Is a 12 MB/s microSD overkill for what the glamo driver does?

Jim Colton jimcolt at gmail.com
Wed Jul 30 23:07:45 CEST 2008


Oh well, I should have bought a slower card.  At least it won't be a
limiting factor.
I'll compare speeds I get with your 3M bytes/sec. anyway.

I was meaning 12 megabits /sec....
By 12MB/s I was referencing what I see here
http://en.wikipedia.org/wiki/Secure_Digital_card#Speeds
12MB/s is not in the table shown in that link however I am about to receive
a 4G 80x or 12MB/s card in the mail .

Thanks for your input Tim and Andy,
Jim

On Wed, Jul 30, 2008 at 1:05 PM, Andy Green <andy at openmoko.com> wrote:

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> Somebody in the thread at some point said:
> | Hey Tim,
> |
> | "no" it's not overkill or "no" is  the glamo driver  able to read that
> fast?
> | Are you involved with or knowledgeable of  how the glamo drive works?
> | I'm not.
>
> I have that not very marketable distinction.
>
> We read from it at 16MHz / 4 bits, so not sure where this 12MBytes/sec
> figure came from.  "Reading from SD Card" means collecting the block
> data into Glamo RAM, after we have it there we have to copy it into CPU
> RAM additionally.
>
> With some pending Glamo speedup patches in, effective Read speed is
> around 3MBytes/sec measured by md5sum-ing a 40MByte test file.
>
> - -Andy
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