摘要:
A high-speed ''''on-the-fly'''' printer, wherein timing means is provided to identify the position of the print characters on a movable type-carrying member, to denote the instant for actuation of the print operation, and to control the speed of the motor driving the type-carrying member.
摘要:
A bistable multivibrator employs a single transistor, a capacitor, a pair of four-layer diodes and a pair of transistors. Trigger pulses applied to the base of the transistor caused the multivibrator to be switched each time a positive pulse is applied.
摘要:
A pair of silicon-controlled rectifiers, a center tapped inductor, a pair of commutating capacitors, a transformer, and a pair of low-voltage diodes convert a relatively large value of unregulated DC voltage to a relatively small value of regulated DC voltage. A pair of conventional diodes connected across the commutating capacitors limit the reverse voltage across these capacitors and limit the operating currents and voltages in the other elements of the switching regulator.
摘要:
Division apparatus in a data processing system includes the selection of a number of quotient characters to be formed and employs operating registers of the data processing system. The most significant characters of the dividend and the divisor are used to develop a trial quotient and the trial quotient is used with the rest of the characters to obtain the actual quotient and remainder.
摘要:
Two unique instructions for the instruction set of a target 36-bit machine which is emulated on a host 64-bit machine are provided in order to achieve visibility, to an emulated application program, of a “containing” word stored in the memory of the host machine. A “LOAD64” instruction loads the emulator memory location representing an emulated “Q” (supplementary accumulator) register with the “normal” 36-bits of the containing word. At the same time, the “upper” 28 bits of the 64-bit containing word is copied into the emulator memory location representing an emulated “A” (accumulator) register. Thus, the emulated 36-bit machine “sees” and can examine the 64-bit word in its entirety. A “Store64” instruction stores the emulated “Q” register contents into the lower 36-bits of the 64-bit containing word, and at the same time stores the lower 28 bits of the emulated “A” register contents into the upper 28 bits of the 64-bit containing word.
摘要:
A computer system includes a central processing unit, an addressable main memory storing data pages and a page table, and an associative memory. The associative memory stores a plurality of entries in accordance with a low order virtual address component issued by the CPU's processor when access to a given page in main memory is sought. Each entry in the associative memory includes fields respectively holding: 1) a high order virtual address component; 2) a real page address; and 3) a multi-digit validity count. An incrementable multi-digit counter in the CPU stores a current validity count. When access to a data page is sought, a comparator receives: 1) the high order virtual address component of the data page; 2) the high order virtual address component read from the associative memory entry; 3) the multi-digit validity count read from the associative memory entry; and 4) the multi-digit current validity count in the counter. If there is a full match, a switch issues the real page address read from the associative memory entry. If there is not a match, the page table is consulted to obtain the real address of the requested page, and the associative memory is updated accordingly.
摘要:
Atomic multiple word reads are provided when emulating a target system that supports atomic multiple word reads on a host system that does not. For each except the last word to be read, a gate flag is read using an advanced speculative load, and tested, until found unlocked. Check speculation instructions are utilized after the gate flag tests to verify that the corresponding cache lines have not been invalidated through a write by another processor since the speculative loads were issued. In a host system with a longer word size than the target system, the gate flags can be stored in otherwise unused bits in the host system words containing the target system words to be written.
摘要:
A data processing system participating in two-phase transaction processing operations which, when a system failure occurs while one or more transactions are in process, can successfully rebuild “in-doubt” states even when another system failure occurs during an attempt to effect the rebuild. The system includes a file management system having exclusive access to reserved locations in the memory for reading and writing meta-data therein and physical file access logic selectively coupling the memory and the database access application, the physical file access logic incorporating file protections which are controlled by the file management system; such that, in the event of a failure, the local state of the transaction can be faithfully rebuilt after restart by accessing the meta-data. Upon restart after a failure, the results of incomplete non-“in-doubt” transactions are removed, the files which have been updated by “in-doubt” transactions are locked and normal access to the affected database is then permitted.
摘要:
Bulk data is read or written by an application on a first computer system to a file on a second heterogeneous computer system. Alternatively it is read or written as bulk data directly between applications on these heterogeneous systems. Jobs or tasks are started from one system to execute on a second heterogeneous system. Results are then returned to the first system. Checkpointing and later restarting is also initiated from a first system for execution on the second heterogeneous system.
摘要:
Atomic multiple word reads are provided when emulating a target system that supports atomic multiple word reads on a host system that does not. For each except the last word to be read, a gate flag is read using an advanced speculative load, and tested, until found unlocked. Check speculation instructions are utilized after the gate flag tests to verify that the corresponding cache lines have not been invalidated through a write by another processor since the speculative loads were issued. In a host system with a longer word size than the target system, the gate flags can be stored in otherwise unused bits in the host system words containing the target system words to be written.