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Assuming SSD's are extremely prone to faliure how economical would it be to load an OS into main memory and run it from there?

I can think I can deal with a few obvious drawbacks (I've survived inside the bounds of a 20gig VM for the last 2 years), but what are the pro's, con's, requirements and cost for running Windows 7 or the latest Fedora or Ubuntu distro strictly from RAM.

Just so there's no confusion, I'm not saying run the OS from a USB stick or live CD. I'm saying, start the computer, transfer the entire OS into memory from a external HD or 'the cloud' or a big memory stick and run it there. When the machine turns off, save the state to the external storage.

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What constructive requirement am I missing here? –  Peter Turner Jul 20 '11 at 13:36
    
I agree, Peter, I also reacted to the "-1". +1. –  TFM Jul 20 '11 at 13:38
    
Just for info, this is exactly what FreeNAS 0.7 Embedded does, in order to minimise writes to the OS flash drive. –  sblair Jul 20 '11 at 13:52
    
Boot Knoppix with the 'toram' option; wait for it to copy the CD to memory; ????; Profi-- Entire OS, applications, files, etc. running from memory. Downside: time it takes to read 700MB from a CD rom drive into memory. –  Darth Android Jul 20 '11 at 14:36
    
This seems to be much more unsafe than using a SSD. Most SSDs seem to be very stable and have a long lifespan (with todays fast growing technology you don't want to use such a thing longer than 2-5 years anyway...). One problem for example with loading the system into the RAM would be that power loss means loosing you whole work-data. –  Michael K Jul 20 '11 at 14:38

2 Answers 2

Good question, but I think you're missing something - most of the operating system is already loaded into the system's memory on startup. Every programmer in the world knows what the slowdown/bottleneck is in a computer (the disk drive, regardless of it's type, for you non-programmers), so they all load as much as economically possible into the system RAM.

While it's certainly possible to do what you ask, there's really no point, since you have to load the OS from the storage drive on startup, and then re-write it back to the drive before shutting down. Also, once the operating system has been loaded, there's not much that needs to be retrieved from the storage drive (aside from certain system tasks and updates, etc...).

You would see better performance gains by using a RAM disk as a temporary storage area, or even placing entire applications onto the RAM disk and running them from there. What I'm trying to get at is, it's not the operating system that we truly need to run from a fast storage media - it's the applications that you have to load afterwards. Once most operating systems are loaded, there is not much disk access from the OS itself, but rather, the applications you use.

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+1 for mentioning applications. More times than not, it's the applications that we use that are slow and not the OS. And there is little, if anything, the OS can do to speed up applications. Unless you turn Microsoft back into a monopoly. Which I favor. –  surfasb Jul 20 '11 at 18:26
    
Applications often like to interact with the system drive (i.e., c:). Thus, it totally makes sense to have the OS in RAM. –  Dmitri Nesteruk Mar 14 at 9:44

just some ideas. not really well organised. but let's see how far we can go.

admittedly, with the current price of RAM, it becomes a very attractive option for us to run the whole OS from RAM and loading it from harddisk only in the startup (and writing it during shutdown journal-commit style).

the problem is that doing this particular thing is not easy, and given the estimated users that will do that, it will not be very economically sound for software/OS manufacturers/developers to do that.

however for linux it may be an option and one can try to specify the amount of ram available and make a tailor-made OS for it. e.g. 4gb ram edition/8gb ram edition/16gb ram edition, in which 2gb/4gb/12gb are used to load files from the harddisk... etc.

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