Nadat je laatst een brede guide over Windows's geheugenbeheer kon lezen, kan je je herseninhoud nu aanvullen met nog gedetailleerdere informatie over de precieze werking van het virtuele geheugen. In het gespecialiseerde artikel wordt niet zoveel aandacht besteed aan het bekende oppervlakkige verhaaltje over hoe je het instelt, maar wordt de techniek erachter belicht. Address translation, prepaging, vervangingsalgorithmen en nog veel meer andere zaken komen aan de orde. Een must-read voor iedereen die alles wil weten:
Gone are the good ol' days (well, some may call them good) when your grandfather had to walk to and from school in the snow...uphill...both ways, when 5 and 10 cent stores were really 5 and 10 cents and when all of your programs fit into your "huge" 640KB of RAM. Today, operating systems and applications occupy space in excess of 200MB+! With the relatively substantial cost of system RAM and most systems being limited to 64MB to 128MB, how does it all fit in memory? Well, it doesn't. Rather, applications and OS functions are called from external storage devices (such as a hard disk drive) to system RAM for processing through using something dubbed as "virtual memory".
[...] So how does the logical address get converted to the actual physical address of system memory? The physical memory is broken down into blocks called frames. Logical memory is also broken down into blocks called pages. The page size as well as frame size is defined by the hardware. Each CPU utilizes different page and frame sizes. All numbers discussed henceforth are used for the sake of argument so that you get a general idea of how the paging process works (32-bit memory addressing will be used in these explanations). Logical memory is mapped to the physical memory by use of page directories and through page tables.
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