The raspberrypi.org's documentation recommends to use a minimum class 4 SD card.
There is no information about the format: SD, SDHC, or SDXC. The difference between these formats seems to be the file system.
Is there any recommended or unrecommended format to use for Raspberry or does the system accept any FS?
The best size to get is 4GB or 8GB, and these are all SDHC cards. Regular SD only go up to 2GB so they're too small, and SDXC only start at 32GB so they're unnecessarily big.
Just get an 8GB card, that gives you plenty of space and they're all SDHC. You can put different file systems on an SD card or an SDHC card, but the install image will take care of that for you.
Is there any recommended or unrecommended format to use for Raspberry or does the system accept any FS?
Follow the instructions for the OS you want to install. If you want to use one of the raw images from the download page, I have instructions here for how to use it. As mentioned there, it doesn't matter if or how the SD card is formatted in this case, since you'll be writing the raw image directly on to the card (not an fs partition on the card). Also as mentioned, this seems like the simplest method to me although the download page calls it "recommended for advanced users" -- phooey ;)
It's now 2023 (nearly 2024), and time for an UPDATE!
First of all, the RPi's manufacturer now has this recommendation for SD cards - summarized here for your convenience:
And so as far as the subject question for this thread is concerned, that is the answer - terse as it may be!
Moving on to add some trivia to this answer:
Wrt the OPs comment & question re "file systems", methinks the OP has misapplied the term file system. Here's a convenient table with the type classifications for all currently manufactured micro SD cards:
| Type of SD card | Capacity |
|---|---|
| microSD | 2GB and under |
| microSDHC | More than 2GB, up to 32GB |
| microSDXC | More than 32GB, up to 2TB |
| microSDUC | More than 2TB, up to 128TB |
As for all the other ratings & classifications on SD cards, here are links to a couple of popular blogs (buyer guides) that provide reasonable explanations of these ratings & classifications (REF1, REF2). This Wikipedia article on SD cards is also a good source & provides some historical perspective on their evolution. You can also go to the Ultimate Source for all SD specs & standards - the SD Association website; they have an entire section devoted to specifications and standards. And while you're visiting the SDA website, you should consider downloading a copy of their SD Memory Card formatter; available in Mac, Windoze & Linux formats. And yes - they even have an ARM version for Raspberry Pi!
