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RAM Disks

(7 posts) (3 voices)

Started 9 years ago by mikiem2
Latest reply from Whiterabbit-uk

mikiem2
Moderator

Just a few points sparked by comments on the GOTD download page...
http://en.wikipedia.org/wiki/RAM_drive

A RAM disk or drive is a virtual hard drive stored in RAM rather than on a hard drive. Because memory is faster than hard drives, even SSDs, performance is better. Because anything stored in your PC/laptop memory is lost when you turn it off, it's obviously better for systems that stay up & running 24/7, &/or for temporary storage like Windows cache. Windows, from Vista on likes 8GB RAM -- it'll run with less, it'll run with more, but 8 has always been a sweet spot. If you want to run a RAM Disk & maintain Windows performance then you likely will want more RAM -- when people build PCs, in 2nd place to 8GB, 16GB is the most often used amount.

Running 16GB often presents added challenges -- it's just the way many motherboards work -- with the most popular setup being 4 sticks of 4GB each. 8GB runs in the $50-$75 range in the US, 16GB usually starts around $120 for a matched set of 4 -- preferably use 2 or 4 sticks that are sold as matched rather than packaged individually. For general use on a current, common Intel board, RAM speed isn't that critical -- it can be overclocked or optimized to reach the higher speeds some RAM is rated at, but the performance difference is generally thought minimal, & not worth the effort. If you want the fastest performance from a RAM Drive that's the territory you want/need to explore.

Now, RAM Disks are ancient in PC years -- they've been around an awful long time -- but have never gained a huge following. I think that's because real world advantages are limited. You can read/write to/from a RAM Disk faster than most any other type of storage, but how often does that matter? And how much?

If you can manage to use the files for a game from a RAM Drive, maybe it'll speed things up *if* that game's speed [fps] is limited by how fast that data can be read in the 1st place. If you're working with photos or audio or video, reading a large amount of data from a RAM Drive would be faster, but you'd have to 1st copy that data to the RAM Drive, & once you did, that RAM would be unavailable to store that media while you were working on or with it. Software would start faster from a RAM Disk, & it would be faster reading any of the program's files once it's running, but software doesn't need to read program files all that often, & once it does, those are stored in the RAM Windows & the software uses -- something you'd have less of when/if you created a RAM Drive.

Long story short, there's nothing wrong with trying out a RAM Drive to see if it helps speed up whatever it is you want to do, but unless you've got money to burn, you probably don't want to jump in with both feet, spending lots of money just for a RAM drive until you're satisfied the expense would be worth it to you.

Posted 9 years ago #
Whiterabbit-uk
Games Guru

Thanks for the info Mikiem.

Posted 9 years ago #
goodgotd
Member

Now, RAM Disks are ancient in PC years -- they've been around an awful long time -- but have never gained a huge following.

They had a huge following for a certain period before hdd's got huge, but memory was getting cheaper. RAM Disks were a stopgap for 8086 and 80286, plus other CPU's [if not shifted to the wide-register 'flat memory model' 16 or 32 bit mode] because they couldn't 'see' past 640mb of RAM- and RAM beyond that had to be paged through a driver in the upper area of that- I'll dig out the references for the correct terms and specs later, but some programs weren't able to use RAM that way, so using part of that memory for a RAM disk made loads of sense.

My first 'IBM PC clone' was a '286 with 4 megs of RAM and a pair of 40 meg drives. I knew lots of pros that set up customer's machines that way, and used them for swap drives, additional program space, or just in case the customer wanted a place to store sensitive intermediate data that would vanish as fast as turning the power off. *that* advantage is still there- recovering a Ramdisk's contents after shutdown truly is impossible.

I'm not up to explaining the really cool features that IBM-DOS 7 had in detail, but imagine the fun of running at least 5 serial-connected terminals besides the local keyboard and monitor in time-sharing mode- and the gobs of memory that trick needed...

