Ms-Dos; Overview; Chapter 4 Ms-Dos - Casio IT-2000W Technical Reference Manual

4. MS-DOS

4.1 Overview

In general, if a personal computer is booted-up with a floppy disk in the drive, first an attempt will
be made to read MS-DOS from the floppy disk, and if a copy of MS-DOS does not reside on the
floppy it is loaded from the hard disk (C:).
However, this method cannot be used on this terminal since its basic drive (C:), which corresponds
to the hard disk of a PC, is defined as a read-only device. The MS-DOS on the boot drive (C:) can
be loaded initially provided that no PC card is inserted in the slot, but, in this case, it is not possible
to add the start-up code for user programs to the AUTOEXEC.BAT file. This problem is solved on
the terminal as follows.


At boot-up this terminal searches each drive to locate the CONFIG.SYS and AUTOEXEC.BAT
files and sets it as the current drive, then MS-DOS is loaded into the main memory. As a result,
the CONFIG.SYS and AUTOEXEC.BAT files in the current drive can be processed through
MS-DOS.


The CONFIG.SYS and AUTOEXEC.BAT files will be searched in the following order:
PC card drive -> RAM disk -> F-ROM drive -> Basic drive


The CONFIG.SYS and AUTOEXEC.BAT files on the basic drive will be executed only if the
RESET switch is pressed. As a result, the System Menu, which is the maintenance program for
this terminal, will be initiated.
Since the main part of MS-DOS is always loaded from the basic drive (C:) in this case, it is not
necessary to install MS-DOS and COMMAND.COM on the user drive.
Fig. 4.1
Specifies the basic drive as the current
drive.
LOADING MS-DOS
YES
RESET BUTTON
was pressed?
Load MS-DOS.
Executes CONFIG.SYS and
AUTOEXEC.BAT in the current drive.
76
NO
Specifies the drive on which CONFIG.SYS and
AUTOEXEC.BAT reside as the current drive.