A/UX: "pagesize" Information (9/94)


I assume that a click in A/UX is the normal SysV 2K (2048 bytes). In /usr/include/sys/mmu.h, if the NEW_PMMU is defined, the PAGESIZE is defined as (1 << PAGESHIFT), and the PAGESHIFT is earlier defined as PS4K, that is, 11. So the logical shift makes it 2048. I am unsure if the A/UX kernel has NEW_PMMU set or not.

I need the click size information for shared memory tuning.

From our research, the A/UX 1.1 kernel is compiled with the NEW_PMMU defined in the kernel MAKEFILE.

In the /usr/include/sys/mmu.h file:

The PAGESIZE is defined as #define PAGESIZE (1<<PAGESHIFT)
The PAGESHIFT is defined as #define PAGESHIFT PS4K
The PS4K is defined as #define PS4K 12

From the above formula, the PAGESIZE can be calculated as 1 << 12, which equals 4096. It's 4K, not 2K.

The command, called "pagesize", can also be used to display the current system page size.


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Published Date: Feb 18, 2012