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  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: 52)

  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