Casio IT-2000W manual @Echo Off

CONFIG.SYS which resides on the drive C. However, CARDID.EXE cannot be registered as a device driver at a card boot. If this CARDID.EXE is registered as a device driver, two drives may be enabled concurrently if MS-DOS executes CONFIG.SYS. In addition, if ENDATA.COM is called with the INSTALL command, the drive G is enabled exclusively. However, since MS-DOS is operating under the assumption that the drive F is the current drive, an access error with the drive F, which does not actually exist, occurs because the AUTOEXEC.BAT file has been opened.

Then how about calling ENDATA.COM from AUTOEXEC.BAT? It is apparent that this is also not successful. Although two drives are enabled by executing CONFIG.SYS, the drive G having been enabled by CARDID.EXE is disabled when MS-DOS accesses the drive F to execute the AUTOEXEC.BAT file.

Next, the problem where a large program cannot be directly initiated from AUTOEXEC.BAT is explained. The explanation discusses the restrictions that apply to a card boot. This can be the situation when an attempt is made to read AUTOEXEC.BAT from the drive F while it is being disabled. COMMAND.COM consists of two independent parts called the resident part and non- resident part. The non-resident part will be overwritten by a large application program if it is loaded into the main memory. The resident part checks if the non-resident part has been destroyed at the termination of an application program, and will, if it is found to have been destroyed, reload the non- resident part again from the disk. In this case, accessing the drive F would not cause an error since the COMMAND.COM file to be read at this time was designated by the SHELL command in the CONFIG.SYS file. However, an error will result when an attempt is made by the reloaded COMMAND.COM file to open the AUTOEXEC.BAT file in order to continue its process. This problem can be avoided by shifting control priority from the AUTOEXEC.BAT file to another appropriate batch file in the drive G.

Example of AUTOEXEC.BAT

@ECHO OFF

C:CARDSOFT￿CARDID.EXE C:￿ENDATA.COM

----

Other.bat

In the above example the current drive is moved to the drive G, and the Other.bat file in the drive G is called. Since execution of the Other.bat file is performed under the assumption that the drive G is the current drive, no problem occurs if an attempt is made to open the same batch file in the course of reloading the non-resident part. But, it is prohibited to use a CALL statement to invoke the Other.bat file from AUTOEXEC.BAT. This will cause an error when control is returned to the AUTOEXEC.BAT file.

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