Abstract: An integrated development environment on a client provides for developing transaction programs, web pages, and applets for execution on a high performance transactional based World Wide Web server. The transaction programs are developed on the client, then automatically transferred to the server, where they are automatically compiled, linked, loaded into a TP library, registered with a TP monitor for execution, and tested. Similarly, the web pages and applets are developed on the client, then automatically transferred to the server, loaded into a database, and tested.

Abstract: Disk drives are mirrored through duplication controlled by disk controllers. Each disk controller controls writing to a set of disk drives. A disk write request to one disk controller causes that disk controller to write to one of its disks and to transmit the write request to another controller that in turn writes to its disk. The second controller then acknowledges the write to the first controller, which in turn acknowledges the write to the computer issuing the request. The first controller further logs the writes in a log file. This allows efficient resynchronization after mirroring is broken and reestablished, as well as removing cable length restrictions between controllers.

Abstract: In a NUMA architecture, processors in the same CPU module with a processor opening a spin gate tend to have preferential access to a spin gate in memory when attempting to close the spin gate. This “unfair” memory access to the desired spin gate can result in starvation of processors from other CPU modules. This problem is solved by “balking” or delaying a specified period of time before attempting to close a spin gate whenever either one of the processors in the same CPU module just opened the desired spin gate, or when a processor in another CPU module is spinning trying to close the spin gate. Each processor detects when it is spinning on a spin gate. It then transmits that information to the processors in other CPU modules, allowing them to balk when opening spin gates.

Abstract: In an emulation of a multiprocessor Target computer system on a Host computer system, Host virtual memory addresses are mapped and utilized as Target virtual memory addresses. Target virtual memory control tables are setup accordingly. Virtual-to-real address translation of a Target system effective address to a Host system virtual addresses is performed by identifying a working space for the effective address, selecting a working space base address data structure entry utilizing the corresponding working space number, determining a working space base address from that selected working space base address data structure entry, and then performing a linear translation multiplying the effective address by a constant and adding it to the working space base address to generate the host system virtual address. A corresponding working space limit entry can be utilized to bounds check the addresses generated.

Abstract: When emulating a Target architecture on a Host system having a different architecture, virtual to real address translation is typically expensive in terms of computer cycles. The cost can be significantly reduced by utilizing direct page table pointers to short-circuit the address translation. In a system additionally supporting segments framing portions of virtual memory, the direct page table pointers are associated with segment registers and point to the page table entry corresponding to the first location in a segment. Direct page table pointers are invalidated when underlying virtual memory management tables are modified.

Abstract: A cache used with a pipelined processor includes an instruction cache, instruction buffers for receiving instruction sub-blocks from the instruction cache and providing instructions to the pipelined processor, and a branch cache. The branch cache includes an instruction buffer adjunct for storing an information set for each sub-block resident in the instruction buffers. A branch cache directory stores instruction buffer addresses corresponding to current entries in the instruction buffer adjunct, and a target address RAM stores target addresses developed from prior searches of the branch cache. A delay pipe is used to selectively step an information set read from the buffer instruction adjunct in synchronism with a transfer instruction traversing the pipeline.

Abstract: A data processing system contains a processor supporting both Narrow and Wide instructions and Narrow and Wide word size fixed-point and floating-point operands. The processor communicates over a bus utilizing a Wide word size with the remainder of the data processing system consisting of industry standard memory and peripheral devices. Narrow word sized instructions are stored on Wide word-sized storage devices. In a preferred embodiment, the processor bus has a first integer number of significant data lines. The processor is responsively coupled to the processor bus and includes a first decoder for decoding a first set of instructions received over the set of processor data lines, The first set of instructions each contains a second integer number, less than the first integer number, of significant bits.

Abstract: In a data processing system that includes a safe store buffer containing valid copies of all registers, processor transitions from a higher security routine to a lower security routine can be performed in fewer cycles by utilizing a plurality of sets of registers maintained in a round-robin system. Whenever a transition is made to a higher security environment, a switch is made to a different set of registers. Then, when a transition is made back to the lower security environment, a switch is made back to the previous set of registers. Writes to memory copies of registers are detected, and only those registers whose memory copies have been modified are restored from the memory copy.

Abstract: In the emulation of a target system utilizing a multiprocessor (12) host system (10) with a longer word length than the target system, processor, memory, and cache overhead are minimized by utilizing a locked compare-exchange to update fill words in memory. The old contents of a word (48) in memory are loaded (80) into a first register (52). A loop is then entered. The contents of the first register (52) are copied (82) into a second (54). The contents of the second register (54) are then appropriately modified (84), depending on the instruction being emulated. After a lock (90), the two registers are compare-exchanged (86) with the memory word (48), resulting in the modified second register (54) being written to the memory word (48) if the contents of the first register (52) match. Otherwise, the compare-exchange instruction (86) loads the current copy of the word (48) into the first register (52), and the loop repeats.

Abstract: A database management optimizer detects patterns in SQL that occur when search conditions are present that represent ranges of values across multiple columns of a table. These patterns are recognized and translated into simpler key value ranges that can be used to provide more efficient use of database indexes.

Abstract: A processor (40) in a data processing system simultaneously loads multiple registers (60) with a single value for fast domain switching. A domain switch instruction asserts a register block write signal (112) along with the register write signal (116) when block writing the single value to the set of registers (60). Register address lines (110, 111) are decoded in two sets: a first set of decoded address lines (110) specifying a block of registers; and the second set (111) specifying one register in the block of registers. When the register block write signal (112) is asserted during a register write, the second set of decoded address lines (111) are ignored, and all registers in the block of registers (60) selected by the first set of decoded address lines (110) are simultaneously loaded with a common value. Additional drive requirements are solved either by adding a buffer (226) to each register bit, or by disabling (228) the feedback path (215) in each register bit during block writes.

