[Info-vax] VMS and the (lack of the) TRIM facility.

[Michael Moroney]

I am not familiar with TRIM beyond what people have written here, but
VMS already has an IO$_DSE function that erases blocks with zeroes.
This is different from a WRITE of all zeroes as there is no data transfer
from the CPU to the drive, the drive is simply told to erase the blocks
with zeroes.

It would appear that the correct thing to do on VMS for SSD devices is to
always initialize them with /ERASE_ON_DELETE so that whenever a file is
deleted, it is actually erased, and the SSD does the right thing with 
them.  It knows this because it gets a DSE erase function, which the
file system issues to devices that support it.

(other erase patterns can be defined and erased blocks can be written
multiple times for data security reasons, but that's not applicable here)