Liren Large Software Subsidy 8

home *** CD-ROM | disk | FTP | other *** search

/ Liren Large Software Subsidy 8 / 08.iso / d / d026 / 22.ddi / README.TXT < prev next >

Wrap

Text File | 1992-03-18 | 31.1 KB | 648 lines

********README.TXT for the Windows 3.1 Device Development Kit************ This file contains two sections: Section A: Specific Information/workarounds to help build the drivers provided with the Windows 3.1 DDK. Section B: A Description of the Device Driver Sources Provided. ****SECTION A: Specific Information/Workarounds To Build Drivers********* If WINDEV Directory Already Exists ********************************** If you already have a WINDEV directory installed on your disk prior to installing the DDK, we strongly recommend you use a different directory to install the TOOLS, LIB and INCLUDE files provided with the DDK. Running Out Of Memory ********************* Because it can be very easy to run out of conventional memory when building device drivers and virtual devices when using the NMAKE utility, we are also providing the XMSMAKE utility which will additionally use extended memory. If you are encountering strange errors, you may be running out of memory and we recommend trying XMSMAKE which is located in the \TOOLS directory of the Device Drivers Samples & Tools Disks. Building 386 Grabbers ********************* You MUST use the LINK.EXE in the \TOOLS directory of the Device Driver Samples and Tools Disk Set when building the 386 Grabbers. Binary Compare of the PSCRIPT.DRV, SNDBLST2.DRV, and MCIPIONR.DRV Files *********************************************************************** If you build either the PSCRIPT.DRV, SNDBLST2.DRV or MCIPIONR.DRV drivers, your built driver may not exactly binary compare with the corresponding drivers provided in the Windows 3.1 retail product. The few differences noted are due to different build environments used, machine and memory configurations, etc. The driver you build will function identically to that provided in the retail product. Building VDDVGA.386,VDD8514.386 Virtual Devices ************************************************ When executing the Makefiles MAKEVGA and MAKE8514, please note that the created object files for both share the same object filename. So if you first create the VDDVGA.386 virtual device and then proceed to create the VDD8514.386 device you must be sure to first delete all filenames with the *.obj file extension. Nmake Version ************* If you want to build a driver that binary compares to the driver in the retail version, you need to be sure to use the NMAKE.EXE tool provided in the \TOOLS directory on the Device Driver Samples & Tools disk set. If you use the one provided with the C 6 Compiler, the driver may not binary compare but should function identically. ****SECTION B: Description of Device Driver Sources********************** Below are descriptions of device driver sources contained in the DDK. The information includes where you can find the code on the diskettes, the procedure for building the driver and the features the code demonstrates. NOTE: We recommend that you print out the text file "LAYOUTS.TXT" located in the root directory of the Device Driver Samples and Tools Disk#1 for a listing of the source directories and disk locations for the Samples and Tools Disk Sets. The sources are setup in sub-directories on the enclosed diskettes. You should use the DOS COPY or XCOPY command to copy all files and related sub-directories to your hard disk. It is important that you maintain the structure as provided on the diskettes for the accompanying MAKE and batch files to work properly. Also be sure to expand the compressed files to their normal size after copying them to your hard disk. Display Driver Sources ********************** We are providing 1, 4 and 8 plane display driver sources in the DDK. You will find all the 1 plane driver sources on the Device Driver Samples and Tools Disk Sets under \DISPLAY\1PLANE. The 4 plane sources are under \DISPLAY\4PLANE. The 8 plane sources are under \DISPLAY\8PLANE. 