How To Have More Than 128Mb of Swap

How To Have More Than 128Mb of Swap

Use several swap partitions or swap files. Linux kernels before
version 2.2 supported up to 16 swap areas, each of up to 128Mb. Recent
versions do not have this limitation.

Very old kernels only supported swap partition sizes up to 16Mb.

Linux on machines with 8KB paging, like Alpha and Sparc64, support a
swap partition up to 512MB. The 128MB limitation comes from
PAGE_SIZE*BITSPERBYTE on machines with 4KB paging, but is 512KB on
machines with 8KB paging. The limit is due to the use of a single page
allocation map.

The file mm/swapfile.c has all of the gory details.

[Peter Moulder, Gordon Weast]

How To Prevent Errors when Linking Programs with Math Functions.

Older run-time libraries included the math library in the C run-time
library. It was not necessary to specify the math library separately
when compiling. If the compiler generates a message like this when
linking a program that uses math functions:

/tmp/ccDUQM4J.o: In function `main':
/tmp/ccDUQM4J.o(.text+0x19): undefined reference to `sqrt'
collect2: ld returned 1 exit status

You need use the -lm option with GCC to link with the math libraries:

# gcc -o program program.c -lm

Make sure also to use the statement #include in the source
file.

[Florian Schmidt]

8. Miscellaneous Information and Questions Answered


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