ONORM ENV 41208 Teil.1-1991 信息系统互连．基本级虚拟终端．S模式窗体．第1部分：虚拟终端服务

标准号：ONORM ENV 41208 Teil.1-1991
中文标准名称：信息系统互连．基本级虚拟终端．S模式窗体．第1部分：虚拟终端服务
英文标准名称：Information systems interconnection - Basic class virtual terminal - S-mode forms - Part 1: Virtual terminal service
发布日期：1991/4/1 12:00:00
实施日期：1999/12/31 12:00:00
适用范围：This Functional Standard supports applications where the terminal representation of the interactive data stream is character oriented. The use of character repertoires which provide for simple graphics (eg videotex or line drawing) is optionally supported. Support is not provided for general graphics data streams (eg GKS) .This Functional Standard supports the use of coloured or monochrome screens for character representation together with a number of levels of emphasis (eg blink, reverse video, bold, underline, italic).This Functional Standard includes a specification of those capabilities of the Virtual Terminal that must be realised in the real terminal device. The details of the mapping between the terminal end system and real terminal devices through which these capabilities are realised is not part of this Functional Standard.This Functional Standard includes a minimum specification for the human interface with the terminal. Enhancements to this minimum specification are permitted in an implementation-dependent manner.This Functional Standard supports the use of an auxiliary monochrome or colour printer attached to the terminal configuration. This is intended for use as a means of printing screen contents or small amounts of information, not for bulk printing for which a file transfer oriented profile such as FTAM (ENV 41 204) or MHS (ENV 41 201/202) should be used.This Functional Standard supports a style of operation where the character data is displayed on a whole screen (paged) basis and there is a structure of fields to a page recognised by the VT service. A terminal system may be capable of holding more than one page of character information at any given time in local buffer storage. The total amount of sxich buffered information is available for update by the host subject to access controls in force at any given time, but, in addition, update by the terminal is governed by a number of entry rules (eg local validation rules) that the application may specify for data entry to the defined fields. In addition, facilities are available for local storage of the screen format and entry rules whicheffectively amount to a screen field template. Such screen templates may be either predefined for use at the terminal or may be down line loaded to the terminal from the host application. These facilities may be combined to potentially off-load a significant amount of host application terminal processing which is an important consideration when large numbers of terminals are involved. Other advantages of the use of this style of operation are reduced load on communications facilities and improved reaction time to users' actions.This Functional Standard includes support for a locally attached auxiliary printer as part of the terminal configuration. Support for this is mandatory but any given terminal configuration may not necessarily include such a printer. The specification includes a means for the terminal end to inform the host end whether or not a printer is attached. No further means is provided for management of the printer as a resource shared amongst a population of terminal systems.