1 Plane Drivers - CGA, EGA mono, EGA high res B&W, Hercules, Plasma, and MCGA ***************************************************************************** All of these drivers are 1 plane drivers. These drivers run Bi-Modal (in Real and Protected memory modes), support Device Independent Bitmaps (DIB), and greater than 64K fonts. They are located on the Device Driver Samples and Tools Disk Sets under \DISPLAY\1PLANE. These drivers share common code in many areas. Thus, the directory structures should be copied in their entirety to your hard disk. We suggest you use the MS-DOS XCOPY command to do this. You need to change directory to the appropriate sub-directory for the driver you wish to build. Each driver directory has a Makefile to build the driver. You will find the Makefile for each driver under: \DISPLAY\1PLANE\BW\CGAHERC\CGA\ for CGA \DISPLAY\1PLANE\BW\CGAHERC\PLASMA\ for Compaq Plasma \DISPLAY\1PLANE\BW\CGAHERC\HERCULES\ for Hercules monochrome \DISPLAY\1PLANE\BW\EGA\EGAHIBW\ for EGA hi res black/white \DISPLAY\1PLANE\BW\EGA\EGAMONO\ for EGA monochrome \DISPLAY\1PLANE\BW\EGA\VGAMONO\ for MCGA To build the driver, use the NMAKE utility provided with Microsoft C 6. If your display device is based on the 1 plane CGA, EGA, or Hercules standard, you should base your driver code on one of these drivers. Otherwise, these sources should provide you with the sample code necessary for you to design and plan for a new driver. 4 Plane Drivers - EGA, VGA, and Super VGA ****************************************** The EGA, VGA, and Super VGA driver sources utilize all 4 planes to support 16 colors. The Super VGA display driver is new for Windows 3.1. It is nearly identical to the VGA sources, but determines an appropriate extended resolution mode number from the WIN.INI file. These drivers run Bi-Modal (in Real and Protected memory modes), support Device Independent Bitmaps (DIB), and greater than 64K fonts. The EGA, VGA, and Super VGA driver sources utilize all 4 planes to support 16 colors. All three drivers demonstrate a new feature of Windows 3.1, "Mouse Blur" that leaves "mouse trails" on the screen to improve cursor visibility on LCD screens. These drivers share common code in many areas. Thus, all the files in the \DISPLAY\4PLANE directory structure found on the Device Driver Samples and Tools should be copied in their entirety to your hard disk. We suggest you use the MS-DOS XCOPY command to do this. Be sure to expand the compressed files to their original size before using them. You need to change directory to the appropriate sub-directory for either the EGA, VGA, or Super VGA driver and execute the MakeFile using the NMAKE utility. You will find a makefile file for each driver under: \DISPLAY\4PLANE\EGA\ for EGA hi res color \DISPLAY\4PLANE\SVGA\ for Super VGA \DISPLAY\4PLANE\VGA\ for VGA If your display device is based on the 4 plane EGA or VGA standard, you should base your driver code on either of these drivers. Otherwise, these sources should provide you with the sample code necessary for you to design and plan for a new driver. 4 Plane Drivers - Pen-Capable VGA ********************************* To build Pen-Capable VGA display drivers, set the MS-DOS environment variable PENWIN=1, delete all object files, and rebuild. Note that this procedure is documented in the VGA driver makefile. 8 Plane Driver - Video Seven VRAM, VGA, 8514/a ********************************************** We have provided you sources to the Video Seven VRAM/FastWrite VGA and 8514/a drivers. These drivers use all 8 planes available on the card for 256 color support. The code provides a good example of the use of the Palette Manager and Device Independent Bitmaps (DIB). This driver is adapted to run Bi-Modal and supports >64K fonts. This driver source can also be used as an example of how a packed pixel driver is implemented under Windows. The 8514/s driver provides a sample of how to support the TrueType font technology with a display adapter that does its own font caching. In addition, this driver provides an example of Windows 3.1's multiple-resolution driver feature, which allows a single driver executable to support more than one screen resolution, or supply a variety of resolution-dependent resources (e.g.. small or large fonts). To demonstrate the use of DIBs and the Palette Manager in these drivers, you can run the sample application, SHOWDIB, provided in the SDK. You will find these sources on the Device Driver Samples and Tools Disk Set under the directory \8PLANE. You need to copy the entire directory structure to your hard disk. Use the MS-DOS XCOPY command to do this. Be sure to expand the compressed files to their original size before using