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| | Protected mode - Wikipedia, the free encyclopedia |
 | | Protected mode has a number of new features designed to enhance multitasking and system stability, such as memory protection, a paging system, and hardware support for virtual memory. | | | While software-mediated multitasking is certainly possible on systems running in real mode, the memory protection features of protected mode prevent an erroneous program from damaging the memory "owned" by another task or by the operating system kernel. | | | Protected mode also has hardware support for interrupting a running program and shifting execution context to another, enabling pre-emptive multitasking. |
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http://en.wikipedia.org/wiki/Protected_mode
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| | protected mode - a Whatis.com definition |
| | Protected mode is a mode of program operation in a computer with an Intel-based microprocessor in which the program is restricted to addressing a specific contiguous area of 640 kilobytes. | | | Microsoft developed the DOS Protected Mode Interface to go with a DOS extender included with Windows 3.0 (which was itself a DOS application). | | | Typically, a program running in real mode is one that needs to get to and use or update system data and can be trusted to know how to do this. |
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http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci212838,00.html
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| | Protected Mode Basics |
| | In protected mode, memory segmentation is defined by a set of tables (called descriptor tables) and the segment registers contain pointers into these tables. | | | Protected mode differs from real mode in this respect each time the CPU loads a segment register, it fully loads the descriptor cache register, no previous values are honored. | | | In protected mode, the information pushed on the stack can vary, as can the base address of the interrupt vector table and the size of the interrupt table. |
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http://www.x86.org/articles/pmbasics/tspec_a1_doc.htm
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| | A CRASH COURSE IN PROTECTED MODE |
| | All you need to know to program in protected mode is what descriptors are available to you and what are the selector values of these descriptors. | | | There always must be a GDT when in protected mode because it is in this table where all of the segments are defined. | | | Even the Intel data book states "Real mode is required primarily to set up the processor for Protected Mode operation". |
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http://www.geocities.com/SiliconValley/2151/pmode.html
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| | Introduction to Protected-Mode |
| | When applied, protection can guard against software bugs and help the operating system in performing reliable multitasking. | | | When the original task is rescheduled for execution, the processor uses the saved information to set its internal registers to allow the original task resume its execution. | | | Real-mode does not include support for protection and therefore cannot offer a secure and reliable execution environment. |
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http://www.internals.com/articles/protmode/introduction.htm
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| | "Working in the Protected Mode Environment" |
| | In V86 mode, the 386 operates in protected mode but allows some programs it is running to use a simulated real-mode environment. | | | Starters who wish to merely touch upon "protected mode programming" should generally read only the introduction, while others who require more information can get into the depths. | | | Process protection - In a similar fashion to memory protection, different programs (or parts of a program) can be protected from each other. |
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http://members.tripod.com/protected_mode/prashant/protmode.html
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| | 386 Protected Mode |
| | Every protected mode program must include a table of "descriptors", which are 8 byte data structures that define the start and end of a segment. | | | I recently had the opportunity to design a rather complex embedded system using a 386, and found the experience to be both frustrating and rewarding. | | | Most of us computing with a 386-based PC run the processor in its slowest and least functional mode. |
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http://www.ganssle.com/articles/aprot1.htm
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| | Embedded x86 Programming: Protected Mode |
| | In protected mode, the segment registers are indexes into special tables, all initialized and maintained by the operating system, but interpreted by the CPU. | | | This addressing mode relies on a combination of segment and offset registers to address bytes in memory (instruction or data). | | | This mode also adds some protection in order to run the software that needs it, such as Unix-like systems have. |
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http://www.embedded.com/98/9804fe4.htm
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| | Embedded 80386 Programming: Examples |
| | Protection is not required at that level, so the task and the kernel run with full privileges (CPL 0). | | | Since the EXE file is targeted for Windows, it cannot be used in that format in a stand-alone mode. | | | They will be best understood if you have previously read the series Embedded 80386 Programming, which explains the advanced features of the Pentium CPU family. |
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http://www.exposecorp.com/embedded/ex386.htm
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| | Protected Mode tutorial |
