Wenn ein Prozessor 64 bit Registerbreite hat, dann hat er auch 64 Adressleitungen und kann bis zu 2 ^ 64 Adressen verwalten. Eine Adresse ist gleich einem Byte.
Ich weiß nicht ob du viel damit anfangen kann. Wenn man die 32 bit Version des Linuxkernel (bei mir Version 2.6.32 ) selbst kompiliert , dann kann man die Option High Memory auf Off, 4 Gbyte oder 64 Gbyte einstellen.
Das steht bei der Hilfe zur Option High Memory:
Linux can use up to 64 Gigabytes of physical memory on x86 systems.
?
? However, the address space of 32-bit x86 processors is only 4 ?
? Gigabytes large. That means that, if you have a large amount of ?
? physical memory, not all of it can be "permanently mapped" by the ?
? kernel. The physical memory that's not permanently mapped is called ?
? "high memory". ?
? ?
? If you are compiling a kernel which will never run on a machine with ?
? more than 1 Gigabyte total physical RAM, answer "off" here (default ?
? choice and suitable for most users). This will result in a "3GB/1GB" ?
? split: 3GB are mapped so that each process sees a 3GB virtual memory ?
? space and the remaining part of the 4GB virtual memory space is used ?
? by the kernel to permanently map as much physical memory as ?
? possible. ?
? ?
? If the machine has between 1 and 4 Gigabytes physical RAM, then ?
? answer "4GB" here. ?
? ?
? If more than 4 Gigabytes is used then answer "64GB" here. This ?
? selection turns Intel PAE (Physical Address Extension) mode on. ?
? PAE implements 3-level paging on IA32 processors. PAE is fully ?
? supported by Linux, PAE mode is implemented on all recent Intel ?
? processors (Pentium Pro and better). NOTE: If you say "64GB" here, ?
? then the kernel will not boot on CPUs that don't support PAE! ?
? ?
? The actual amount of total physical memory will either be ?
? auto detected or can be forced by using a kernel command line option
such as "mem=256M". (Try "man bootparam" or see the documentation of ?
? your boot loader (lilo or loadlin) about how to pass options to the ?
? kernel at boot time.)
PS: Von den 64 möglichen Adressleitungen werden aber nur 36 genutzt. 2 ^ 36 Adressen entsprechen 64 Gbyte RAM.
KarstenW
Xdata
