The Advanced Video Attribute Terminal Assembler and Recreator (AVATAR) protocol is a system of
escape sequence
In computer science, an escape sequence is a combination of characters that has a meaning other than the literal characters contained therein; it is marked by one or more preceding (and possibly terminating) characters.
Examples
* In C and ma ...
s occasionally used on
bulletin board systems (BBSes). Its basic level was designed explicitly as a compression of the much longer
ANSI escape code
ANSI escape sequences are a standard for in-band signaling to control cursor location, color, font styling, and other options on video text terminals and terminal emulators. Certain sequences of bytes, most starting with an ASCII escape char ...
s, and can thus render colored text and
artwork faster over slow connections. Even when the terminal didn't understand it, the data on disk could use the AVATAR format and so take up less space.
AVATAR was adapted to Advanced Zansi/Avatar Terminal Handshaking Output Transfer Handler (AZATHOTH). It was never implemented but was included as zazt.sys.
The basic protocol is defined by
FidoNet technical standard proposal FSC-0025.
Avatar was later extended in late 1989 to AVT/0
FSC-0037 - AVT/0 extensions
/ref> (sometimes referred to as AVT/0+) which included facilities to scroll areas of the screen (useful for split screen chat, or full screen mail writing programs), as well as more advanced pattern compression. These extensions were not convertible directly into sequences understood by existing ANSI terminals but instead mirrored extra facilities available in the IBM PC BIOS.
Avatar was originally implemented in the Opus BBS, but later popularised by RemoteAccess
RemoteAccess is a DOS Bulletin Board System (BBS) software package written by Andrew Milner and published by his company Wantree Development in Australia. RemoteAccess was written in Turbo Pascal with some Assembly Language routines. RemoteAccess ...
. RemoteAccess came with a utility, AVTCONV that allowed for easy translation of ANSI documents into Avatar helping its adoption.
Scope
FSC-0025 defines a compression for:
* terminal text attributes: blink, background and foreground 3-bit color.
* repeated bytes (run-length encoding)
* cursor position commands
* terminal clear command (CSI 2 J)
FSC-0037 defines:
* an insert-mode switch
* insert mode deletion (delete and scroll left)
* scroll up/down commands
* area fill/clear commands (run-length encoding in 2D)
* repeat multiple characters (run-length encoding)
See also
*ANSI escape code
ANSI escape sequences are a standard for in-band signaling to control cursor location, color, font styling, and other options on video text terminals and terminal emulators. Certain sequences of bytes, most starting with an ASCII escape char ...
*ANSI art
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organi ...
References
{{microcompu-stub
Bulletin board systems
FidoNet
Computer-related introductions in 1988