Whats the difference between returnil disc caching and memory caching

[wildfllower]

Hello,

I have a couple questions in regards to returnils caching methods.

1: Exactly what is the difference between memory caching and disc caching? Its my understanding that they both use some form of scratch space, so in essense they seem the same to me, but there must be some difference right?

2: Does memory caching and disc cache use the windows pagefile, or can you just delete the windows pagefile altogether when returnil is enabled?


Just to let you guys know, I tried emailing returnil on these subjects but they never really gave me a direct answer. If this is a trade secret then I apologize for inquiring any further, but I am trying to do some troubleshooting and this information would be highly useful....

Thank you!

[Coldmoon]

Hello wildflower and welcome to the forums :)

Please see this and let me know if it helps:

http://www.wilderssecurity.com/showthread.php?t=229206&highlight=disc+cache+memory

Mike

[wildfllower]

Hi Mike,

Thanks very much for the link. However I must apologize as it still confuses me.


My understanding from the link is that even though you are using memory cache it still stores information on a pagefile/although it doesnt specify if its the windows OS pagefile or scratchspace created by returnil....

It makes sense that disc caching would use a pagefile, but again I cant tell if its using windows pagefile or if its creating its own file. my windows pagefile was smaller than the disc cache size I chose so im thinking its using its own?

Would you be able to clarify any of this please?

thanks very much for your time. . .

Toby

[Coldmoon]

-{ Quote: "My understanding from the link is that even though you are using memory cache it still stores information on a pagefile/although it doesnt specify if its the windows OS pagefile or scratchspace created by returnil...." }-

The Windows pagefile is not involved and is really only a way to describe the cache in familiar terms. The actual cache itself uses a combination of RAM and disk where the disk portion (internal to RVS) is used for "overflow" from the RAM when required. In RVS 2010, we use a new caching method where memory and disk are more integrated and disk use is "as needed" rather than pre-determined.

Mike

[wildfllower]

Does returnils memory cache and disc cache use the same caching method that you described?

If not, please explain how they are different?

Thank you Mike.

[Coldmoon]

In 2008 they are seperate but both use disk to some extent (Memory = RAM + Disk) and Disk is exactly that. In the first, disk allocation is internal and only used when required. In Disk, the size of the cache is pre-determined but unlike other similar types of ISR, it does not require contiguous space to be created.

In 2010, you can look at the new dynamic caching as a combination of the best aspects of both Memory and Disk caching that only requires the user to determine the maximum percentage of free space on their system partition that will be allowed for the cache. This is set at a default of 50%, but can be adjusted as needed.

Mike

[I no more]

This is something I've been wondering about. If the pagefile is not involved at all, then what happens when you leave the pagefile enabled while using Returnil (or other similar software). Is that just wasted space on the hard drive?

Also, is it possible to run the equivalent of a fully write-protected system (i.e. all changes are written to RAM only). This would be useful because all chance of data recovery would be eliminated once the system is shut down. I realize that the space Returnil uses can be overwritten, but a fully write-protected system doesn't require anything to be done to prevent data recovery. I also do realize that this is not Returnil's primary purpose, but I was thinking software like this could be used as an alternative to full system encryption.

Thanks

[Coldmoon]

Hi I no more than U and welcome to the forums :)

-{ Quote: "This is something I've been wondering about. If the pagefile is not involved at all, then what happens when you leave the pagefile enabled while using Returnil (or other similar software). Is that just wasted space on the hard drive?" }-

The Windows page and hibernation files are not virtualized.

-{ Quote: "Also, is it possible to run the equivalent of a fully write-protected system (i.e. all changes are written to RAM only)..." }-

It is possible, but would be something for specialized systems that have a great deal more RAM than you would see on an average system; at least for the near future...

-{ Quote: "I also do realize that this is not Returnil's primary purpose, but I was thinking software like this could be used as an alternative to full system encryption." }-

Perhaps in time, depending on market forces requesting this type of feature focus. For the time being however, there are other, more urgent things that have priority so I suggest that you might want to wait for a while before you abandon strong encryption.

Mike

[wildfllower]

Hi Mike. I appreciate your answer. I think it makes sense now..

I do have another question. I know they say to turn off all programs before starting up returnil, but what about driver based programs, such as comodo firewall for one example? Or perhaps Sandboxie? Should those programs be enabled before or after turning on returnil? I know they run either way but not sure if could affect security or cause any performance loss?

Thanks,,,,

[Coldmoon]

-{ Quote: "Hi Mike. I appreciate your answer. I think it makes sense now..

I do have another question. I know they say to turn off all programs before starting up returnil, but what about driver based programs, such as comodo firewall for one example? Or perhaps Sandboxie? Should those programs be enabled before or after turning on returnil? I know they run either way but not sure if could affect security or cause any performance loss?

Thanks,,,," }-

The warning is so that the user will have an opportunity to save their current work and not meant to suggest that you should turn off ALL programs. Remember that RVS virtualization is set by default to drop all changes which means that if you were working on a presentation or WORD document, you might loose any work after the last auto-save or manual saving of your work to that point...

There is no issue with SBIE or Comodo regardless of whether they are active or not.

HTH
Mike