of bytes, which is a sum of the APK size, the size of files extracted from the APK, and files that were generated on the device such as ahead-of-time (AOT) compiled code. This number is not very insightful in terms of how your app is using storage.

Android 15 adds the StorageStats.getAppBytesByDataType([type]) API, which allows you to get insight into how your app is using up all that space, including apk file splits, AOT and speedup related code, dex metadata, libraries, and guided profiles.

Changes to foreground services

Android 14 began requiring Foreground Service Types. The documentation mentions that the dataSync Foreground Service type will be deprecated in a future version of Android.

To support migrating away from the dataSync Foreground Service type, Android 15 includes the mediaProcessing Foreground Service type, which is used to perform time-consuming operations on media assets, like converting media to different formats. In a future Beta release, this service will have a runtime limit of 6 hours.

SQLite database

Android 15 introduces new SQLite APIs that expose advanced features from the underlying SQLite engine that target specific performance issues that can manifest in apps.

Developers should consult best practices for SQLite performance to get the most out of their SQLite database, especially when working with large databases or when running latency-sensitive queries.

  • Row counts and IDs: new APIs were added to retrieve the count of changed rows or the last inserted row ID without issuing an additional query. getLastChangedRowCount() will return the number of rows that were inserted, updated, or deleted by the most recent SQL statement within the current transaction, while getTotalChangedRowCount() will return the count on the current connection. getLastInsertRowId() will return the "rowid" of the last row to be inserted on the current connection.
  • Raw statements: issue a raw SQlite statement, bypassing convenience wrappers and any additional processing overhead that they may incur.

Media refinements

Each release of Android focuses on improving the media experience.

HDR Headroom Control

side by side images of SDR content
The image on the left shows a view with SDR content. The image on the right simulates perceived headroom issues with SDR and HDR mixed content, which we can avoid by setting the desired HDR headroom.

Android 15 chooses HDR headroom that is appropriate for the underlying device capabilities and bit-depth of the panel; for pages that have lots of SDR content such as a messaging app displaying a single HDR thumbnail, this can end up adversely influencing the perceived brightness of the SDR content. Android 15 allows you to control the HDR headroom with setDesiredHdrHeadroom to strike a balance between SDR and HDR content.

Loudness Control

moving image of Droid wearing headphones and bopping his head rhythmically

Android 15 introduces support for the CTA-2075 loudness standard to help you avoid audio loudness inconsistencies and ensure users don't have to constantly adjust volume when switching between content. The system leverages known characteristics of the output devices (headphones, speaker) along with loudness metadata available in AAC audio content to intelligently adjust the audio loudness and dynamic range compression levels.

To enable this feature, you need to ensure loudness metadata is available in your AAC content and enable the platform feature in your app. For this, you instantiate a LoudnessCodecController object by calling its create factory method with the audio session ID from the associated AudioTrack; this automatically starts applying audio updates. You can pass an OnLoudnessCodecUpdateListener to modify/filter loudness parameters before they are applied on the MediaCodec.

// media contains metadata of type MPEG_4 OR MPEG_D
val mediaCodec = ...
val audioTrack = AudioTrack.Builder()
                                .setSessionId(sessionId)
                                .build()
...
// create new loudness controller that applies the parameters to the MediaCodec
try {
   val lcController = LoudnessCodecController.create(mSessionId)
   // starts applying audio updates for each added MediaCodec

AndroidX media3 ExoPlayer will soon be updated to leverage LoudnessCodecController APIs for a seamless app integration.

Use Spatializer instead of Virtualizer

Android 12 included the Spatializer class, which enables querying the capabilities and behavior of sound spatialization on the device. In Android 15, we're deprecating the Virtualizer class; instead use AudioAttributes.Builder.setSpatializationBehavior to characterize how you want your content to be played when spatialization is supported.

