One aspect of the invention relates to a method for detecting architectural violations in a multiprocessor computer system. In one version of the invention, the method includes the steps of generating a testcase instruction stream having a plurality of instructions, executable by the processors, which access a memory which is shared by the processors; detecting dependent instructions in the testcase instruction stream; and modifying the testcase instruction stream by inserting logging instructio...

A computer system having two processors and storage where storage is segmented so as to permit simultaneous access by the two processors with the address path of one processor being limited to a particular segment of storage so as to eliminate contention in other segments. One processor can address all segments of storage and place processed data into and retrieve data from the segment of storage accessible by the other processor. This eliminates the need for cycle stealing because the other pro...

In a digital computer system which employs a plurality of host processors, at least two system buses and a plurality of peripheral input/output ports, an input/output system is provided whereby ownership of the input/output channels is shared. The device controller employs a first port controller having a first ownership latch, a second port controller having a second ownership latch, a first bus, a dedicated microprocessor having control over the first bus (the MPU bus), a second, higher-speed ...

A data processing system includes the functionality of a commercial instruction processor, a scientific instruction processor and a basic instruction processor integrated into a single semiconductor logic element.

One aspect of the invention relates to a method for detecting synchronization violations in a multiprocessor computer system having a memory location which controls access to a portion of memory shared by the processors, the memory location having at least one lock bit indicating whether the portion of memory is locked by one of the processors and a plurality of bits for storing a data value. The method comprises reading the memory location by an individual processor; testing the lock bit to det...

The problem of extending modern operating systems to run efficiently on large-scale shared memory multiprocessors without a large implementation effort is solved by a unique type of virtual machine monitor. Virtual machines are used to run multiple commodity operating systems on a scalable multiprocessor. To reduce the memory overheads associated with running multiple operating systems, virtual machines transparently share major data structures such as the operating system code and the file syst...

A shared memory multiprocessor having a packet switched bus, together with write back caches for connecting individual processor to that bus, employs a consistency protocol that permits the caches to store multiple copies of read/write data at identical physical addresses for use as needed by the respective processors. The protocol causes the hardware to automatically and transparently maintain the consistency of this data. To that end, the caches detect when a datum becomes shared by monitoring...

Method and apparatus for facilitating barrier and eureka synchronization in a massively parallel processing system. The present barrier/eureka mechanism provides a partitionable, low-latency, immediately reusable, robust mechanism which can operate on a physical data-communications network and can be used to alert all processor entities (PEs) in a partition when all of the PEs in that partition have reached a designated barrier point in their individual program code, or when any one of the PEs i...

The disclosure describes a separate trace table for each CPU in an MP to avoid inter-CPU interference in making trace table entries for explicit and implicit tracing instructions enabled by flag bits in a control register (CR). Explicit tracing entries are made for an enabled explicit tracing instruction. Implicit tracing entries are made for predetermined instructions (when enabled for tracing) which do not have tracing as their primary purpose. A storage operand of the trace instruction contai...

A multiprocessor integrated circuit is disclosed. A preferred embodiment of a multiprocessor chip has microprocessors formed on silicon-on-insulator regions and dynamic random access memory level-2cache memories or level-3 cache memories formed on bulk regions of the chip. A preferred embodiment includes a redundant architecture having a signal bus for coupling the microprocessors to the level-2 or level-3 cache memories in which the signal bus includes a programmable selector circuit for bypass...