Some Pandora questions

[Prometheus]

To my knowledge, the only SD and SDHC Cards that are unlikely to work (or unlikely to work *properly*) would be fakes or poor-quality cards. SDXC, on the other hand, would definitely be a good idea, as I gather that as time goes on SDXC Cards will be using a different specification and may not be readable on current equipment.

 

[Caine]

as I gather that as time goes on SDXC Cards will be using a different specification and may not be readable on current equipment.

Exactly. This wikipedia reference provides somewhat more details.

 

[b1ueskycomp1ex]

I'm not wrong. Usb and sd cards are backwards compatible.

Saying that in general USB version and SD versions are backward compatible is just a bad statement to make. For example, I've got an old USB SD card reader. It only reads SD cards, not SDHC or SDXC (which I hadn't known to exist prior to reading this thread.) The pandora has a USB 2.0 Host controller, and USB 1 Mice, keyboards, webcams, gamepads, etc. Don't function. Why? Because usb 2.0 isn't compatible with USB 1.0 or 1.1.


HOWEVER, usb 2.0 devices are compatible with usb 1.0/1.1 controllers, but operate at USB 1.0/1.1 speeds (which makes some if not all of them useless. A USB 1.1 Hard drive? Tape backups are probably faster!) So no, USB is not backwards compatible in most cases. Newer SD card readers are backwards compatible with OLDER SD cards, but NEWER cards aren't backward compatible with OLD readers, for the most part.

 

[WizardStan]

Three points: (sorry to single you out joseLuis, but your posts are ripe for summarizing and additional content )

Pandora has a usb port USB 2.0 compatible which doesn't detect USB 1.1 devices. And it also has another USB 1.1 compatible port that doesn't detect USB 2.0 devices

The OTG port actually contains both the USB2.0 and the USB1.1 controller, but the host only contains a USB2.0 controller.

And regarding SD cards, the Slots in the pandora are SDHC compatible. And SDXC cards are only SDHC compatible until version 3.0. So for the upcoming 4.0 version of the standard, SDXC cards wont be readable from SDHC readers.

SD3.0 compatible cards are not guaranteed to be compatible with SDHC readers: the SDHC spec says the max is 32GB, so some readers may not be able to access beyond that, or even recognize the card at all. The Pandora can because it was coded to look at all the bits, regardless of what the spec says, which brings me to...

Not the form factor, but the electronic interface is different.

The "electronic interface" most likely refers to the command and data structures. If that's the case, if the voltages and logic levels and all that remain the same (and there's no reason I can think of that they won't) then we can simply recode the driver to handle these new commands and data structures: we still get SDXC compatibility, even with SD4.0 cards, just at slower speeds.


Unless the spec explicitly says it must have a minimum speed. Then we're screwed.

 

[maplesugarlover]

SD3.0 compatible cards are not guaranteed to be compatible with SDHC readers: the SDHC spec says the max is 32GB, so some readers may not be able to access beyond that, or even recognize the card at all. The Pandora can because it was coded to look at all the bits, regardless of what the spec says, which brings me to...


The "electronic interface" most likely refers to the command and data structures. If that's the case, if the voltages and logic levels and all that remain the same (and there's no reason I can think of that they won't) then we can simply recode the driver to handle these new commands and data structures: we still get SDXC compatibility, even with SD4.0 cards, just at slower speeds.


Unless the spec explicitly says it must have a minimum speed. Then we're screwed.

Thanks wizardstan : ) Updating the driver to read the cards , just at lower speeds is what I was trying to say. Guess, I am not good at getting my ideas across: (

 

[joseLuís]

Thank you Wizard Stan. Those are the kind of constructive comments I love. B)

 

[gatogrek94]

Thank you for adding that. I didn't want to go into too much detail, hence the "in theory"


If I understand correctly, those libraries can also be supplied in the .pnd file.


To be clear, as OP suspected it will also be possible to run the OS (be it Angstrom, Debian, Gentoo/neuvoo and whatnot) directly from one of the SD cards.


edit: neuvoo link added.

one question,will it be able to run puppy linux,dsl as long as the OS is in a .pnd file?

 

[TrashyMG]

one question,will it be able to run puppy linux,dsl as long as the OS is in a .pnd file?

Well there are ARM versions of Puppy Linux and Damn Small Linux.. you either need to create a bootable SD image(safest method) or flash over your NAND (not recommended), Both methods are not necessarily straight forward, the SD card method requires partitioning the SD card and copying specific boot files to the first partition and then copy the OS files to another. Your best bet is to check with the tutorials on the Puppy Linux or DSL linux site to see how you can create a bootable SD card. Although I found Angstrom the Linux Distro the Pandora OS is based on to be very good and I don't believe I will need to try out too many different Distributions.


Also .PND files are a package format developed specifically although not necessarily limited to the Pandora to keep software easily managed on Removable storage.. As far as I know PND files can't boot operating systems or at least not yet.


Edit: Typos.. Also Disclaimer I don't have my Pandora yet, but I've had similar dealing with bootable SD cards with my Beagleboard and other ARM devices.