CSI/MR-94-1
February 1994
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Product Datasheet:	CHORUS(R) Nucleus v3 r4.2

* Microkernel for operating systems
* Supports multiple-server and single-server operating system architectures
* Provides support for UNIX(R)-based, object-oriented and other operating
  systems
* Multiple concurrent threads per actor (process)
* (A)symmetric shared memory multi-processor hardware support
* Real-time functionality and behavior
* Fast, transparent location-independent message-passing system
* Provides both system space and user space actors (processes)
* Communication protocols, drivers and memory mappers external to Nucleus

The CHORUS(R) Nucleus v3 is the heart of the CHORUS family of
real-time distributed operating system products, notably the
CHORUS/MiX(TM) UNIX(R)-based operating systems.  The Nucleus provides
a unified virtual machine interface for various operating system
(subsystem) implementations.  Each subsystem implements one operating
system interface by using the Nucleus services.  Full low-level
services are provided to subsystems by the Nucleus working in
association with independent device drivers, network drivers,
communication protocols, and memory mappers (paging, swapping, etc.).
                                                          
The product of over thirteen years of refinement and in its fourth
generation, the Nucleus v3 is an extremely efficient, compact and
modular microkernel with a stable interface.  With the release in 1989
of CHORUS/MiX V.3.2, the Nucleus was the first microkernel supporting
commercial multi-server operating systems with performance equaling or
bettering native monolithic operating systems.  Performance-tuned to
ensure responsiveness and fast Inter-Process Communication, the
Nucleus integrates these essential services:

   o A real-time executive synchronizes and preemptively schedules
     priority-based tasks.
   o Modern, optimized Inter-Process Communication (asynchronous IPC
     and Remote Procedure Call (RPC)) mechanisms give efficient,
     transparent access to resources distributed on a network or bus.
   o A low-level hardware supervisor dynamically loads interrupt and
     trap handlers.
   o An advanced (optional) distributed virtual memory manager
     optimizes distributed object copying.
   o Support for symmetric and asymmetric shared memory multi-processors.

Main Benefits
   o Rapid real-time response to external events
   o Simple, dynamic migration, evolution and 
     reconfiguration of systems and servers
   o Easier, transparent distributed programming with 
     automatic localization
   o Fast, efficient local and remote RPC and IPC
   o Contains very short critical sections for 
     maximum interruptibility
   o Increased continuity of service via enabling 
     technologies for fault-tolerant servers
   o Enabling technologies for secure systems
   o Supports multiple operating systems 
     ("personalities") simultaneously
   o (A)symmetric shared memory multi-processing
   o Supports both system space and user space 
     actors
   o Dynamically loadable device drivers, not 
     embedded in the microkernel
   o Configurable kernel from 100 Kbytes
   static size to 250 Kbytes 

Real-time Executive
   o Light-weight threads (tasks/actors)
   o Preemptive priority-based scheduler
   o 256 priority levels, FIFO within levels
   o Multiple scheduling classes
   o Synchronization by events, mutexes, 
     semaphores and mini-messages
   o Execution control ("suspend", "resume")
   o Separate address spaces (optional)
   o Time-outs (optional)
   o Allocation/deallocation of memory
   o Dynamic kernel resource management
   o 11 microseconds Interrupt Latency
		on Compaq 486 at 50 Mhz
   o 22 microseconds Context Switch
		on Compaq 486 at 50 Mhz

Inter-Process Communication
   o Fast, distribution-transparent IPC and RPC
   o Optimized local and distant communication 
   o Small untyped messages for fastest processing 
     by network interfaces
   o Efficient low-overhead internal protocols
   o Automatic localization of distributed objects 
     providing transparent remote access to distant 
     objects as if they were local
   o A high level network interface independent of 
     specific network protocols
   o Supports standard or private network protocols
   o Supports multiple subnets, each with its own 
     network protocol
   o Various facilities for managing and broadcasting 
     to groups of destinations
   o At-most-once RPC semantics
   o Unique "light-weight RPC" performance 
     optimization
   o Abort propagation through RPC's

Distributed Virtual Memory Management
   o Optional: deconfigurable for real-time use
   o Demand-paged possibly over network so pages 
     are brought into memory only when needed
   o Separate, protected address spaces
   o Can share memory between different tasks
   o Supports linear, protected (segmented) and paged 
     virtual memory

Hardware Supervisor
   o Dynamic (de)install of interrupt, trap handlers
   o User-level handlers installable in system space
   o Multiple priority-ordered handlers
   o Dynamic resource allocation and management

Validation
   o Comprehensive suite of specially designed tests 
     for exercising both local and remote operations
   o Execution of CHORUS/MiX V.3.2 and/or 
     CHORUS/MiX V.4 validation tests (see 
     corresponding data sheets)

