
	Where results make sense

Topic: Flat memory model

Related Topics

flat racing

The Earth Is Flat

Flat engine

flat tax

Flat Rock

Bonneville Salt Flats

Big Flats

flat module

Flat Earth Society

flat 4

Flat file database

Lebreton Flats

In the News (Sat 22 Nov 08)

Lee Scott

Annika Sorenstam

Norm Coleman

Benji Madden

Freddie Mac

Puerto Rico

Vladimir Putin

Treasury Department

Mitt Romney

Giovanni Trapattoni

	Flat memory model - Wikipedia, the free encyclopedia
		The opposite of the flat memory model is the segmented memory architecture, as implemented on the now ubiquitous Intel 80x86 family of microprocessors.
		The advantage of the flat memory model is that applications running in such a model, unlike applications running in a segmented memory model, do not have to switch segments to access additional code or data.
		Put another way, microprocessors utilising a flat memory model have often been shown to achieve equivalent performance of a processor utilising a segmented memory model despite the fact they are running slower clock speeds and have simpler (and cheaper) architectures.
	en.wikipedia.org /wiki/Flat_memory_model (655 words)

	Flat (disambiguation) - Wikipedia, the free encyclopedia
		A tower block, block of flats, or apartment block is (in the 21st century) usually a high-rise apartment building.
		Flat is a commune of the Puy-de-Dôme département, in France.
		The Flats, a shortened form of the "industrial flats," is an entertainment district in Cleveland, Ohio, popular primarily during the 1990's.
	en.wikipedia.org /wiki/Flat_(disambiguation) (329 words)

	[No title] (Site not responding. Last check: 2007-10-13)
		If more memory is present on the system than the number of address lines will allow, in other words if log 2 (Size of memory) is greater than the number of address lines, that memory cannot be accessed, unless a scheme like bank-switching is used.
		C) Simple flat memory model: To implement a simple flat memory model, you "turn off" segmentation by initializing all the segment registers with the same address and initializing the segment limits for 4 GB each.
		Flat memory model: A flat memory model is a memory model that does not use segmentation.
	coscorrosa.com /school/sophomore/cs201/201-8.html (722 words)

	flat foot - Hutchinson encyclopedia article about flat foot
		Under the age of one and a half years 97% of children have flat feet, but only 4% have flat feet by the age of ten years.
		Treatment is best directed to flat foot which gives symptoms, or which is associated with abnormality of nerve, muscle, or bone.
		His flat foot crashed over the keyhole, the lock gave, the door flew open, and in the sudden draught the landing gas heeled over like a cobble in a squall; as the flame righted itself I saw a fixed bath, two bath-towels knotted together--an open window--a cowering figure--and Raffles struck aghast on the threshold.
	encyclopedia.farlex.com /flat+foot (315 words)

	Windows NT: Lesson 7 - The Virtual Memory Manager
		Memory fragmentation refers to the situation where free (available) memory becomes broken into small, scattered pieces that are not large enough to be used by applications (Figure 1).
		The 32-bit flat memory model makes Windows NT portable because it is compatible with the memory addressing of processors such as the MIPS R4000 and DEC Alpha.
		Memory in the upper 2Gb of the address space can only be accessed by privileged (kernel mode) code (that is, code in the NT Executive).
	www.microsoft.com /technet/archive/winntas/training/ntarchitectoview/ntarc_7.mspx (2957 words)

	CHAPTER 2
		A block of memory of discrete size, called a “physical segment.”; The number of bytes in a physical memory segment is 64K for 16-bit processors or 4 gigabytes for 32-bit processors.
		With the exception of the flat model, which requires instructions specific to the 80386/486, your choice of a memory model does not limit the kind of instructions you can write.
		The memory model does, however, control segment defaults and determine whether data and code are near or far by default, as indicated in the following table.
	webster.cs.ucr.edu /AsmTools/MASM/MASMDoc/ProgrammersGuide/Chap_02.htm (2468 words)

	Guide: About the 80386 architecture
		The size of memory operands must be specified by appending a single character to the end of the opcode.
		The "Flat" memory model is similar to the Motorola 680x0 processor memory model which the GNU tools were original designed to support.
		It is used in the segmented memory model.
	www.delorie.com /djgpp/doc/ug/asm/about-386.html (3744 words)

	CS554A Syllabus: Memory Management Tutorial. (Site not responding. Last check: 2007-10-13)
		On some segmented machines, a flat memory model allows each segment to be protected by a different segment register.
		Because the machine's memory is finite, there will always be pages that don't fit in physical memory: these pages will be paged out to mass storage by the OS, and swapped back in when required.
		If later that physical memory block is needed for another page, the currently present page is swapped out to mass storage, and the space is used for a new page.
	www.rivier.edu /faculty/amoreira/web/cs554a/Tut3 (1676 words)

