Browse Prior Art Database

Memory Resident Program Loader for Pc-Dos/Ms-Dos

IP.com Disclosure Number: IPCOM000061628D
Original Publication Date: 1986-Sep-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Cummins, EM: AUTHOR

Abstract

This procedure creates a resident save area in computer memory and stores a copy of the transient loader portion of the COMMAND.COM program in it. It then monitors subsequent program loading by the operating system. When the program terminates, this procedure restores the COMMAND.COM loader to high memory from the resident save area. As a result, the operating system does not have to reload the transient portion of COMMAND.COM from disk. The problem addressed by this procedure is found primarily in micro-computer systems that do not have fixed disk drives. The program loader portion of the operating system is moved to high computer memory for execution. A program loaded by the operating system is allowed to use this same high memory, if necessary, thus overlaying the program loader code.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 87% of the total text.

Page 1 of 1

Memory Resident Program Loader for Pc-Dos/Ms-Dos

This procedure creates a resident save area in computer memory and stores a copy of the transient loader portion of the COMMAND.COM program in it. It then monitors subsequent program loading by the operating system. When the program terminates, this procedure restores the COMMAND.COM loader to high memory from the resident save area. As a result, the operating system does not have to reload the transient portion of COMMAND.COM from disk. The problem addressed by this procedure is found primarily in micro-computer systems that do not have fixed disk drives. The program loader portion of the operating system is moved to high computer memory for execution. A program loaded by the operating system is allowed to use this same high memory, if necessary, thus overlaying the program loader code. When the program terminates and returns to the operating system, a checksum is done on the high memory area to determine if the program loader code has been corrupted. If so, the operating system attempts to restore the program loader code from the disk drive that was used to boot up the system. This requires that all floppy disks which may be used in the boot drive must have the COMMAND.COM program on them, which occupies up to 25,000 bytes of disk space. This is wasteful and time consuming for the required disk operations. This problem is amplified on single diskette systems. This procedure is an improvement over previous methods...