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Browse Prior Art Database

Program Product Switching Using a Hard Disk

IP.com Disclosure Number: IPCOM000043031D
Original Publication Date: 1984-Jul-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Dohhaku, Y: AUTHOR [+4]

Abstract

In a contemplated hard disk-based system, the hard disk can be shared by a plurality of different program products. But, how can a user finish one program product and switch control easily to another program product? The present method allows any program product to switch to another without worrying about how to pass control. When a user receives a hard disk-based system from a supplier, the user will initially run a hard disk formatter utility to format the hard disk and to create partition allocations on the hard disk to contain a set of program products. As a result of the partition function, a hard disk IPL extension program, called "IPL-2 code", along with font and menu data for the "IPL Next Program Product menu" are written into a common area within the hard disk.

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Program Product Switching Using a Hard Disk

In a contemplated hard disk-based system, the hard disk can be shared by a plurality of different program products. But, how can a user finish one program product and switch control easily to another program product? The present method allows any program product to switch to another without worrying about how to pass control. When a user receives a hard disk-based system from a supplier, the user will initially run a hard disk formatter utility to format the hard disk and to create partition allocations on the hard disk to contain a set of program products. As a result of the partition function, a hard disk IPL extension program, called "IPL-2 code", along with font and menu data for the "IPL Next Program Product menu" are written into a common area within the hard disk. They are used to support the program product switch function which is described below. When these functions are completed, read-only storage (ROS) will load and execute IPL-2 code. This IPL-2 code will read a common media control record (MCR) from cylinder 0, head 0, sector 0 of the hard disk and will determine if the user specified a default IPL option. If so, control will pass to the default program product by changing the loadlist of IPL-2 code to point to the IPL'ing program product. If not, IPL-2 code will display the IPL Next Program Product menu, whereby the user is prompted to select a program product that the user wants to IPL. After the selection is made, control is passed to that program product. It is accomplished by IPL-2 code by finding the starting and ending sector numbers for the selected program product on the hard disk and by reading and verifying the MCR. If a read error occurs, then the backup MCR is used. If the MCR is read successfully, then the loadlist of the selected program product is read from the hard disk and pointers are updated to pass control to ROS to co...