AndroidX media3 ExoPlayer 1.0 enables spatial audio by default for multichannel audio when the device supports it. See the blog post and documentation for more information, including APIs to control the feature.

User Experience

AutomaticZenRules allow apps to customize Attention Management (Do Not Disturb) rules and decide when to activate/deactivate them. Android 15 greatly enhances these rules with the goal of improving the user experience. It does this by:

  • Adding types to AutomaticZenRule, allowing the system to apply special treatment to some rules
  • Adding an icon to AutomaticZenRule, helping to make the modes be more recognizable
  • Adding a triggerDescription string to AutomaticZenRule that describes the conditions on which the rule should become active for the user
  • Added ZenDeviceEffects to AutomaticZenRule, allowing rules to trigger things like grayscale display, night mode, or dimming the wallpaper

Behavior changes

Because backward compatibility is so important to us, we try to limit impactful behavior changes, but some are inevitable.

Elegant fonts everywhere

Once your app targets Android 15, the elegantTextHeight TextView attribute becomes true by default, replacing the compact font used by default with some scripts that have large vertical metrics with one that is much more readable. The compact font was introduced to prevent breaking layouts; Android 13 prevents many of these breakages by allowing the text layout to stretch the vertical height utilizing the fallbackLineSpacing attribute. In Android 15, the compact font still remains in the system, so your app can set elegantTextHeight to false to get the same behavior as before, but it is unlikely to be supported in upcoming releases. So, if your application supports the following scripts: Arabic, Lao, Myanmar, Tamil, Gujarati, Kannada, Malayalam, Odia, Telugu or Thai, please test your applications by setting elegantTextHeight to true.

Examples and screenshots

Default behavior as of Android 14

Default behavior as of Android 14

Default behavior for applications that target Android 15

Default behavior as of Android 14

App compatibility

Android 15 release timeline

To give you more time to plan for app compatibility work, we're letting you know our Platform Stability milestone well in advance.

At this milestone, we'll deliver final SDK/NDK APIs and also final internal APIs and app-facing system behaviors. We're expecting to reach Platform Stability in June 2024, and from that time you'll have several months before the official release to do your final testing. The release timeline details are here.

Get started with Android 15

The Developer Preview has everything you need to try the Android 15 features, test your apps, and give us feedback. You can get started today by flashing a system image onto a Pixel 6, 7, or 8 series device, along with the Pixel Fold and Pixel Tablet. We are not offering sideload images for Developer Preview 2. If you don't have a Pixel device, you can use the 64-bit system images with the Android Emulator in Android Studio. If you've already installed Android 15 Developer Preview 1, you should get an over-the-air update to Android 15 Developer Preview 2.

For the best development experience with Android 15, we recommend that you use the latest preview of Android Studio Jellyfish (or more recent Jellyfish+ versions). Once you're set up, here are some of the things you should do:

  • Try the new features and APIs - your feedback is critical during the early part of the developer preview. Report issues in our tracker on the feedback page.
  • Test your current app for compatibility - learn whether your app is affected by changes in Android 15; install your app onto a device or emulator running Android 15 and extensively test it.

We'll update the preview system images and SDK regularly throughout the Android 15 release cycle. This preview release is for developers only and not intended for daily or consumer use, so we're making it available by manual download only. Once you've manually installed a preview build, you'll automatically get future updates over-the-air for all later previews and Betas. Read more here.

If you intend to move from the Android 14 QPR Beta program to the Android 15 Developer Preview program and don't want to have to wipe your device, we recommend that you move to Developer Preview 2 now. Otherwise you may run into time periods where the Android 14 Beta will have a more recent build date which will prevent you from going directly to the Android 15 Developer Preview without doing a data wipe.

As we reach our Beta releases, we'll be inviting consumers to try Android 15 as well, and we'll open up enrollment for the Android Beta program at that time. For now, please note that the Android Beta program is not yet available for Android 15.

For complete information, visit the Android 15 developer site.

Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.

21 Mar 2024 6:00pm GMT

14 Mar 2024

feedAndroid Developers Blog

Tune in for Google I/O on May 14

Posted by Jeanine Banks - VP & General Manager, Developer X, and Head of Developer Relations

Google I/O is arriving this year on May 14th and you're invited to join us online! I/O offers something for everyone, whether you are developing a new application, modernizing an existing one, or transforming it into a business.

The Gemini era unlocks new possibilities for developers to build creative and productive AI-enabled applications. I/O is where you'll hear how you can get from idea to production AI applications faster. We're excited to share what's new for mobile, web, and multiplatform development, and how to scale your applications in the cloud. You will be able to dive deeper into topics that interest you with over 100 sessions, workshops, codelabs, and demos.

Visit the Google I/O site and register to stay informed about I/O and other related events coming soon. The livestreamed keynotes start May 14 at 10am PT, so mark your calendar.

If you haven't already, go try out our newest Google I/O puzzle and head to @googlefordevs on Instagram if you need a hint.

14 Mar 2024 8:00pm GMT

02 Feb 2024

feedPlanet Maemo

libSDL2 and VVVVVV for the Wii

Just a quick update on something that I've been working on in my free time.

I recently refurbished my old Nintendo Wii, and for some reason I cannot yet explain (not even to myself) I got into homebrew programming and decided to port libSDL (the 2.x version -- a 1.x port already existed) to it. The result of this work is already available via the devkitPro distribution, and although I'm sure there are still many bugs, it's overall quite usable.

In order to prove it, I ported the game VVVVVV to the Wii:

During the process I had to fix quite a few bugs in my libSDL port and in a couple of other libraries used by VVVVVV, which will hopefully will make it easier to port more games. There's still an issue that bothers me, where the screen resolution seems to be not totally supported by my TV (or is it the HDMI adaptor's fault?), resulting in a few pixels being cut at the top and at the bottom of the screen. But unless you are a perfectionist, it's a minor issue.

In case you have a Wii to spare, or wouldn't mind playing on the Dolphin emulator, here's the link to the VVVVVV release. Have fun! :-)

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02 Feb 2024 5:50pm GMT

30 Nov 2023

feedPlanet Maemo

Maemo Community e.V. - Invitation to the General Assembly 2023

Maemo Community e.V. - Invitation to the General Assembly 2023

Dear Member,

The meeting will be held on Friday, December 29th 2023 at 12:00 CET on irc.libera.chat channel #maemo-meeting.

Unless any further issues are raised, the agenda includes the following topics:
1. Welcome by the Chairman of the Board
2. Determination of the proper convocation and the quorum of the General Assembly
3. Acceptance of the annual report for the fiscal year and actions of the Executive
6. Any other business

Requests for additions to the agenda must be submitted to the Board in writing one week prior to the meeting (§ 9.2 of the Statutes).

On Behalf of the Maemo Council, Jussi Ohenoja

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30 Nov 2023 8:52am GMT

15 Nov 2023

feedPlanet Maemo

stb_image_resize2.h – performance

Recently there was an large rework to the STB single-file image_resize library (STBIR) bumping it to 2.0. While the v1 was really slow and merely usable if you needed to quickly get some code running, the 2.0 rewrite claims to be more considerate of performance by using SIMD. So lets put it to a test.

As references, I chose the moderately optimized C only implementation of Ogre3D and the highly optimized SIMD implementation in OpenCV.

Below you find time to scale a 1024x1024px byte image to 512x512px. All libraries were set to linear interpolation. The time is the accumulated time for 200 runs.

RGB RGBA
Ogre3D 14.1.2 660 ms 668 ms
STBIR 2.01 632 ms 690 ms
OpenCV 4.8 245 ms 254 ms

For the RGBA test, STIBIR was set to the STBIR_4CHANNEL pixel layout. All libraries were compiled with -O2 -msse. Additionally OpenCV could dispatch AVX2 code. Enabling AVX2 with STBIR actually decreased performance.

