Disk operating system loadable from read only memory using installable file system interface
First Claim
Patent Images
1. A personal computer comprising:
- a disk drive for storing files in clusters of sectors, said disk drive haivng a disk based file system that comrpises a file allocation table (FAT) and directory means for locating and accessing said files;
a microprocessor that operates in a real mode and in a protected mode;
a memory system comprising a random access memory (RAM), a first read only memory (ROM), and a second ROM, said memory system having a memory address space including a first region, which is accessible when said microprocessor operates in either one of said modes, and a second region which is accessible only when said microprocessor operates in said protected mode;
said first ROM and said RAM are located in said first region, and said second ROM is located in said second region, of said memory address space;
said first ROM storing a power-on self test (POST) program;
said second ROM storing a ROM disk operating system (DOS) comprisingDOS kernal programs for providing minimum operating system support for operating said personal computer, said DOS kernal programs further comprising initialization code for setting up said personal computer and a RAM loader program for loading programs from said second ROM into said RAM,additional DOS programs for providing, in conjunction with said DOS kernel programs, full operating system support for operation of said personal computer, anda bootstrap record containing information for accessing said DOS programs in said second ROM, and a ROMBOOT program for loading said DOS kernel; and
boot-up means, including said microprocessor, for booting said personal computer in response to said personal computer being powered on, said boot-up means being operative to execute said POST program to thereby test said personal computer, to load said bootstrap record from said second ROM into said RAM, to execute said ROMBOOT program and load said DOS kernel programs into said RAM from said second ROM, and to execute said initialization code to thereby set up said personal computer for further operation under said ROM DOS.
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Accused Products
Abstract
A data processing system, such as a personal computer, contains bootable DOS programs that are stored in a ROM as an alternate file system in which the files are stored in packed format. When the system is powered on, the programs are rapidly booted up or loaded from ROM into RAM and executed to "instantly" (as it appears to the user) place the system in operation.
275 Citations
17 Claims
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1. A personal computer comprising:
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a disk drive for storing files in clusters of sectors, said disk drive haivng a disk based file system that comrpises a file allocation table (FAT) and directory means for locating and accessing said files; a microprocessor that operates in a real mode and in a protected mode; a memory system comprising a random access memory (RAM), a first read only memory (ROM), and a second ROM, said memory system having a memory address space including a first region, which is accessible when said microprocessor operates in either one of said modes, and a second region which is accessible only when said microprocessor operates in said protected mode; said first ROM and said RAM are located in said first region, and said second ROM is located in said second region, of said memory address space; said first ROM storing a power-on self test (POST) program; said second ROM storing a ROM disk operating system (DOS) comprising DOS kernal programs for providing minimum operating system support for operating said personal computer, said DOS kernal programs further comprising initialization code for setting up said personal computer and a RAM loader program for loading programs from said second ROM into said RAM, additional DOS programs for providing, in conjunction with said DOS kernel programs, full operating system support for operation of said personal computer, and a bootstrap record containing information for accessing said DOS programs in said second ROM, and a ROMBOOT program for loading said DOS kernel; and boot-up means, including said microprocessor, for booting said personal computer in response to said personal computer being powered on, said boot-up means being operative to execute said POST program to thereby test said personal computer, to load said bootstrap record from said second ROM into said RAM, to execute said ROMBOOT program and load said DOS kernel programs into said RAM from said second ROM, and to execute said initialization code to thereby set up said personal computer for further operation under said ROM DOS. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A personal computer that operates under a disk operating system (DOS), comprising:
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a microprocessor that operates in a real mode and in a protected mode; a memory system comprising a random access memory (RAM), and a read-only memory (ROM), said memory system having a memory address space including a first region, which is accessible when said microprocessor operates in either one of said modes, and a second region which is accessible only when said microprocessor operates in said protected mode; said RAM is located in said first region, and said ROM is located in said second region, of said memory address space; an installable file system (IFS) for accessing said ROM as a ROM disk drive; said ROM having a ROM file system for storing a ROM DOS comprising DOS kernel programs for providing minimum operating system support for operation of said personal computer, said DOS kernel programs further comprising initialization code for setting up said personal computer, a RAM loader program or loading programs from said ROM into said RAM, and an IFS handler for accessing said ROM disk drive, additional DOS programs for providing, in conjunction with said DOS kernel programs, full operating system support for operation of said personal computer, and a bootstrap record containing information for accessing said DOS program in said second ROM, and a ROMBOOT program for loading said DOS kernel; and boot-up means, including said microprocessor, for booting said personal computer in response to said personal computer being powered on, said boot-up means being operative to execute said POST program and thereby test said personal computer, to load said bootstrap record from said second ROM into said RAM, to execute said ROMBOOT program and load said DOS kernel programs into said RAM from said second ROM, to attach said IFS and create said ROM disk drive, and to execute said initialization code to thereby set up said personal computer for further operation under said ROM DOS. - View Dependent Claims (8, 9, 10, 11, 12)
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13. The method of operating a personal computer comprising a disk drive for storing files in clusters of sectors, said disk drive having a disk based file system that comprises a file allocation tale (FAT) and directory means for locating and accessing said files;
- a microprocessor that operates in a real mode and in a protected mode;
a memory system comprising a random access memory (RAM), a first read only memory (ROM), and a second ROM, said memory system having a memory address space including a first region, which is accessible when said microprocessor operates in either one of said modes, and a second region which is accessible only when said microprocessor operates in said protected mode; and
said first ROM and said RAM are located in said first region, and said second ROM is located in said second region, of said memory address space;
said method comprising;storing a power-on self test (POST) program in said first ROM; storing a ROM disk operating system (DOS) in said second ROM, aid ROM DOS comprising DOS kernel programs for providing minimum operating system support for operating said personal computer, said DOS kernel programs further comprising initialization code for setting up said personal computer and a RAM loader program for loading programs from said second ROM into said RAM, additional DOS programs for producing, in conjunction with said DOS kernel programs, full operating system support for operation of said personal computer, and a bootstrap record containing information for accessing said DOS programs in said second ROM, and a ROMBOOT program for loading said DOS kernel; and booting said personal computer in response to said personal computer being powered on, by steps comprising executing said POST program to thereby test said personal computer, loading said bootstrap record from said second ROM into said RAM, executing said ROMBOOT program to load said DOS kernel programs into said RAM from said second ROM, and executing said initialization code to thereby set up said personal computer for further operation under said ROM DOS. - View Dependent Claims (14, 15, 16, 17)
- a microprocessor that operates in a real mode and in a protected mode;
Specification