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  Power loss and removing power
Posted by: Armin@netPI - October-31st-2017, 07:25 AM - Forum: Hardware - No Replies

netPI does not have a physical reset button. The official method to shutdown the device is clicking "shutdown" within "Control Panel" management tile under the tab "System". The shutdown will take about 10 seconds and is finished when netPI's heartbeat LED "ACT" goes on for a second first and finally remains off forever. Only in this state it is allowed to remove netPI from its power source. This ensures there are no more write accesses to the SD card media that could else easily damage the file system when interrupted during an active write.

On the other hand, a power loss or an intended/unintended remove from power source cannot be controlled and can happen at any time still. netPI's industrial grade SD card supports a mechanism called Data Clone System (DCS) to prevent data corruption during active writes. DCS holds the data to be written in a second clone buffer always. On every power cycle the card checks the last written target block's data against the buffer. If different it re-writes it and solves the problem. This mechanism vastly reduce the risk of a damaged file system.


  Access netPI via Firefox Browser times out
Posted by: Armin@netPI - October-30th-2017, 08:37 PM - Forum: Software - No Replies

This issue is affecting web sites to be opened in Firefox Browser (e.g. netPI's web GUI landing page) if self-signed certificates are used. It can be encountered when the certificate has been replaced multiple times by Firefox with new same certificates that all have identical Subject/Issuer information. This is the case if you restore your  netPI to factory default and Firefox wants you to reaccept the untrusted certificate during the next browser session.

A way to correct this problem is to browse about:support in your Firefox address bar instead of an URL. Click then Open Folder under topic Profile Folder. Locate certx.db e.g. cert8.db in your file explorer and rename or delete it (e.g. “cert8.db.bak”). It may be necessary to have Firefox close to access the file.

Start your Firefox and visit netPI's landing page again and the problem is gone.


  [SOLVED] "Image unavailable" “no such image” message during deploy
Posted by: Armin@netPI - October-28th-2017, 06:27 AM - Forum: Software - Replies (3)

KWhenever an image is loaded from Docker Hub a certificate is exhanged between the device that pulls the image and the Docker site. This is because of security reasons. The certificate contains next to others also an information about when it was created and until it is valid. During the pulling process Docker Hub compares these times against its system time to release an image or not.

If now the expiration time - even if it is just a second - is in the past and signals the image certificate has expired an image cannot be loaded. So on netPI the same scenario happens if netPI's system time is not set up right and different to the actual time Docker Hub is referencing on ... an "image unavailable" message is reported in this case although available on Docker Hub. So make sure you manually set netPI's time correctly or setup an NTP server keeping an eye on the system time automatically.


  System software modifications
Posted by: Armin@netPI - October-28th-2017, 05:42 AM - Forum: Software - No Replies

By definition system software modifications by users are not possible on netPI. There is not even an SSH service or a shell running on it that could grant you access to the operating system level.

We simply see netPI as a Docker hosting platform having a "hardened" Linux environment as basis you can rely on where you contribute with your knowlegde in isolated software containers only. The concept follows the principle of "Open Innovation" with splitted tasks. netPI delivers the first half of work in hardware and basic software, you deliver the other with your dockerized software to complete with confidence.


  SD card duration
Posted by: Armin@netPI - October-27th-2017, 05:43 PM - Forum: Hardware - Replies (1)

Before you read on watch this story first: https://insideevs.com/news/376037/tesla-...ory-issue/

So categorize your containerized applications how write intensive they are stressing the non-volatile storage media used on embedded devices such as netPI.

Critical are those applications writing data at high volumes like databases. But not only the applications could get critical:
Docker daemon logs all container's console activity too. So if you have an application running at debug level for example that outputs tons of textual information on the console (even no one would read it) will lead to a worn-out-effect easily too.

netPI includes an 8GB micro SD card of type MLC-NAND from seller company Xmore with part number SDU008GXASMM-001E (Nowadays it is SANDISK SDSDQAF3-008G-I). The most critical thing about a NAND flash memory is its finite number of erase/program cycles (P/E cycles) also referred to as "memory wear". The wear begins to deteriorate the integrity of the memory until it is becoming unusable in the end.

MLC technology in general has a limit of 3000 to 5000 P/E cycles per flash block specified by a FLASH manufacturers (https://en.wikipedia.org/wiki/Write_amplification). The limit per block makes a NAND-flash endurance directly dependent on its overall size, so the bigger the more blocks,  the better. An auto-wear leveling mechanism in the card's memory controller ensures the next erase/program cycle is performed on another flash block and hence distributes them evenly across the medium.

10 years life time in theory: There is a lifetime calculator available (from Toshiba) estimating the expected NAND flash life time. With netPI's 8GB @ 3000 P/E cycles it outputs a ratio of 1650 MBytes/day (chunks of 1000 x 1,65MB) you may write to the SD card to guarantee a 10 years life. In total this is 1650MB x 365days x 10years = 6022500MB or 6022GB or 6 TB of data the SD card tolerates. An other calculation can be for example like 25000 times a write of 64KByte chunks per day.

30 years Life time in practice: We made tough tests with an SD card to check its endurance under real life conditions. We brought a card to its limits at a incredible rate of 450000MB/day and realized the first failure after writing 18TB of data. So in reality an SD card has a 3 times higher endurance compared to the very conservative value the calculator provides.

There are two methods to increase the durability:

  1. Increase the memory card size while the NAND technology remains the same (MLC). Rule of thumb: double size, double durability.
  2. Switch to memory cards based on a  different NAND technology. Type "pSLC" has roughly 6x higher durability, type "SLC" has 30x higher durability compared to MLC
... so keep an eye on your applications.


  Sealed microSD memory card (no more)
Posted by: Armin@netPI - October-27th-2017, 05:28 PM - Forum: Hardware - Replies (1)

If you open netPI's housing you will notice the micro SD memory card is irreversible glued to its socket. It cannot be removed or exchanged without destroying the device physically.

This measure is part of netPI's security concept and ensures nobody is able to manipulate the system software and guarantees you and us a constant system behaviour.


  netPI RTE 3 schematics
Posted by: Armin@netPI - October-27th-2017, 02:03 PM - Forum: Hardware - Replies (2)

For all those interested in netPI RTE 3 schematics find the correspondent document appended.

Since our netPI design partner company Element14 (Farnell Group) licensed the Raspberry Pi 3 schematics on non-disclosure provisions it is clear that the netPI document does of course not contain the Raspberry Pi 3 schematics part.



Attached Files
.pdf   P1651001.pdf (Size: 475.24 KB / Downloads: 48)

  System Software V1.1.3.0RC3 out now!
Posted by: hilscherforum_admin - Less than 1 minute ago - Forum: News - Replies (3)

Hi there,

yes this is correct. Since netPI - from the initial idea - is just a Docker host platform ready to deploy images/containers from a remote registry resource the image/container original should never be stored on netPI itself.

So even if the conainer are destroyed due to a software update - as you mention - the original containers are available on the registry still and can be pulled to netPI after the update.

Thx
Armin