| | Protected mode allows programs to access more than 1 megabyte of physical memory, and protects against misuse of memory (i.e. | | | This is the maximum amount of physical memory addressable by a CPU with a 32-bit address bus. | | | In particular, there was no easy way to access more than 1 megabyte of physical memory. |
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http://my.execpc.com/~geezer/os/pm.htm
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| | 386 Protected Mode |
| | An I/O protection level is defined in the processor's EFLAGS register. | | | The whole issue of capturing address violation errors is perhaps a bit new to the embedded world, but with the proliferation of ever more complex systems will certainly become important in the next few years. | | | These 8 byte data structures are known as andquot;descriptorsandquot;, and are grouped into tables. |
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http://www.avocetsystems.com/company/articles/magazine/aprot2.htm
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| | Advocacy for Protected Mode Programming |
| | Protected Mode was designed by Intel to deal with the inadequacies of the 16-bit segemented architecture, mainly, the 1MB limit. | | | Balance the ability to have 16MB of memory immediately accessable versus having to swap it in and out using XMS or EMS. | | | I am well aware that the indexing could be done more efficiently outside of the procedure call. |
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http://www.monstersoft.com/tutorial1/PM_adv.html
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| | Introduction to Protected Mode Programming |
| | This mode allows a maximum alloctaion of 64 terabytes of memory (the maximum amount supported by the Intel chipset). | | | The only way to generate a protection fault is to write to a memory address above the memory installed or above the segment limits (which are almost always set to 4 gigabytes). | | | Offsets simply start at 0 into the segment (ie, if ES is the allocated memory segment, ES:[0] is the first byte of the memory). |
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http://www.monstersoft.com/tutorial1/PM_intro.html
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| | OSRC: Protected Mode |
| | A game engine is the game equivalent of a data base engine, a set of software modules you can use as a base to build lots of different games with the same underlying "animation and sound model". | | | "The DOS Protected Mode Interface (DPMI) was defined to allow DOS programs to access the extended memory of PC architecture computers while maintaining system protection." - DPMI is the interface you have to use if running under windows. | | | It shows you everything you need to program your own PM environment and is intended for those who don't have any experiences with it yet." The source file package is available here. |
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http://www.nondot.org/%7Esabre/os/articles/ProtectedMode
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| | ProtectedMode overview [deinmeister.de] |
| | This is more theoretical, not only due to CPU speed and memory limits, but mainly because you need the Protected Mode for preventing programs from disturbing other programs or the OS. | | | The only difference to pure Real Mode is that these programs are only allowed to use the instructions available in Privilege Level 3. | | | The simulated Real Mode memory can be mapped everywhere inside the Protected Mode address space, including memory swapping. |
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http://www.deinmeister.de/x86modes.htm
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| | OS-FAQ Wiki - Protected Mode |
| | Protected mode unleashes the real power of your CPU, so you better get informed about it if you are considering writing an OS. | | | It allows the developer to work with several virtual address spaces, each of which has 4GB of addressable memory and allows the system to enforce strict memory protection as well as restricting the available instruction set (so that your application cannot control the hard disk directly while the kernel can ;) | | | Bona Fide, including in-detail tutorials and realmode/pmode switch programs. |
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http://mega-tokyo.com/osfaq2/index.php/ProtectedMode?...
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| | Output Content Protection and Windows Longhorn |
| | New output content protection mechanisms planned for the next version of Microsoft® Windows® codenamed "Longhorn" protect against hardware attacks while playing premium content and complement the protection against software attacks provided by the Protected Environment in Windows Longhorn. | | | This paper discusses output content protection mechanisms planned for Windows Longhorn and future versions of Windows. | | | PVP-OPM: Protected Video Path - Output Protection Management |
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http://www.microsoft.com/whdc/device/stream/output_protect.mspx
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| | Porting C Programs to 80386 Protected Mode |
| | The protected graphics editor, Draftsman-EE, also shows a factor of two improvement for compute bound processes. | | | Whenever the protected-mode code runs the draw list interpreter, it first copies the protected struct over to the real-mode version, and then uses Phar Lap function Ox2510 to call the real mode draw list interpreter. | | | We solved this problem in our real-mode programs by supplying a family of video driver TSR (terminate and stay resident) programs. |
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http://www.casano.com/ddj_0890.html
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| | protected mode - Glossary - CNET.com |
| | In protected mode, different parts of memory are assigned to different programs. | | | This way, memory is "protected" in the sense that only the assigned program can access it. | | | The phrase is often used to describe device drivers that operate in this mode. |
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http://www.cnet.com/Resources/Info/Glossary/Terms/protected.html
