Talk:RAM drive

Tmp

I am curious; doesn't Gentoo Linux also grow and shrink /tmp as necessary? Isn't that in fact a usual feature of source-based distros? -- Maru Dubshinki

A RAM drive is a physical piece of solid state hardware that behaves like a ordinary hard drive in most respects but delivers far superior performance regarding access time and thru put. What you refer to in this wiki is a Virtual RAM Drive where the storage device is emulated in system memory. A virtual RAM drive achieves that same effect as a RAM drive but with a few limitations, namely, virtual RAM drives are limited in capacity to your system memory and they utilize system CPU time when accessing data. The system memory limitation is largely due to the fact that many operating systems simply do not support large quantities of system memory (not large enough for big RAM drives). Windows vista as an example limits system memory to 8GB with the high end of the OS release. Physical RAM drives on the other hand such as the HyperDrive IV and GigaByte I-RAM have their own RAM on board and the memory limits are dependant on the manufacture. Capacities can vary between 4GB and 16GB. It’s important to note, since most RAM drives act identically to normal hard drives, that you can place RAM drives into a RAID configuration in order to extend the space available or protect data with mirroring. Enhancements in data thru put should not be expected in a RAM drive RAID configuration because the data bottle neck for RAM drives is the BUS architecture and not the speed of the drives. Another complication with RAM drives is the manor in which they retain data. When the system is shut down or when a power outage occurs RAM normally loses all stored data because RAM must be continually powered to hold data. Manufactures of RAM Drives utilize a battery that can keep the memory active but most systems can not keep memory active for more than 16 hours without power. It is recommended by some professionals that you utilize a UPS system with such system configurations to lower the chances of data loss. Another important safety tip for those using RAM drives is to regularly copy the RAM drive image to a local magnetic hard drive particularly before shutting down the system. — Preceding unsigned comment added by 122.167.128.113 (talk • contribs) 10:40, 31 July 2007

Name

http://www.eniro.se/cgi-bin/popularimeter.cgi?kl=sv&q1=%22RAM+disk%22&q2=RAM-disk&q3=RAMdisk&q4=RAM-drive&q5=%22RAM+drive%22&what=web&search=S%F6kningen+p%E5g%E5r... I think "RAM-disk" seems to be the most widely used name. — Preceding unsigned comment added by Frap (talk • contribs) 2006-01-27

Actually, "ram drive" has more hits on Google than "ram disk", "ramdisk" and "ram-disk", moreover "disk" is an improper name as it doesn't contain any disk. ekerazha (talk) 11:14, 19 June 2012 (UTC)

Renaming article to ram drive is appropriate but claiming "ram drive" is improper is an original research. On Amiga Workbench it is always ram disk. I can search Workbench manuals for a reference. Xorxos (talk) 17:29, 21 June 2012 (UTC)

I should have some Amiga Workbench manuals somewhere... still it's an improper name. It could be used by everybody, still it would be objectively wrong as ram doesn't contain any disk, it's just a wrong name borrowed from the fact that a ram drive is showed to the end user as something that can be used as a sort of hard disk drive. However this wrong name is often used, so I kept it as secondary name in the article. ekerazha (talk) 10:53, 22 June 2012 (UTC)

The article currently uses "RAM drive" and labels "RAM disk" as being incorrect. This is false, but more importantly, original research. See Google ngrams for "ram disk,ram drive" and "ramdisk,ramdrive" for evidence that "ram disk" or "ramdisk" is a lot more common. As an encyclopaedia, we have no business deciding what is "factually correct" or not. (Though, for the record, both would be incorrect by Ekerazha's reasoning, as a RAM disk is typically a mount point, and neither a disk or a drive.) The page should be moved to "RAM disk", but I am not able to do this myself as I have not been autoconfirmed yet. I would appreciate it someone else could do it, and fix up the references to the name in the article itself. Noah Slater (talk) 21:13, 17 February 2013 (UTC)

I removed the words "incorrectly referred to as" from "RAM disk" the article, since nobody has provided a reliable source for the claim. (And, for that matter, both terms have been in use for decades.) I also added the {{requested move}} template to the top of this section. --Closeapple (talk) 00:03, 18 February 2013 (UTC)

Thanks! Noah Slater (talk) 19:13, 4 March 2013 (UTC)

Linux / Windows

The Article and all the links seem very much Linux-centric. I don't have a problem with that, (although I came here specifically to learn about the current status of Ramdisks in Windows, so I think it would be nice to include that also) but it should be made clear in the article that most of that which is said applies only to a certain kind of OS.--BjKa 09:53, 30 July 2007 (UTC)

Sources?

This article contains no references to sources... Sources showing appropriate info needs to be added. 71.178.208.209 (talk) 01:12, 11 January 2008 (UTC)

2GB of RAM?

