psoul wrote:ok but apart this how long is the life of a solid drive?
i mean normal hd if treat well can live for a long time... of course they are fragile, but i'm curious about normal use
You're right to consider this - all SSDs are not created equal.
There are two types of flash memory used: MLC and SLC.
MLC (multi layer cell) flash can last as little as 5000 write cycles on a cell, but SLC (single layer cell) can be good for up to 100,000.
However, MLC drives have a lot of spare cells included and clever wear levelling systems to overcome the problem. In something like the MPC where you would typically put a bunch of sounds on a disk then load them in quite often (read cycles) an MLC disc should be fine. When you're saving programs/multis/sequences a lot (write cycles), it's not a big deal because these items only use tiny amounts of memory.
The read cycles limit is often said to be infinite, but usually the maker will give a figure of 1 million or 10 million, after which they offer no guarantee. Every time the disk is used there will be electronic currents present in the flash that can eventually disturb the integrity of the cells. What usually happens is the drive will get slower as the controller has to do multiple reads of cells to retrieve the data. I doubt it would be an issue for our MPC uses.
The worries over MLC SSDs all stem from when they were first used in Windows laptops as the primary HDD, where Windows was writing so much temporary crap on to the drive all the time (to give us the nice features we like) that the drives were dying in less than 12 months. Now Windows can be optimised to manage an SSD properly.
Personally I would always try to get an SLC drive, but they are 3 or 4 times the price, although you can get lucky on ebay with NOS drives getting sold by re-sellers clearing old stock.
And, as already pointed out - always have the data backed up somewhere!