Q123408: History of Microsoft MS-DOS CD-ROM Extensions (MSCDEX)
Article: Q123408
Product(s): Microsoft Disk Operating System
Version(s): 2.1,2.2,2.21,2.22,2.23
Operating System(s):
Keyword(s): win31 msdos kbgraphxlinkcritical
Last Modified: 13-JUN-2001
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The information in this article applies to:
- Microsoft CD-ROM Extensions (MSCDEX) for MS-DOS, versions 2.1, 2.2, 2.21, 2.22, 2.23
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SUMMARY
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This article documents the changes in the Microsoft MS-DOS CD-ROM Extensions
(MSCDEX) from version 2.1 to version 2.23.
MSCDEX version Microsoft product that MSCDEX ships with
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2.1-2.2 None
2.21 Windows for Workgroups 3.1
2.22 MS-DOS 6.0
2.23 MS-DOS 6.2, 6.21, 6.22, Windows for Workgroups 3.11
MORE INFORMATION
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Changes from Version 2.1 to 2.2
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- Approximately 12K of conventional memory is freed by moving the dynamic
buffers to EMS (expanded memory specification) memory.
- SETUP.EXE now detects EMS memory and automatically uses the /E option for
installation when EMS memory is available.
- A set "Owner ID" bit in the directory entry is now recognized.
- The expanded memory interface now avoids writing extraneous data into the
expanded memory buffers of an application.
- Function request #8, Absolute Disk Read, no longer returns an error when 0
(zero) sectors are requested.
- The MS-DOS version 4.0 interface now returns the "Access denied" or "File Not
Found" error message, as it should, when appropriate.
- The return value of the READ Device Status command now indicates whether
reading of the R-W subchannels is supported. The corresponding description
for obtaining the audio subchannel information has been expanded to cover the
need for obtaining this information concurrently with audio data.
Changes from Version 2.2 to 2.21
--------------------------------
- Version 2.21 corrects the problem that can occur when you use the /S switch
to share a CD-ROM drive on a network and hang the computer.
- Version 2.21 changes the MS-DOS version check to allow MS-DOS version 5.0, so
a SETVER entry is no longer needed.
Changes from Version 2.21 to 2.22
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- MSCDEX now loads into UMA. If there is enough memory available, MSCDEX
version 2.21 and earlier can load into upper memory. MSCDEX version 2.21 and
earlier require the load size of MSCDEX (which varies for different
configurations) plus 48K of memory to load. The extra 48K of memory is added
to ensure there is enough memory to load COMMAND.COM.
MSCDEX version 2.22 checks to see if the driver is being loaded above 640K. If
it is, MSCDEX does not add 48K to the initialization load size because it
does not need to be concerned with the transient portion of COMMAND.COM.
- MSCDEX is no longer version dependent. If you are using MS-DOS 5.0 or 6.0,
earlier version of MSCDEX require that you use SETVER.EXE to tell MSCDEX the
MS-DOS version is 4.0.
- The /V switch now reports accurate memory statistics. Earlier versions of
MSCDEX were not accurate.
Changes from Version 2.22 to 2.23
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- MSCDEX version 2.22 erroneously assumes that files in a directory on a CD-ROM
are sorted (collated by ASCII code value). Performing a file search could
result in missed files if the files on the CD-ROM are not sorted. MSCDEX
version 2.23 does not assume that the files are sorted but instead searches
the entire directory and does not return a "File not found" error message
unless the file does not actually exist.
- MSCDEX version 2.23 allows files and directory names to begin with an
exclamation point (!), allowing EISA configuration files to be shipped on
CD-ROMs.
NOTE: MSCDEX.EXE version 2.23 has been made available for customers. Only the
English language version of this file is available. MSCDEX.EXE version 2.23 is
available as a self-extracting file named MSCDX223.EXE.
The following file is available for download from the Microsoft Download Center:
DownloadDownload Mscdx223.exe now
For additional information about how to download Microsoft Support files, click
the article number below to view the article in the Microsoft Knowledge Base:
Q119591 How to Obtain Microsoft Support Files from Online Services
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Additional query words: 2.10 2.20 2.21 2.22 2.23 mmtitles cdg nec sony hitachi panasonic pro audio soundblaster SCSI homemm history
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Keywords : win31 msdos kbgraphxlinkcritical
Technology : kbAudDeveloper kbMSCDEXSearch kbMSCDEX210DOS kbMSCDEX220DOS kbMSCDEX221DOS kbMSCDEX222DOS kbMSCDEX223DOS
Version : :2.1,2.2,2.21,2.22,2.23
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