anyone ever use memory as harddisk ?

[sucahyo]

I try some utilities that can make your memory as your harddisk, but I never able to succed on making 1GB memory as 1GB disk. Do anyone know how?
I try cenatek ramdisk, but only succed for memory bellow 250MB, it gives me blue screen when I try to increase the allocation.
If I can use memory as harddisk, encoding/editing vcd or movie will be much faster, and buying 2GB memory will not be a waste.

[fewtch]

You want a RAM disk that can self-resize, i.e. auto-resizing. Try the one from here:

http://www.ramdisk.tk

I have very little personal experience with it, so can't advise further. You want the "standard" or "pro" version though.

[Neo Neko]

It is a rare occasion indeed when disk speed impacts encoding performance. Encoding speeds are typically effected by CPU speed. Even for VCD.

[fewtch]

Editing could certainly be speeded up though. Also stuff like demuxing/remuxing & some other things...

I used to use a very good self-resizing RAM disk under Win98SE, that came with an old utility called Helix Hurricane... unfortunately it's a VxD and won't work with Win2k or I'd probably still be using it (not for video editing tho, I don't have that much RAM ;)).

[sucahyo]

Originally posted by fewtch
You want a RAM disk that can self-resize, i.e. auto-resizing. Try the one from here:
http://www.ramdisk.tk

Ok, I'll try that.

[nephilim]

I remember seeing this old PCI device that would take several banks of off-the-shelf RAM and call them a hard drive. The unit had a plug on the outside to maintain data when the PC was off, and I think it would accept anything up to PC133. Just going by the current price of PC133 you could get a VERY fast 4GB hard drive for relatively cheap and not have to sacrifice system memory to do it.

[wertherman]

Originally posted by nephilim
I remember seeing this old PCI device that would take several banks of off-the-shelf RAM and call them a hard drive. The unit had a plug on the outside to maintain data when the PC was off, and I think it would accept anything up to PC133. Just going by the current price of PC133 you could get a VERY fast 4GB hard drive for relatively cheap and not have to sacrifice system memory to do it.


Um, surely you'ld still be limited by the speed of the pci bus (the largest theoretical maximum is 127.2 MB per second with possible contention issues from other things on the bus (such as soundcards, wireless lan cards and suchlike). You'll be better off striping a few sata drives and getting more capacity.

[fewtch]

IMO the main attraction of a RAM disk may be security rather than speed (just pull the plug and contents are gone forever). Of course, one would have to have a need for such security.

Speed may have been a much greater consideration about 10 years ago, when hard drives were considerably slower. Of course, RAM was also considerably more expensive then too... :p

[nephilim]

Precisely what do you think your onboard SATA controller uses? Just because it isn't in a dedicated slot doesn't mean that it doesn't use the same bus as everything else. (Perhaps newer onboards will use PCIE, but that's not today.) Besides, the issue with speed here is less a matter of transfer speed and more a matter of access. RAM is faster.
Granted four Raptor drives would be godlessly fast, that's why I bought them, but for anything that requires random reads and seeking the ram's speed is measured in nanoseconds while the hard drives are measured in miliseconds. Besides, the guy was asking about ramdisks.
If you want something fast and (relatively) cheap you can use an 80x Compact Flash card along with a CF-to-IDE connector. I have one running my firewall/router/game server that takes all of ten seconds to boot. (Knoppix LiveCD image with the config/log files on a normal hard drive.)
Originally posted by wertherman
Um, surely you'ld still be limited by the speed of the pci bus (the largest theoretical maximum is 127.2 MB per second with possible contention issues from other things on the bus (such as soundcards, wireless lan cards and suchlike). You'll be better off striping a few sata drives and getting more capacity.

[b00zed]

Originally posted by nephilim
Precisely what do you think your onboard SATA controller uses?

They're connected directly to the south bridge, if they're not a part of the south bridge itself. This gives them a path to the CPU with much greater bandwidth than the PCI bus.

If one of these add-in cards were running on PCI-X then it would of course have quite a lot of bandwidth at its disposal. If you had a use for large amounts of storage with massive bandwidth, chances are you'd have a few 133 MHz 64 bit PCI-X slots to spare :D

[nephilim]

Not quite. The controller chip is separate from the south bridge, take a look at the labels on your motherboard sometime if you have onboard RAID. (Standard IDE IS integrated onto the south bridge chip.) And while they are addressed by the south bridge, so is every PCI device on your PC. Onboard controllers are PCI devices that aren't connected by PCI slots since they're integrated. Even the integrated controller logic native to modern chipsets is still addressed as a PCI device, and suffers the same limitation. Bandwidth is shared accross the board because they use the same transport bus.
Check the benchmarks. Onboard RAID or standard SATA controllers routinely lose to their counterparts because the dedicated cards often do a bit more to take the load off of the system bus by handling things natively. Granted that there's a physical difference. If nothing else the onboard controller is usually physically closer to the bus, but there you're talking latency in the microseconds. Far more time is wasted waiting for the interrupt to pick up.

[b00zed]

Originally posted by nephilim
The controller chip is separate from the south bridge
This is not always true - and is becoming increasingly infrequent as native south bridge support for SATA is quite common these days - but please go back and read my original post a little more carefully.

If you look at any current chipset block diagrams, you'll notice that there's no association between the integrated (S)ATA controllers and the PCI bus.

What would be the point of SATA and SATA-2 respectively having 150MB/s and 300MB/s of bandwidth if they were going to be limited by being placed on the PCI bus?

[nephilim]

Okay, my bad. Apparently new chipsets DO integrate SATA onto the southbridge in such a way as to remove the 133MB/sec limit. However, older controllers integrated to the southbridge DID use the PCI bus anyway. (I was working on antiquated data.) Still, only in a momentary burst will the 133MB/sec limit come into play, which kind of minimizes the effect of flooding the bus for us mere mortals. (Big servers would obviously have difficulty.)
Now here's the kicker. Researching this disagreement, notably in the case of my own motherboard, turns up that the integrated nVRAID controller on my A8N-SLI Deluxe is actually outpaced by a hefty margin by the SI3114 that is onboard but not integrated. (IE, is on the PCI bus.) Apparently that's an issue of drivers and architecture, though.
Anyway, that's it for me as this has gone seriously OT.