Abstract: This invention relates to personal computer systems and, more particularly, to such a system having security features enabling control over access to data retained in such a system.

Abstract: An apparatus for loading BIOS stored on a direct access storage device in a personal computer system, the system comprising direct access storage device, and a processor card removably mounted to a planar board. The processor card comprises a system processor and ROM memory, while the planar board includes a main memory. A master boot record is stored on the direct access storage device. The master boot record contains a data segment and an executable code segment, the data segment representing the hardware configuration of the personal computer system. A first portion of BIOS included in the ROM memory initializes the system and causes loading of the master boot record into main memory. This first portion of BIOS further compares the hardware configuration data of the master boot record with the hardware configuration data in the ROM memory to verify compatibility with the system processor.

Abstract: This invention relates to personal computer systems and, more particularly, to such a system having security features enabling control over access to data retained in such a system. This invention contemplates protecting a personal computer system which has the capability of becoming a secure system from being placed into that condition by an attack on an unsecured machine. Additionally, in a network environment, it is important to maintaining network security that any given particular system be uniquely identified to the network, in order to guard against the substitution of an insecure "alternate" which would open the network to attack through an insecure system. This invention contemplates provision for such identification in a secure manner.

Abstract: A method and medialess personal computer system workstation (or LAN station as herein defined) adaptable for securing the system against attack on a secured network with which the LAN station is associated. A flag bit is set in system memory during a power on self test to indicate whether access may be had to certain security features of the system, and a procedure is described by which access to a network stored configuration setting program may be gained in order to install, change or remove a password used for securing the LAN station while avoiding passing the critical password data through the network.

Abstract: This invention relates to personal computer systems and in particular to an apparatus and method for loading BIOS into a personal computer system from a remote storage location. More particularly, this invention provides a personal computer adapted for use as an economical workstation in a local area network environment (a "LAN station") with provision for loading BIOS into the LAN station from a remote memory storage where the BIOS code is maintained apart from the LAN station.

Abstract: A personal computer system according to the present invention comprises a system processor, a random access memory, a read only memory, and at least one direct access storage device. A direct access storage device controller coupled between the system processor and direct access storage device includes a protection mechanism for protecting a region of the storage device. The protected region of the storage device includes a master boot record, a BIOS image and a system reference diskette image. The BIOS image includes a section known as Power on Self Test (POST). POST is used to test and initialize a system. Upon detecting any configuration error, system utilities from the system reference diskette image, such as set configuration programs, diagnostic programs and utility programs can be automatically activated from the direct access storage device.

Abstract: An apparatus and method for loading BIOS stored on a direct access storage device into a personal computer system. The personal computer system comprises a system processor, a system planar, a random access main memory, a read only memory, and at least one direct access storage device. The first portion of BIOS initializes the system and the direct access storage device to read in a master boot record into the system from the direct access storage device. The master boot record includes a data segment and an executable code segment. The first BIOS portion vectors the system processor to execute the executable code segment of the master boot record. The executable code segment loads in the remaining BIOS portion from the direct access storage device into random access memory.

Abstract: A computer system and method for operating a computer system capable of running in mutually incompatible real and protected addressing modes, in which programs written for one mode can be run in the other mode without modification. The BIOS assembles two different common data areas for the two modes, each inclusive of device block pointers, function transfer table pointers, data pointers, and function pointers. The common data area for the real mode is assembled first. To assembly the pointers for the protected mode common data area, the offset values from the real mode area ae copied directly, and then selector values are inserted whose physical addresses correspond to the segments of the corresponding pointers in the real mode area. The selector values are derived from a segment descriptor table.

Abstract: An apparatus and method for reclaiming a portion of random access memory in a personal computer system. The personal computer system comprises a system processor, a memory controller, a random access main memory, a read only memory, and at least one direct access storage device. The read only memory includes operating system microcode. The memory controller regulates communications between main memory and the system processor. In response to signals from the system processor, the memory controller can either execute the microcode out of the read only memory and recover main memory previously used to store the microcode, or disable read only memory, copy the microcode to main memory and execute the microcode out of main memory.

Abstract: An apparatus and method for decreasing the memory requirements of BIOS in a personal computer system includes storing a first portion of BIOS in memory and a second portion on a direct storage access device. The personal computer system comprises a system processor, a random access main memory, a read only memory, and at least one direct access storage device. The first portion of BIOS only includes routines for initializing the system and the direct access storage device to read in a master boot record into the system from the direct access storage device. The master boot record includes a data segment and an executable code segment. The first BIOS portion vectors the system processor to execute the executable code segment of the master boot record. The executable code segment loads in the remaining BIOS portion from the direct access storage device into random access memory superseding the first BIOS portion.

Abstract: A personal computer system according to the present invention comprises a system processor, a random access memory, a read only memory, and at least one direct access storage device. A direct access storage device controller coupled between the system processor and direct access storage device includes a protection mechanism for protecting a region of the storage device. The protected region of the storage device includes a master boot record, a BIOS image and a system reference diskette image. The BIOS image includes a section known as Power on Self Test (POST). POST is used to test and initialize a system. Upon detecting any configuration error, system utilities from the system reference diskette image, such as set configuration programs, diagnostic programs and utility programs can be automatically activated from the direct access storage device.

Abstract: A data processing system has a microprocessor, a memory system and a plurality of system devices the operation of which is controlled by BIOS routines. The BIOS routines are accessed through protected entry points. When an application program attempts to access one of the routines by using a hard coded instruction for jumping to such entry point, a BIOS signaling routine is executed which provides a signal to an operating system allowing the operating system to control the access without being bypassed.

Abstract: An apparatus and method for protecting BIOS stored on a direct access storage device into a personnal computer system. The personal computer system comprises a system processor, a system planar, a random access main memory, a read only memory, a protection means and at least one direct access storage device. The read only memory includes a first portion of BIOS and data representing the type of system processor and system planar I/O configuration. The first portion of BIOS initializes the system and the direct access storage device, and resets the protection means in order to read in a master boot record into the random access memory from a protectable partition on the direct access storage device.

Abstract: Diskette drive determination in which a read/write head in a diskette drive is instructed to move to a track that is inaccessible on one type of diskette drive. The head is then stepped back toward a track associated with a sensor indicating the positioning of the head over the track. The number of steps required to activate the sensor determines which type of drive is being used.

Abstract: A computer system and method for operating a computer system capable of running in mutually incompatible real and protected addressing modes, in which programs written for one mode can be run in the other mode without modification. The operating system using BIOS assembles two different common data areas for the two modes, each inclusive of device block pointers, function transfer table pointers, data pointers, and function pointers. The common data area for the real mode is assembled first. To assemble the pointers for the protected mode common data area, the offset values from the real mode area are copied directly, and then selector values are inserted whose physical addresses correspond to the segments of the corresponding pointers in the real mode area. The selector values are derived from a segment descriptor table.

Abstract: Diskette media and drive determination in which a diskette controller attempts to read the diskette according to a variety of formats having, for instance, different data transfer rates. A successful read is registered by the controller and that format is thereafter identified with the diskette drive and the diskette media inserted in the drive.