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| | IEBlog : More details on Protected Mode IE in Windows Vista |
| | Even Windows 2000 users still have a glimmer of hope by using least privilege, and creating a shortcut to Run As IE when elevated privileges are needed. | | | It was about time that NT had ACLs on USER objects, hell, it's even possible to kill some badly coded interactive services by finding one of their windows and sending a WM_QUIT! | | | And, even if they do, IE still won't have all the priveleges of the user they're running it as (see previous blog posts). |
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http://blogs.msdn.com/ie/archive/2005/09/20/471975.aspx
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| | IEBlog : Clarifying Low-Rights IE |
| | The only way to move data in between modes is to do some willful operation, akin to a file transfer over a well-known, well-secured network protocol. | | | When users run programs with limited user privileges, they are safer from attack than when they run with Administrator privileges because Windows can restrict the malicious code from taking damaging actions. | | | Microsoft and other software makers provide tools to help protect against spyware downloads. |
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http://blogs.msdn.com/ie/archive/2005/06/09/427410.aspx
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| | Protected Mode Memory Addressing |
| | Indicates how the instructions (80386 and up) access register and memory data in protected mode. | | | An LDT can optionally be defined on a per-task basis and is used to expand the addressable range of the task. | | | Access is granted if the RPL value is lower (higher in privilege) than the AR of the segment. |
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http://www.cs.umbc.edu/~plusquel/310/slides/micro_arch2.html
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| | a386 |
| | The virtual machine is an abstraction of an Intel 386 running in protected mode. | | | There is an attempt to port Linux to a386. | | | Bare hardware support is started for x86, m68k, ARM, and Sparc. |
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http://a386.nocrew.org
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| | Protected mode and operating systems |
| | Basic pmode, unreal mode, interrupts and exceptions, multitasking with TSSes and without, Ring 0 versus Ring 3, etc. This was a by-product of my attempt to write an operating system, so it's missing Local Descriptor Tables (LDTs), Virtual 8086 mode, DPMI, etc. | | | Realtime clock code now works with BCD or binary modes, and uses interrupt instead of polling to wait for end of update | | | Make process creates disassembly and symbol table files |
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http://my.execpc.com/CE/AC/geezer/os
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| | PC Assembly Language |
| | All the examples use the free NASM (Netwide) assembler. | | | I also did not want students to have to go out and buy expensive software for the course. | | | I could not find a textbook that covered 32-bit protected mode assembly programming! |
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http://www.drpaulcarter.com/pcasm
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| | DPMIONE Documentation File |
| | The DOS Protected Mode Interface (DPMI) Specification version 0.9 was created by the DPMI Committee in 1990, and extended to version 1.0 in 1991. | | | With this spec, it becomes especially easy to write a program which enters Protected Mode (PM), and has access to all of the system's extended memory. | | | From the introduction to the DPMI 1.0 spec, "The DOS Protected Mode Interface (DPMI) allows DOS programmers to access the advanced features of 80286, 80386, and 80486-based PCs in a well-behaved, hardware-independent fashion that does not compromise system protection". |
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http://www.sudleyplace.com/dpmione
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| | Overview of the Protected Mode Operations of the Intel Architechrure |
| | As the Intel Architecture moves off the desktop into other computing applications, developers need to design their systems to take full advantage of Intel architecture’s performance and extended addressing. | | | Overview of the Protected Mode Operations of the Intel Architechrure | | | This paper will provide for an introduction into the architecture’s internal data structures that enable the extended address space, protection, multi-tasking, paging, and virtual-86 mode operation. |
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http://www.intel.com/design/intarch/papers/exc_ia.htm
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| | Utilized Protected Mode Features |
| | With this hurdle cleared, it will also be possible to allocate threads in different protected memory segments, allowing for the protection of one thread from another's errors. | | | When in real-mode (for disk reads, console input and output) the results of I/O must be transfered to a real-mode segment. | | | Once these services can be provided in protected mode, the flat memory model will become more useful. |
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http://www.cs.virginia.edu/~bah6f/nachos486/paper/node15.html
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| | DOS Protected Mode Interface - Wikipedia, the free encyclopedia |
| | This article was originally based on material from the Free On-line Dictionary of Computing, used with permission. | | | DPMI is the method which Microsoft prescribes for a DOS program to run in protected mode and to access extended memory under a multitasking operating system like Microsoft Windows 3.0 and later. | | | Indeed, because the virtual 8086 mode fully isolates programs from the hardware, without some support from the control program, it is not possible for another program to switch to protected mode by itself. |