In what way are most PCs "limited to 2GB of RAM"? The article provides no context for this statement. —Preceding unsigned comment added by 71.237.182.119 (talk) 19:49, 7 February 2009 (UTC)

In 32 bit operating systems, pcs are limited to 3 gigs of ram. Some pcs are actually sold with a 32 bit operating systems and 4 gigs of ram so the extra 1 gig can be used as a ram disk. 207.81.100.209 (talk) 00:52, 14 March 2010 (UTC)

Most 32 bit Windows can use 4GB (excluding the starter editions and servers). You are probably talking about the address space reserved for the system, but freeing those address space regions would only mean each processes can use more ram now, as a result you would see less free ram as a whole, definitely that is not something you could cal it "extra gig for RAM disk".

RAM Disk paragraph moved from SSD article

The following paragraph was moved from the SSD article because it gets into more detail than is covered for related technologies. There were no sources stated, so they should be checked before being considered as added into the RAM disk article here (likely in the historical section).

RAM "disks" were popular as boot media in the 1980s when hard drives were expensive, floppy drives were slow, and a few systems, such as the Amiga series, the Apple IIgs, and later the Macintosh Portable, supported such booting. At the cost of some main memory, the system could be soft-rebooted and be back in the operating system in mere seconds instead of minutes. Some systems were battery-backed so contents could persist when the system was shut down.

Music Sorter (talk) 22:36, 13 June 2010 (UTC)

Software

Should we be including software at the end of the article? Would any non-biased readers find it advantageous to have direct links to known freeware, seeing as the use of a RAMDisk could provide the user with more knowledge of the subject? --Wmw71190 (talk) 13:12, 23 June 2010 (UTC)

yes 218.214.18.240 (talk) 09:31, 8 August 2010 (UTC)

Anyone else? I'm going to place the software back on there if no one else seems to have a problem with it..--Wmw71190 (talk) 15:24, 12 August 2010 (UTC)

Yes, this would be useful. Pasado (talk) 05:46, 19 April 2011 (UTC)

Requested move

The following discussion is an archived discussion of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the proposal was no consensus. --BDD (talk) 00:51, 5 March 2013 (UTC) (non-admin closure)

RAM drive → RAM disk – proposed in 2006, sporadic discussion in 2012, then revived in February 2013 relisted --Mike Cline (talk) 19:53, 26 February 2013 (UTC) Closeapple (talk) 00:03, 18 February 2013 (UTC)

• Oppose "RAM drive" is a pretty frequently used name for the thing. And it isn't a physical disk, it's a virtual drive. There have been various "RAM disks" (physical as opposed to virtual drives) over the years as well, such as ones with battery-backed NVRAM. -- 65.92.180.137 (talk) 03:02, 18 February 2013 (UTC)
• Note: This discussion was already underway (slowly) at #Name above, but the template was moved into this new section today. --Closeapple (talk) 01:24, 19 February 2013 (UTC)

The above discussion is preserved as an archive of the proposal. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

RAM drive vs paging (and virtual memory) (See also)

• Paging: scheme by which a computer can store and retrieve data from secondary storage for use in primary storage
• RAM drive: block of primary storage that a computer's software uses as secondary storage

I think that, at least conceptually, paging is the opposite of RAM drive. So paging (and virtual memory) should appear at least in "See also". --Edupedro (talk) 08:08, 21 July 2014 (UTC)

No, it only seems that way because you have chosen to describe them in these words, which are carefully arranged as opposite pairs. In fact they are so different in purpose, implementation, and use that to describe them as "opposites" is grossly misleading; it implies a relationship that does not exist. Jeh (talk) 08:34, 21 July 2014 (UTC)

I agree with user Jeh that this comparison is confusing because they're very different kinds of things; one is an integral feature of the CPU/architecture and implemented by the operating system, the other is a storage device (virtualized or peripheral). -- intgr [talk] 08:45, 21 July 2014 (UTC)

With a RAM drive, primary storage is sort-of used as secondary storage, but it's usually not persistent secondary storage, as data in RAM used for a RAM drive usually doesn't persist across reboots. With paging, secondary storage isn't used as primary storage, it's used as "backing store" for virtual memory. they're not simple opposites.

And what happens if you memory-map a file that's on a RAM drive? :-) Guy Harris (talk) 09:46, 21 July 2014 (UTC)

(Or if you put a pagefile on a RAM drive—approximately the worst idea in memory management ever, but I used to routinely see people suggest it in forum posts.) Then people like me will post your name in public places, under the heading "Idiot Unclear on the concept". :D Jeh (talk) 10:01, 21 July 2014 (UTC)

Memory-mapping files on tmpfs, at least, probably happens rather a lot on SunOS 4.x and 5.x, actually; if you were to, for example, put the source to a test program in /tmp, compile it, and run the executable from /tmp, its executable image will be memory-mapped from a file system backed by (virtual) memory. Given that, to avoid memory-mapping files on a RAM drive or tmpfs, the code that calls `mmap()` or `MapViewOfFile()` would have to check whether the file is on a memory-backed file system and not memory map in that instance, it's not clear that it's worth going through the effort to avoid it.