them. Note, the 8PLANE directory contains an empty sub-directory called DEBUG. You must have this directory available when you build the driver, otherwise the MAKE files will fail. To build the drivers, you need to run the batch file: \DISPLAY\8PLANE\V7VGA\ for Video 7 VRAM VGA (NOTE: This builds the driver file V731VGA.DRV. This driver is renamed to V7VGA.DRV in Windows 3.1) \DISPLAY\8PLANE\8514\SOURCE for 8514/a NOTE: Be sure to use the /E parameter when XCOPYING the 8514 sources to your disk. The makefile is expecting to have the empty subdirectory \DISPLAY\8PLANE\8514\SOURCE\OBJ and will generate an error if this subdirectory is not present. Windows Real and Standard Mode Grabbers *************************************** The Windows real and standard mode grabbers are on the Device Driver Samples and Tools under \GRABBERS. Since much of the grabber code for different displays are common, you should copy the GRABBERS sub-directory in its entirety to your hard disk. Be sure to expand the compressed files to their original size before using them. The individual grabbers are in the following directories: \DISPLAY\GRABBERS\CGAHERC\CGA \DISPLAY\GRABBERS\CGAHERC\HERCULES \DISPLAY\GRABBERS\EGA\EGACOLOR \DISPLAY\GRABBERS\EGA\EGAMONO \DISPLAY\GRABBERS\VGA\VGACOLOR \DISPLAY\GRABBERS\VGA\VGAMONO You should run the NMAKE utility with the Makefiles provided in each of these directories to build the appropriate grabber. System Font Sources ******************* We have provided the Windows 3.1 proportional system font and the Windows 2.0 fixed pitch system font. If your display driver supports resolutions other than the display resolutions provided in Windows, you may need to modify the system fonts for your display. You will need to copy the \FONTS directory to your hard disk in its entirety. Use the MS-DOS XCOPY command to do this. You will find this directory on the Device Driver Samples and Tools. The 3.x proportional system fonts are hand tuned for the screen and match the Adobe font widths for their Helvetica font. If you need to adapt the system font for a display with a different horizontal resolution than the ones supported by these fonts, you need to adjust the font widths accordingly. This will ensure the character will best "copy fit" the printed character with those on the screen. You can modify these files with the Font Editor tool provided with the SDK. Before you will be able to build any fonts, you must make the FONTS.OBJ file. You do this by running: MASM FONTS; from the \FONTS directory. You only need to do this once. To build the proportional system font files, execute the Makefile by using NMAKE from the \FONTS\SYSTEM directory: The font file names for the new proportional system fonts are: CGASYS.FON for (640 x 200) CGA resolution EGASYS.FON for (640 x 350) EGA high resolution VGASYS.FON for (640 x 480) VGA resolution 8514SYS.FON for (1024 x 768) 8514/a resolution In addition to the 3.x system font, the Windows 2.0 fixed pitch system font is necessary for older Windows applications running under Windows 3.0 and 3.1. All Windows applications which are not "marked" to run with the new proportional font, or which were not developed as a Windows 3.x application, will be given the fixed pitch font for displaying text in dialog and message boxes, and the client area. Windows 3.x supports both of these files, so it may be necessary for you to also modify the appropriate fixed pitch font. You will find these fonts in the \FONTS\FIXED directory. The Makefile is executed from this directory by running NMAKE. The font file names for the 2.0 fixed pitch system fonts are: CGAFIX.FON for (640 x 200) CGA resolution EGAFIX.FON for (640 x 350) EGA high resolution VGAFIX.FON for (640 x 480) VGA resolution (square pixels) 8514FIX.FON for (1024 x 768) 8514/a resolution (square pixels) 8514OEM.FON Uses the OEM Character Set CGAOEM.FON Uses the OEM Character Set EGAOEM.FON Uses the OEM Character Set VGAOEM.FON Uses the OEM Character Set VGA850.FON Uses Code Page 850 VGA860.FON Uses Code Page 860 VGA861.FON Uses Code Page 861 VGA863.FON Uses Code Page 863 VGA865.FON Uses Code Page 865 Printer Driver Sources ********************** We are providing driver sources for our PCL5/HP LaserJet III and Postscript printer drivers. In additional, sample sources for dot-matrix black/white and color raster printers are also included. Building "Minidriver" Printer