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Glossary
APIC
Advanced Peripheral Interrupt Controller.Application loader
Loads an RT application into the INtime software memory area. The RT kernel then starts the application.Asynchronous
An asynchronous event occurs at times not coordinated with other events or times.
Big-endian
Multi-byte values stored in memory from the highest byte (the "big end") to the lowest byte. For example, the value 0x12345678 is stored as (0x12 0x34 0x56 0x78) in big-endian format.Basic I/O System. The layer of a Windows system that provides an asynchronous interface to the input/output system.
The same acronym is used in the context of PCs for the code that resides in ROM to supply OS-independent access to the computer’s hardware system.
BSOD
Blue Screen of Death. A casual term that refers to the blue-colored Windows screen that is displayed when the system crashes.
Ceiling
The smallest integer that is greater than or equal to the value.Client
An entity that establishes communications with one or more servers and requests data from, or sends data to, a server. An RT application can be a server for one conversation and a client for another.One of many cores in a multi-core processor.
When Hyper-threading is active, two logical cores use one physical core with possible interaction resulting in increased jitter, especially when a physical core is shared between Windows and INtime.
Datagram
A self-contained, independent entity of data carrying sufficient information to be routed from the source to the destination computer without reliance on earlier exchanges between this source and destination computer and the transporting network.Deadline
Time limit for when a task can complete processing an event.Descriptor
An 8-byte data structure taken from a descriptor table in memory. Descriptors provide information about memory segments, system call procedures, interrupt and trap handling procedures, and hardware-supported tasks.Determinism
Predictable response time. Enables threads to execute before their deadlines expire.Device controller
The hardware interface between the CPU or system bus and a device unit.Device driver
The software module with directly interfaces to a device controller.Domain Name System (DNS)
Domain Name Service, Internet system to translate names into IP addresses.
Encapsulation
A characteristic of object-based systems. The representation of an object is hidden from the user of that object. Only the object’s type manager can manipulate an object. Users of an object can manipulate the object only by invoking type manager functions for the object.End Of Interrupt
(EOI) A command sent to an interrupt controller to indicate that an interrupt handler has completed processing an interrupt.Event-driven
Applications that respond to interrupts as they occur; they do not waste time polling for interrupts.Exception handler
A program that receives control when an error is detected by the operating system or by the hardware.Exchange objects
Generic name for semaphores, mailboxes, and regions, that allow tasks to synchronize and communicate with each other.Execution state
Thread status. Thread execution states include: running, ready, asleep, suspended, or asleep-suspended.
Flat memory model
A memory addressing model where the CPU can access all of the available memory locations in a given address space. The code, data and stack occupy the same address space.
GDT
Global Descriptor Table. A CPU structure that contains descriptors for code, data, and other system elements.GUI
Graphical User Interface. A type of user interface that allows users to interact with the computer with images rather than text commands.
HAL
The Windows Hardware Abstraction Layer component.High-level ticks
The system high-level tick is 10ms. This is the unit of wait time for many calls. Parameters which convert to high-level ticks take a value in milliseconds and truncate it to the nearest 10ms multiple. For example 9 is truncated to 0ms, 21 is truncated to 20ms. For the purposes of calculating wait or sleep times, this value is then converted to a number of Low-level ticks. Also known as the Nucleus Tick Interval used by the INtime OS.Hive
In the Windows registry, a hive is a discrete body of keys, subkeys, and values that is rooted at the top of the registry hierarchy.Host
Individual computers on a network are called hosts in the INtime system architecture with shared memory & IO bus - one BIOS on one for more cores - one or more sockets. A host is typically one computer enclosure sharing a single reset.HPET
High-Precision Event Timer. A feature of many PC chipsets providing a 64-bit counter and programmable timer features.
