SSD

[Bill Campbell]

On Tue, May 12, 2009, vu pham wrote:
> Tim Wunder wrote:
>> vu pham wrote:
>>> I just changed my hard drive in my desktop to SSD. 
>> <snippage>
>>> I also changed the IO scheduler to NOOP.
>>>
>> Yes, it is very important to change more than one thing so you're never
>> certain where system performance improvement or degradation comes from. ;)
>
> Thanks, Tim. I should have said clearer: All the numbers I showed are  
> before I changed the IO scheduler.
>
> I don't believe changing the IO scheduler could make such a big  
> improvement. I just think that there is no moving parts here with the  
> SSD so the IO scheduler should not add any overhead which may be helpful  
> for disks with plates/heads.

Back when I was managing Burroughs Medium Systems mainframes, we
had head-per-track disks which were extremely fast compared to
the IBM removable platters.  The Burroughs disks had 4ms average
access time to any data on the disk, with some very smart disk
controllers which handled all I/O asynchronously direct to RAM,
and raised an interrupt when the operation was complete.

These disks were pretty large, about 4ft high and about the size
of a large filing cabinet.  Declassifying one to keep the Navy
security people happy involved large sledge hammers.

Bill
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