MaDeMoiSeLLe :)

microsoft

differencesS

unix/linux

a page file is allocated on disk, does not used the memory mostly. leaving more RAM for actively used

when an object is needed, it can be brought back into the memory.

placed the file on seperate partition and Windows will remember it.

unfortunately, this slows down the I/O due to the sleek time involved in switching back and forth between the two partition.

Memory Management

use a swap partition where the disk space allocated for paging is seperate from general data.

this reduces the slowdown of the I/O.

Linux uses a Least Recently Used (LRU) page aging technique to fairly choose pages which might be removed from the system.

This scheme involves every page in the system having an age which changes as the page is accessed. The more that a page is accessed, the younger it is; the less that it is accessed the older and more stale it becomes. Old pages are good candidates for swapping.

Windows uses structured exception handling to report page fault-based invalid accesses as access violation exceptions

recent versions of Windows often report such problems with less technical error messages simply stating something along the lines of "this program must close" (an experienced user or programmer with access to debugger can still retrieve detailed information, if necessary). Additionally, recent Windows versions also write a minidump (similar in principle to acore dump) describing the state of the crashed process for later analysis alongside such less-technical error messages

Page Faults

UNIX (and UNIX-like) systems typically using signals,such as SIGSEGV, to report these error conditions to programs.

UNIX and UNIX-like operating systems typically report these conditions to the user with error messages such as "segmentation violation", or "bus error"

The page file in XP is a hidden file called pagefile.sys. It is regenerated at each boot — there is no need to include it in a backup. To see it you need to have Folder Options View set to ‘Show Hidden and System files’, and not to ‘Hide Protected mode System files’.

Page Sizes

The size of the block of pages examined is higher if the kernel swap daemon is intensively swapping; that is if the number of free pages in the system has fallen dangerously low. The blocks of pages are examined in a cyclical manner; a different block of pages is examined each time an attempt is made to shrink the memory map. This is known as the clock algorithm as, rather like the minute hand of a clock, the whole mem_map page vector is examined a few pages at a time.

Trashing a file, if possible, is an atomic, constant time operation that will never error out due to out-of-space or other issue. Even trashing large files is instant, which is important because the user
don't expect trashing to be a costly operations, especially considering that most trash operations are never undone.

The out-of-space handling is importang, because it solves the "trashing files to make space on a full disk" problem that you have if you copy files to the trash.

Trashing

On non-unix system you see this strange .Trash-user directory

On unix system the trash dir is hidden, and its not obvious that the media is not empty, because the connection with the files in
the trash location is not very explicit, or even logical.