Abstract: A data processing system with a RAID cache disk subsystem utilizes three RAID cache disk controllers to provide increased performance along with increased reliability, especially in the event of a failure of one of the disk controllers. Disk writes are mirrored in two disk controllers in order to guarantee integrity in the event of a disk controller or interface failure. Typically this write caching must be terminated when one of the controllers fails in order to maintain integrity. In the present invention, write caching continues utilizing the two remaining disk controllers.

Abstract: In order to obtain mixed and space efficient use of mass memory units having different form factors into a single package, a specially configured connector plane module is provided. The connector plane module includes three identical, aligned, connector plane connectors arranged in a new configuration. Two spaced apart connector plane connectors are disposed in the same orientation with one another; but the third connector plane connector is spaced apart from and disposed in 180° orientation with respect to the second connector. With this configurtion, two mass memory storage units having a first form factor or three mass memory storage units of a second, smaller, form factor may be coupled to the connector plane to occupy substantially the same space, one mass memory unit in each case being oriented at 180° with respect to the one or two other mass memory units.

Abstract: A cache used with a pipelined processor includes an instruction cache, instruction buffers for receiving instruction sub-blocks from the instruction cache and providing instructions to the pipelined processor, and a branch cache. The branch cache includes an instruction buffer adjunct for storing an information set for each sub-block resident in the instruction buffers. A branch cache directory stores instruction buffer addresses corresponding to current entries in the instruction buffer adjunct, and a target address RAM stores target addresses developed from prior searches of the branch cache. A delay pipe, constituting serially-coupled registers, is used to step an information set read from the buffer instruction adjunct in synchronism with a transfer instruction traversing the pipeline.

Abstract: A pipelined processor for simultaneously performs one of a plurality of successive operations on each of a plurality of successive instructions within the pipeline, the successive operations including at least an instruction fetch stage, an operand address stage, an operand fetch stage, an execution stage and a result handling stage. The processor also maintains a plurality of indicators which are selectively updated during the result handling stage for a given instruction to reflect the results obtained during the execution stage thereof. When the second instruction of first and second successively fetched instructions is a conditional transfer, a determination is made as to which indicators may be affected by the execution of the first instruction, and a determination is also made as to which indicator the conditional transfer is to test to decide whether there is a GO or a NOGO condition.

Abstract: A redundant computer system including two systems capable of independent operation. The two systems correspondingly employ two independent clock generation and distribution (CGD) units which each issue clock and clock definer signals. The clock and definer signals of each system are used internally and are also sent to the other system. When the two systems are split, phase locked loops in each system are disabled, and each system is controlled by a precision oscillator in its own CGD unit When the two systems are merged, one CGD is designated as master and remains under control of its internal oscillator. The clock and definer signals of the master system are employed in the slave system to derive a signal which is used as the reference input to the slave system's phase locked loop from which the slave system's clock and definer signals are developed. Preferably, dual flip-flop phase detector type phase locked loops are employed.

Abstract: In order to gather, store temporarily and efficiently deliver safestore information in a CPU having data manipulation circuitry including a register bank, first and second serially oriented safestore buffers are employed. At suitable times during the processing of information, a copy of the instantaneous contents of the register bank is transferred into the first safestore buffer. After a brief delay, a copy of the first safestore buffer is transferred into the second safestore buffer. If a call for a domain change (which might include a process change or a fault) is sensed, a safestore frame is sent to cache, and the first safestore buffer is loaded from he second safestore buffer rather than from the register bank.

Abstract: A computer system includes a main processor and a supervisory processor. The main processor provides status signals when a fault condition exists and responds to control signals for fault recovery. The supervisory processor instantiates objects from a fault class in response to the status signals. Objects are polymorphic in that each object has substantially the same methods available at its interface though each object corresponds to a different fault. Methods accomplish fault recovery by providing the control signals. System operation exhibits fewer errors by the supervisory processor and system expansion is more easily accommodated with greater reuse of proven program code than possible with prior supervisory processor software.

Abstract: A computer system including a group of CPUs, each having a private cache which communicates with its CPU to receive requests for information blocks and for servicing such requests includes a CPU bus coupled to all the private caches and to a shared cache. Each private cache includes a cache memory and a cache controller including pairs of half-block operand buffers, each divided into quarter block segments. The operand buffer set is coupled to selectively receive, under control of an input multiplexer, requested information blocks from the CPU bus in quarter-block segments and is further coupled to selectively send, under control of an output multiplexer, received quarter-block segments to the CPU and received full blocks to the cache memory.

Abstract: In a coprocessor which processes operands and issues a result word which may include overflow, result and truncation fields and which normally sets a truncation indicator if truncation is employed, the setting of the truncation indicator is inhibited under certain conditions to facilitate later handling of the result. Determinations are made as to whether the result and truncation fields of the result word are zero and as to whether the overflow field is non-zero. If the result and truncation fields are zero, the setting of the truncation indicator is inhibited notwithstanding a non-zero value in the overflow field. Break point position information is processed to obtain masks of bits having logic "1" values for testing the result and truncation fields and logic "0" values for testing the overflow field, the masks then being logically ANDed with the result word. If the result of the ANDing process is a logic "0", the truncation indicator is inhibited from being set.