Filesystems/Discussion/General/Power safe filesystem/List of Posts
 
Forum Topic - Power safe filesystem: (5 Items)
   
Update
Lakshminarayanan R
04/22/2009 1:18 AM
post27686
Power safe filesystem   
Hello,

I require a power safe file system in my CF. I understand that ETFS and QNX6 are power safe file systems. Correct??

Experimentally, I construe that QNX6 cannot be used with CF. Correct??

Also, ETFS cannot be used in CF as it is only for flash. Correct??

Please suggest me if any other alternative is available since a power safe system is indispensably required.

Thanks,
Lakshminarayanan.R
Mario Charest
04/22/2009 10:31 AM
post27746
RE: Power safe filesystem   

> -----Original Message-----
> From: Lakshminarayanan R [mailto:community-noreply@qnx.com]
> Sent: April-22-09 1:19 AM
> To: general-filesystems
> Subject: Power safe filesystem
> 
> Hello,
> 
> I require a power safe file system in my CF. I understand that ETFS and
> QNX6 are power safe file systems. Correct??
> 
> Experimentally, I construe that QNX6 cannot be used with CF. Correct??

Not correct, it can be use.

> 
> Also, ETFS cannot be used in CF as it is only for flash. Correct??

Yes

> 
> Please suggest me if any other alternative is available since a power
> safe system is indispensably required.

I think it's the wrong hardware for that.

If CF is unavoidable, create a CF with two partitions, one for your software/OS which is read-only thus reducing likely 
hood of corruption.  The other one for data which you run chkfsys at startup.  Plus setup devb-eide with commit=high to 
write data to the device ASAP.  


> 
> Thanks,
> Lakshminarayanan.R
> 
> _______________________________________________
> General
> http://community.qnx.com/sf/go/post27686
>
Lakshminarayanan R
04/24/2009 9:02 AM
post27979
Re: RE: Power safe filesystem   
Firstly, I tried with few more CF's but all are behaving the same way i.e) I'm gets mounted as read only. Can you 
suggest some CF vendor with which QNX6 is tested and is working?

Secondly, on your suggestion on having two partitions I have these two constraints. 
1. I'm not allowed to write even my SW/ OS after initializing it. It just has the blank partition.
2. Running chkfsys at startup would be too costly for me. I cannot afford to have it.
Mario Charest
04/24/2009 9:08 AM
post27981
RE: RE: Power safe filesystem   

> -----Original Message-----
> From: Lakshminarayanan R [mailto:community-noreply@qnx.com]
> Sent: April-24-09 9:02 AM
> To: general-filesystems
> Subject: Re: RE: Power safe filesystem
> 
> Firstly, I tried with few more CF's but all are behaving the same way
> i.e) I'm gets mounted as read only. Can you suggest some CF vendor with
> which QNX6 is tested and is working?
> 
> Secondly, on your suggestion on having two partitions I have these two
> constraints.
> 1. I'm not allowed to write even my SW/ OS after initializing it. It
> just has the blank partition.

If you are not allow to write then what is the problem with using the QNX4FS?  Just mount the partition as read-only 
after you've initialized it.  

> 2. Running chkfsys at startup would be too costly for me. I cannot
> afford to have it.
> 
> _______________________________________________
> General
> http://community.qnx.com/sf/go/post27979
>
John Garvey(deleted)
04/25/2009 12:45 PM
post28090
Re: RE: Power safe filesystem   
> Firstly, I tried with few more CF's but all are behaving the same way i.e) I'm
>  gets mounted as read only. 

Is this using "-o sync=optional" as discussed elsewhere?  The problem is CF lies about its sync support, some devices 
claim to support it but do nothing, others fail the command, some are write-through and don't need it, etc.  You would 
have to evaluate your selected h/w.

> Secondly, on your suggestion on having two partitions I have these two 
> constraints. 
> 1. I'm not allowed to write even my SW/ OS after initializing it. It just has 
> the blank partition.
> 2. Running chkfsys at startup would be too costly for me. I cannot afford to 
> have it.

If you will not be writing to the partition at runtime I don't understand your requirement for power-safety?!  In this 
case fs-qnx4 will have the most efficient extent layout, and will not need a chkfsys provided you mount it read-only 
(I'd start "devb-eide block ro" to ensure this).

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