Posted 9 years ago #
mikiem2
Moderator

"*that* advantage is still there- recovering a Ramdisk's contents after shutdown truly is impossible. "

From what I've read there's a Very tiny window of time where the contents of RAM *may* be recovered, but AFAIK we're talking theory more than practical application, as the discussions focused on getting Truecrypt [& similar] keys & potential weaknesses. I think it's fair to say impossible. :) That's one possible application of the mini Windows setups at reboot.pro -- booting win7 or LiveXP from disc or USB stick loads everything into a RAM disk it creates. There's also an app there called VHD_W7_Compact -- from the ReadMe:

"VHD_W7_Compact.exe - Make Portable Win 7 in 2 GB VHD booting from USB or HDD x64 version needs 3 GB VHD because of extra 1 GB SysWOW64 folder"

"Mini 7 has smallest Size of about 600 MB by removing Windows Media Player and by further reduction of system32 and DriverStore.
Mini 7 is very useful to Boot from RAMDISK on known hardware, since servicing for Adding Driver Packages has also been removed."

If you have a win7 VM <1GB its VHD could easily & conveniently be copied to & run from a RAM disk. With VBox installed, & presumably VMs on hdd, you're not trying to hide anything. So a VM is set up to run from a path on a RAM disk -- what's faster? Come something like Update Tuesday, afterwards run disk cleanup to remove old files, & copy the VHD to hdd. The biggest hassle I'd think would be compacting the VHD every so often. [For VHDs I attached them as a 2nd drive to the XP Mode VM -- for VBox's .vdi I attach then defrag then CloneVDI using compact option.]

At any rate, a project without need or reason [just playing] I plan on getting to some day. :)

Posted 9 years ago #
goodgotd
Member

That's one possible application of the mini Windows setups at reboot.pro -- booting win7 or LiveXP from disc or USB stick loads everything into a RAM disk it creates. There's also an app there called VHD_W7_Compact -- from the ReadMe

then there's a [hopefully rare- but if you're booting for diagnostics...] problem that can really be Annoying- a funky memory stick can corrupt a RAMdisk and be a pain to figure out.

BTW, the paged-block memory was called Expanded Memory- if you accessed it through a driver without paging it was Extended Memory.

[yes, I still have a functioning 80386 monochrome MS-DOS v5/Win 3.1 system with 4 megs of RAM and 120MB in 2 HDD's- and a Commodore 64, Atari 400 and more...]

Posted 9 years ago #
mikiem2
Moderator

[yes, I still have a functioning 80386 monochrome MS-DOS v5/Win 3.1 system with 4 megs of RAM and 120MB in 2 HDD's- and a Commodore 64, Atari 400 and more...]

Cool.

We recycled everything but the Atari. The 286 became a 386, then a 486, & I think maybe we even had one of the Pentiums in there. I think I'm on only my 3rd case in 20 years! And I still have parts that I use occasionally from the last one. :)

My wife & older son are less demanding, and the price difference between mid & lower-end high range isn't that great, so as their systems get old the younger son & I tend to upgrade & put together sort of hand me down PCs for them -- they're still quite respectable systems, e.g. my wife's running a 2600K.

And then every once in a while we'll put together a system when we have too many spare parts & give it away to someone less fortunate.

Posted 9 years ago #
Whiterabbit-uk
Games Guru

I've been using DVD RAM discs for years and found them brilliant for recording TV programs or movies that I wasn't intending on keeping, but couldn't watch at the time. You can edit out the adverts unlike rewritable DVD's and apart from a couple that were damaged, they are pretty scratch resistant (though not as good as Blu Ray disc in that regard).

I have around 200 RAM discs that I've used over and over for years and they still work well. The only disadvantage is if you want an HD recording. You can only record an hours worth of programs at the highest setting and even then, it's not as good as recording onto a 25GB Blue Ray disc. Though re-recordable Blue Rays cost so much I won't buy them. I use those single recordable Blue Ray discs for creating a third backup of my programs, video and photographs. We keep a copy at my wifes parent just in case the house burns down. :)

I've considered online storage, but to be honest, don't trust it..

I don't use them as often as I used to since the advent of DVD recorders with hard drives and my TIVO box, but I still use them when my HDD's are full.

I usually buy any movie I enjoy watching, tohugh my wife has said I should start using the online services. Personally I like having a physical disc with a case.

Posted 9 years ago #

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