The purpose of this document is to identify and define certain terminology that appears frequently in the documents of the SCHEMESTATION project. This document is assumed to evolve during the project.
| Term | Definition |
| SCHEMESTATION | An intended operating system under development in HUT CS lab.
|
| CDK | core domain kernel agent
|
| DKI | domain kernel interface agent
|
| TCA | Terminal controlling agent; that part of a terminal driver
that runs on the top of the SCHEMESTATION virtual machine.
|
| [SCHEMESTATION] byte code | (1) The input language of the SCHEMESTATION virtual machine.
(2) Any specific word of the language, i.e. a sequence
of byte code instructions in symbolic or binary form.
|
| [SCHEMESTATION] domain | (1) A region of execution, inside which all executing agents
share a local address space and have mutually different local
addresses. (2) A workstation running the SCHEMESTATION operating system.
(3) Any other software/hardware unit that has the external
behaviour of the SCHEMESTATION operating system.
|
| actor | agent
|
| agent | An individual process, capable of sending and receiving messages.
|
| core domain kernel agent | The special agent controlling a SCHEMESTATION domain as a whole.
Commonly abbreviated as CDK.
|
| core file | In the SCHEMESTATION context, a UNIX file system file that contains the internal state of a domain that has been previously shut down. |
| domain kernel interface agent | A normal agent that interfaces between the local CDK and
the rest of the world. Commonly abbreviates as DKI.
|
| external agent | A process
that does not run inside any SCHEMESTATION domain but
on a non-SCHEMESTATION platform, and provides services to SCHEMESTATION domains
from there via the SCHEMESTATION external agent interface.
|
| garbage collection | The technical act of reclaiming physical storage in a memory system
that corresponds to objects that in principle reside in a heap
but that cannot be referenced any more.
|
| heap | (1) Any list-structured amount of data. (2) The abstract data type
containing all list-structured amounts of data, and nothing else.
(3) A software unit that is able to maintain the heap ADT on the
top of a conventional linear memory architecture.
|
| kernel-implementing agent | Any agent that runs on the top of the SCHEMESTATION virtual machine
and can be considered a part of the kernel implementation.
The only kernel-implementing agent currently is the DKI,
but others could exist if, for example, the functionality
of DKI were split into many smaller agents.
|
| migration | The act of an agent changing its domain of execution during its
lifetime.
|
| persistence | In the SCHEMESTATION context, persistence denotes the fact that
SCHEMESTATION domain instances can be completely shut down and later
revived so, that the internal state of the domain immediately
after the wake-up is equivalent to the state just before the
shutdown, to the applicable extent.
|
| special agent | An agent that cannot run as a standard [user] program on the
top of the SCHEMESTATION virtual machine due to e.g. needs to
communicate directly with hardware. For example, the
core domain kernel agent (CDK) is a special agent, and device
drivers are also.
|
| transparent migration | Migration that does not create any qualitative changes in the
environment observed by the subject of the migration, or any other
normal agents.
|
| virtual machine | Software unit that is able to execute programs described in a low-level
language, e.g. as sequences of byte code instructions.
|