I don't need that much more storage space. I do, however, need faster seek times. Build a drive that does RAID-1 across platters and I will buy it.
May 14th, 2008 |
11 comments to
How will RAID-1 across platters help? If it just stripes data at the same cylinder on two platters, it doesn’t help seek time. If it puts the second copy at a different cylinder, then it will help read seek times, but write times become horrible as each write requires two seeks, and if the drive loses power between pairs of writes you end up with inconsistent data on reads.
I also don’t know if seek times on modern hard drives are proportional to the distance of the seek (IE maybe it only takes a little longer to seek all the way across the disk than to seek 2 cylinders over).
Well, maybe RAID-1 isn’t exactly what I want, but surely there is some way to cut seek times in half by doubling the cost.
Maybe if I wait just a few more years, flash drives will become viable.
Entire product designs have taken reduced seek times as their primary goal. The end result is was 15K RPM server drives.
There’s your half seek times for double cost.
Yeah, but this is for my laptop.
Didn’t I mention I also want low-power and low-heat?
Ah! Then you want a $16000 MacBook Air
After posting this I went to check it out. Apparently flash drives have come down in price. Now you can get a solid state drive for only $1000 instead of (what I recall as being) much much more.
If they can bring the price down another order of magnitude, I’m all over it!
I would like to have a couple of terabytes.
What are you doing? What’s wrong with buying more RAM and letting the OS cache pags?
I already have 4 GB in this machine (although I can only access 3.4 GB of it due to memory-mapped hardware—grr), so buying more RAM isn’t possible.
Caching blocks is great for frequently-accessed blocks, but it doesn’t help when I want to access a large number of infrequently accessed blocks or when caching for some reason does not apply.
– booting (no cache yet)
– writing to a database (ACID requires flushing the cache)
– BitTorrent or similar software