Drivers ************************************* In order to build the printer drivers created by UNITOOL.EXE from the Minidriver disk, make sure to install the include & library files into the first directory on your LIB and INCLUDE MS-DOS environment variables. PCL5/HP LaserJet III Printer driver *********************************** The PCL5/HP LaserJet III driver sources are being provided as an example of how to support the dynamic downloading of TrueType fonts as well as the new ResetDC API on PCL-type laser device. It now does printer memory tracking as well. The PCL5/HP LaserJet III core driver sources are on the Device Driver Samples and Tools Disk Set under \PRINTERS\HPPCL5A. The HPPCL5A directory contains subdirectories necessary for building the driver. You can build the driver by running the MAKEIT.BAT batch file from the ..\HPPCL5A directory. NOTE: Be sure to maximize the amount of conventional memory available when building this driver. We recommend using MS-DOS Version 5.0 to provide as much conventional memory as possible. The PFM Editor (PFMEDIT.EXE) for PCL fonts is documented in the Printer and Fonts Kit and is provided on the Device Driver Samples and Tools Disk Set under \TOOLS. The PFM Editor is for editing PCL fonts files that use the 3.0 PFM font file format. Please note that the PFM font files that are used with the Universal driver for PCL devices uses a new updated 3.1 file format and they are modified via the UniTool tool. If you want to use these 3.1 format PFM files with the PFM editor, you must first run them through a file converter we provide, CVTHPPFM.EXE which is provided under the \TOOLS directory. This is a simple DOS utility that takes as its first parameter the 3.1 PFM Font file and creates a new 3.0 PFM font file with the name specified in the second parameter. The Printer Font Installer source is on the Device Driver Samples and Tools Disk Set under \PRINTERS\FINSTALL. You can build the font installer by running the MAKEIT.BAT file from the ..\FINSTALL directory. This module is called by selecting the "Fonts..." button in the HPPCL5A driver dialog box. The HPPCL5A driver and the Printer Font Installer are being provided to serve as a base for your Windows 3.1 printer driver development. PostScript Printer driver version 3.5 ************************************* The PostScript driver is also a good example of how to support the downloading of TrueType fonts on a PostScript printer. It also provides the ability to map TrueType fonts to Type 1 fonts in your PostScript printer. In addition, several other new features have been added: the ability to specify the resolution, per page downloading of fonts, setting the half-tone frequency, setting the halftone angle, printing a negative image, printing a mirror image, generating output that conforms to the Adobe Structured Document conventions and others. The driver dialogs have also been updated to better conform to the suggested design conventions for printer dialog boxes, according to the Microsoft Style Guide. The driver sources are on the Device Driver Samples and Tools Disk Sets under \PRINTERS\PS35. To build the driver execute the Makefile by running NMAKE. It is likely that you may run out of memory in building the driver. To prevent this, run NMAKE in the RES and UTILS subdirectories prior to running NMAKE in the PS35 directory. To build this driver, you will need to be sure to install the Alternate Math Small libraries during the SDK Install. The name of the needed library is SDLLCAW.LIB NOTE: Be sure to maximize the amount of conventional memory available when building this driver. We recommend using MS-DOS Version 5.0 to provide as much conventional memory as possible. The PostScript driver is designed to make it easy to add new device support, without modifying the source files. Provided in the DDK is a tool called MKPRN.EXE. You use this tool to compile PostScript Printer Description (PPD) files into Windows Printer Description (WPD) files. You can then install .WPD files for the PostScript driver by creating a driver distribution disk just as for any other printer driver. There is no longer an "Add Printer" option in the driver's Print Setup dialog box. Refer to the file CONTROL.INF in the Windows SYSTEM subdirectory to see an example of how to create the WPD entry for an OEMSETUP.INF file for installing unlisted PostScript