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MSCDEX

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"Microsoft CD-ROM Extensions" redirects here. For Microsoft's extension to the ISO 9660 format, seeJoliet (file system).

MSCDEX
Developer(s)Microsoft
Initial release1986, 37–38 years ago
Stable release
2.25 / 1995;29 years ago(1995)
Operating systemDOS,Windows
Platformx86
TypeCommand
LicenseProprietarycommercial software

MSCDEXorMicrosoft CD-ROM Extensionsis asoftware programproduced byMicrosoftand included withMS-DOS6.x[1]and certain versions ofWindowsto provideCD-ROMsupport.[2]Earlier versions of MSCDEX since 1986 were installable add-ons forMS-DOS 3.1and higher.[3][4]

Overview[edit]

The program is a driver executable which allowsDOSprograms to recognize, read, and control CD-ROMs using theHigh Sierraand – since version 2.0 as of 1988 – also theISO 9660file systems.[5][6]This requires the previous loading of an appropriate CD-ROMdevice driver(example: OAKCDROM.SYS), usually fromCONFIG.SYS.

The final version of the MSCDEX program was 2.25,[citation needed]included withWindows 95and 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 essentially looks similar to a network drive from the system perspective. It is implemented as aterminate-and-stay-resident program[6]and an extension to theredirectorinterface (CDEX).

DatalightROM-DOSincludes an implementation of MSCDEX.[7]

Alternatives[edit]

Novell DOS 7,Caldera OpenDOS 7.01andDR-DOS 7.02and higher provide a functional equivalent to MSCDEX namedNWCDEX,which also runs under MS-DOS andPC DOS.It has more flexibleload-highcapabilities, also allowing torelocateand run inprotected modethroughDPMSon286and higher processors, thereby leaving only a 7 KB stub inconventionalorupper memory(in comparison to MSCDEX, which occupies some 16 KB).[8]UsingEMSwith apage frame,NWCDEX can reduce its footprint even down to a few bytes in conventional memory.[8]In contrast to MSCDEX, the driver does not depend on undocumentedDOS APIs[8][9]and therefore, with a third-party helper tool namedINSTCDEX,[8][10][11][12]can be loaded viaINSTALLstatements and be fully functional inCONFIG.SYSthereby increasing chances to load the driver high and, under these operating systems, allow to load other drivers not only from hard disk but also from CD-ROM while the operating system is still processing CONFIG.SYS.[8][12]An alternative solution, but less flexible, some versions of DR-DOS offer to delay the installation of a driver in CONFIG.SYS until after the DOS data segment relocation viaINSTALLLAST.

Based on NWCDEX,IMSREAL/32,a successor toNovell'sMultiuser DOSandDigital Research'sConcurrent DOS,provides a similar driver namedIMSCDEX.[8]

A cloaked variant of MSCDEX was provided as part ofHelix Software'sMultimedia Cloakingproduct. It usesCloakingto relocate and run in protected mode on386and higher processors.

CorelofferedCORELCDX.COMas alternative to MSCDEX.[13]

There's a free alternative calledSHSUCDX[14]that is used with theIDE/ATAdriver UIDE.SYS[15]first released in 2005.[16]It is often used withFreeDOSand works with other DOSes as well.

In 1998,Calderaprovided aDRFAT32driver for DR-DOS to dynamically mount and unmountFAT32volumes on DOS versions otherwise not natively supporting FAT32. DRFAT32 uses a variation and extension of the CDEXAPIin order to achieve this and work with older DOS versions.[17]

See also[edit]

References[edit]

