Microsoft KB Archive/12357

IBM 3270 PC Supervisor Crash

PSS ID Number: Q12357 Article last modified on 11-02-1994

3.x

MS-DOS

= SUMMARY =

In Word version 3.00, the use of Interrupt Vector 9 is incompatible with Control Program version 3.00, the operating system of the 3270 PC.

According to IBM, “registers must be unchanged when an application IRETs back to its caller or jumps to the chainon address.” Apparently, the programs in multiple sessions share interrupt vectors by chaining to them, but they must actually be hiding some information in the registers.

When Word gets an INT 9, it seemingly modifies the registers, then calls the next in the chain (the one which was in the INT location when the program started). Operating the way it does, Word actually causes the supervisor to crash.

This problem was corrected in Word versions 4.00 5.00 and 5.50.

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================================================================ Copyright Microsoft Corporation 1994.