models. The MKPRN.EXE tool is on Device Driver Samples and Tools under \TOOLS. Generic / Text Only Driver (TTY) Sample Sources *********************************************** Sample sources for the Generic / Text Only driver are included in this kit. You can use the Generic / Text Only printer driver with any printer for printing text with no graphics. Since this driver uses the printer's internal character set (or sets), it is a convenient driver for printing quick drafts of large documents or spreadsheets. The files are on the Device Driver Samples and Tools Disk Set under \PRINTERS\TTY. To build the TTY driver execute the Makefile under \PRINTERS\TTY using the NMAKE utility. Keyboard Driver Sources *********************** The keyboard sources are on the Device Driver Samples and Tools Disk Set under \KEYBOARD. There is a batch file provided to build the IBM style keyboard driver and all the international tables for foreign keyboards. They keyboard driver structure has not been changed since Windows 3.0. To build the drivers, execute the Makefile by running NMAKE in the \KEYBOARD directory. Please note that this makefile builds the driver file KBD.DRV. This driver is renamed to KEYBOARD.DRV in Windows 3.1. Mouse Driver Sources ******************** The Microsoft Mouse drive sources are on the Device Driver Samples and Tools Disk Set . Copy all the files from the \MOUSE directory to your hard disk with the MS-DOS XCOPY or COPY command. Be sure to expand the compressed files to their original size before using them. To build the driver, run: NMAKE in the \MOUSE directory. The mouse driver has few changes from the version shipped with the Windows 3.0 DDK. No changes are expected, except bug fixes. Note that this driver will not binary compare with the Mouse driver provided with Windows 3.1 since this driver contains proprietary source code. COMM Driver Sources ******************* The COMM driver sources are on the Device Driver Samples and Tools Disk Set. Copy all the files from the \COMM directory to your hard disk with the MS-DOS XCOPY command. Be sure to expand the compressed files to their original size before using them. To build the driver, execute the Makefile by running the Nmake utility. This driver requires the include file INT31.INC. You will need to copy this file from the Virtual Devices and Tools Disk Set from the \INCLUDE directory. Make sure this file is in your include path. Sound Driver Sources ******************** The sound driver sources are on the Device Driver Samples and Tools Disk Set. Copy all the files from the \SOUND directory to your hard disk with the MS-DOS XCOPY or COPY command. Be sure to expand the compressed files to their original size before using them. To build the driver, execute the Makefile by running the Nmake utility. The sound driver has few changes from the version shipped with the Windows 3.0 DDK. The driver was only modified for bug fixes. Network Driver Sources ********************** The MS-Net network driver sources are on the Device Driver Samples and Tools Disk Set. Copy all the files from the \NET directory to your hard disk with the MS-DOS XCOPY or COPY command. Be sure to expand the compressed files to their original size before using them. To build the driver, execute the Makefile by running the Nmake utility. Appendix B: Description of Virtual Device Sources ************************************************** Each source directory contains one or more .ASM source files, a .DEF file, and a Makefile. The Makefile is for use with Microsoft NMAKE or with other Unix-style MAKE utilities. Note, NMAKE is not provided in the DDK, but is included with some of the Microsoft language products (for example,C 6.00A). These MAKE files offer examples of the proper uses of the tools, options, and general build procedures that should be followed in developing virtual devices. As mentioned previously, these sources are provided for you to begin development for Windows 3.1 386 enhanced mode virtual device support. The Display Devices (CGA, EGA, VGA, 8514, HERC, V7VGA) ****************************************************** This device virtualizes the video display and is the most complex of the devices supplied in the DDK. The various VDD sources are on the Virtual Device Samples and Tools Disk Sets under the directories \VDDCGA, \VDDEGA ,\VDDVGA, \VDDHERC, and \VDDV7VGA. The \VDDCGA