Note that while STBIR has no performance advantage over a C only implementation for the simple resizing case, it offers some neat features if you want to handle SRGB data or non-premultiplied alpha.

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15 Nov 2023 1:50pm GMT

18 Sep 2022

feedPlanet Openmoko

Harald "LaF0rge" Welte: Deployment of future community TDMoIP hub

I've mentioned some of my various retronetworking projects in some past blog posts. One of those projects is Osmocom Community TDM over IP (OCTOI). During the past 5 or so months, we have been using a number of GPS-synchronized open source icE1usb interconnected by a new, efficient but strill transparent TDMoIP protocol in order to run a distributed TDM/PDH network. This network is currently only used to provide ISDN services to retronetworking enthusiasts, but other uses like frame relay have also been validated.

So far, the central hub of this OCTOI network has been operating in the basement of my home, behind a consumer-grade DOCSIS cable modem connection. Given that TDMoIP is relatively sensitive to packet loss, this has been sub-optimal.

Luckily some of my old friends at noris.net have agreed to host a new OCTOI hub free of charge in one of their ultra-reliable co-location data centres. I'm already hosting some other machines there for 20+ years, and noris.net is a good fit given that they were - in their early days as an ISP - the driving force in the early 90s behind one of the Linux kernel ISDN stracks called u-isdn. So after many decades, ISDN returns to them in a very different way.

Side note: In case you're curious, a reconstructed partial release history of the u-isdn code can be found on gitea.osmocom.org

But I digress. So today, there was the installation of this new OCTOI hub setup. It has been prepared for several weeks in advance, and the hub contains two circuit boards designed entirely only for this use case. The most difficult challenge was the fact that this data centre has no existing GPS RF distribution, and the roof is ~ 100m of CAT5 cable (no fiber!) away from the roof. So we faced the challenge of passing the 1PPS (1 pulse per second) signal reliably through several steps of lightning/over-voltage protection into the icE1usb whose internal GPS-DO serves as a grandmaster clock for the TDM network.

The equipment deployed in this installation currently contains:

For more details, see this wiki page and this ticket

Now that the physical deployment has been made, the next steps will be to migrate all the TDMoIP links from the existing user base over to the new hub. We hope the reliability and performance will be much better than behind DOCSIS.

In any case, this new setup for sure has a lot of capacity to connect many more more users to this network. At this point we can still only offer E1 PRI interfaces. I expect that at some point during the coming winter the project for remote TDMoIP BRI (S/T, S0-Bus) connectivity will become available.

Acknowledgements

I'd like to thank anyone helping this effort, specifically * Sylvain "tnt" Munaut for his work on the RS422 interface board (+ gateware/firmware) * noris.net for sponsoring the co-location * sysmocom for sponsoring the EPYC server hardware

18 Sep 2022 10:00pm GMT

08 Sep 2022

feedPlanet Openmoko

Harald "LaF0rge" Welte: Progress on the ITU-T V5 access network front

Almost one year after my post regarding first steps towards a V5 implementation, some friends and I were finally able to visit Wobcom, a small German city carrier and pick up a lot of decommissioned POTS/ISDN/PDH/SDH equipment, primarily V5 access networks.

This means that a number of retronetworking enthusiasts now have a chance to play with Siemens Fastlink, Nokia EKSOS and DeTeWe ALIAN access networks/multiplexers.

My primary interest is in Nokia EKSOS, which looks like an rather easy, low-complexity target. As one of the first steps, I took PCB photographs of the various modules/cards in the shelf, take note of the main chip designations and started to search for the related data sheets.

The results can be found in the Osmocom retronetworking wiki, with https://osmocom.org/projects/retronetworking/wiki/Nokia_EKSOS being the main entry page, and sub-pages about

In short: Unsurprisingly, a lot of Infineon analog and digital ICs for the POTS and ISDN ports, as well as a number of Motorola M68k based QUICC32 microprocessors and several unknown ASICs.