	Overview of the OS/2 Operating System
		Memory management is the way in which an operating system allows applications to access the system's memory, either for private use by a single application or to be shared between applications.
		Memory objects or parts of memory objects, which are not reuired by the currently executing process, may be temporarily migrated out to secondary storage(disk).
		The smallest memory unit in the flat model is a page(4KB on the 80386), compared to a byte in the 16-bit segmented model.
	www.cs.wayne.edu /~tom/guide/os2.html (17176 words)

	[No title]
		For example, the most common model dependent feature regardless of CPU family is the presence or absence of a floating point unit or coprocessor.
		The appropriate memory model for RTEMS provided by the targeted processor and related characteristics of that model are described in this chapter.
		The amount of memory allocated for the interrupt stack is determined by the interrupt_stack_size field in the CPU Configuration Table.
	www.rtems.com /onlinedocs/rtems-doc-20030417/info/i960.info-1 (5160 words)

	Memory Model Flat Memory Model (Site not responding. Last check: 2007-10-13)
		Memory accesses within this address space are performed in big endian fashion by the SPARC.
		Memory accesses which are not properly aligned generate a "memory address not aligned" trap (type number 7).
		RTEMS does not support any SPARC Memory Management Units, therefore, virtual memory or segmentation systems involving the SPARC are not supported.
	www.engr.usask.ca /classes/EP/424/lab/rtemsdocs/sparc/sparc00025.html (236 words)

	[No title]
		Whenever memory is accessed, be it instruction fetch, data read or data write, the attributes of the used segment are checked against the instruction.
		However, the idea of the Flat Model is that all segment selector registers are set-up initially to descriptors that point to the full 4 Gbyte address space.
		Code in the Flat model will typically execute 15-20% faster compared to the Segmented model, so if performance is of the highest priority, and safety of a lesser priority, then we recommend the Flat Mode.
	www.ddci.com /art_10040.php (663 words)

	6.8 NUMA and Peripheral Devices
		Unlike caches and the virtual memory subsystem that operate in a transparent fashion, programs that write to NUMA devices must be aware of this and minimize the accesses whenever possible (e.g., by using an off-screen bitmap to hold temporary results).
		The basic idea behind the segmentation model is that memory is managed using a set of segments.
		Segments are an especially powerful memory management system when a program needs to manipulate different variable sized objects and the program cannot determine the size of the objects before run time.
	webster.cs.ucr.edu /AoA/Windows/HTML/MemoryArchitecturea4.html (5625 words)

	Cogsys: Data Segments
		Unlike modern operating systems, which have a flat memory model, real mode requires the programmer to access memory with two addresses: a 16-bit segment followed by a 16-bit offset.
		Most unfortunately, the highest memory address is not a 32-bit quantity (4 GB, the protected, flat model limit) but rather a 20-bit one, 1 MB.
		The data segment is a segment of memory where some of this function's data, including certain constants, local array structures and many other variables specific to the function, resides.
	condor.depaul.edu /~dallbrit/extra/cogsys-html/cogref_89.html (1272 words)

	Optimizing Memory and Processing
		With a segmented memory model, memory is broken into a number of 64K chunks called segments.”; These segments create artificial boundaries that developers are forced to code around, an often difficult and tedious task.
		This limitation of the segmented memory model is the cause of many of the inherent limitations and problems with MS-DOS and Windows 3.x’s designs, including the 64K resource heap limit that is imposed on the User, GDI, and Kernel heaps in Windows 3.x.
		Although virtual memory management is a cool concept, it is also important to note that a system’s CPU can only access data directly when it resides in real physical memory.
	www.windowsitlibrary.com /Content/435/05/2.html (2202 words)

	Runtime Environment
		The memory model chosen determines whether near or far addressing is used to access various objects like procedures, variables, parameters, and pointers.
		Note: Since a fixed memory model is used for 32-bit mode, the remainder of the memory model discussion pertains to 16-bit mode only.
		If you use the memory model option to change the stack to reside in the data segment, the startup code adjusts the stack segment and stack pointer to make the stack segment the same as the data segment.
	www.modula2.org /sb/websitearchive/env/index590.htm (1824 words)

	Stack pointer etc
		As to where the ESP points, Windows uses the model where the stack space (and heap space) is specifically allocated, and the scheme where the stack and heap grow towards each other is not used.
		This is because segments don't matter in virtual memory, the memory access is according to the page tables.
		There is nothing in the x86 that prevents the classical virtual memory model from being used, ie, program at 0, stack at 0 (which is the wrapped top of memory), and all memory unregulated and virtual.
	www.codecomments.com /message169077.html (1077 words)