IDT
Interrupt Descriptor Table. A CPU structure consisting of up to 256 entries, one for each interrupt vector to handle.Interrupt
A signal from a device to the CPU that indicates the occurrence of an external event.Interrupt handler
A system hardware-invoked handler that responds to an asynchronous interrupt from an external source, based on its entry number in the IDT. The handler takes control immediately and saves the register contents of the running thread so it can restart later.Interrupt level
An encoded value which represents a specific interrupt source, used in the interrupt system calls. Interrupt source can include interrupt signals on an interrupt controller (IRQs) or Message-Signaled Interrupts (MSIs) directly from certain devices.The time between a physical interrupt happening and the system beginning to execute the interrupt handler. A predictable worst-case response time to interrupt processing ensures that incoming data is handled before it becomes invalid.
Also called the "interrupt latency".
INtime application
A collection of Windows processes and RT processes that cooperate to perform useful work or provide a set of services to other software that performs useful work. See also RTAIPI
Inter-Processor Interrupt. Used to signal between individual processors in a multi-processor environment.ISA
Industry Standard Architecture. A legacy PC bus standard.1. Interrupt Service Routine. A function called by the CPU directly to handle an interrupt.
2. In-Service Register. A register in an interrupt controller which keeps track of which interrupt signals are currently active.
IST
Interrupt Service Thread. A thread which is reserved for handling a specific interrupt signal. Control is passed from the interrupt service routine (ISR) to the IST when there is work to be done.
Kernel clock tick
See Low-level ticks.
Multi-byte values stored in memory from the lowest byte (the "little end") to the highest byte. For example, the value 0x12345678 is stored as (0x78 0x56 0x34 0x12) in little-endian format.
Local Node Configuration library
Used to configure an INtime system programmatically for deployment.
A node is described with a LOCATION value when making API calls. A LOCATION value for a given node may not be the same on different modes.
The special value THIS_LOCATION always refers to the local node's location.
LONGMAX
The value of LONGMAX is 21474836471 (<code>0x7FFFFFFF</code>).Low-level Ticks
Kernel clock interrupts, or low-level ticks. This are the interrupts produced by the system timer hardware. The system timer period is configurable in the configuration utility. Also known as System timer ticks or Base System Clock.
MAC
Media Access Control. The lowest addressable level of network hierarchy, addressed by the MAC address. A MAC address is a 6-byte value.
Node
One OS controlled entity. An instance of the INtime or Windows kernel with associated applications and services. A node may span multiple cores. An INtime node can have multiple active INtime processes. An INtime process contains one or more SW threads and may contain other processes.NTX
Windows extension (NTX) calls: Windows uses these calls to communicate with the INtime kernel. NTX calls allow Windows applications to operate on objects created by, stored in, and controlled by the INtime kernel.
object
In INtime, an object is a reference to a resource. An object can be a thread, a data mailbox, an object mailbox, a message queue, a semaphore, a region, an alarm, memory, a file, an RSL, a reference object, etc.
PIC
Peripheral Interrupt Controller. A device which arbitrates between interrupt sources and delivers an interrupt signal to the CPU.Process
In INtime, the top level Process is a SW container with the resources for an executable instance of an application. An INtime process contains one or more SW threads and may contain other processes.
RSL
The RSL extension on a file denotes an INtime Real Time Library. This is the INtime equivalent of an DLL file in Windows.RTA
The RTA extension on a file denotes an INtime Real Time Application. This is the INtime equivalent of an EXE or executable file in Windows.
System
For INtime: The entire networked entity - one or more hosts - the extent of the GOBs net visibility.The number of seconds and microseconds since the INtime epoch (January 1st, 1978). System time is not subject to locale or time-zone adjustments.
On INtime for Windows the C library treats the system time value as UTC, and makes adjustments according to the value of the TZ environment variable for those calls which use local time. On INtime Distributed RTOS systems there is a configuration where the system time can be assumed to be local time instead of UTC.
System timer ticks
See Low-level ticks.
Thread
An INtime software object type managed by the kernel. An independently scheduled thread of execution. Multiple INtime threads can be contained in one INtime process. A thread is the same as a process in the general OS literature.
Workload
The entire set of software executing on a node, including all processes as well as the OS - i.e. all of the work done by a node.