December 11, 2000, 11:26 AM — In the past, I've bemoaned the fact that storage (in the form of hard disks) has
gotten only about 2.5 times faster in the past 10 years, in comparison to 50 to 500
times for other parts of the typical computer. I've been looking for promising
technologies that might improve storage-access speed, but nothing appears to be
anywhere close to providing decent relief.
So what can you do?
Adding more cache to disk systems will speed up some operations considerably. You
can also add more spindles and divide the data across a plethora of drives. A full-
size EMC disk subsystem with 256 18-GB disks (for a total of 2.3 TB of usable mirrored
storage) will have 16 GB of cache -- a great system if you have almost two million
bucks handy. I suspect most of you do not.
For an alternative, see
announcement by Solid Data Systems about new
entry-level silicon disks, which might provide assistance in some instances.
What is a silicon disk?
Remember back in the bad old days, when getting around the 640-KB RAM limit in DOS was
a problem? Most of us used RAM disks to speed up some operations. The operating system
saw the RAM disk as a small, fast disk, though it was actually a segment of the
system's memory. Of course, every time you booted the system, everything on the RAM
disk went away.
While having a RAM disk sped up some operations, only static information (such as
programs and lookup tables) could reliably be kept on a RAM disk.
As x86 operating systems became more robust, RAM disks faded out of the picture. A
certain company based in Redmond, Wash., does still make a RAM disk driver for its
newest operating systems, but hardly anybody uses it. Hard disks have grown too large
for a RAM disk to be very useful.
A silicon disk is a separate box with its own power supply and battery backup. It can
connect to any system that supports either SCSI or Fibre Channel disk interfaces. Some
drives even have their own hard disks, for true non-volatility. If power is lost for
more than a minute or two, the silicon drive backs up all its data on the hard disk.
When power is restored, the data is copied back into RAM.
This week, Solid Data announced new products that give the company a line of silicon
disks ranging in size from 0.5 to 17 GB.
Where can you put a silicon disk to the best use? Not by caching a 50-GB database --
at an expected street price of about $9,000 for the smallest silicon disk, caching
everything is too expensive. Consider putting your most frequently accessed tables and
indexes on a silicon drive.