Good source of Class 4 SD memory

Hiya,

I have a Pi I use for Flightaware, class 10 SD memory corrupts over time with Flightaware (maybe to do with IO?) , a Class 4 seems to do the trick. Can any one recommend a good source, I've tried buying a few, and the online stores have 'upgraded me ' to Class 10 which isn't that useful :-)

Nick.

Reply to
Nick Mackechnie
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I would buy from Amazon and filter by 'sold by Amazon.co.uk' (or whichever locale you're in). That way you avoid third party sellers (who may have counterfeits) and Amazon are usually fairly good at separating things by SKU.

I also stick to brands who have flash fabs: Sandisk, Samsung, Toshiba. The danger with other brands is they buy flash on the spot market and might change what's inside without changing the model number.

Though you may find that the Class 4 cards are all old stock, so that's why you're getting 'upgraded' - there may not be so many Class 4 cards in production any more.

Theo

Reply to
Theo

Out of curiosity, are you overclocking? Is your power supply really adequate?

Reply to
ray carter

On 9 Mar 2018 16:46:54 GMT, ray carter declaimed the following:

Class 6, if found, should also be usable.

Class 2/4/6 SD cards are rated for /fragmented/ file I/O (what one would get on a still frame camera with picture deletions).

Class 10 SD cards are based upon /streaming/ file I/O (as would result from video recording), and that is on a freshly formatted card.

Cheaper C-10 cards may only maintain 2 "open allocation units" -- one for the streaming data, and one for the "directory". Writing multiple files in parallel (system log, user data, what have you) requires such a card to close an allocation unit, obtain a free one and open it, copy anything from the front of the modified file and free that older allocation unit for reuse, then write new data... Better cards will allow for 4-6 open allocation units, which means interleaved file writing doesn't trigger allocation unit swapping.

--
	Wulfraed                 Dennis Lee Bieber         AF6VN 
	wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/
Reply to
Dennis Lee Bieber

No overclocking, std PSU.

Nick

Reply to
Nick Mackechnie

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