On-line Real-time Systems

Real-time means immediately, now! Military leaders, scientists, top management very frequently require knowledge of current information, immediately, to make crucial time-sensitive decisions. Quite often it becomes imperative that dangerous or costly time-lags be eliminated. The time between the happpening of an important event and the discovery by executives that it has occurred is required to be insignificant to fulfil the concept of real-time. The cognizance of the event must be "in time" to control the conclusion of the event itself. More formal definitions of real-time are given below, as are the steps of the development of this capability by computer systems and the new advances in information technology. Action must be predicted presently on "occurring" changes rather than on tomorrow's predictions, yesterday's analyses, or last year's disasters. It has been estimated by many of the industry's leaders that by 1978 substantially all data-processing systems will be on-line real-time (OLRT). Cost analyses will most often be based on the question, "Can we afford not to have OLRT in our operations?"" Tomorrow's fierce international competition in science, business, military systems, and education force the quickened pace of progress.

聯(lián)機(jī)實(shí)時(shí)系統(tǒng)

實(shí)時(shí)的意思是立即、現(xiàn)在！軍事領(lǐng)導(dǎo)人、科學(xué)家、高級管理人員都極為經(jīng)常地需要立即知道目前的情況，以作出對時(shí)間敏感的重要判定。常常必須避免帶來危險(xiǎn)的、代價(jià)高昂的時(shí)間上的延誤。要實(shí)現(xiàn)實(shí)時(shí)這個(gè)概念，從重大事件的發(fā)生到執(zhí)行人員發(fā)現(xiàn)這一事件已經(jīng)發(fā)生之間的時(shí)間差必須是微不足道的。對于事件的觀察必須及時(shí)，這樣才能對事件本身的結(jié)局加以控制。下面對實(shí)時(shí)這一概念進(jìn)行了更為正式的定義，也給出了由計(jì)算機(jī)系統(tǒng)來發(fā)展這種能力的步驟以及信息技術(shù)上的新進(jìn)展。必須即刻對“正在發(fā)生著”的變化的作用進(jìn)行預(yù)測，而不是要你去預(yù)測明天，或者去分析昨天或去年的災(zāi)難的后果。許多工業(yè)界的領(lǐng)導(dǎo)人已經(jīng)估計(jì)到，到1978年，所有的數(shù)據(jù)處理系統(tǒng)大體上都將是聯(lián)機(jī)實(shí)時(shí)（OLRT)系統(tǒng)。成本分析的根據(jù)往往是這樣一個(gè)問題：“我們操作時(shí)如果沒有OLRT能行嗎？”將來在科學(xué)，商業(yè)、軍事系統(tǒng)和教育方面極為激烈的國際競爭迫使我們加快前進(jìn)的步伐。

Real-time is the necessary base for time-sharing systems (TSS), and time sharing makes real-time possible for every size and type of business firm, scientific or educational research unit. For, OLRT-TSS provides every individual the opportunity to originate, retrieve, or in innumerable ways to utilize data and information in "conversation mode" with multiple-direction flows whenever a response is required and in the quantum of time desired.

Because modern computers are too fast to serve only one person at a time, to make economic sense the control computer must be shared. Segments of computing time must be made available to many users.

實(shí)時(shí)是分時(shí)系統(tǒng)(TSS)的必要基礎(chǔ)，而分時(shí)又能使實(shí)時(shí)為各種大小商號、科學(xué)研究與教育研究單位所使用。因?yàn)?，OLRT-TSS給每一個(gè)人提供了這樣的機(jī)會，即凡在需要作出而且還要在需要的時(shí)間限度內(nèi)作出響應(yīng)時(shí)，均可以與多方向流“進(jìn)行會話的方式”首創(chuàng)、檢索，或以多種多樣的方式利用數(shù)據(jù)和信息。

因?yàn)楝F(xiàn)代計(jì)算機(jī)的運(yùn)行速度快得能在同一時(shí)間內(nèi)為不止一個(gè)人服務(wù)，因而，從經(jīng)濟(jì)上著想，控制計(jì)算機(jī)必須共同使用。必須使各分段計(jì)算時(shí)間都能為許多用戶利用。