DavidS wrote: ↑
Sat Jul 13, 2019 4:13 pm
That is the reason I suggested using a RAM disk on both targets, so that we are not comparing the storage media, though using something identical, and fast enough not to have a notable effect on the results.
That's an interesting idea. Linux uses different file systems for ram disks by the way.
(tmpfs for virtual memory is the most common, or ramfs which is rarely used).
RAM disks as such are not popular because the memory is allocated all at once and is unavailable to the rest of the system. A 500MB RAM disk takes 500MB of memory even if there is only a couple of small files on it. Not good!
TMPFS disks on the other hand reside in virtual memory which means that 1) they only use enough memory to hold the files and 2) if the system runs low on memory, the memory used by the TMPFS disk may be paged out.
My choice for the test would be two identical SD cards. Brand new and from the same batch if possible.
Freshly install each OS on each SD card. No tweaking, tuning, nothing. Just a simple, typical, install.
Write a test program to create some files, copy a few small files around and a very large file, do some random access and updates, finally delete the files. The program should obviously be portable.
Reboot the machine and time the program.
Rebooting ensures that nothing is in the cache (running the program twice would yield different results - which might in themselves be interesting).