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Microsoft CD-ROM Extensions
MSCDEX or Microsoft CD-ROM Extensions is a software program produced by Microsoft and included with MS-DOS 6.x and certain versions of Windows to provide CD-ROM support. Earlier versions of MSCDEX since 1986 were installable add-ons for MS-DOS 3.1 and higher. Overview The program is a driver executable which allows DOS programs to recognize, read, and control CD-ROMs using the High Sierra and – since version 2.0 as of 1988 – also the ISO 9660 file systems. This requires the previous loading of an appropriate CD-ROM device driver (example: OAKCDROM.SYS), usually from CONFIG.SYS. The final version of the MSCDEX program was 2.25, included with Windows 95 and used when creating bootable floppy disks with CD-ROM support. Starting with Windows 95, CD-ROM access became possible through a 32-bit CDFS driver. The driver uses the Microsoft networks interface in MS-DOS. This is the reason that at least version 3.1 of MS-DOS is required. The driver essentiall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows 98
Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. The second operating system in the 9x line, it is the successor to Windows 95, and was released to manufacturing on May 15, 1998, and generally to retail on June 25, 1998. Like its predecessor, it is a hybrid 16-bit and 32-bit monolithic product with the boot stage based on MS-DOS. Windows 98 is a web-integrated operating system that bears numerous similarities to its predecessor. Most of its improvements were cosmetic or designed to improve the user experience, but there were also a handful of features introduced to enhance system functionality and capabilities, including improved USB support and accessibility, as well as support for hardware advancements such as DVD players. Windows 98 was the first edition of Windows to adopt the Windows Driver Model, and introduced features that would become standard in future generations of Wind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Redirector
In DOS and Windows, a network redirector, or redirector, is an operating system driver that sends data to and receives data from a remote device. A network redirector provides mechanisms to locate, open, read, write, and delete files and submit print jobs. It provides application services such as named pipes and MailSlots. When an application needs to send or receive data from a remote device, it sends a call to the redirector. The redirector provides the functionality of the presentation layer of the OSI model. Networks Hosts communicate through use of this client software: Shells, Redirectors and Requesters. In Microsoft Networking, the network redirectors are implemented as Installable File System (IFS) drivers. See also * Universal Naming Convention (UNC) References External links Network Redirector Driversat Microsoft Docs Microsoft Docs is the library of technical documentation for end users, developers, and IT professionals who work with Microsoft produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Memory
In DOS memory management, the upper memory area (UMA) refers to memory between the addresses of 640 KB and 1024 KB ( 0xA0000–0xFFFFF) in an IBM PC or compatible. IBM reserved the uppermost 384 KB of the 8088 CPU's 1024 KB address space for BIOS ROM, Video BIOS, Option ROMs, video RAM, RAM on peripherals, memory-mapped I/O, and obsoleted ROM BASIC. However, even with video RAM, the ROM BIOS, the Video BIOS, the Option ROMs, and I/O ports for peripherals, much of this 384 KB of address space was unused. As the 640 KB memory restriction became ever more of an obstacle, techniques were found to fill the empty areas with RAM. These areas were referred to as upper memory blocks (UMBs). Usage The next stage in the evolution of DOS was for the operating system to use upper memory blocks (UMBs) and the high memory area (HMA). This occurred with the release of DR DOS 5.0 in 1990. DR DOS' built-in memory manager, EMM386.EXE, could perform most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conventional Memory
In DOS memory management, conventional memory, also called base memory, is the first 640 kilobytes of the memory on IBM PC or compatible systems. It is the read-write memory directly addressable by the processor for use by the operating system and application programs. As memory prices rapidly declined, this design decision became a limitation in the use of large memory capacities until the introduction of operating systems and processors that made it irrelevant. 640 KB barrier The 640 KB barrier is an architectural limitation of IBM PC compatible PCs. The Intel 8088 CPU, used in the original IBM PC, was able to address 1 MB (220 bytes), since the chip offered 20 address lines. In the design of the PC, the memory below 640 KB was for random-access memory on the motherboard or on expansion boards, and it was called the conventional memory area. The first memory segment (64 KB) of the conventional memory area is named lower memory or low memory area. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel 80286
