摘要:
A data processing system includes a plurality of system units all connected in common to a system bus. The system units include a central processor (CPU), a memory system and a high speed buffer or cache system. The cache system is word oriented and comprises a directory, a data buffer and associated control logic. The CPU requests data words by sending a main memory address of the requested data word to the cache system. If the cache does not have the information, apparatus in the cache requests the information from main memory, and in addition, the apparatus requests additional information from consecutively higher addresses. If main memory is busy, the cache has apparatus to request fewer words.
摘要:
A data processing system having a system bus; a plurality of system units including a main memory, a cache memory, a central processing unit (CPU) and a communications controller all connected in parallel to the system bus. The controller operates to supervise interconnection between the units via the system bus to transfer data therebetween, and the CPU includes a memory request device for generating data requests in response to the CPU. The cache memory includes a private interface connecting the CPU to the cache memory for permitting direct transmission of data requests from the CPU to the cache memory and direct transmission of requested data from the cache memory to the CPU; a cache directory and data buffer for evaluating the data requests to determine when the requested data is not present in the cache memory; and a system bus interface connecting the cache memory to the system bus for obtaining CPU requested data not found in the cache memory from the main memory via the system bus in response to the cache directory and data buffer. The cache memory may also include replacement and update apparatus for determining when the system bus is transmitting data to be written into a specific address in main memory and for replacing the data in a corresponding specific address in the cache memory with the data then on the system bus.
摘要:
A word oriented data processing system includes a plurality of system units all connected in common to a system bus. Included are a central processor unit (CPU), a memory system and a high speed buffer or cache system. The cache system is also coupled to the CPU. The cache includes an address directory and a data store with each address location of directory addressing its respective word in data store. The CPU requests a word of cache by sending a memory request to cache which includes a memory address location. If the requested word is stored in the data store, then it is sent to the CPU. If the word is not stored in cache, the cache requests the word of memory. When the cache receives the word from memory, the word is sent to the CPU and also stored in the data store.
摘要:
A data processing system includes a plurality of system units all connected in common to a system bus. Included are a main memory system and a high speed buffer or cache store. System units communicate with each other over the system bus. Apparatus in the cache store monitors each communication between system units to determine if it is a communication from a system unit to main memory which will update a word location in main memory. If that word location is also stored in cache then the word location in cache will be updated in addition to the word location in main memory.
摘要:
In a data processing system which includes a plurality of system units such as a central processing unit (CPU), main memory, and cache memory all connected in common to a system bus and communicating with each other via the system bus, and also having a private CPU-cache memory interface for permitting direct cache memory read access by the CPU, a multi-configurable cache store control unit for permitting cache memory to operate in any of the following word modes:1. Single pull banked;2. Double pull banked;3. Single pull interleaved;4. Double pull interleaved.The number of words read is a function of the main store configuration and the amount of memory interference from I/O controllers and other subsystems. The number ranges from one to four under the various conditions.
摘要:
A secure memory card includes a microprocessor on a single semiconductor chip which interconnects through an internal bus to a number of non-volatile addressable memory chips. The microprocessor includes an addressable non-volatile memory for storing information including a number of key values and program instruction information. Each chip's memory is organized into a number of blocks, each block including a number of rows of byte locations. Each row of each block further includes a lock bit location, the total number of which provide storage for a lock value uniquely coded to utilize a predetermined characteristic of the memory to ensure data protection. Each memory chip is constructed to include security control logic circuits which include a security access control unit and a volatile access control memory containing a plurality of access control storage elements. Under the control of a predetermined set of instructions, the security access control unit performs a predetermined key validation operation by comparing key values against the bit contents of lock bit locations read out a bit at a time during an authentication procedure with a host computer. After the successful performance of the key validation procedure, the microprocessor sets one of the storage elements of the volatile access control memory for enabling user access to block data.
摘要:
A communications controller interface for emulating the previous system employing a plurality of line units in which data is transmitted and received. The interface includes a microprocessor-controlled interface control unit having an interface memory having a plurality of addressable storage locations. The interface memory is mapped by dividing it into a number of groups of locations corresponding to the number of communication lines with each group of locations being subdivided into further locations including a location for storage of receive data, a location for storage of transmit data, and a control location. There are a number of control elements each for generating a sequence of signals for different tasks to be performed by the interface control unit. These control elements are interconnected to the interface control unit and to the interface memory so that the multi-line communications unit is able to access different ones of the control locations for updating the status of the lines and further enabling the microprocessor-controlled interface control unit to transfer data to and from the transmit data and receive data locations of the lines in the predetermined sequence consistent with the status.
摘要:
A high definition page display system for graphics and text utilizing multiple beams in a CRT is disclosed. Information for the several lines which are written simultaneously is made available in parallel. The invention is described in terms of a character set and text generation, but the same principles apply to any other graphic or bit map and to storage in ROMs or loadable RAMs. Each beam of a multiple CRT tube is biased to generate a portion of a character or graphic as it scans across the tube. It takes 12 lines to scan a character with a N-beam tube, 12 over N character scans are therefore required. With the same scanning speed as with a single beam, this factor can be used to increase definition (i.e. number of lines). Also the advantage of multiple beams can be used to reduce scanning speed, if this is useful to improve brightness or spot definition, or to increase the number of dots per line. Reduced scanning speed can also reduce costs, particularly if it brings the scan rate in line with standard components available commerically. Another way to use the advantages would be higher refresh rates.
摘要:
A communications subsystem having a microprocessor coupled to an address bus and a data bus includes a latching register also coupled to the address bus and the data bus. The latching register is responsive to signals from the data bus and address bus for storing bits representative of a direct connect mode, a clear to send mode, and a bit oriented or byte control protocol mode.
摘要:
A memory having a plurality of word locations, each having a bit location, includes a parity word in one of the word locations. Bit selector means selects a column of bits made up of like positioned bits in each of the word locations. All bits in a column are added together to indicate whether there is a successful parity check. Each such column is successively checked thereby verifying the integrity of the stored information on a column basis.