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Browse Prior Art Database

Override of Swap Lock

IP.com Disclosure Number: IPCOM000038840D
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bartek, BA: AUTHOR [+4]

Abstract

A method is described for overriding the lock of swapping from operating system utility mode to host communication mode on a microcomputer. It is important to prevent a user from leaving a utility in the middle of processing and entering another function, such as host communication mode. The problem with doing this is that the utility functions are not reentrant. That means that if the utility is invoked again, the utility will not function properly. A lock is provided to prevent the user from switching and reinvoking a utility. However, if processing cannot continue unless some action is taken outside of the utility processing, the user must be allowed to exit.

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Override of Swap Lock

A method is described for overriding the lock of swapping from operating system utility mode to host communication mode on a microcomputer. It is important to prevent a user from leaving a utility in the middle of processing and entering another function, such as host communication mode. The problem with doing this is that the utility functions are not reentrant. That means that if the utility is invoked again, the utility will not function properly. A lock is provided to prevent the user from switching and reinvoking a utility. However, if processing cannot continue unless some action is taken outside of the utility processing, the user must be allowed to exit. For example, if the user is processing a directory utility and an unsolicited message arrives, the user cannot return to the directory utility until the message is responded to. An unsolicited message is a message sent without an initial communication requesting the message be sent. There has to be a way for the user to exit and respond to the message. The solution is to detect lockup situations like the one described above. When they occur, provide the user with a prompt and a special set of keys to press to switch out and respond to the problem. While responding, any operating system utilities which are already active must be disallowed. Appropriate prompts would be provided to steer the user away from any attempts to use the utilities. The advantage to this approach is the user ca...