  1. ^Wolverton, Van (2003).Running MS-DOS Version 6.22.20th Anniversary Edition (6th revised ed.).Microsoft Press.ISBN0-7356-1812-7.
  2. ^"History of Microsoft MS-DOS CD-ROM Extensions (MSCDEX)".Microsoft Product Support Services.Microsoft Corporation.2000-01-18. Q123408. Archived fromthe originalon 2008-07-08.Retrieved2007-11-24.[1](NB. Has information on MSCDEX versions 2.1, 2.2, 2.21, 2.22, 2.23.)
  3. ^Barney, Douglas (1986-09-22)."Microsoft lets micros read CD-ROMs".Computerworld:13.Retrieved2016-11-18.
  4. ^Mace, Scott (1986-09-22)."Extensions to MS-DOS Run CD-ROM".InfoWorld.8(38): 1, 8.Retrieved2016-11-09.
  5. ^Johnston, Stuart J. (1988-03-07)."Microsoft Steals Show At Its CD ROM Meeting - Firm Unveils Two Business Titles".InfoWorld:198.
  6. ^ab"Microsoft MS-DOS CD-ROM Extensions 2.1"(MSCDEX21.DOC). Version 2.10 Beta.Microsoft.1994-03-16 [1992-05-30]. 000080010-100-O00-1186.Archivedfrom the original on 2018-05-11.Retrieved2018-05-11.[2]
  7. ^"Datalight ROM-DOS User's Guide"(PDF).Datalight, Inc.April 2005. Part No. 3010-0200-0716.Archived(PDF)from the original on 2021-12-06.Retrieved2021-01-02.(268 pages)
  8. ^abcdefPaul, Matthias R. (1997-07-30) [1994-05-01].NWDOS-TIPs — Tips & Tricks rund um Novell DOS 7, mit Blick auf undokumentierte Details, Bugs und Workarounds.Release 157 (in German) (3 ed.).Archivedfrom the original on 2016-11-04.Retrieved2014-08-06.{{cite book}}:|work=ignored (help)(NB. NWDOSTIP.TXT is a comprehensive work onNovell DOS 7andOpenDOS 7.01,including the description of many undocumented features and internals. It is part of the author's yet larger MPDOSTIP.ZIP collection maintained up to 2001 and distributed on many sites at the time. The provided link points to a HTML-converted older version of the NWDOSTIP.TXT file.)[3]
  9. ^Schulman, Andrew;Brown, Ralf D.;Maxey, David; Michels, Raymond J.; Kyle, Jim (1994) [November 1993].Undocumented DOS: A programmer's guide to reserved MS-DOS functions and data structures - expanded to include MS-DOS 6, Novell DOS and Windows 3.1(2 ed.).Addison Wesley.ISBN0-201-63287-X.(xviii+856+vi pages, 3.5 "-floppy) Errata:[4][5]
  10. ^Paul, Matthias R. (1997-03-03) [1996]."INSTCDEX v2.12".Archived fromthe originalon 2009-02-15.Retrieved2018-07-16.[…] load CD-ROM drivers like NWCDEX.EXE/MSCDEX.EXE in CONFIG.SYS by using INSTCDEX […] more flexibility […] loading order of drivers […] more freeUMB-RAM during installation […] better highloading memory consuming redirector drivers […] install […] other drivers […] from CD-ROM during execution of CONFIG.SYS […] setting the local CD-ROM flag […]
  11. ^Paul, Matthias R. (1997-06-26)."NWCDEX".OpenDOS.Archivedfrom the original on 2018-05-10.Retrieved2018-05-10.[…] SinceNovell DOSthe pre-CDS[…] is an internal array containing 26 entries located at the upper end of theconventional memory,although the lastdrive entries inSYSVARSonly report a lower value.LASTDRIVE=is one of those directives taking effect only *after*CONFIG.SYS,and the CDS array will be moved to its target position and will be reduced down to the LASTDRIVE= (or other minimum) or will be expanded up to 32 entries. […] INSTCDEX […] free already assigned drive slots for NWCDEX and thus allows NWCDEX to load in CONFIG.SYS. However, it will be unlinked after CONFIG.SYS, since the CDS-array is moved. INSTCDEX also provides means to save the status of the CDS-entry in CONFIG.SYS and relink […] NWCDEX to the new CDS inAUTOEXEC.BAT.[…]
  12. ^abPaul, Matthias R. (1997-10-02)."Caldera OpenDOS 7.01/7.02 Update Alpha 3 IBMBIO.COM README.TXT".Archived fromthe originalon 2003-10-04.Retrieved2009-03-29.[6]
  13. ^Mention of CORELCDX,retrieved2023-12-31
  14. ^Platt, Robert; Spiegl, W. (2008) [2003]."Command: shsucdx".FreeDOSSpec Command HOWTO.Archivedfrom the original on 2018-05-11.Retrieved2018-05-11.
  15. ^Ellis, Jack; Spiegl, W. (2011) [2007]."Command: uide.sys / uidejr.sys".FreeDOSSpec Command HOWTO.Archivedfrom the original on 2018-05-11.Retrieved2018-05-11.
  16. ^"SHSUCDX V3.03A CD-ROM Interface Driver".2005-12-26. SHCDX33A.ZIP. Archived fromthe originalon 2006-10-12.
  17. ^Ralf D. Brown.Ralf Brown's Interrupt List,INTER61 as of 2000-07-16 ([7])

Further reading[edit]

External links[edit]

Wikibooks has a book on the topic of:Guide to Windows Commands
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