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Hybrid "64-Bit" eComStation

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Hi there.
Yesterday I was thinking about 64 bits and eComStation. The biggest limitation eComStation has when working on 64 bit systems is the 4GiB barrier. I know it is not a simple limit to overcome, but I have been thinking of some measures to allow the use of extra memory, although it will be a limited one.
Several users are running eComStation inside a virtual machine and are ok with most of its limitations. On the other hand, I think running an OS inside another full blown OS is somewhat annoying for daily use (one have to cope with problems and annoyances of both OSs). This way, I was thinking if it is not possible to make one of those "OS/2 5.0" projects, like OS Free, make its kernel 64 bits and configure its environment to support 32 bit systems (virtualization with almost full access to guest OS) and run eComStation inside of it. What is the point of doing that?
Well, at first, this will enable the underlying OS (OS Free, for instance) to access the entire memory. The memory unnused by eComStation could be used as a virtual drive (emulation), which could be used as a normal harddisk by eComStation. This virtual drive space could be used in two main ways:

a) Store swapper.dat
b) Store temporary application files (like the "undo" files of Ceres Sound Studio!)

This would provide a usefull extra memory space. I know it is not the same and the lower and upper shared/private arena problems would remain the same, but at least some things could use it. At least, AFAIK, swapped data is not limited to 4GiB (Virtual Address Space should go up to 64TiB).
Would that be possible (considering the available community/serenity resources)?

Daniel Caetano

PS: As an extra, this approach would provide a use for these "new OS/2 kernel projects", allowing them to improve faster. In time, some original OS/2 services could be moved to the new kernel and privileges could be removed from the guest OS... allowing a slow transition between systems.

Doug Bissett:

--- Quote ---a) Store swapper.dat

--- End quote ---

I haven't seen any indication that swapper.dat ever gets used, when I have 1.5 GB, or more, installed. It may be possible to get it to be used, but I don't think I have enough programs installed to be able to do that, unless I run more than one virtual machine.

In fact, I have been using RAMFS to create a memory drive for the %TEMP% stuff, when I have more than 2 GB installed. I think that 2 GB would be the minimum to be able to do that, but I have had no indication that it causes a problem.

It might take a bit of fancy programming, but I think that modifying RAMFS to use memory above the (normally) accessible area, might be possible, and it wouldn't involve playing with the kernel.

Dave Yeo:
I use a RAMFS volume with 1 GB, seems to work fine. Also with 1 GB, my swap hardly ever grows to over 300 MB so 1.5 GB should be ideal. I did have Thunderbird run away one day and the system crashed with a swapfile full error. Seems that it was actually a 2 GB limit on the swapfile.

Neil Waldhauer:
One of the strong points of running OS/2 is to continue to run the 16-bit parts and old programs. But with the x86-64 architecture, the real mode and virtual mode are not available to programs running in long (64-bit) mode.

Getting OS/2 to run in long mode would be a long struggle. We'd lose a lot of what makes OS/2 what it is.

It would probably be easier just to port the parts of OS/2 that you like to Linux.

Hi Neil,
There is no way to keep V86 and access memory above 4GB? Is it possible to enable the use of PAE on eComStation?


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