	Some fundamental OS/2 concepts - Part 2 (Site not responding. Last check: 2007-10-13)
		With modern processors, we also find that the main memory is itself a bottleneck, in that it can't deal with data as fast as the processor can produce or consume the data.
		When this code has to be bumped out of main memory to make room for something else, the memory image doesn't need to be saved in the swap file; it can be re-read, the next time it's swapped in, from the original source file.
		And that's what the "flat memory model" of the 80x86 (more precisely, the 80386 or higher) is all about.
	www.os2ss.com /Information/Fundamentals/conc2.html (5391 words)

	[No title] (Site not responding. Last check: 2007-10-13)
		Flat Model xe "aa" \z "SEGMNW.DOC-1363" The flat memory model is a nonsegmented configuration available in 32-bit operating systems.
		Near Code Segments XE "Memory models:near code segments" \z "SEGMNW.DOC-1166" The small memory model is often the best choice for assembly programs that are not linked to modules in other languages, especially if you do not need more than 64K of code.
		This memory model defaults to near (two-byte) addresses for code and data, which makes the program run faster and use less memory.
	www.mathcs.sjsu.edu /faculty/kennedy/cs140/prguide/chap_02.doc (7170 words)

	EETimes.com - Embedding security into servers (Site not responding. Last check: 2007-10-13)
		In a flat memory model, a single diagnostic task (or other process) can examine the protection bits at any time to see if a task has run off the end of a buffer.
		In a segmented memory model, all processes must watch out for themselves in the event that a process clobbers its own buffer.
		Similar protection word mechanisms are sometimes used by debuggers and memory managers in any kind of memory model, but it's possible to use the bits for so much more.
	www.eetimes.com /in_focus/communications/OEG20021014S0063 (1745 words)

	[No title] (Site not responding. Last check: 2007-10-13)
		This isn't a problem in real-mode, as everything is there, but in protected mode, memory allocated with malloc may be anywhere in physical memory.
		There are three calls that are relevant to conventional memory, 100h/101h/102h, which are for allocating, freeing, and resizing buffers of conventional memory.
		Watcom has a split memory model, with the first megabyte of physical memory mapped to the first megabyte of its logical address space and the data segment and the rest of memory mapped starting at 0x400000.
	homepages.cae.wisc.edu /~brodskye/tomes/watcom.txt (560 words)

	Porting MicroC/OS-II to the X86 (PM) (Site not responding. Last check: 2007-10-13)
		This page describes the port of MicroC/OS-II to a protected mode, 32-bit, flat memory model of the 80386, 80486, Pentium and Pentium II CPUs.
		DEBUG loads the file in memory at offset 0100h (the segment address is irrelevant) and copies 512 bytes from offset 100h (where the file is) onto drive A, on track 0, for 1 sector (512 bytes).
		The protected mode is activated with a flat memory model that spans 4GB of physical memory.
	www.exposecorp.com /embedded/portx86p-2.htm (1498 words)

	Memory Model Flat Memory Model (Site not responding. Last check: 2007-10-13)
		This memory model supports a flat 32-bit address space with addresses ranging from 0x00000000 to 0xFFFFFFFF (4 gigabytes).
		Each address is represented by a 32-bit value and memory is addressable.
		By not requiring that logical addresses map directly to physical addresses, the memory space of an RTEMS space can be separated from that of a ROM monitor.
	www.rtems.com /onlinedocs/releases/4.0.0/doc/support/c_hppa1_1/a00014.html (297 words)

	Format of Pointers in Unix
		Hello, On a x86 machine, what is the format of a pointer in C? I know for a fact that the x86 p-mode uses a /selector:offset/ notation where the selector is defined in either the GDT or LDT.
		Of course, since segmentation in the x86 can't be disabled, the cpu internally still accesses memory using a selector:offset pair, but since the selector always refers to a 4GB segment, this effectively results in practice in a flat memory model.
		The address space appears flat locally, where you are allowed to see it, such as inside the contents of a single array.
	www.codecomments.com /message197115.html (1999 words)

	ERCB: DDJ Programmer's Bookshelf December 1992
		You can dereference a pointer to access a page of memory, even if that page is currently on disk; a page-fault handler within the operating system will take care of loading the page without you being aware of it.
		Obviously, the presence of virtual memory is no more relevant to your average programmer than is, say, the presence of an instruction prefetch queue on the processor.
		As Stone shows, paged virtual memory depends on the fact that all programs have reasonably sized working sets or "footprints;" that is, that all programs can run for a while with only discrete, page-sized bits of themselves in memory at any given time.
	www.ercb.com /ddj/1992/ddj.9212.html (1414 words)

Try your search on: Qwika (all wikis)