On Nov 26, 2022, at 10:00 AM, Chris Thompson <chrisethompson@gmail.com> wrote:
This reminds me to post my analysis of the potential storage requirements.
I modelled with an assumption that we might have 30 active users uploading about 3 meesags a day and that someone uploads a small image every day. The files expire after 10 days. I also modelled some telemetry and science data which expires more quickly but is higher volume.
I then did a second minimal scenario with smaller PACSAT File Headers and shorter retention times.
This indicates that we likely need 2MB of memory. More would be better. But these models are only as good as the input parameters. Feel free to play with the settings and see what you come up with.
73Chris
On Fri, Nov 25, 2022 at 9:40 PM Burns Fisher (AMSAT) <wb1fj@fisher.cc> wrote:
I forgot to include the link. Oddly, Mouser has them but Digikey does not even list them. Long lead time, but Mouser has a few hundred and are expecting even more in January.
73,
Burns Fisher, WB1FJAMSAT(R) Engineering -- Flight Software
-----------------------------------------------On Fri, Nov 25, 2022 at 4:21 PM Burns Fisher (AMSAT) <wb1fj@fisher.cc> wrote:
I just noticed that there is another brand with a similar technology called FRAM made by Infineon (which has taken over the former maker, Cypress. In any case, they do have 8Mbx8 (i.e. 1 megabyte) parts.
73,
Burns Fisher, WB1FJAMSAT(R) Engineering -- Flight Software
On Thu, Nov 17, 2022 at 9:22 PM Burns Fisher (AMSAT) <wb1fj@fisher.cc> wrote:
Thanks for checking deeper!
73,
Burns Fisher, WB1FJAMSAT(R) Engineering -- Flight Software
On Thu, Nov 17, 2022 at 9:21 PM Jim McCullers <wa4cwi@bellsouth.net> wrote:
-----------------------------------------------MR25H40
4Mbit (512k x 8) is the largest they offer with SPI.
The larger ones are parallel with a larger form factor.
$17 to $27 Digi-Key depending on speed and temperature rating.
Jim McCullers
WA4CWI
It appears that there are 8Megabyte MRAM chips available at Digikey at about $50. Everspin is the brand we have been using. I think they invented the technology.
73,
Burns Fisher, WB1FJ
AMSAT(R) Engineering -- Flight Software
pacsat-dev mailing list -- pacsat-dev@amsat.org
View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/pacsat-dev@amsat.org
To unsubscribe send an email to pacsat-dev-leave@amsat.org
Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org
pacsat-dev mailing list -- pacsat-dev@amsat.org
View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/pacsat-dev@amsat.org
To unsubscribe send an email to pacsat-dev-leave@amsat.org
Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org
--
-----------------------------------------------
pacsat-dev mailing list -- pacsat-dev@amsat.org
View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/pacsat-dev@amsat.org
To unsubscribe send an email to pacsat-dev-leave@amsat.org
Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org