1-1 A Brief History of FORTRAN/Fortran
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(Thanks to John Nebel for the nice description of a FORTRAN's user
point of view)
A note on names
---------------
Both forms of the language name, FORTRAN and Fortran, are used.
In this text, older versions (before and including 1977) of the
language will be referred to as FORTRAN, post-1977 ones will be
referred to as 'Fortran 90', 'Fortran 95' etc.
The development of FORTRAN I
----------------------------
The first FORTRAN compiler was a milestone in the history of computing,
at that time computers had very small memories (on the order of 15KB,
it was common then to count memory capacities in bits), they were slow
and had very primitive operating systems (if they had them at all).
At those days it seemed that the only practical way is to program in
assembly language.
The pioneers of FORTRAN didn't invent the idea of writing programs in a
High Level Language (HLL) and compiling the source code to object code
with an optimizing compiler, but they produced the first successful HLL.
They designed an HLL that is still widely used, and an optimizing compiler
that produced very efficient code, in fact the FORTRAN I compiler held
the record for optimizing code for 20 years!
This wonderful first FORTRAN compiler was designed and written from
scratch in 1954-57 by an IBM team lead by John W. Backus and staffed with
super-programmers like Sheldon F. Best, Harlan Herrick, Peter Sheridan,
Roy Nutt, Robert Nelson, Irving Ziller, Richard Goldberg, Lois Haibt
and David Sayre. By the way, Backus was also system co-designer of the
computer that run the first compiler, the IBM 704.
The new invention caught quickly, no wonder, programs computing nuclear
power reactor parameters took now hours instead of weeks to write, and
required much less programming skill. Another great advantage of the new
invention was that programs now became portable. Fortran won the battle
against Assembly language, the first in a series of battles to come,
and was adopted by the scientific and military communities and used
extensively in the Space Program and military projects.
The phenomenal success of the FORTRAN I team, can be attributed in part
to the friendly non-authoritative group climate. Another factor may be
that IBM management had the sense to shelter and protect the group,
even though the project took much more time than was first anticipated.
FORTRAN II, III, IV and FORTRAN 66
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FORTRAN II (1958) was a significant improvement, it added the capability
for separate compilation of program modules, assembly language modules
could also be 'linked loaded' with FORTRAN modules.
FORTRAN III (1958) was never released to the public. It made possible
using assembly language code right in the middle of the FORTRAN code.
Such "inlined" assembly code can be more efficient, but the advantages
of an HLL are lost (e.g. portability, ease of use).
FORTRAN IV (1961) was a 'clean up' of FORTRAN II, improving things
like the implementation of the COMMON and EQUIVALENCE statements,
and eliminating some machine-dependant language irregularities.
A FORTRAN II to FORTRAN IV translator was used to retain backward
compatibility with earlier FORTRAN programs.
On May 1962 another milestone was traversed, an ASA committee started
developing a standard for the FORTRAN language, a very important step
that made it worthwhile for vendors to produce FORTRAN systems for
every new computer, and made FORTRAN an even more popular HLL.
The new ASA standard was published in 1966, and was known accordingly
as FORTRAN 66, it was the first HLL standard in the world.
FORTRAN 77 standard
-------------------
Formally outdated many years ago, compilers for FORTRAN 77 are still
used today, mainly to re-compile legacy code.
FORTRAN 77 added:
o DO loops with a decreasing control variable (index).
o Block if statements IF ... THEN ... ELSE ... ENDIF.
Before F77 there were only IF GOTO statements.
o Pre-test of DO loops. Before F77 DO loops were always
executed at least once, so you had to add an IF GOTO
before the loop if you wanted the expected behaviour.
o CHARACTER data type. Before F77 characters were always
stored inside INTEGER variables.
o Apostrophe delimited character string constants.
o Main program termination without a STOP statement.
The next Fortran standard (fortran 90) was published too many years
after Fortran 77 was out, allowing other programming languages to
evolve and compete with Fortran. For example, the system-programming
language C, and its evolved variant C++, became more popular in the
traditional strongholds of Fortran: the scientific and engineering
worlds, in spite of being non-computationally oriented.
The delay in publishing a new standard can be attributed in part
to political reasons as testified by Brian Meek in:
The Fortran Saga
Fortran 90 standard
-------------------
A new standard has been designed and widely implemented in recent years.
It is unofficially called Fortran 90, and adds many powerful extensions
to FORTRAN 77. The language in its present form is competitive with
computer languages created later (e.g. C).