CHORUS Nucleus Calls

actorCreate	mutexInit	svCallConnect		threadDelay
actorDebugged	mutexRel	svCallDisConnect	threadDelete
actorDelete	mutexTry	svCheckUserSpace	threadList
actorExcept	portCreate	svCopyIn		threadLoadR
actorPi	port	Declare		svCopyOut		threadPriority
actorPriority	portDelete	svExcHandler		threadResume
actorSelf	portDisable	svItConnect		threadScheduler
actorStart	portEnable	svItDisConnect		threadSelf
actorStop	portLi		svLock			threadStoreR
chorusCtx	portMigrate	svLockInit		threadSuspend
chorusPTimer	portPi		svMaskAll		threadTimes
chorusSite	portUi		svMaskedLockGet		uiBuild
chorusTime	rgnAllocate	svMaskedLockRel		uiClear
chorusTimeL	rgnDup		svMsgHandler		uiCreate
chorusTod	rgnFree		svMsgHdlReply		uiDeclare
grpAllocate	rgnInit		svPagesAllocate		uiForget
grpPortInsert	rgnInitFromActor svPagesFree		uiIsLocal
grpPortRemove	rgnMap		svSpinLockGet		uiSite
ipcCall		rgnMapFromActor	svSpinLockRel		uiValid
ipcGetData	rgnSetInherit	svSpinLockTry		vmCopy
ipcReceive	rgnSetOpaque	svTimeOut		vmFlush
ipcReply	rgnSetPaging	svTimeOutL		vmFree
ipcRestore	rgnSetProtect	svTrapConnect		vmLock
ipcSave		rgnStat		svUnLock		vmPageSize
ipcSend		semPnAbort	svTrapDisConnect	vmStat
ipcSysInfo	semInit		svUnCTimeOut		vmPhysAddr
ipcTarget	semP		svUnMask		vmSetPar
lcFlush		semV		svUnMaskAll		vmUnLock
lcSetRights	sgFlush		svUnTimeOut	
lcStat		sgRead		threadAbort	
mpInit		sgStat		threadAborted	
mpReceive	sgSyncAll	threadBind	
mpSend		sgWrite		threadContext	
mutexGet	svAbortHandler	threadCreate	

Memory Mapper Calls
MpCreate 	MpPullIn	MpPushOut	MpRelease
MpGetAccess			

			

CHORUS Nucleus Deliverables
The license fee for the CHORUS Nucleus reference 
port includes delivery of the following items.

Nucleus Deliverables
CHORUS Nucleus, including the following major 
components:
   o Real-time Executive
   o Virtual Memory (VM)
   o Inter-Process Communication (IPC)
   o Supervisor
   o Networking protocols, Ethernet CHORUS 
     Network Protocol
System-dependent code:
   o Booting/initialization
   o Port to the Intel i386(R) and Intel i486(R), 
     COMPAQ(R) Deskpro and Portables family
   o Network driver: Excelan/Federal Tech Exos 
     205T, Western Digital 80x3
Include files and libraries for the above

Documentation Deliverables
Programmer's Reference Manual:
   o Nucleus Specification and Interface
   o Nucleus Programmer's Reference Manual
   o Nucleus From r4.0 to r4.2
   o Nucleus  Kernel Debugger User's Manual for 
     COMPAQ Deskpro
Implementation Guide:
   o Kernel Implementation Guide
   o Kernel Network Architecture
   o Kernel Network Devices Manager
   o Source Installation Guide

Build Environment Deliverables
   o Makefiles
   o Test programs
   o Porting utilities
   o Validation tests
   o Makedepend (determines file dependencies)
   o Uu (encode/decode tools)


Pre-requisites
   o Standard "C" development environment (make, 
     "C", ...)
   o Compilers: Glockenspiel C++ version 2.0A
   o A machine capable of reading QIC streamer 
     tapes
Recommended:
   o COMPAQ reference machine (see separate 
     configuration information)

Media
   o Source-code products: 60 MB QIC-24 streamer  
cartridge tape

	Reference Machine
	o COMPAQ 386/486

	Additional Ports
	o Motorola 680x0
	o Sun SPARC
	o MIPS R3000
	o Inmos Transputer T425/T805
			
--
CHORUS is a registered trademark of Chorus Systems.
CHORUS/MiX is a trademark of Chorus Systems.
UNIX is a registered trademark of Unix System Laboratories, a wholly-owned 
subsidiary of Novell, Inc.
All other trademarks mentioned belong to their respective owners.
Specifications are subject to change without notice.
(c)1989-1994, Chorus Systems.
CSI/MR-94-1.  Printed in USA.
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