ASiair Plus OS backup

[pmrid]

The ASiair Pro still used a SD card for the OS. The newer Plus version has no accessible SD card for the OS. The OS seems to be embedded in the eMMC device instead which raises a question about how to backup and restore it. Does anyone have any info on this?

[Nikolas]

it doesnt need to be backed up it is supposed to be "self healing"

[pmrid]

I ask because embedded MultiMediaCards (eMMC) are reported to have an estimated 3000 write/erase cycles before failure.

[Zuts]

so 10 years if you use it every night?

[pmrid]

Maybe not. On a single night of imaging, you might take 50 or 60 light frames and the OS will also save small JPGs for each image (damned ifbI know why) - so in a single night there could be a couple of hundred write operations. I don’t know how these things are counted, I must admit, but I’d be very interested to find out.

[Zuts]

My understanding is they are whole drive writes as the controller uses a wear levelling algorithm. If it didn't and since the drive is used by the cpu and OS for other things than just storing your images then I don't think it would last very long.

Additionally the drive is over-provisioned with spare blocks which it can use if the wear on a particular block passes a certain threshold.

Like most things in electronics there is a lot going on under the covers.

https://elinux.org/images/2/2c/Wear_Estimation_for_Devices_with_eM MC_Flash_Memory.pdf

[Nikolas]

I would not use the mmc for anything but rather rely on a usb thumb drive for data acquisition, That way you remove it and transfer across.

[Zuts]

The ASIAirPlus has a removable microsd card as well and you can tell it to write the images to this.

However it only has about 30% the write speed of the internal drive and so I don't use it.

Transferring images is easy as the 'Plus has a USB 3 output which can be connected to a laptop or a phone to copy the nights data.

[Nikolas]

I just transfer the images across the network on my Pro, I write the images to the USB drive and use my home network to transfer files across.