--- In "naturalwatt" <> wrote:
>
> Hi.
>
> Looking for advice. I have been using the TS7250 for a couple of years, with
> about 50 out in the field. I use a few bytes in the NVRAM chip that is part
> of the RTC to store tiny amounts of data that I want to preserve across power
> outages (planned or unplanned). Every minute or so I write the latest
> highest value into a pair of bytes. I don't think there is a risk of NVRAM
> wearing out. The usual downside to NVRAM is that it slow to write to and
> small in capacity, I think.
>
> I want to move to the new TS7500. This does not have a NVRAM driver although
> it has an RTC as option. Access to the RTC is via a userland program. I
> think the bootup sequence reads the RTC to set the kernel time and date.
>
> Should I try and get an NVRAM driver for 2.6, or use a file in the filesystem
> (on the SDCARD) to preserve my state information?
>
> In order to minimise the risk of Flash wearout should my program
> open/write/close a small file each time, or open/write/flush and keep open
> the same file?
>
probably depends on the fs in question.
recent discussion on yaffs2 shows that current implementation of flush does not
write metadata. So that is probably a 50% saving in your case.
there is some discussion as to whether this is correct implementation of
command line flush. If done programatically , there are several flush*
procedures that will allow you to flush data without flushing meta data.
HTH
> I did ask Technologic some time ago and got a deafening silence in response.
> I will go and hassle them again, but I hoped this group might have some words
> of wisdom.
>
> Martin
>
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