Particularities of Operating Systems
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4.
Then the boot manager reads the DOS configuration file (CONFIG.SYS) and if it
contains multiple configurations, displays a menu on the screen prompting you to
choose one of them; otherwise it just reads the configuration and loads the
indicated drivers and operating system parts from the second DOS file.
5.
After the configuration file has been processed, the command interpreter (default
COMMAND.COM) is loaded and executed. The command interpreter is a plain DOS
program.
There are several differences between DOS versions from different vendors:
•
MS-DOS 5.x–6.x and PC-DOS assume that their files should be the first ones in the
root folder
•
MS-DOS 5.x–6.x system files have names IO.SYS and MSDOS.SYS
•
PC-DOS and DR-DOS 7.x system files have names IBMBIO.COM and IBMDOS.COM
•
MS-DOS 7.x/8.0 has one large system file IO.SYS and MSDOS.SYS becomes a
configuration file
•
Letter assignment order differs for different DOS versions
•
MS-DOS and PC-DOS assume the boot partition as the partition to which letter C: has
been assigned
•
The CONFIG.SYS command set differs for different DOS versions
•
MS-DOS 7.x/8.0 starts WIN.COM instead of COMMAND.COM if the MSDOS.SYS file
includes BOOTGUI=1
•
MS-DOS 8.0 cannot function as a stand-alone operating system. CONFIG.SYS and
AUTOEXEC.BAT files processing are blocked. It can only boot the Windows operating
system. A special MS-DOS 8.0 version on the Windows Me boot disk can function as a
stand-alone operating system, but a check is built into it so that it can only be booted
from a diskette
B.1.3
System and Configuration Files
Here is the DOS system files list:
•
IO.SYS (mandatory for MS-DOS)
•
MSDOS.SYS (mandatory for MS-DOS 5.x–6.x)
•
IBMBIO.COM (mandatory for PC-DOS)
•
IBMDOS.COM (mandatory for PC-DOS)
•
DBLSPACE.BIN (mandatory for MS-DOS 5.x–6.2)
•
DRVSPACE.BIN (mandatory for MS-DOS 6.22–8.0)
•
LOGO.SYS (optional for MS-DOS 7.x/8.0)
•
COMMAND.COM (optional for all DOS versions)
Configuration files list:
•
MSDOS.SYS (for MS-DOS 7.x/8.0)