Putting a pagefile/swapfile on a RAM drive is much different on the silly scale (about the only argument I could see for it would be if you were in some circumstance in which partitioning main memory in that fashion was useful; I can't think of any offhand, but I might be missing something). Guy Harris (talk) 17:25, 21 July 2014 (UTC)

I don't see it. The relation gets even more tenuous for a virtual drive implemented with virtual memory rather than with dedicated real memory, e.g., VIO on MVS. Shmuel (Seymour J.) Metz Username:Chatul (talk) 18:17, 21 July 2014 (UTC)

But for the two or three Wikipedia users who aren't computer science grads, don't you think it would be useful to give a "see also" in case they had some muzzy ideas about RAM pretending to be disks and disks pretending to be RAM? --Wtshymanski (talk) 15:34, 22 July 2014 (UTC)

This is like listing "Brakes (car)" as a "see also" under "Engine (car)". After all, one turns kinetic energy into heat, and the other turns heat into kinetic energy. There, opposites! Seriously, W., as someone who makes part of his living explaining this stuff to people, I think it is just (you should pardon the expression) the opposite. Listing "Ram drive" as an alternative for "paging" would be far more confusing than helpful. Jeh (talk) 16:41, 22 July 2014 (UTC)

If I was reading about automobiles, I'd want to read about all the parts of an automobile, wouldn't I? But if I were teaching "car science", I'd be so hung up on the details taht I wouldn't pay any attention to the duality of the two concepts and would chastise my students for talking about "brakes" during "engine class". That's our mission here on WP - no hair too fine. --Wtshymanski (talk) 18:13, 22 July 2014 (UTC)

If I was teaching such a class I might well mention the duality of the concepts. It's an interesting point in TD terms, if nothing else. But then I would be quick to qualify "but they don't do those jobs in anything like the same way." Simply mentioning the TD functions as "opposites" doesn't help anyone understand how they work, and anyone looking for something that "looks like the opposite of the engine" isn't likely to find the brakes in a cutaway view. That's the "misleading" part. We can't do a proper job of qualification in a "See also" wikilink, so it would do more harm than good. Jeh (talk) 19:12, 22 July 2014 (UTC)

Thanks. I'm not an expert in CS and my ideas about the concepts are basic (and English is not my native language). In that superficial knowledge those concepts seem to be opposite. But now, with your explanations, not so much. By the way, above TD seems to be an abbreviation of Thermodynamics but in TD the second doesn't appear. I see that the first is used in more web sites as an abbreviation of the second, so it could be added to the article. Regards, Edupedro (talk) 10:56, 23 July 2014 (UTC)

Thank you for your calmly reasoned response! As for putting "Thermodynamics" on TD's disambiguation page, I'm not certain. I'm not a physics SME so I don't know if that abbreviation is "official" enough. 10:24, 24 July 2014 (UTC)

I believe versions of MVS pre-XA did approximately this. Real storage above 16mb was used for paging. I'm not familiar with the details but I think the system was unable to use this storage as conventional memory. Peter Flass (talk) 21:01, 27 November 2017 (UTC)

A possibly less twisted analogous-abstraction might be:

• Memory Map: block of secondary storage that a computer's software uses as if primary storage
• RAM Drive: block of primary storage that a computer's software uses as if secondary storage — Preceding unsigned comment added by 2601:600:9d80:f0c0:fcd3:1873:987e:e1f7 (talk) 07:36, 17 February 2020 (UTC)

Presumably meaning

• Memory-Mapped File: space in secondary storage that a computer's software uses as if primary storage

What's being discussed there is a file (thus considered to have a permanent home on secondary storage, e.g. if the drive is removable, and you unplug the drive and plug it into a different computer, that computer could, if the permissions allow, read or write that file), and a mapping constructed in the process's address space, so that the data in the file appears as if it were placed into its address space, with loads from it getting data from the file and stores into it modify data in the file. Guy Harris (talk) 09:06, 17 February 2020 (UTC)

Relevance to VPN's

So, one major use of RAM drives today is for servers for VPN's to better protect privacy. In theory, unlike a conventional hard drive, deleted files on a RAM drive shouldn't be recoverable. This use for VPN servers is probably their most common use today. CessnaMan1989 (talk) 16:43, 4 November 2021 (UTC)

Implementation Issues

There are many current and relatively recent issues with implementing modern RAM drives. One issue is that many modern operating systems, especially Windows, use a hybrid-boot feature, which, long story short, sometimes results in temporary storage from a previous session actually persisting into the next session once the computer is turned back on. This has effected how RAM drives are implemented now.

Another, somewhat related issue, issue that most functional RAM drives today are actually sections of RAM that are partitioned by software such as SoftPerfect to be virtual disks or functional RAM drives, which make the implementation entirely dependent of the software used. Plus, some computer architectures that come from FPGA's actually use partitioned portions of hard disk to be the RAM drive, which I admit is unusual, but it does exist. What sort of sources should I cite to include these kinds of issues in the article? CessnaMan1989 (talk) 16:53, 4 November 2021 (UTC)