memory address space การใช้

• It normally occupied the top 1 MB of physical memory address space.
• In electronic digital computers, there are different limitations on the usable memory address space.
• The top 1 MB of physical memory address space was reserved for the monochrome frame buffer.
• If implemented as part of the memory controller, interrupts are mapped into the system's memory address space.
• :In X, the only system I'm intimately familiar with, it lives in the computer's memory address space.
• Thus, they produce compact code when used for small memory address spaces, but have no advantage over belt encoding in larger spaces.
• PAGEEXEC has the advantage of not dividing the memory address space in half; tasks still each get a 3 performance detriment in some cases.
• It assumes a global memory address space that is logically partitioned and a portion of it is local to each process, thread, or processing element.
• The original ROMs in the Macintosh II contained a bug which prevented the system from recognizing more than one megabyte of memory address space on a Nubus card.
• These types of kernels normally provide only the minimal services such as defining memory address spaces, Inter-process communication ( IPC ) and the process management.
• A successful overlay destroys the previous memory address space of the process, and all its memory areas, that were not shared, are reclaimed by the operating system.
• The operating system may intercept changes to Gate A20 and make corresponding changes to the virtual memory address space, which also makes irrelevant the efficiency of Gate-A20 toggling.
• It was also necessary to completely simulate the memory address space of a Macintosh Plus, including the behavior of certain illegal addresses that were deliberately exploited by certain applications ( primarily games ).
• Since all segments are 64 KB long, this explains how overlap can occur between segments and why any location in the linear memory address space can be accessed with many segment : offset pairs.
• Note that even if I / O chips like VIC-II only uses 64 positions in the memory address space, it will occupy 1, 024 addresses because some address bits are left undecoded.
• For system architectures in which port I / O is a distinct address space from the memory address space, an IOMMU is not used when the CPU communicates with devices via I / O ports.
• Systems may still be vulnerable to a DMA attack by an external device if they have a PCI and PCI Express in general, connects attached devices directly to the physical rather than virtual memory address space.
• Space for the 128-bit stretched version of the ISA was reserved, because 60 years of industry experience has shown that the most unrecoverable error in instruction set design is a lack of memory address space.
• I / O devices were connected to the system via the Q-Bus, whose 22-bit address space was mapped onto the 24-bit memory address space of the Firefly by using mapping registers controlled by the master processor.
• Historically, to be able to support memory address spaces larger than the native size of the internal address register would allow, early CPUs implemented a system of segmentation whereby they would store a small set of indexes to use as offsets to certain areas.