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2   Glossary

This is a list of terms that have a special meaning in Simics documentation.

• callback — A user-defined function installed so that it will be called from Simics, for example when a hap occurs.
• checkpoint — The state of simulation, saved as a number of files, that can be loaded to continue simulation at the point the checkpoint was saved.
• CLI — See Command Line Interface.
• Command Line Interface — The default Simics command-line (user interface). It uses a simple language implemented in Python, and is variously called the Simics "front end" or the "CLI".
• component — A component is typically the smallest hardware unit that can be used when configuring a real machine, and examples include motherboards, PCI cards, hard disks, and backplanes. Components are usually implemented in Simics using several configuration objects.
• configuration — A configuration is a description of a target architecture, and is loaded into Simics with the read-configuration command. Note that a configuration can also include the state of the target, and saved from within Simics using the write-configuration command, in which case it provides a portable checkpoint facility.
• configuration object — Simics's configuration system is object-oriented: a simulated machine is represented as a set of components, which are implemented by configuration objects.
• context — Each processor has a current context, which represents the virtual address space currently visible to code running on the processor.
• craff — Compressed Random Access File Format, used to save raw data for objects, such as disk dumps and target memory contents. A separate utility allows you to compress input data to Simics, such as target disk dumps, in a format that Simics can use directly.
• cycle — The smallest unit of time in Simics. When using Simics in its default mode, the cycle count is usually the same as the step count, but this can be changed in various ways to improve the fidelity of the simulation.
• device — A module modeling a hardware device.
• event — A Simics event occurs at some predefined point of simulated time. Time can be specified either as a number of steps on a simulated processor, or a number of simulated clock cycles.
• extension — A module which is not a device, but adds features to Simics; e.g., a statistics collection module.
• hap — Defined simulation or simulator state changes that may trigger callback functions.
• Hindsight™ — The technology utilized by Simics to achieve reverse execution.
• host addresses — Logical memory addresses on the host machine; i.e., addresses in the virtual memory space that the simulator itself is running in.
• host — The machine the simulator (Simics) is running on.
• logical addresses — Memory addresses corresponding to virtual or logical addresses on the target machine. These are typically translated by a memory management unit (MMU) to physical addresses.
• memory hierarchy — A user defined module that simulates caches and timing of memory operations. Interfaces to Simics using a memory transaction data structure.
• module — A dynamically linked library or a script that interfaces to Simics and extends the functionality of the simulator. A module is either an extension or a device.
• object — See Configuration object.
• physical addresses — Memory addresses corresponding to physical/real addresses on the target machine; i.e., the actual address bits put out on the memory bus.
• Python — An object oriented script language. See http://www.python.org for more info.
• reverse execution — Execution of a simulation backwards in simulated time.
• Simics console — The Simics console is a text console where you can issue commands to Simics, and where Simics will display status information, log messages, and printout from issued commands. The Simics console is available in all Simics user interfaces but in slightly different versions.
• SimicsFS — A "magic" feature allowing simple accesses from a simulated system to the host's real file system. Pre-configured disk dumps use the /host mount point for the magic device. This is presently only supported when running Solaris or Linux on the target machine.
• Simics object — See Configuration object.
• STC — Simulator Translation Cache. A mechanism in the simulator to improve simulator performance. Among other things, it filters uninteresting memory accesses from the memory hierarchy.
• step — An issued instruction that completes or causes an exception, or an external interrupt.
• system level instruction set simulation — The effect of every single instruction is simulated both on user and supervisor level. At any instruction, the simulation can be stopped and state can be inspected (and changed).
• target — The simulated machine.
• virtual machine — The simulated machine.
• workspace — The primary area where the user's files (scripts, checkpoints, source code, etc.) are placed.

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