Personal Computer system

Claim 2

A personal computer in accordance with claim 1 comprising: a display connected to said control means and providing a user with a visual output from said personal computer system, said display requiring a warmup period after said computer system has been turned on in order to provide a visually perceptible screen, said control means being operative to output through said display a screen visible to the user at the end of said warmup period to provide an appearance to the user of an instant startup of said personal computer system.

Claim 3

A personal computer in accordance with claim 1 wherein: said operating system (OS) programs provide a disk operating system (DOS), said disk based file system is a file allocation table (FAT) file system in which files therein are stored in clusters of sectors with each file beginning at the beginning of a different sector, said files being located through a tree structure of directories and a file allocation table stored in said disk drive; and said read only memory (ROM) based file system stores said operating system (OS) programs of said disk operating system (DOS) in a packed format.

Claim 4

A personal computer in accordance with claim 3 comprising: disk based DOS programs stored in said disk drive; and a non-volatile memory containing a flag settable to a first condition for booting said computer from said disk operating system (DOS) programs stored in said read only memory (ROM), and to a second condition for booting said computer from said disk operating system (DOS) programs stored in said disk drive.

Claim 5

A personal computer in accordance with claim 3 or 4 wherein: said random access memory (RAM) has a first region for storing said disk operating system (DOS) programs, and a second region for storing application programs, said first and second regions forming a disk operating system (DOS) address space; and said read only memory (ROM) comprises addressable locations lying outside of said disk operating system (DOS) address space.

Claim 6

A personal computer in accordance with claim 5 wherein: said microprocessor is operable in a real mode and in a protected mode, said disk operating system (DOS) programs loaded into said disk operating system (DOS) address space being accessible when said processor is in said real mode, and said disk operating system (DOS) programs stored in said read only memory (ROM) being accessible when said microprocessor is in said protected mode.

Claim 7

A personal computer in accordance with claim 3 comprising: an installable file system (IFS) including said read only memory (ROM) based file system, and a handler for accessing said disk operating system (DOS) programs in said read only memory (ROM), said handler being contained in said disk operating system (DOS) programs loaded from read only memory (ROM) and callable at a system level to thereby bypass said file allocation table (FAT) file system and provide rapid access through said installable file system (IFS) handler to files in said read only memory (ROM).

Claim 8

A personal computer system (PCS) operable under a disk operating system (DOS) comprising: a disk drive for storing files in a file allocation table (FAT) file system, said files including a first set of disk operating system (DOS) programs; a random access memory (RAM) for storing disk operating system (DOS) programs and an application program in a disk operating system (DOS) address space for execution therefrom; a read only memory (ROM) for storing a second set of disk operating system (DOS) programs in an installable file system (IFS), said second set including a disk operating system (DOS) kernel and a handler for accessing files in said read only memory (ROM); and initialisation means including a microprocessor operable under program control in response to said personal computer system (PCS) being turned on to sequentially boot said disk operating system (DOS) kernel from said read only memory (ROM) into said random access memory (RAM), execute said disk operating system (DOS) kernel, and start up said personal computer system (PCS).

Claim 9

Personal computer system (PCS) in accordance with claim 8 wherein said read only memory (ROM) has addressable locations outside of said disk operating system (DOS) address space, and said second set of disk operating system (DOS) programs includes a random access memory (RAM) loader for loading programs from said read only memory (ROM) into said random access memory (RAM).

Claim 10

A personal computer system (PCS) in accordance with claim 9 wherein said microprocessor is operable in a real mode and in a protected mode, said disk operating system (DOS) address space being accessible when said microprocessor is operating in said real mode, and said read only memory (ROM) being accessible when said microprocessor is operating in said protected mode, said random access memory (RAM) loader being operative to cause said microprocessor to be switched between said modes.

Claim 11

A personal computer system (PCS) in accordance with claim 11 wherein: said read only memory (ROM) stores a header containing information identifying each program stored in said read only memory (ROM), where each program is stored in said read only memory (ROM), and the size of each program, said installable file system (IFS) handler being operable to read such information and rapidly access said programs in said read only memory (ROM).

Claim 12

A personal computer system (PCS) in accordance with claim 11 comprising: an interrupt handling routine in said disk operating system (DOS) kernel operable at a system level to invoke said installable file system (IFS) handler and access a program in read only memory (ROM).

Claim 13

A personal computer system (PCS) in accordance with claim 12 wherein said disk operating system (DOS) kernel contains code for accessing files in said file allocation table (FAT) system, said system level being above said code to bypass it and rapidly access programs in said read only memory (ROM) through said installable file system (IFS).

Claim 14

A personal computer system (PCS) in accordance with claim 13 wherein said second set of disk operating system (DOS) programs is stored in said read only memory (ROM) in a packed format.

Claim 15

A personal computer system (PCS) in accordance with any one of claims 8 to 14 comprising: an output device comprising a display providing a user with a visual output from said personal computer system (PCS), said display requiring a warmup period after said computer system has been turned on in order to provide a visually perceptible screen; said initialisation means being operative to output through said display a screen visible to the user at the end of said warmup period to provide an appearance to the user of an instant startup of said personal computer system.

Claim 16

A personal computer system (PCS) in accordance with claim 15 comprising: a graphical user interface program stored in said read only memory (ROM) and being operable to present at least one screen to the user; said initialisation means being operative to load into and execute said graphical user interface program from said random access memory (RAM) to output through said display said one screen at the end of said warmup period to provide an appearance to the user of an instant startup of said personal computer.

Claim 17

A personal computer system (PCS) in accordance with claim 14 wherein: said read only memory (ROM) further stores a booting program in locations following said header; and said personal computer system (PCS) further comprises a second read only memory (ROM) storing a power on self test program which is executed after said personal computer system (PCS) is turned on and terminates execution by first loading said header and said booting program from said first mentioned read only memory (ROM) in random access memory (RAM) and then transferring control to said booting program.