End-users may need to get to DOS for several reasons, the most likely being to translate Obsession showfiles to newer versions. The method of getting there varies a bit depending on software version:
In versions of Obsession and Obsession II code previous to 4.3, performing a [Right-Shift]+[Tab]+[Tab] on the alphanumeric keyboard will exit the Obsession program and take you to DOS. The complete procedure is:
With Obsession II 4.3 software and higher the processor is running VxWorks, so exiting to DOS follows a different process. The running processor now reboots when you perform a [Right-Shift]+[Tab]+[Tab].
The preferred process for getting to DOS from a running Obsession II processor is:
Other Options for 4.3 and Higher Systems
While rebooting, there is a 5-second window (while the dots appear in the bottom left) to hit [Ctrl]-[D] which puts you into DOS mode. If you miss the window, start over again.
These dots appear after a series of messages (NIC type, Bus type, Slot, Bus No, I/O base, Interrupt, Transceiver, Ethernet Address, and Packet Driver Interrupt). The place where the 5 periods are displayed are two lines below the Packet Driver Interrupt line.
Attached is a utility disk which makes the process a little easier. This disk allows you to exit to DOS directly on an Obsession II running VxWorks after performing a [Right-Shift]-[Tab]-[Tab]. It will also allow you to boot directly to DOS when powering up a processor. http://www3.etcconnect.com/Community/cfs-file.ashx/__key/CommunityServer.Wikis.Components.Files/products/6765.dosxdisk.exe
This disk is primarily intended for VxWorks Obsession systems (Version 4.3 and later). However, DOS exit on boot functionality is fully backward compatible with all released versions of Obsession II software, and all Obsession (I) software versions.
How It Works
This disk contains (3) DOS batch files. STARTUP.BAT, INSTALL.BAT, and DELBAT.BAT. The first two files mimic the filenames of the files on a software upgrade disk. On boot or restart, the Obsession II thinks these files are part of a software upgrade, so they are loaded before the Obsession executable. However, these two little files interrupt the boot process and cause a direct, but safe exit to DOS. It is a safe DOS exit because it runs the full AUTOEXEC.BAT file, unlike exiting with control-c. This means it is safe to run the Obsession executable without worrying about crashing as can happen with a control-c exit.
STARTUP.BAT is loaded by AUTOEXEC.BAT. STARTUP.BAT then renames the OBS.EXE file to TEMPOBS.EXE and copies INSTALL.BAT from the A drive to C:\ETC\OBS.BAT. Once that is done, the rest of the AUTOEXEC.BAT file executes and the file "obs" is called. Instead of launching the Obsession executable as intended, this runs the OBS.BAT file. The OBS.BAT file then renames TEMPOBS.EXE as OBS.EXE and then runs the batch file DELBAT.BAT. DELBAT.BAT deletes the OBS.BAT file, restoring the C drive to it's normalstate. DELBAT.BAT then outputs descriptions of some common Obsession DOS commands.
The only file modified by these batch files is the OBS.EXE executable. If Obsession fails to start up properly after use of this disk, check to see if the OBS.EXE is still named TEMPOBS.EXE. This could be caused by a disk error or a corrupt file on the disk. Type "ren tempobs.exe obs.exe" and hit enter to fix this problem. Also delete the file OBS.BAT if it is present in the c:\etc directory by typing "del obs.bat enter". The Obsession system should then function normally.
There is a third alternate method to get to DOS on an Obsession II running VxWorks, but it is not recommended unless you have no other option. This method is to press the F5 key during boot after the "Starting MS-DOS" message. This bypasses the autoexec.bat and config.sys files sending you straight to DOS just like control-c does on the Obsession (I). This method has been known to lead to GPF's if you launch the Obsession program or show translator from DOS. It is also possible for this to disable the keyboard if the key is pressed too early (before the keyboard is detected). The other methods listed above are much safer.