Fortran 90 added:
o Free format source code form (column independent)
o Modern control structures (CASE & DO WHILE)
o Records/structures - called "Derived Data Types"
o Powerful array notation (array sections, array operators, etc.)
o Dynamic memory allocation
o Operator overloading
o Keyword argument passing
o The INTENT (in, out, inout) procedure argument attribute
o Control of numeric precision and range
o Modules - packages containing variable and code
Fortran 95 standard
-------------------
Fortran 95 added some minor improvements to the Fortran 90 standard.
Fortran from a user point of view
---------------------------------
... yes, it was FORTRAN on the IBM 7094. [I] Have written volumes
of Fortran code and have suffered through "it ought to be written
in assembly language", "it ought to be written in PL/1", "it ought
to be written in COBOL", "it ought to be written in Pascal", "it
ought to be written in C", etc. depending on what generation of
programmers was doing the criticizing.
A few years ago, in the COBOL era, one of the users resorted to
replying to questioners by showing them some function they liked
and asking "you tell me, what language was that written in?"
... It was good to see someone else cognizant of the language's
obvious merits.
Bibliography on FORTRAN history
-------------------------------
Annals of History of Computing, 6, 1, January, 1984 (whole issue).
Programming Systems and Languages (S. Rosen ed.), McGraw Hill,
1967, pp 29-47 (this is Backus's original paper).
History of Programming Languages (R.L. Wexelblat ed.),
Academic Press, 1981, pp 25-74.
A summary appears in vol. 5 of the Encyclopedia of Science
and Technology, Academic Press, 1986, under 'Fortran'.
and in Chapter 1 of Fortran 90 Explained (Oxford, 1990).
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| FORTRAN IS THE COMPUTING LANGUAGE OF CHOICE |
+-------------------------------------------------+
A much more important factor in the social movement than those already mentioned was the ever-increasing influence of women. This probably stood at the lowest point to which it has ever fallen, during the classic age of Greek life and thought. In the history of Thucydides, so far as it forms a connected series of events, four times only during a period of nearly seventy years does a woman cross the scene. In each instance her apparition only lasts for a moment. In three of the four instances she is a queen or a princess, and belongs either to the half-barbarous kingdoms of northern Hellas or to wholly barbarous Thrace. In the one remaining instance208— that of the woman who helps some of the trapped Thebans to make their escape from Plataea—while her deed of mercy will live for ever, her name is for ever lost.319 But no sooner did philosophy abandon physics for ethics and religion than the importance of those subjects to women was perceived, first by Socrates, and after him by Xenophon and Plato. Women are said to have attended Plato’s lectures disguised as men. Women formed part of the circle which gathered round Epicurus in his suburban retreat. Others aspired not only to learn but to teach. Arêtê, the daughter of Aristippus, handed on the Cyrenaic doctrine to her son, the younger Aristippus. Hipparchia, the wife of Crates the Cynic, earned a place among the representatives of his school. But all these were exceptions; some of them belonged to the class of Hetaerae; and philosophy, although it might address itself to them, remained unaffected by their influence. The case was widely different in Rome, where women were far more highly honoured than in Greece;320 and even if the prominent part assigned to them in the legendary history of the city be a proof, among others, of its untrustworthiness, still that such stories should be thought worth inventing and preserving is an indirect proof of the extent to which feminine influence prevailed. With the loss of political liberty, their importance, as always happens at such a conjuncture, was considerably increased. Under a personal government there is far more scope for intrigue than where law is king; and as intriguers women are at least the209 equals of men. Moreover, they profited fully by the levelling tendencies of the age. One great service of the imperial jurisconsults was to remove some of the disabilities under which women formerly suffered. According to the old law, they were placed under male guardianship through their whole life, but this restraint was first reduced to a legal fiction by compelling the guardian to do what they wished, and at last it was entirely abolished. Their powers both of inheritance and bequest were extended; they frequently possessed immense wealth; and their wealth was sometimes expended for purposes of public munificence. Their social freedom seems to have been unlimited, and they formed combinations among themselves which probably served to increase their general influence.321 The old religions of Greece and Italy were essentially oracular. While inculcating the existence of supernatural beings, and prescribing the modes according to which such beings were to be worshipped, they paid most attention to the interpretation of the signs by which either future events in general, or the consequences of particular actions, were supposed to be divinely revealed. Of these intimations, some were given to the whole world, so that he who ran might read, others were reserved for certain favoured localities, and only communicated through the appointed ministers of the god. The Delphic oracle in particular enjoyed an enormous reputation both among Greeks and barbarians for guidance afforded under the latter conditions; and during a considerable period it may even be said to have directed the course of Hellenic civilisation. It was also under this form