Dear forum members,
We are delighted to inform you that our forums are back online. Every single topic and post are now on their places and everything works just as before, only better. Welcome back!


Discussion on Article:
Seagate Momentus XT: Hybrid Drive in Action

Started by: io-waiter | Date 08/18/10 09:05:35 AM
Comments: 10 | Last Comment:  12/16/15 10:23:57 PM


The momentus uses 4GB of SLC flash, it doesn´t cache writes and the reads are only cached if they are non sequential.The flash is completly transparent for the OS and the caching seems to be based on the LBA table. Much of this is stated in the seagate info material.

Nice to see the cache trashed though I had my suspicions about that but this seems to be the first test that looks into the scenario.
0 0 [Posted by: io-waiter  | Date: 08/18/10 09:05:35 AM]

mistake on the first page you but GB when it should be MB (
(the previous Momentus 7200.4 series used to have only 16 GB)

only issue i can see here is benchmarks that do not read the same LBA block more then 2-3 times will not get onto the flash

the Drive works at the LBA level so if LBA 2342342 is accessed 2-3 times it will get copied to the SLC flash and then Maps the LBA to point to the flash its fully independent of the OS TRIM is not used as the flash is only used for reading when the same LBA block has been accessed

what is interesting the drive Could do 2 I/O operations at the same time 1 reading from the flash and one Writing to the HDD at the same time

rebooting the system 2-3 times would make the LBA blocks that are Read on boot up end up on the flash as that would improve the read speeds

4 of these in RAID 0 (or 1+0) would give you 16GB of read Flash to work with
0 0 [Posted by: leexgx  | Date: 08/19/10 05:59:04 AM]

nice! 4GB of flash memory?

what is the usual buffer? 2MB , 8 or 16? on mechanical 7200rpm drives? i have forgotten all those numbers, i was a computer fanatic expert 1995-2006 like totally.
0 0 [Posted by: mike1101  | Date: 09/02/10 06:48:35 AM]

oh i see its a hybrid ... that's right lol my mistake...
0 0 [Posted by: mike1101  | Date: 09/02/10 06:49:54 AM]


Back to the Article

Add your Comment