CPU cache

A CPU cache is a cache used by the central processing unit (CPU) of a computer to reduce the average time to access data from the main memory. The cache is a smaller, faster memory which stores copies of the data from frequently used main memory locations. Most CPUs have different independent caches, including instruction and data caches, where the data cache is usually organized as a hierarchy of more cache levels (L1, L2, etc.).

Overview

When the processor needs to read from or write to a location in main memory, it first checks whether a copy of that data is in the cache. If so, the processor immediately reads from or writes to the cache, which is much faster than reading from or writing to main memory.

Most modern desktop and server CPUs have at least three independent caches: an instruction cache to speed up executable instruction fetch, a data cache to speed up data fetch and store, and a translation lookaside buffer (TLB) used to speed up virtual-to-physical address translation for both executable instructions and data. The data cache is usually organized as a hierarchy of more cache levels (L1, L2, etc.; see also multi-level caches below). However, a TLB cache is part of the memory management unit (MMU) and not directly related to the CPU caches.

Cache

Cache or caching may refer to:

Computing

Cache (Aosta)

Cache (Aosta) is a frazione in the Province of Aosta in the Aosta Valley region of Italy.

Coordinates: 45°45′40″N 7°19′29″E / 45.76111°N 7.32472°E / 45.76111; 7.32472

InterSystems Caché

InterSystems Caché is a commercial object-oriented database management system from InterSystems, used to develop healthcare management and telecommunications software. Customer software can use the database with object and SQL code. Caché also allows developers to directly manipulate its underlying data structures: hierarchical arrays known as M technology.

Description

Internally, Caché stores data in multidimensional arrays capable of carrying hierarchically structured data. These are the same “global” data structures used by the MUMPS programming language, which influenced the design of Caché, and are similar to those used by MultiValue (aka PICK) systems. In most applications, however, object and/or SQL access methods are used.

Caché ObjectScript, Caché Basic or T-SQL can be used to develop application business logic. External interfaces include native object binding for C++, Java, EJB, ActiveX, and .NET. Caché supports JDBC and ODBC for relational access. XML and web services are also supported.

Central processing unit

A central processing unit (CPU) is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. The term has been used in the computer industry at least since the early 1960s. Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.

The form, design and implementation of CPUs have changed over the course of their history, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that fetches instructions from memory and "executes" them by directing the coordinated operations of the ALU, registers and other components.

Freescale 683XX

The Freescale 683xx (formerly Motorola 683xx) is a family of compatible microcontrollers that use a Freescale 68000-based CPU core. The family was designed using a hardware description language, making the parts synthesizable, and amenable to improved fabrication processes, such as die shrinks.

There are two CPU cores used in the 683xx family: the 68EC000 and the CPU32. The instruction set of the CPU32 core is similar to the 68020 without bitfield instructions, and with a few instructions unique to the CPU32 core, such as table lookup and interpolate instructions, and a low-power stop mode.

The modules of the microcontroller were designed independently and released as new CPUs could be tested. This process let the architects perform "design-ahead" so that when silicon technologies were available, Motorola had designs ready to implement and go to market. Many of these submodules have been carried forward into the Coldfire line of processors.

The microcontrollers consist of a series of modules, connected by an internal bus:

Standard Performance Evaluation Corporation

The Standard Performance Evaluation Corporation (SPEC) is an American non-profit organization that aims to "produce, establish, maintain and endorse a standardized set" of performance benchmarks for computers.

SPEC was founded in 1988. SPEC benchmarks are widely used to evaluate the performance of computer systems; the test results are published on the SPEC website. Results are sometimes informally referred to as "SPECmarks" or just "SPEC".

SPEC evolved into an umbrella organization encompassing four diverse groups; Graphics and Workstation Performance Group (GWPG), the High Performance Group (HPG), the Open Systems Group (OSG) and the newest, the Research Group (RG). More details are on their website; .

Membership

Membership in SPEC is open to any interested company or entity that is willing to commit to SPEC's standards. It allows: