Maybe someone can be kind enough answer this somewhat technical question I have about SSD's.
My understanding is that SSD's, performance aside, have limits on the number of times that each page/sector/whatever can be written to, and, like all flash memory, the limit is rather low, i.e. in the tens or hundreds of thousands of times. Once the limit is reached, you can't write to that sector reliably any more and have to replace the drive.
Using a mortal SSD as a system drive would seem to be fine, since what you mostly do from a system/application drive is read, right? Except there's one problem.
If you look at a get info of any file, one of the pieces of information you get, inherited from UNIX, is the date and time of the last time the file was opened. So that info has to be updated with a disk write every time the file is opened, even if it's opened for read-only as when you boot your system or launch an executable. (Actually when you boot your system all kinds of other files are written like mount tables and other Unix-type arcana on the system drive).
My question is now obvious: if your read-only SSD gets written to a lot in reality, and has only a limited number of writes to each given spot before it goes bad, why is it OK to use it as a system drive? How long does it take to do 100,000 writes to let's say a file system catalog or index sector that holds last-open times?
Any corrections to my world-view appreciated.
Thanks.
TD
My understanding is that SSD's, performance aside, have limits on the number of times that each page/sector/whatever can be written to, and, like all flash memory, the limit is rather low, i.e. in the tens or hundreds of thousands of times. Once the limit is reached, you can't write to that sector reliably any more and have to replace the drive.
Using a mortal SSD as a system drive would seem to be fine, since what you mostly do from a system/application drive is read, right? Except there's one problem.
If you look at a get info of any file, one of the pieces of information you get, inherited from UNIX, is the date and time of the last time the file was opened. So that info has to be updated with a disk write every time the file is opened, even if it's opened for read-only as when you boot your system or launch an executable. (Actually when you boot your system all kinds of other files are written like mount tables and other Unix-type arcana on the system drive).
My question is now obvious: if your read-only SSD gets written to a lot in reality, and has only a limited number of writes to each given spot before it goes bad, why is it OK to use it as a system drive? How long does it take to do 100,000 writes to let's say a file system catalog or index sector that holds last-open times?
Any corrections to my world-view appreciated.
Thanks.
TD