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http://en.wikipedia.org/wiki/DOS_Protected_Mode_Interface
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| | CauseWay Source and Binary Code Release |
| | For those who wish to modify or re-use the source code, please remember that messing about with externally created source to a commercial DOS extender and linker is not for the faint-hearted nor for those not extremely well-versed in the arts of assembly language and protected mode. | | | The CauseWay source and binary files are available for downloading in separate files. | | | User must have a valid version of Clipper to be able to use the encrypted package, thereby ensuring they already have the code being protected. |
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http://www.devoresoftware.com/freesource/cwsrc.htm
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| | ABC News: Internet Explorer 7.0 (beta) |
| | One such advance is Protected Mode, which puts the browser into a limited-privilege state that prevents write to the IE7 cache without explicit user permission. | | | The Microsoft crew that showed us the latest IE emphasized that Redmond completely rewrote the code for its rendering engine. | | | The company is touting a number of other security improvements, though several will only be available in the Vista version of IE7. |
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http://abcnews.go.com/Technology/ZDM/story?id=1561535
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| | Protected-Mode CD-ROM Drive Support in Windows |
| | Therefore, you may want to disable (instead of remove) the real-mode CD-ROM driver in the Config.sys file and Mscdex.exe in the Autoexec.bat file, and keep a copy of the real-mode CD-ROM driver on the hard disk. | | | For information about CD-ROM drives that are supported in protected mode, but require real-mode drivers to either work in Windows or be detected by Windows, please see the following article in the Microsoft Knowledge Base: | | | If Windows does not include a protected-mode driver for the SCSI, IDE, or proprietary CD-ROM controller that your CD-ROM drive is connected to, contact the manufacturer of the device to inquire whether a protected-mode driver that is compatible with Windows is available. |
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http://support.microsoft.com/support/kb/articles/Q151/6/34.asp
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| | 13. Protected Mode Programming |
| | Top Document: x86 Assembly Language FAQ - General Part 1/3 | | | 13.1 PMODE Tutorials, FAQ, and other reference documentation Protected Mode Basics by Robert Collins http://x86.ddj.com/articles/pmbasics/tspec_a1_doc.htm Excellent starting tutorial with source code. |
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http://www.faqs.org/faqs/assembly-language/x86/general/part1/section-13.html
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| | Embedded RTOS for x86 Embedded Systems |
| | On Time's royalty-free embedded operating system for protected mode 32-bit x86 CPUs meets hard real-time requirements and implements a Windows subset kernel in only 16k of memory. | | | It can be fully integrated in Microsoft Visual Studio and supports about 250 Win32 API functions. |
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http://www.on-time.com
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| | Sudley Place Software |
| | For System Level programmers of Intel 386 and later CPUs, there's a discussion on How to Use Expand Down Stacks, as well as a discussion of how to program the Transition from Protected Mode to Real Mode. | | | This tool installs as a DOS device driver, and can debug almost any DOS Real Mode, Virtual Mode, and Protected Mode (VCPI and DPMI) program as well as the Windows 3.x and Win95/98 kernel, VxDs, and user-level applications. | | | Note that in some cases, a tool may be free for non-commercial use only; consult the documentation for each tool for specific information. |
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http://www.sudleyplace.com
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| | Maverick - The Operating System |
| | That means a partition would always start at cylinder x, head y and sector 1, where x and y can be any given number (but still within the limits of the disk). | | | When dealing with partitions beyond this limit, the packed CHS information in the 'Start of partition' and 'End of partition' fields should be set to the maximum possible, and only the LBA address is used. | | | The Master Boot Record is in first sector on the disk. |
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http://www.maverick-os.dk/FileSystemFormats/Standard_DiskFormat.html
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| | High-res high-speed VESA tutorial |
| | If you are intimidated by some of the terms (or you just don't know what they mean), take a look at our glossary. | | | Getting VESA information from Protected Mode or Real Mode |
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http://www.monstersoft.com/tutorial1
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| | Intel 80386 Programmer's Reference 1986 |
| | Chapter 13 Executing 80286 Protected-Mode Code Chapter 14 80386 Real-Address Mode Chapter 15 Virtual 8088 Mode Chapter 16 Mixing 16-Bit and 32-Bit Code | | | Chapter 4 Systems Architecture Chapter 5 Memory Management Chapter 6 Protection Chapter 7 Multitasking Chapter 8 Input/Output Chapter 9 Exceptions and Interrupts Chapter 10 Initialization Chapter 11 Coprocessing and Multiprocessing Chapter 12 Debugging |
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http://www.online.ee/~andre/i80386
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| | DPMI: Table of Contents |
| | 5.2 Calling the Real to Protected Mode Switch Entry Point | | | 5.1 Obtaining the Real to Protected Mode Switch Entry Point | | | 11.2 301h -- Call Real Mode Procedure With Far Return Frame |
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http://www.tenberry.com/web/dpmi/toc.htm
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