What does Abort, Retry, Fail and Ignore mean (and how does the MonTel server handle it).

Abort, Retry, Fail and Ignore.

Abort, Retry, Fail and Ignore are the possible responses to a DOS critical error message. For those of us who remember, it was a common occurrence in the days of Floppy Disks, when you had forgotten to close the drive door, format the disk or what ever.

Typically you might see a text message saying:

A:\>dir

Not ready reading drive A

Abort, Retry, Fail?

Today it is less common, but you will some times see it in network error messages, depending on how the network re-director has been linked to DOS.

Note that while this new feature has been extensively tested, networks are not always implemented in the same way. For example on an Peer to peer TCP/IP (MS-NET) implementation, when the network was disconnected while MonTel was running (by the rather drastic step to disconnecting the BNC bayonet connector), the program would freeze for up to 2 and a half minutes, and then report permission denied errors, rather than DOS critical errors. Even more oddly, the program would pick up and run again quite normally if the connector was re-attached, with out any apparent side effects (apart from an over flowing serial port buffer). This was tested in pure DOS and in Windows 98 on the same computer. Other DOS applications don't always respond so robustly!

What does it all mean?

Well basically it is an error message that DOS is reporting to the user. These are the possible prompts and the responses (not all errors or DOS versions have the same responses).

Abort: Exit the application immediately. This may not allow the application to finish all of its processing, and often leaves DOS in and unstable state. (This is not generally true though of simple DOS commands like DIR).

Retry: DOS attempts to do what ever cause the problem in the first place again. This happens inside DOS and the application never knows about it. It may well cause another message to be displayed if the cause of the error still exists.

Ignore: DOS gives up trying, and returns to the application as though it had succeeded. This may well cascade other errors depending on what the operation was.

Fail: DOS gives up trying, and returns to the application an error message. It is then up to the application program as to how it responds.

How does MonTel (server) deal with it?

MonTel intercepts the DOS reporting of these errors and handles them all internally. Essentially it performs the same actions, except that for Abort, it tells DOS to ignore the message, and then exits the MonTel server, closing it down in the normal way. As it traverses the loop that controls all processing, his may result in more critical errors, however MonTel ignores these and proceeds to exit.

You can control whether you want MonTel to display a message on the screen (this by default):

STATUS & ERRORS:

DOS CRITICAL ERROR: Press (R)etry,(I)gnore,(A)bort ? (I in 4 secs)

DOS CRITICAL ERROR: 'drive not ready' on 'A' drive

15:38:29 LOGGED: Using (H:\MONTEL\PABX.INI) for settings for this session.

15:38:19 LOGGED: Started MonTel (DOS) SERVER module 1.2.170.

Or alternatively always press ignore: change this setting in the [MonTelServer] section of the PABX.INI file.

IgnoreDOSCriticalErrors = 1

Or have MonTel exit with a DOS error level by this setting in the [MonTelServer] section of the PABX.INI file.

DOSCriticalErrorExitLevel = 64

Where the number (it needs to be greater than 0 and less than 256) is the error level reported to a batch file when MonTel Exits.