The Intel 80286 (also marketed as the iAPX 286 and often called Intel 286) is a 16-bit microprocessor that was introduced on February 1, 1982. It was the first 8086-based CPU with separate, non-multiplexed address and data buses and also the first with memory management and wide protection abilities. The 80286 used approximately 134,000 transistors in its original nMOS (HMOS) incarnation and, just like the contemporary 80186, it could correctly execute most software written for the earlier Intel 8086 and 8088 processors. The 80286 was employed for the IBM PC/AT, introduced in 1984, and then widely used in most PC/AT compatible computers until the early 1990s. In 1987, Intel shipped its five-millionth 80286 microprocessor. History and performance Intel's first 80286 chips were specified for a maximum clockrate of 5, 6 or 8 MHz and later releases for 12.5 MHz. AMD and Harris later produced 16 MHz, 20 MHz and 25 MHz parts, respectively. Intersil and Fuj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DOS Protected Mode Services
DOS Protected Mode Services (DPMS) is a set of extended DOS memory management services to allow DPMS-enabled DOS drivers to load and execute in extended memory and protected mode. Not being a DOS extender by itself, DPMS is a minimal set of extended DOS memory management services to allow slightly modified DOS resident system extensions ( RSX) such as device drivers or TSRs (as so called ''DPMS clients'') to relocate themselves into extended memory and run in 16-bit or 32-bit protected mode while leaving only a tiny stub in conventional memory as an interface to communicate with the conventional DOS environment. The DPMS clients do so through DPMS services provided by a previously loaded ''DPMS server''. The necessary size of the remaining stub depends on the type of driver, but often can be reduced to a few hundred bytes for just the header even for complex drivers. By executing the driver in extended memory and freeing up conventional memory, DPMS not only allows very lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protected Mode
In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units (CPUs). It allows system software to use features such as virtual memory, paging and safe multi-tasking designed to increase an operating system's control over application software. When a processor that supports x86 protected mode is powered on, it begins executing instructions in real mode, in order to maintain backward compatibility with earlier x86 processors. Protected mode may only be entered after the system software sets up one descriptor table and enables the Protection Enable (PE) bit in the control register 0 (CR0). Protected mode was first added to the x86 architecture in 1982, with the release of Intel's 80286 (286) processor, and later extended with the release of the 80386 (386) in 1985. Due to the enhancements added by protected mode, it has become widely adopted and has become the foundation for all subsequent enhancements ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-relocation
In computer programming, a self-relocating program is a program that relocates its own address-dependent instructions and data when run, and is therefore capable of being loaded into memory at any address. In many cases, self-relocating code is also a form of self-modifying code. Overview Self-relocation is similar to the relocation process employed by the linker-loader when a program is copied from external storage into main memory; the difference is that it is the loaded program itself rather than the loader in the operating system or shell that performs the relocation. One form of self-relocation occurs when a program copies the code of its instructions from one sequence of locations to another sequence of locations within the main memory of a single computer, and then transfers processor control from the instructions found at the source locations of memory to the instructions found at the destination locations of memory. As such, the data operated upon by the algorithm of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loadhigh
In computing, (abbreviated ) is an internal DOS command in COMMAND.COM that is used to load a program into the upper memory area (UMA) instead of conventional memory. The command was introduced with MS-DOS 5.0 / PC DOS 5.0 in 1991, copying the built-in command earlier introduced with DR DOS 5.0 in 1990. DR DOS 6.0 added support for this naming variant as well in 1991. Overview Due to design of the IBM PC, DOS suffered from what was known as the 640 KB barrier. The size of this memory area, known as conventional memory, was fixed and independent of the amount of system memory actually installed. Various schemes were developed to support extra memory (see also EMS, XMS) and DOS extenders, but conventional memory was still an issue due to compatibility issues. It was a scarce resource as many applications demanded a large part of this basic memory fragment at runtime. Therefore, it was often necessary to move high some TSR programs like the mouse driver or the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caldera OpenDOS 7
A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is gone. The ground surface then collapses into the emptied or partially emptied magma chamber, leaving a large depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Compared to the thousands of volcanic eruptions that occur each century, the formation of a caldera is a rare event, occurring only a few times per century. Only seven caldera-forming collapses are known to have occurred between 1911 and 2016. More recently, a caldera collapse occurred at Kīlauea, Hawaii in 2018. Etymology The term ''caldera'' comes from Spanish ', and Latin ', meaning "coo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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