that supernatural religion suffered most injury from the great intellectual movement which followed the Persian wars. Men who had learned to study the constant sequences of Nature for themselves, and to shape their conduct according to fixed principles of prudence or of justice, either thought it irreverent to trouble the god about questions on which they were competent to form an opinion for themselves, or did not choose to place a well-considered scheme at the mercy of his possibly interested responses. That such a revolution occurred about the middle of the fifth century B.C., seems proved by the great change of tone in reference to this subject which one perceives on passing from Aeschylus to Sophocles. That anyone should question the veracity of an oracle is a supposition which never crosses the mind of the elder dramatist. A knowledge of augury counts among the greatest benefits222 conferred by Prometheus on mankind, and the Titan brings Zeus himself to terms by his acquaintance with the secrets of destiny. Sophocles, on the other hand, evidently has to deal with a sceptical generation, despising prophecies and needing to be warned of the fearful consequences brought about by neglecting their injunctions. The stranger had a pleasant, round face, with eyes that twinkled in spite of the creases around them that showed worry. No wonder he was worried, Sandy thought: having deserted the craft they had foiled in its attempt to get the gems, the man had returned from some short foray to discover his craft replaced by another. “Thanks,” Dick retorted, without smiling. When they reached him, in the dying glow of the flashlight Dick trained on a body lying in a heap, they identified the man who had been warned by his gypsy fortune teller to “look out for a hidden enemy.” He was lying at full length in the mould and leaves. "But that is sport," she answered carelessly. On the retirement of Townshend, Walpole reigned supreme and without a rival in the Cabinet. Henry Pelham was made Secretary at War; Compton Earl of Wilmington Privy Seal. He left foreign affairs chiefly to Stanhope, now Lord Harrington, and to the Duke of Newcastle, impressing on them by all means to avoid quarrels with foreign Powers, and maintain the blessings of peace. With all the faults of Walpole, this was the praise of his political system, which system, on the meeting of Parliament in the spring of 1731, was violently attacked by Wyndham and Pulteney, on the plea that we were making ruinous treaties, and sacrificing British interests, in order to benefit Hanover, the eternal millstone round the neck of England. Pulteney and Bolingbroke carried the same attack into the pages of The Craftsman, but they failed to move Walpole, or to shake his power. The English Government, instead of treating Wilkes with a dignified indifference, was weak enough to show how deeply it was touched by him, dismissed him from his commission of Colonel of the Buckinghamshire Militia, and treated Lord Temple as an abettor of his, by depriving him of the Lord-Lieutenancy of the same county, and striking his name from the list of Privy Councillors, giving the Lord-Lieutenancy to Dashwood, now Lord Le Despencer. "I tell you what I'll do," said the Deacon, after a little consideration. "I feel as if both Si and you kin stand a little more'n you had yesterday. I'll cook two to-day. We'll send a big cupful over to Capt. McGillicuddy. That'll leave us two for to-morrer. After that we'll have to trust to Providence." "Indeed you won't," said the Surgeon decisively. "You'll go straight home, and stay there until you are well. You won't be fit for duty for at least a month yet, if then. If you went out into camp now you would have a relapse, and be dead inside of a week. The country between here and Chattanooga is dotted with the graves of men who have been sent back to the front too soon." "Adone do wud that—though you sound more as if you wur in a black temper wud me than as if you pitied me." "Wot about this gal he's married?" "Don't come any further." "Davy, it 'ud be cruel of us to go and leave him." "Insolent priest!" interrupted De Boteler, "do you dare to justify what you have done? Now, by my faith, if you had with proper humility acknowledged your fault and sued for pardon—pardon you should have had. But now, you leave this castle instantly. I will teach you that De Boteler will yet be master of his own house, and his own vassals. And here I swear (and the baron of Sudley uttered an imprecation) that, for your meddling knavery, no priest or monk shall ever again abide here. If the varlets want to shrieve, they can go to the Abbey; and if they want to hear mass, a priest can come from Winchcombe. But never shall another of your meddling fraternity abide at Sudley while Roland de Boteler is its lord." "My lord," said Edith, in her defence, "this woman has sworn falsely. The medicine I gave was a sovereign remedy, if given as I ordered. Ten drops would have saved the child's life; but the contents of the phial destroyed it. The words I uttered were prayers for the life of the child. My children, and all who know me, can bear witness that I have a custom of asking His blessing upon all I take in hand. I raised my eyes towards heaven, and muttered words; but, my lord, they were words of prayer—and I looked up as I prayed, to the footstool of the Lord. But it is in vain to contend: the malice of the wicked will triumph, and Edith Holgrave, who even in thought never harmed one of God's creatures, must be sacrificed to cover the guilt, or hide the thoughtlessness of another." "Aye, Sir Treasurer, thou hast reason to sink thy head! Thy odious poll-tax has mingled vengeance—nay, blood—with the cry of the bond." HoME古一级毛片免费观看
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