Abstract: A multi-master digital computer system has a bus, a plurality of master devices connected to the bus, a plurality of slave devices connected to the bus, and a bus controller for arbitrating bus requests by the master devices and for granting the bus to a selected one of the plurality of the master devices. Each master device is capable of originating a bus cycle to transmit data to or receive data from a desired slave device. The bus controller grants the bus to a selected master device which enters an address master state and addresses the desired slave device. The selected master device is transferred to a bus master state where a data transfer to or from the slave device is initiated. The selected master device then transfers to a data master state unless the selected master device wants, and is permitted through an arbiter, to retain control of the bus. The bus controller grants a bus request to a requesting master device through to the arbiter.

Abstract: Disclosed are a circuit and method for dynamically determining cache memory size. The method comprises the steps of (1) writing a replacement data pattern into a first addressable location of a cacheable portion of addressable space, thereby placing the replacement data pattern into a corresponding first addressable location in a cache memory and setting a tag in the first addressable location, (2) accessing an assumed number of remaining addressable locations in the portion of the addressable space thereby setting tags in each of the remaining addressable locations and (3) reading the first addressable location in the cache memory to determine whether the replacement data pattern remains in the first addressable location, the cache memory being of an assumed size if the replacement data pattern is not in the first addressable location in the cache memory. The circuit and method are able to size cache memory without reference to cache size data stored in cache controllers or hardware timers.

Abstract: A method for configuring at least one composite drive for a disk drive array controller. A disk drive array controller having a memory portion on which a list of composite drives which may be installed on a bus of a computer system is stored thereon is provided. A plurality of disk drives are then installed on the bus of the computer system. Each of the disk drives includes a user data region, a first portion of which contains a first field containing a composite drive ID number for a composite drive and a second field which indicates the total number of disk drives in the composite drive corresponding to the composite drive ID number and a second portion of which contains a position of the disk drive within the composite drive corresponding to the composite drive ID number.

Abstract: A computer system and method of operation thereof are provided including an improved graphical user interface (GUI). A conditional cascading menuing method and apparatus which shield novice users from being overwhelmed by advanced operations in the desktop which appears on the user's computer screen. The conditional cascading feature provides the user with the ability to select a basic function or action from a main menu on the desktop, in which case the default behavior of the function will be performed, or to conditionally display, by pressing a mini push-button next to the main menu item text, a submenu of all forms of function or action. The default submenu behavior or item is indicated by a checkmark adjacent the default item in the submenu. Each time the user selects a submenu item which is different from the default submenu item, the presently selected submenu item becomes the default item or behavior.

Abstract: This invention relates to the use of a multiplexing technique to allow for the unambiguous enabling of remotely located receiving devices. In particular, a plurality of pushbutton switches, each capable of controlling a distinct function, has a common node whose output is transmitted through the single slip-ring usually found on the steering column of an automotive vehicle. This slip-ring is normally used to conduct an electrical voltage from the horn ring to the horn control relay independent of the position of the steering wheel. The multiplexing technique disclosed herein allows for separate and independent control of not only the horn but also other functions such as a cruise control using the existing single slip-ring as the mechanism to transmit the desired signal commands. The demultiplexed signals are derived from logic circuitry located at the distal point of the slip-ring assembly.

Abstract: A crystal filter including at least one acoustically coupled crystal with at least three resonators thereon with an impedance block connected between the input and output of each crystal and the input and output phases of each crystal being adjusted so that attenuation zeros symmetric about a center frequency are produced to improve the frequency response of the filter without increasing the number of poles.