Is the OS soft or hard float?

[dennisarts]

hi guys,

following questions regarding the revpi:
[*]is the OS hard or soft float?
[*]if i need to flash another OS to the EMMC, how would i do that? / is it possible at all?
[*]Will it stay at the same hardware revision for a longer period (important for us because of processor / soft float topic)


Thank you much for helping us out here,

Dennis

[volker]

Dennis,
as far as I'm informed there is no longer any Rasbian Wheezy with soft float and so we have used the hard float version as base for our image - but I will give that an aditional check with our Linux sw team.
If you will need soft float you probably will need to compile your own kernel version for the CM1 or switch for soft float friendly JAVA etc.

You can flash whatever you want on the eMMC. The instructions for installing img files is given in the tutorial about images. You will use the micro USB connector to get access to the eMMC with a Master device (Windows or Linux PC) to wirte the image to the eMMC. Please note that you will need several specific changes / additions to any distribution to use all of the RevPi peripherals (like the real time clock or the piControl driver for the piBridge). Using IOs on the RevPi is fundamental different to using GPIOs on a Raspi.

We will have the RevPi Core and other modules available for at least several years. Any hardware-revisions will always be absolutely backward compatible but we may need to change certain parts if no longer available from the vendors (like the eMMC which will be changed in a view weeks) or any yet unknown bugs have to be removed. We also will constantly deliver updates for the software components and ii's your choice to either stay with a software for years (including all bugs and security issues) or to update.

In about 2 weeks e.g. we will change our production to jessie image and new versions of all sw components (including firmware for DIO modules). If you buy such newer items you have the choice to simply flash the older images which you may download on Github or archive yourself for such purpose. But as most customers will be happy to get the latest techique and less bugs/issues we will definitly sell the latest hw with the latest image version without calling this a different "hw revision".

Hope this answers your questions.Please wait for affirmation on the soft/hard float toppic.

[lukas]

Just to confirm Volker's statement, yes the OS shipping on the RevPi Core (which is essentially a stock Raspbian + kernel with RT patches + a few userland additions) does make use of the ARM CPU's hard float capability.

In case you're interested in the gory details, the ARM CPU on the Compute Module 1 supports the ARMv6 instruction set with VFP2 instructions and the Foundation compiles all Raspbian packages specifically for that architecture. The Foundation called this architecture "armhf".

Unfortunately Debian, from which Raspbian is derived, also has an "armhf" architecture but compiles everything for ARMv7 with VFP3. These packages fail to work on the RevPi Core (or *any* Raspberry Pi 1, for that matter), usually with an "Illegal instruction" or "Segmentation fault" error. Some people have resorted to installing Debian packages compiled for the "armel" architecture. These packages are compiled for ARMv4 with soft float, so the hard float capability of the Compute Module is unused. See the Debian Wiki for details.

Kind regards,

Lukas

[dennisarts]

Thank you very much, guys - all questions perfectly answered!

I asked because of our compiler licenses. Hope we can move to hard float, cause personally, I would love to use the RevPi image.


Have agreat time,

Dennis