Glossary

iTivity™ User Guide Glossary

Attended Agent

An iTivity agent that allows users of Windows computers to connect to an hyperserver and request support. The support request is then displayed in the iTivity console. The attended agent creates an "on-demand" rather than a persistent connection. It also allows users to chat with an administrator responding to their help request. Users can install the agent on Windows computer through one-click install.

Copy Rectangle Encoding

Used when the client already has the same pixel data elsewhere in its framebuffer. The encoding simply consists of an X,Y coordinate. This gives a position in the framebuffer from which the client can copy the rectangle of pixel data.

Corre Encoding

CoRRE is a variant of RRE, where the largest rectangle sent is no larger than 255x255 pixels. If a rectangle is larger than this, the server splits it up and sends several smaller RFB rectangles. Within each of these smaller rectangles, a single byte is used to represent the dimensions of the subrectangles.

Encoding

Refers to how a rectangle of pixel data will be sent on the wire. Every rectangle of pixel data is prefixed by a header giving the X,Y position of the rectangle on the screen, the width and height of the rectangle, and an encoding type that specifies the encoding of the pixel data.

Hextile Encoding

A variation of CoRRE encoding. With Hextile encoding, rectangles are split up into 16x16 titles. This allows the dimensions of the subrectangles to be specified in 4 bits each, 16 bits total. Each tile is coded as either raw pixel data or as a variation on RRE, specified by a type byte for each tile.

Host

A computer being viewed or remotely controlled another computer. In iTivity, the agent computers are considered hosts when viewed by an console user.

Agent

An iTivity component that allows secure connections to an hyperserver and remote viewing and control of the computer on which it is installed. This computer is referred to as an agent computer.

Hyperserver

The main engine of iTivity. The hyperserver creates and coordinates secure connections over the Internet using 1028-bit encryption. It also provides "reverse connections" allowing remote users to connect back to your hyperserver over the Internet without having to change firewall settings. The hyperserver is available in Windows and Linux versions.

iTivity Console

The component of iTivity that provides the interface for administrators and support personnel to view and manage agent computers. The iTivity console can be installed on the same computer as the hyperserver software or on a different computer either within or outside a firewall.

Mouse Definition

A specifier that defines a combination of mouse buttons in the form of the word Mouse (or any initial part of it), followed immediately by a decimal number representing the state of the mouse buttons in a bitwise fashion. The least significant bit is button 1.

For example, Mouse0 corresponds to all mouse buttons released (i.e. 0 in every bit position). Mo1 corresponds to all mouse buttons released, apart from button 1, which is pressed (i.e. 0 in every bit position except the first one). M2 is button 2 only, while M3 is both button 2 and button 3 pressed together (i.e., both bit positions 0 and 1 combining to give 3). M4 is button 3 only.

One-Click Install

The method of installing an iTivity agent from a web page, desktop icon, or e-mail simply by clicking a single link. The agent installation settings are pre-configured by an administrator.

Polling

A communications technique that determines when a terminal is ready to send data. The computer continually interrogates its connected terminals in a round robin sequence. If a terminal has data to send, it sends back an acknowledgement and the transmission begins. Contrast with interrupt-driven, in which the terminal generates a signal when it has data to send.

Protocol

Rules governing transmitting and receiving of data.

Raw Encoding

The simplest encoding type, raw pixel data consists of n pixel values where n is the width multiplied by the height of the rectangle. These values represent each pixel in left-to-right scanline order.

Remote

Term used to describe a computer running the iTivity Manager. It may be used by a help desk engineer, system administrator, or anyone who can help another user.

Remote FrameBuffer (RFB)

A simple protocol for remote access to graphical user interfaces. It allows a server to update the framebuffer displayed on a viewer. Because this protocol works at the framebuffer level, it is potentially applicable to all operating systems, windowing systems and applications.

RRE Encoding

(Rise-and-run-length encoding) A two-dimensional analogue of run-length encoding. RRE-encoded rectangles are compressed and arrive at the client in a form that can be rendered immediately and efficiently by simple graphic engines.

Server-Side Definition

The sequence of X key syms that represents the sequence of key presses to send to the server when a user presses the key defined by the viewer-side definition. When considered as part of a key map command, it's the section following the colon.

Sockets

A name given to the package of sub-routines that provide access to TCP/IP on most systems.

Specifier

An expression of a value or sequence of values, either as hexadecimal (e.g., 0xffe9, 0x60), ascii (e.g., 'x', 'A string'), a label (e.g., K_Delete) or a mouse definition (e.g., M3, Mouse0). The number of labels understood is limited and is displayed in the X Keys menu of the key map dialog box.

Support Module

An iTivity component you can install from the iTivity web site. This component contains all the files an administrator needs to create web pages or e-mail links to allow one-click install of the iTivity agents.

Unattended Agent

An iTivity agent that provides for remote viewing and administration of Windows or Linux systems. On Windows, this agent can be installed from a web link or via a distribution MSI. It provides a persistent, "always-on" connection. If the connection is lost, the unattended agent automatically attempts to reconnect.

Viewer

A thin client that actually draws the display on your screen.

Viewer Side Definition

The sequence of keywords and specifiers that represents which key (or key combination) a user should press to activate the key map command. It's the section preceding the colon.

Virtual Key Code

An 8-bit number that identifies one key on a particular keyboard. Each keyboard calculates it individually and so varies from one to another i.e., on one keyboard the space key may be 0x31, but it should not be assumed that it is the same on another. Hence, key maps defined in terms of virtual keycodes are keyboard-specific.

VNC

Developed by the ORL research team, a software-only version of ORL' s ATM network computer that allowed for greater mobility. Since this viewer provided the user with virtual desktops that can be created or deleted as needed, the system was named Virtual Network Computing, or VNC for short.

zlib encoding

Provides standard compression capabilities based on the deflate/inflate algorithms. Generally, zlib encoding can represent screen updates with half the space or less needed by hextile. On slow connections, such as modem or ISDN links, this can provide a substantial performance improvement.

WebTunnel

An iTivity feature that allows console users to see and interact with network applications running on a connected agent computer. WebTunnel discovers available network applications and provides remote access to those applications through an encrypted SSL connection.

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