14 lines
1.4 KiB
HTML
14 lines
1.4 KiB
HTML
<HTML>
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<HEAD>
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<LINK rel="stylesheet" type="text/css" href="H&S.css">
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<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=windows-1252">
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<META NAME="Generator" CONTENT="Microsoft Word 97">
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<TITLE>What is a VxD</TITLE>
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</HEAD>
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<BODY LINK="#0000ff" VLINK="#800080">
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<FONT FACE="Arial"><STRONG><H3>Learning about VxDs</H3>
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</FONT><P>A virtual device driver (VxD) is a 32-bit, protected-mode driver that manages system resources, such as a hardware device or installed software, so that more than one application can use a resource at the same time. The term "VxD" refers to a general virtual device driver, where the x represents the type of device driver. For example, a virtual device driver for a display device is known as a VDD, a virtual device driver for a timer device is a VTD, a virtual device driver for a printer device is a VPD, and so forth.</P>
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<P>The terminology protected-mode means the microprocessor can access the largest amount of memory. In this mode, the processor can only run programs designed for protected mode, not programs designed for earlier processors such as the 8088. The contrast to protected-mode is real-mode. Real-mode is an operating mode were a microprocessor acts like an earlier computer such as an 8086 or 8088. It has a maximum of one megabyte of memory of which only 640k is available to user programs. DOS runs in real-mode; Windows 95, Windows 98 and Millennium run in protected-mode. </P></STRONG></BODY>
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</HTML>
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