Re: AZFS file system proposal

From: Jan Engelhardt
Date: Tue Jun 17 2008 - 05:35:42 EST



On Tuesday 2008-06-17 11:06, Maxim Shchetynin wrote:
>
>> (a) What is axonram?
>> (b) why is axonram direct_access, and my other devices (including
>> standard PC RAM) not?
>
>[Axonram is a module specific for IBM CellBlade and allows access to
>a DDR2 memory attached onto Axon controller.] You don't need
>direct_access and not azfs for main memory because there is already
>a pretty nice tmpfs for it.

So the reason azfs could be useful is...?

>> >+ Mounting such device with azfs gives memory mapped
>> >access to the + underlying memory to user space.
>>
>> Can't I just mmap(/dev/theblockdevice), why would I need to go through
>> azfs?
>
>Yes, you can mmap it. But what does it have to do with a file system.

Exactly, that's what I was asking myself.

>I would say you can either mmap it or place a file system on it.

The help text implies that I *need* azfs to mmap it - and that sounds
like a Rube Goldberg machine.
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