About a minor (Home-Screen) nuisance I’ve experienced on Android deviceS.

I have owned several Android-based devices, and some of those were purchased from Samsung, those being:

  • A Galaxy Tab S, First Generation,
  • (An earlier Smart-Phone),
  • A Galaxy S6 Smart-Phone,
  • A Galaxy S9 Smart-Phone.

A feature which all these devices have, is the Touchwiz Home-Screen (program). This is the default of what the devices display, when not displaying a specific app, when not displaying the app drawer, and when not displaying ‘Bixby’ (most recently). An unfortunate behaviour of the devices is, that Touchwiz will sometimes crash. In my experience, when it does, this is no big deal, because it restarts automatically, and after a few minutes, even my Notification-Bar Entries will reappear. If certain apps fail to make their notifications reappear by themselves, then launching those apps from the application groups will make their notifications reappear.

I tend to rate each Android device, according to how rarely its Home-Screen will crash in this way. According to that, my Google Pixel C Tablet fared better because its home-screen has never crashed on me. My S9 Phone fared almost as well, in that Touchwiz seldom crashed. But now I think I’ve identified a situation which will frequently cause Touchwiz to crash on the S9 Phone.

Firstly, as I’m writing this, the firmware on that phone is at its latest version, that being the October 1 patch, of 2019, of Android 9.

I discovered that I can trigger this situation, as I was experimenting with the Super-Slow-Mo camera recording mode, in which the camera can record up to 0.4 seconds of video at 960FPS, at a resolution of 1280×720. When the camera does this, it generates a 20MB video, after that has been compressed via a standard H.264 CODEC into an .MP4 container-file. I have the default set, to record all camera footage to the external Micro SD Card. Having recorded the super-slow-mo video once, triggered this behaviour.

There is a simple way to interpret what has caused this, that does not seem to lay any blame on Samsung: When the camera is recording video that fast, it’s generating data faster than the external SD Card can store it. Therefore, the data takes up RAM, until some later point in time, when the O/S has transferred the data to the SD Card, by writing it out. This moment was reached several seconds later.

Here’s where the news gets a bit worse. I can download This 3rd-party app, that’s designed to test what speed of external SD Card I have. The reason I need to do this is the fact that I never seem to remember exactly what type of SD Card I purchased, for use with one specific device.

According to this app, my external SD Card can be written to sequentially at ~12MBytes/Sec. That makes it a Class 10 card. Yet, 20MB of data are to be stored in 0.4 seconds. In fact, simply running the benchmarking app caused a second Touchwiz crash, which was just as inconsequential as the first, that I was trying to investigate. What this seems to suggest is, that virtually no SD Card that I can buy, can really be fast enough to be written to at the speed with which the camera app can generate its data. The camera app will need to cache its footage in RAM, before that footage has been written to the SD Card.

Further, the footage is certainly being stored in RAM in an uncompressed form of data (384 raw frames), while what’s to be written to the SD Card is finally compressed. (:1)

And yet, either of these two apps will cause the Touchwiz crash. Hmm… I think that for the moment, I’ll just hold my horses, and record a maximum of 0.2 seconds of Super-Slow-Mo. Thankfully, this is a parameter that I can choose, with the little icon in the upper-right-hand corner of the view, before shooting.

(Updated 11/17/2019, 12h10 … )

Continue reading About a minor (Home-Screen) nuisance I’ve experienced on Android deviceS.

Plausible does not mean Assumed

I could make hypothetical guesses, as to why crashes like this one happen, on the machine I name ‘Phoenix’, which was manufactured in 2008. This time I noticed, that the cursor on the screen stopped moving, then that mouse-input was not being interpreted, then that the screen just filled with an image, which was a diagonally-scrambled version of the normal screen content:

  • It could be that the old GPU is no longer reliable at the hardware level, and that it may now suffer from random crashes, which also crash the X-server. The “” (‘‘) feature I have seen the nVidia Driver execute properly in past situations, may just not kick in.
  • When I reinstalled, replacing the old 32-bit O/S with the current 64-bit O/S, I also replaced the 2GB of RAM with completely new, 4GB of RAM, and the “” (‘‘) of the new RAM has also become faster, that becoming 800MHz instead of the earlier 600MHz. Either set of DDR RAM modules was running with dual-channel capability. The motherboard may detect this capability of the new RAM modules and start using it, as the motherboard itself may have the stated capability of running at 800MHz. Yet, at 800MHz, the way this Motherboard works may not be stable.
  • There could be some sort of kernel issue…

What I do find a bit more specific, is the fact that there seem to be no log entries for the , suggesting that although an X-server crash eventually takes place, this may not be the root cause. Also, the fact that the mouse has become unresponsive for a few seconds, before screen-content collapses, seems to suggest the same thing…

But the most important fact for me to observe, is that simply being able to suggest plausible reasons for the crash, is not the same thing as having diagnosed the crashes. Honestly, I do not know at present, why this type of crash happens.

One of the observations about this machine which had impressed me in the past, was that I had pushed 3D rendering beyond the limits of the old GPU, thereby crashing this graphics chip, but that the desktop manager I had in place was able to restart the GPU, and to resume the session, without requiring any action from me, but displaying a well-behaved message to the effect that the GPU needed to be rebooted. This is called “” (‘‘), and does the same thing under Linux, that it does under Windows, and depends on stable graphics drivers.

The fact that I do possess ‘‘ on this machine suggests, that a simple failure of the graphics chip, should not take out my session.

Addendum:

According to my latest inquiry, this Motherboard is ‘only’ running at 66MHz. Therefore, the maximum speed of the newer RAM Module should not be an issue after all.

ram_phoenix_1

Dirk

Continue reading Plausible does not mean Assumed

My Server was just down for an Upgrade.

From 14h30 until 15h30, I needed to do some upgrading to the hardware of the computer which I name ‘Phoenix’.

Link To Previous Posting

This old computer from 2008 may be running the most powerful Linux version at my disposal, in 64-bit mode, and its dual-core CPU may clock up to 2.6GHz, but until now, it had still only possessed 2GB of RAM! This box still uses DDR2 RAM modules, and I had upgraded it from 2x 512MB to 2x 1GB in the year 2008. But what I needed to do today, was to upgrade it to 2x 2GB, finally giving it its maximum of 4GB of RAM.

This time around, I no longer felt I’d have the dexterity to prevent static damage to the RAM modules, just by controlling the sequence with which I touched parts. And so this time, I also felt I needed to use an actual anti-static bracelet.

Further, the CPU heat sink was plugged full of dust, so that the CPU fan was no longer able to push any cooling air through it. I knew for a long time that this also needed to be remedied, but had procrastinated in doing so. While I had the tower open today, I also took care of the dust in the CPU heat sink, with a bottle of compressed gas.

One reason I was not so eager to do this much-needed work, was the knowledge that if I had botched this, I’d have lost my one and only server. But I was also reminded, that if the server was to fail, because the CPU was consistently running too hot, the outage would take longer than 1 hour to fix. And so I finally chose the 1 hour preventative action.

I am glad that now the CPU is being cooled properly again, and that I finally have 4GB of RAM on this 64-bit machine.

Also, this was one situation in which I could not post a Maintenance Mode Notice on my blog, because for 1 hour, there was no server to render the Maintenance message screen.

Dirk