IBMBIO.COM
IBMBIO.COM is a system file in many DOS operating systems. It contains the system initialization code and all built-in device drivers. It also loads the DOS kernel (IBMDOS.COM) and optional pre-loadable system components (like for disk compression or security),[1][2] displays boot menus, processes configuration files (like CONFIG.SYS) and launches the shell (like COMMAND.COM).
The file is part of
The file is located in the
In the
If this is a VBR of PC DOS before 3.3 it would load both system files into memory by itself.
If the loaded boot sector is a
- Loads the rest of itself into memory. Before
- Loads the DOS kernel. The kernel is stored in IBMDOS.COM.
- Initializes each default device driver in turn (console, disk, serial port, et cetera). At this point, the default devices are available.
- Calls the DOS kernel's initialization routine.
Under
Microsoft sometimes calls this component the I/O system, but is also used to describe a similar component or layer in other operating systems by Digital Research, IBM, Microsoft and many others.
In a more generic sense, some vendors refer to this portion as the RAM BIOS of operating systems such as DOS or CP/M in order to contrast it with the built-in ROM BIOS of a machine.[21]
See also
- List of DOS system files
- Hardware abstraction layer(HAL)
- RPLOADER
Notes
- SYS command.[a]The boot loader would simply ignore a set file password while loading the file, but once the system has been booted, the system files could not be accessed without knowing the password, thereby providing an additional level of protection from accidental attempts to delete or modify the system files. (This file password feature is independent of volume or boot passwords also provided by DR-DOS in certain configurations.)
- ^ SYScontinues to take care of these requirements.
- PC DOSVBR, which would load only the first three sectors of the file into memory.
- chain loadscenarios.
References
- ^ a b c d e f g h Paul, Matthias R. (1997-10-02) [1997-09-29]. "Caldera OpenDOS 7.01/7.02 Update Alpha 3 IBMBIO.COM - README.TXT and BOOT.TXT - A short description of how OpenDOS is booted". Archived from the original on 2003-10-04. Retrieved 2009-03-29. [3]
- ^ SYS. Afterwards, you could just copy over the remaining DR-DOS files, including the system files. It is important to know that, in contrast to MS-DOS/PC DOS, DR-DOS has "smart" boot sectors which will actually "mount" the file-system to search for and load the system files in the root directory instead of expecting them to be placed at a certain location. Physically, the system files can be located anywhere and also can be fragmented. […]
- ^ )
- ^ OpenDOS 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 file.) [5] - ^ a b c d Paul, Matthias R. (2001-04-09). NWDOS-TIPs — Tips & Tricks rund um Novell DOS 7, mit Blick auf undokumentierte Details, Bugs und Workarounds. MPDOSTIP (in German) (3 ed.).
- ^ SYSutility while in fact this is a feature of the advanced bootstrap loader in the boot sector. SYS just plants this sector onto the disk.)
- ^ BOOT.LSTfile. […]
- Caldera, Inc. 1998-12-24. Archived from the originalon 2019-04-08. Retrieved 2019-04-08.
[…] Added a stub which displays the build info if COUNTRY.SYS was erroneously considered being an device driver (DEVICE=COUNTRY.SYS). Also displays the same info if started as .COM program. […] Added a second compression method to further decrease the size of IBMBIO.COM. […]
- ^
- ^ Paul, Matthias R. (2001-01-17). "FAT32 in DR-DOS". opendos@delorie. Archived from the original on 2017-10-06. Retrieved 2017-10-06.
[…] The DR-DOS boot sector […] searches for the IBMBIO.COM (DRBIOS.SYS) file and then loads the *whole* file into memory before it passes control to it. […]
- ^ Poarch, Mad (April 1993). "Booting Multiple Operating Systems with the DR Multiuser DOS LOADER Utility". Developer Support Bullets. 5 (4). Novell. Archived from the original on 2012-03-22. Retrieved 2013-06-28.
- ISSN 0899-9341. Archived from the original(PDF) on 2012-05-31.
- ^ Paterson, Tim (2007-09-30). "Design of DOS". DosMan Drivel. Archived from the original on 2013-01-20. Retrieved 2011-07-04.
- Lawrence Livermore Laboratories(LLL)
[…] /* 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 */ […]
- CP/M version 1.3, which eventually evolved into an operating system called IMDOS. […]
- ^ Shustek, Len (2016-08-02). "In His Own Words: Gary Kildall". Remarkable People. Computer History Museum. Archived from the original on 2020-03-24. Retrieved 2020-02-24.
- Kildall, Gary Arlen (2016-08-02) [1993]. Kildall, Scott; Kildall, Kristin (eds.). Computer Connections: People, Places, and Events in the Evolution of the Personal Computer Industry (Manuscript, part 1). Kildall Family. Archived(PDF) from the original on 2016-11-17. Retrieved 2016-11-17.
- IMSAIwas a joint effort between Glenn and Gary. […]
- Bill was down there making arrangements with Gary Kildall to license CP/M. […] Now that the BIOS is separated out, anybody could write a BIOS for their machine, if it was 8080-based, and run this, so he started selling that separately under the company Digital Researchthat he formed and did quite well."
- ACT (International) Limited. 1984. Retrieved 2020-01-13. (228 pages)