So with V5 hardware at my disposal, I've slowly re-started my efforts to implement the LE (local exchange) side of the V5 protocol stack, with the goal of eventually being able to interface those V5 AN with the Osmocom Community TDM over IP network. Once that is in place, we should also be able to offer real ISDN Uk0 (BRI) and POTS lines at retrocomputing events or hacker camps in the coming years.

08 Sep 2022 10:00pm GMT

Harald "LaF0rge" Welte: Clock sync trouble with Digium cards and timing cables

If you have ever worked with Digium (now part of Sangoma) digital telephony interface cards such as the TE110/410/420/820 (single to octal E1/T1/J1 PRI cards), you will probably have seen that they always have a timing connector, where the timing information can be passed from one card to another.

In PDH/ISDN (or even SDH) networks, it is very important to have a synchronized clock across the network. If the clocks are drifting, there will be underruns or overruns, with associated phase jumps that are particularly dangerous when analog modem calls are transported.

In traditional ISDN use cases, the clock is always provided by the network operator, and any customer/user side equipment is expected to synchronize to that clock.

So this Digium timing cable is needed in applications where you have more PRI lines than possible with one card, but only a subset of your lines (spans) are connected to the public operator. The timing cable should make sure that the clock received on one port from the public operator should be used as transmit bit-clock on all of the other ports, no matter on which card.

Unfortunately this decades-old Digium timing cable approach seems to suffer from some problems.

bursty bit clock changes until link is up

The first problem is that downstream port transmit bit clock was jumping around in bursts every two or so seconds. You can see an oscillogram of the E1 master signal (yellow) received by one TE820 card and the transmit of the slave ports on the other card at https://people.osmocom.org/laforge/photos/te820_timingcable_problem.mp4

As you can see, for some seconds the two clocks seem to be in perfect lock/sync, but in between there are periods of immense clock drift.

What I'd have expected is the behavior that can be seen at https://people.osmocom.org/laforge/photos/te820_notimingcable_loopback.mp4 - which shows a similar setup but without the use of a timing cable: Both the master clock input and the clock output were connected on the same TE820 card.

As I found out much later, this problem only occurs until any of the downstream/slave ports is fully OK/GREEN.

This is surprising, as any other E1 equipment I've seen always transmits at a constant bit clock irrespective whether there's any signal in the opposite direction, and irrespective of whether any other ports are up/aligned or not.

But ok, once you adjust your expectations to this Digium peculiarity, you can actually proceed.

clock drift between master and slave cards

Once any of the spans of a slave card on the timing bus are fully aligned, the transmit bit clocks of all of its ports appear to be in sync/lock - yay - but unfortunately only at the very first glance.

When looking at it for more than a few seconds, one can see a slow, continuous drift of the slave bit clocks compared to the master :(

Some initial measurements show that the clock of the slave card of the timing cable is drifting at about 12.5 ppb (parts per billion) when compared against the master clock reference.

This is rather disappointing, given that the whole point of a timing cable is to ensure you have one reference clock with all signals locked to it.

The work-around

If you are willing to sacrifice one port (span) of each card, you can work around that slow-clock-drift issue by connecting an external loopback cable. So the master card is configured to use the clock provided by the upstream provider. Its other ports (spans) will transmit at the exact recovered clock rate with no drift. You can use any of those ports to provide the clock reference to a port on the slave card using an external loopback cable.

In this setup, your slave card[s] will have perfect bit clock sync/lock.

Its just rather sad that you need to sacrifice ports just for achieving proper clock sync - something that the timing connectors and cables claim to do, but in reality don't achieve, at least not in my setup with the most modern and high-end octal-port PCIe cards (TE820).

08 Sep 2022 10:00pm GMT