Slashdot Mirror
Hard Drive of the Future: Ram Drive
benzick writes "3d Retreat has posted a hands on look at a 2gig ram drive called the Rocket Drive. Article blurb: Overall the rocket drive is the best in I/O performance I have seen. It outperforms U160 SCSI drives by almost a factor of two. Yet there are some drawbacks to the Rocket drive, foremost is the price, although listed at the end of the review is some alternative pricing options to make it less expensive. And the rocket drive can not act as a boot drive. Also, if you have some extra money to spend, you can use multiple rocket drives in parallel."
Product: Rocket Drive (2 gig)
Manufacturer: Cenatek
Web site: Product Information
Price (MSRP): $2,999 (as tested)
Release Date: Available Now
Keeps that data after the pc is turned off, which i bet your amstrad didn't do.
It has an external supply that keeps the card powered.
And i believe this is the whole point of this card, its pretty much useless otherwise.
Also the xfer speeds are limited to PCI (66mhz) speeds, that is why "its only" 2x as fast as a U160 scsi.
This is really pretty interesting. The device has it's own power supply that actually allows you to save data when you shut down your computer. It doesn't seem like it would be too reliable, but it does provide a reason as to why this is better than a traditional RAM drive (provided you have it hooked up to a UPS).
The official website lists the capacity as 4 GB.
I know this article doesn't exactly seem to be chock full of information, but the comments can at least be intelligent.
This is different from using a RAM disk and just using RAM for a disk drive. A RAM drive can actually store information - which is something that RAM disks, which aren't really storage devices at all, cannot do.
This even means you can store stuff and it's still gonna be there when you reboot. Although, granted, this isn't exactly new technology. I remember talking with a company at Internet World probably 6 or 7 years ago that sold these things to big companies with deep wallets.
I've nothing to say here...
The bios is set so you can only put in the amount of memory that was specified by the card. So If I purchased the 2Gig empty card. My only option is to put in 4 sticks of 512 pc133 memory. If I wanted to upgrade my card to 4gig. I would have to pay for an upgrade, and then replace all the sticks of memory with 1024Meg sticks.
I use Macs to up my productivity, so up yours Microsoft!
Wasn't there just a slashdot story a while ago saying how it was Power supplies that were the huge cause?
This tells you very little about the relative performance of the drives since image processing is typically not disk bound.
Actually, the author of the article made it disk bound, by forcing Photoshop to go into swap space with an image much larger than the available memory.
And you missed the HD testing pictures, measuring high throughput (sp?) and unbelievable low latency.
I would buy extra ram instead of this rocketdrive. The bandwidth of my system ram is 2.1GB/s. This rocketdrive benchmarks at 78MB/s.
Liberty.
On the first-generation IBM PS/2s, the amount of ram on the motherboard (or in IBM-speak 'planar') was limited, with more added by plugging cards into the MCA bus. I have a Model 80 which has only eight megabytes on the motherboard but another 32 on a Kingston MCA card. Back then, RAM speeds were a lot slower and the new bus was fast - memory on the expansion card is only about twice as slow as that on the motherboard. (I haven't yet found a way of persuading Linux of this fact, I would prefer the kernel to use the lower eight megs preferentially.)
There was even a feature called 'matched memory cycles' in the very early machines where the MCA bus would be temporarily underclocked when accessing memory so that it could work synchronously (cutting some wait states). But then the increasing speed of RAM and the fairly constant bus speed (MCA was 32 bits wide at 10MHz, standard PCI not that much better at 33MHz, while RAM access times have gone down hugely from 85ns to goodness knows what) made the idea look silly, and IBM abandonded MCA-bus memory cards for its second-generation models in 1992 or so. Nowadays you could never get away with using something so slow as the PCI bus for 'memory', so it has to be marketed as 'RAM disk'.
-- Ed Avis ed@membled.com
While profiling a high-volume qmail server with fast mirrored drives, I noticed that I could get at least an order of magnitude sustained mail throughput by eliminating the fsync() system call, which essentially forces the disk subsystem to stop whatever else its doing and get a few specific blocks all the way onto disk. You can't run it in production this way, as the SMTP RFC specifies that the mail must be actually on disk before the server can claim that its done.
The problem is that magnetic-media drives can only seek a few hundred times per second. Regardless of their claimed sustained throughput, if you are writing a bunch of small files to disk, you are completely dependent on the seek time of the drive.
But mounting a magnetic-media-based ext3 with data=journal and the journal on an NVRAM block device would essentially use this as a trusted write-cache. Linux will return from the fsync() system call as soon as the data is in the journal, which could happen instantly on an NVRAM disk as there is no seek time. It then reads from the journal in its spare time, sorts it to minimize seeks, and writes the data out to disk.
I suspect that this should offer roughly the same speed as eliminating the fsync()s entirely.
I was looking into ordering a similar product to test this. I found:
Aaron
Any Xeon motherboard. Not all x86 OSes support the Xeon addressing model, and it's a segmented addressing system that still restricts you to 4 GB chunks per process.
You must've missed the article on here a few months/year back about the guy (@ MIT?) that was disassembling RAM and able to find the 'most used position' of transistors to recover data out of memory, similiar to how they can do it from mechanical hard drives if not completely wiped.
I don't know why a hobbyist website is reviewing this unit - the target market is not for hard-core gamerz or other home user types. Solid state disks are primarily used as database accelerators. Although the throughput of a solid state disk like this can be easily beat by a reasonably small raid, it takes a much larger raid to beat the io/s rate. If you have indices that don't fit in ram, you stick them on the solid-state disk and watch your database speed up by an order of magnitude.
Alternatively, as at least one other poster has already mentioned - if you use a journalling filesystem like ext3 or rieserfs, then putting the journal on a seperate solid-state disk is a huge performance gain.
When information is power, privacy is freedom.