Re: HDD vs SSD

[email protected] wrote:
> Aren't all digital photos recorded and stored in the camera on
> flash memory SSDs ? My wife and I have been doing this for many
> yaers on multiple cameras without any problem whatsoever.

There's a difference in the churn rate.

Your cameras are a mix of SLC, MLC, TLC.
The ones with the smallest internal memories
are SLC, good for 100,000 writes per cell.

TLC is good for 3000 writes per cell.

Modern SD cards (used in some cameras), use TLC and
also have poor wear leveling.

The SSD has the most work put into wear leveling,
which is the insuring that the cells have roughly
equal numbers of writes. The SSD "tries not to
burn a hole in a single location inside".

SD and flash sticks are supposed to have that,
but we can't really be sure.

The SD writes at 10MB/sec. The SSD writes at
450-500MB/sec (for SATA ones), or 2500MB/sec for
NVMe ones.

You can chart the daily usage of an SSD, because
there is a counter recording the usage. Using the SSD
toolbox, in theory they could make a nice graph for
you, of daily usage.

Back when I was initially charting it, I was doing
around 20GB per day of SSD writes, which is roughly
the equivalent of all the pictures on your
busiest camera in one year. Done in one day.

And while it's fun to pretend the general NAND matrix is
the only failure point with flash, there's a thing
called "critical data" used to manage the flash. On a
TLC device, a small amount of SLC would be present,
and the devices "grocery list" stays on there. That
might be frequently updated, but because the area
supports more writes, it's provisioned to make it work.
Juggling stuff like this, is why it took a couple
years for SSD firmware to have all the bugs worked
out. Initially, catastrophic failures could happen
out of the blue, because some part of critical
data was mis-handled. The "fault model" then, is
not completely hardware, but also includes a firmware
component. Which was a significant issue at first on
SSD drives. And why a guy like me tells you to
"back it up".

    Paul