IBMDOS.COM

{{Short description|System file (DOS kernel) in PC DOS and DR-DOS}} {{Use dmy dates|date=April 2019|cs1-dates=y}} {{Use list-defined references|date=December 2021}} [[File:IBM PC DOS 1.0 screenshot.png|thumb|300px|<code>IBMDOS.COM</code> (second in the list of COM files) in IBM PC DOS 1.0.]] '''{{mono|IBMDOS.COM}}''' is the filename of the IBM PC DOS and DR-DOS kernel. Loaded and initially invoked by the DOS BIOS in IBMBIO.COM during the boot process,<ref name="Paul_1997_OD-A3"/> it contains the hardware-independent parts of the operating system, including the embedded FAT12, FAT16 and, in newer versions, the FAT32 file system code, as well as the code to provide the DOS API to applications.

The file exists in PC DOS 1.0 to 7.10 and DR DOS 5.0 and higher<ref name="Paul_2017_DR"/> (except for DR-DOS 7.06), with MS-DOS using MSDOS.SYS (from version 1.10 to 6.22) for the same purpose. DR DOS 3.31 to 3.41 used the equivalent DRBDOS.SYS file instead.<ref name="Paul_2017_DR"/><ref name="Paul_1997_OD-A3"/> (For compatibility purposes with some DOS applications the IBMDOS.COM file name was briefly also used by the IBM version of OS/2 1.0, where it resembled the OS2DOS.COM OS/2 kernel file as used by Microsoft.)

By default, the file is located in the root directory of the bootable drive/partition (normally C:\) and has the ''hidden'', ''read-only'', and ''system'' file attributes set.<ref name="Paul_2017_DR"/> As IBMDOS.COM is a binary image containing executable code rather than a true COM-style program, the ''hidden'' attribute is set to keep the file from being accidentally invoked at the command prompt, which would lead to a crash. This is not necessary for DR-DOS 7.02 and higher, because under these systems the file is a fat binary also containing a tiny COM-style stub just displaying some version info and exiting gracefully when loaded inappropriately.<ref name="Caldera_1998_NEW703"/><ref name="Paul_1997_OD-A3"/>

In Digital Research terminology, the kernel component of the operating system is called the BDOS (Basic Disk Operating System),<ref name="Paul_1997_OD-A3"/> a term originally coined by Gary Kildall in 1975 for CP/M,<ref name="Kildall_1975_BDOS"/> but which is continued to be used in all other DRI operating systems (except for Concurrent DOS 286 and FlexOS). Microsoft has used this name as well when referring to the kernel of the MSX-DOS operating system. The FAT file system specific code is called the FDOS in DRI terminology.

==See also== * IBMBIO.COM * MSDOS.SYS  * List of DOS system files

==References== {{Reflist|refs= <ref name="Kildall_1975_BDOS">{{citation |title=CP/M 1.1 or 1.2 BIOS and BDOS for Lawrence Livermore Laboratories |date=June 1975 |author-first=Gary Arlen |author-last=Kildall |author-link=Gary Arlen Kildall |quote=An excerpt of the BDOS.PLM file header in the PL/M source code of CP/M 1.1 or CP/M 1.2 for Lawrence Livermore Laboratories (LLL):}}<pre>[…] /* C P / M B A S I C I / O S Y S T E M (B I O S) COPYRIGHT (C) GARY A. KILDALL JUNE, 1975 */ […] /* B A S I C D I S K O P E R A T I N G S Y S T E M (B D O S) COPYRIGHT (C) GARY A. KILDALL JUNE, 1975 */ […]</pre></ref> <ref name="Paul_2017_DR">{{cite web |title=The continuing saga of Windows 3.1 in enhanced mode on OmniBook 300 |author-first=Matthias R. |author-last=Paul |orig-year=2017-08-07 |date=2017-08-14 |work=MoHPC - the Museum of HP Calculators |url=http://hpmuseum.org/forum/thread-8774-post-76925.html#pid76925 |access-date=2017-10-06 |url-status=live |archive-url=https://web.archive.org/web/20171006204718/http://hpmuseum.org/forum/thread-8774-post-76925.html |archive-date=2017-10-06 |quote=[…] In case no source drive and path is given, SYS will assume the system files to reside on the drive containing the SYS.COM program. If this is a local drive, it will try to locate them in the root of this drive, otherwise it will search for them in the SYS.COM directory itself. […] /K Keep original attributes of system files (else set to +RSH). […] /3 or /5 Name either DRBIOS.SYS/DRBDOS.SYS or IBMBIO.COM/IBMDOS.COM. […]}}</ref> <ref name="Caldera_1998_NEW703">{{cite book |title=DR-DOS 7.03 WHATSNEW.TXT - Changes from DR-DOS 7.02 to DR-DOS 7.03 |publisher=Caldera, Inc. |date=1998-12-24 |url=http://www.lookas.net/ftp/incoming/darbui/Justas/DRDOS/WHATSNEW.TXT |access-date=2019-04-08 |url-status=dead |archive-url=https://web.archive.org/web/20190408142232/http://www.lookas.net/ftp/incoming/darbui/Justas/DRDOS/WHATSNEW.TXT |archive-date=2019-04-08}}</ref> <ref name="Paul_1997_OD-A3">{{cite web |author-first=Matthias R. |author-last=Paul |title=Caldera OpenDOS 7.01/7.02 Update Alpha 3 IBMBIO.COM - README.TXT and BOOT.TXT - A short description of how OpenDOS is booted |url=http://www.uni-bonn.de/~uzs180/download/ibmbioa3.zip |date=1997-10-02 |orig-year=1997-09-29 |access-date=2009-03-29 |url-status=dead |archive-url=https://web.archive.org/web/20031004074600/http://www-student.informatik.uni-bonn.de/~frinke/ibmbioa3.zip |archive-date=2003-10-04}} [https://web.archive.org/web/20181225154705/http://mirror.macintosharchive.org/max1zzz.co.uk/+Windows%20&%20DOS/DOS/System/Novell/Support/Bins/Op702src.zip]</ref> }}

Category:DOS kernel Category:DOS files