source tree contains files to only build the CGA VDD. This VDD also provides support for the Compaq Plasma display (also called IDC). The \VDDEGA source tree contains files to only build the VDDEGA. The \VDDVGA source tree provided uses conditional assembly to build two separate virtual devices to handle standard VGA and 8514/a video adapters. The \VDDHERC source tree contains files to only build the Hercules VDD. The \VDDV7VGA source tree contains files to only build the Video 7 VDD. You will find different Makefiles for each of the VDDs in the appropriate directories mentioned above. Listed below are the Makefile names for each VDD: * Adapter NMAKE * CGA MAKEFILE EGA MAKEFILE VGA MAKEVGA 8514 MAKE8514 Hercules MAKEFILE Video 7 MAKEVGA NMAKE by default will use the "Makefile" file to process. You can also specify the Makefile to use by using the /F parameter. The VGA and 8514 Makefiles are located in the same directory and so they have different names for the Makefile. The Display/Windows Interface (GRABBER) *************************************** The grabbers for 386 enhanced mode are different than the grabbers run in real or standard modes. They are responsible for rendering a virtual machine's display context within a window; therefore, they are closely bound with the virtual display device (VDD). Each VDD needs to be accompanied by its own grabber as a linked pair. The sources are on the Virtual Device Samples and Tools Disk Sets under the \GRABBERS directory structure. The DDK contains source for CGA, EGA, VGA, 8514/a, Compaq Plasma, Hercules, and Video 7 grabbers. Since they are all built in the same directory, different Makefiles are provided for each of them. Below are the Makefile names for each grabber: * Adapter NMAKE * CGA MAKECGA. EGA MAKEFILE. VGA MAKEVGA. 8514 MAKEDIB. Hercules MAKEHERC. AT&T/Compaq MAKEPLSM. Video 7 MKV7. NMAKE by default will use the "Makefile" file to process. You can also specify the Makefile to use by using the /F parameter. These Makefiles require that the CMACROS.INC include file be located in the \GRABBERS directory. This file is provided in the \OEMFONTS directory. The font files used by the grabbers when running in a window are provided in this kit. You will find them on disk 2 under \OEMFONTS. Run the Nmake utility to execute the Makefile here. The DMA Device (VDMAD) ********************** This device handles direct memory access devices. Virtual devices can support hardware cards which use DMA by calling the DMA Services provided by the VDMAD. These services are documented in the DDK documentation. See the section on the Floppy Drive Device, for an example of a device which uses the DMA Services. The VDMAD itself should not normally need to be customized; it would only need to be altered to support DMA on machines with non-standard architectures. The sources are on the Virtual Device Samples and Tools Disk Set under the \VDMAD directory structure. The EBIOS Device (EBIOS) ************************ This device detects the EBIOS page on machines (such as the PS/2) where it is used, identifies it, and ensures that it is reserved as global memory. It will probably not need to be modified, but is provided here as an example of a relatively simple device which passively accommodates something in the environment. The sources are on the Virtual Device Samples and Tools Disk Set under the \EBIOS directory structure. The Keyboard Device (VKD) ************************* This is one of the more complicated devices, as it not only virtualizes the keyboard but also interacts with the Windows shell to handle hotkeys and other special functions. It should be modified to support other, nonstandard keyboards. The sources are on the Virtual Device Samples and Tools Disk Set under the \VKD directory structure. The Mouse Device (VMD) ********************** This device virtualizes the mouse and maps the INT 33H API between protect and virtual modes. The sources are on the Virtual Device Samples and Tools Disk Set under the \VMD directory structure. The Netbios Device (VNETBIOS) ***************************** This device maps the Netbios API between protect and virtual modes, allowing Windows applications to access the network. It also handles asynchronous network transactions by mapping the application's buffer into global memory, so the network software can access it when the asynchronous event occurs (even if another virtual machine is running at the time). This should be modified by network vendors who extend the standard NetBIOS interface and also serve as a guide to writing virtual devices for other types of network software. The sources are on the Virtual Device Samples and Tools Disk Set under the \VNETBIOS directory structure. The Network Device (LDOSNET) **************************** In general, this device manages network connections and assures network integrity across all virtual machines. This device is not part of the Windows 3.1 retail package. It is provided as a sample source to demonstrate some mechanisms used in supporting network functionality. The device should be modified when your software does not use standard MS-DOS redirector calls for handling network connections. You will find the sources on the Virtual Device Samples and Tools Disk Set under the \LDOSNET directory. The BIOS Device (BIOSXLAT) ************************** This device maps the ROM BIOS API between protected mode and virtual 8086 mode, allowing Windows applications and device drivers access to ROM BIOS services. This should be modified when there are non-standard ROM BIOS calls that pass pointers to memory and which are used by Windows applications or device drives. You will find the sources on the Virtual Device Samples and Tools Disk Set under the \BIOSXLAT directory, The Paging Device (PAGESWAP) **************************** This device is used by 386 enhanced mode for demand paging at either the INT 21H or INT 13H level. The sources are on the Virtual Device Samples and Tools Disk Set under the \PAGESWAP directory structure. The Printer Device (VPD) ************************ The Printer Device virtualizes access to the parallel ports. If a second virtual machine tries to access one of the ports while it is being used by another application, a contention dialog is presented to the user allowing them to resolve the dispute of ownership. This virtual device was installed by default in Windows 3.0 but is no longer used with Windows 3.1. It is a simple VxD and is used as an example in the Virtual Device Adaptation Guide. The sources are on the Virtual Device Samples and Tools Disk Set under the \VPD directory structure. The COMM Device (VCD) ********************* This device virtualizes the standard serial ports on ISA architecture machines. It supports COM1 through COM4. It should be modified to add support for different chip sets or for additional COM ports. You will find the sources on the Virtual Device Samples and Tools Disk Set under the \VCD directory. The Virtual COMM Device (COMBUFF) ********************************* This device works with the Vitual COMM Device (VCD) to buffer com input for MS-DOS Virtual Machines. It supports COM1 through COM4. It can be modified to provide other handshaking protocols, or just used as sample source for virtualizing COM ports by cooperating with VCD. You will find the sources on the Virtual Device Samples and Tools Disk Set under the \COMBUFF directory. The Floppy Drive Device (VFD) ***************************** This device is responsible for two things: -- It removes special timer port trappings to ensure copy protection schemes work properly. -- It communicates with the VDMAD to synchronize DMA channel usage. You will find the sources on the Virtual Device Samples and Tools Disk Set under the \VFD directory. The 386 Enhanced Mode Block Device (WDCTRL) ******************************************* This virtual device is used to talk directly to hard-drive controllers that are Western Digital 1003 compatible. This allows us to do disk i/o entirely in ring 0 protected mode, bypassing the real mode BIOS. You will find the sources on the Virtual Device Samples and Tools Disk Set under the \WDCTRL directory. The PageFile Device (PAGEFILE) ****************************** This virtual device handles our virtual memory paging file, and will always call through BlockDev if any FastDisk devices are available. You will find the sources on the Virtual Device Samples and Tools Disk Set under the \PAGEFILE directory. The INT13 Virtual Device (INT13) ******************************** The Int13 device is used in conjunction with the 386 Enhanced Mode Block Device. It traps and emulates Int 13h BIOS calls. You will find the sources on the Virtual Device Samples and Tools Disk Set under the \INT13 directory.