Conquest FS: "The Disk Is Dead"

andfarm writes "A few days ago, I sat in at a presentation of a what seems to be a new file system concept: Conquest. Apparently they've developed a FS that stores all the metadata and a lot of the small files in battery-backed RAM. (No, not flash-RAM. That'd be stupid.) According to benchmarks, it's almost as fast as ramfs. Impressive." The page linked above is actually more of a summary page - there's some good .ps research reports in there.

Comments

Drawback

[ifreakshow]

One quick draw back I see in this system is on a computer where you have more small files than available RAM space. How does the system decide which small files to keep on the regular disk and which ones to keep in RAM?

Re:Drawback

[ottffssent]

LRU eviction is somewhat costly, but highly effective. Pseudo-LRU can be much cheaper and nearly as effective. The replacement policy is not hard - it is a well-researched problem in cache design.

What I find telling is that such a system has to be implemented at all. It seems clear to me that the operating system's filesystem, in conjunction with the VM, should implement this automatically. In Linux, this is true - large portions of the filesystem get cached if you have gobs of RAM lying around. Why certain more commonly-used OSes do the exact opposite is beyond me.

From my perspective, the right way to handle this is obvious. RAM is there to be used. Just as we have multiprogramming to make more efficient use of CPU and disk resources, we should be making the best possible use of available RAM. Letting it sit idle on the odd chance the user will suddenly need hundreds of meg of RAM out of nowhere is rediculous. From the perspective of the CPU, RAM is dog slow, but from the perspective of the disk, it's blazing fast. ANYTHING that can be done to shift the burden from magnetic storage to RAM should be done. Magnetic storage excels in one area and one area only: cheap permanent storage of vast amounts of data. RAM should be used to cache oft-used data. Why is this not painfully obvious to anyone designing an operating system?

The next boost will be

[scorp1us]

Execute in Place (EIP)- currently, your system will copy the program to RAM. Here, you'd copy everything from volatile ram to Non-volatile ram - a rather wasteful operation don't you think?

This is not just for exe's but for datafiles as well...

Re:well and good

[DoraLives]

I see a real opportunity for a system when you have one gig of solid-state storage for your structured data

It will be OS-on-a-chip (and a good OS at that), it will go for about twenty bucks a pop down at WalMart or CompUSA and Bill Gates will die of an apoplectic fit when it hits the streets. Hackers will figure out ways to diddle it, but corporations and average users will upgrade by merely dropping another sawbuck on the counter and plugging the damned thing in when they get back to their machine(s). Computers will come with these things preinstalled, so there'll be no bitching about not having an OS with any given machine. High-end weirdness will, as ever, continue to drive a niche market, but everybody else will regard it about the same as they regard their pair of pliers; just another tool. Ho hum.