Ceci n'est pas une pipe

I quote here a post appeared Blog OSRevolution dated September 24. The topic is not explored in depth, but this post can be a good starting point for many, therefore deserves to be read.

This article is for those who had installed 2 or more gigabytes of ram on a 32bit Linux distro, is facing the problem of lack of ram, because the same is not used by the system. I draw inspiration from an article in Linux.com on how to make the ram over 1 GB on the penguin 32bit, at least 2 years I compile my kernel with this feature enabled.

The article explains in broad terms why today this option is not enabled by default on the main distro kernel, not least of all. The main factor that is highly technical and 32bit systems are not able to exploit more than 1 Gb of ram, but we will see that this solution exists for some time and the difference is to use as virtual memory, this difference is remapped, all using a kernel compiled with this feature.

Well remember that the support for the HighMem has two possible options, for more than 1 GB to 4 GB must enable HIGHMEM4G, more than 4 GB up to 64 GB instead you must enable HIGMEM64G. Taking as example the Debian kernel memory that supports up to 4 GB is given by the kernel 686 (linux-image-2.6-686) while up to 64 Gb from 686-bigmem kernel (linux-image-2.6-686-bigmem) , but those series * -486 or even lower, so do not have this feature included is set to "off". Using a kernel of this series (486) exceeds your ram to 1 GB will not be totally exploited by the system!

In case anyone wants to rebuild the kernel, remember that the rumors are to be set in "Processor type and features" to "High Memory Support".

A quick check on any kernel you can do grep-went to the configuration file, I show you my having 2 GB RAM:

$ egrep -i highmem /boot/config-$(uname -r)
# CONFIG_NOHIGHMEM is not set
CONFIG_HIGHMEM4G=y
# CONFIG_HIGHMEM64G is not set
CONFIG_HIGHMEM=y $ egrep -i highmem /boot/config-$(uname -r)
# CONFIG_NOHIGHMEM is not set
CONFIG_HIGHMEM4G=y
# CONFIG_HIGHMEM64G is not set
CONFIG_HIGHMEM=y otherwise listed before installing a kernel or compiled with these options.