المرجع الالكتروني للمعلوماتية
المرجع الألكتروني للمعلوماتية

الرياضيات
عدد المواضيع في هذا القسم 9761 موضوعاً
تاريخ الرياضيات
الرياضيات المتقطعة
الجبر
الهندسة
المعادلات التفاضلية و التكاملية
التحليل
علماء الرياضيات

Untitled Document
أبحث عن شيء أخر


John Warner Backus  
  
43   01:15 مساءً   date: 25-1-2018
Author : J W Backus
Book or Source : The History of Fortran I, II and III, History of Programming Languages
Page and Part : ...


Read More
Date: 17-1-2018 34
Date: 8-2-2018 157
Date: 17-2-2018 158

Born: 3 December 1924 in Philadelphia, Pennsylvania, USA

Died: 17 Mar 2007 in Ashland, Oregon, USA


John Backus spent his first years in Wilmington, Delaware and attended the Hill School in Pottstown, Pennsylvania. He graduated in 1942 although according to his own account he did not take his studies at Hill School too seriously:-

I flunked out every year. I never studied. I hated studying. I was just goofing around. It had the delightful consequence that every year I went to summer school in New Hampshire where I spent the summer sailing and having a nice time.

He entered the University of Virginia to study chemistry at his father's request. However he was no more diligent than at school and in 1943 his studies were terminated. That year he joined the army.

In the army he took medical training, working in an Atlantic City hospital in a neurosurgery ward that treated head wounds. Strangely he was found to have a bone tumour and had a plate fitted in his head. A medical training seemed to be the right direction for Backus but after nine months of medical school he gave this up too:-

I hated it. They don't like thinking in medical school. They memorize - that's all they want you to do. You must not think.

Again without any idea which direction he should take, he took an apartment in New York. He describes (see [2]) what happened next:-

I really did not know what the hell I wanted to do with my life. I decided that what I wanted was a good hi fi set because I liked music. In those days, they did not really exist so I went to a radio technicians' school. I had a very nice teacher - the first good teacher I ever had - and he asked me to cooperate with him and compute the characteristics of some circuits for a magazine.

I remember doing relatively simple calculations to get a few points on a curve for an amplifier. It was laborious and tedious and horrible, but it got me interested in math. The fact that it had an application - that interested me.

Backus entered Columbia University, New York to study mathematics. He graduated in 1949. Just before he graduated he visited the IBM Computer Center on Madison Avenue. When he told the guide that he was looking for a job she told him to talk to a director.

I said no, I could not. I looked sloppy and dishevelled. But she insisted and so I did. I took a test and did OK.

Backus joined IBM as a programmer in 1950. He is the inventor of FORTRAN, the first high level computer language to be developed. It became commercially available in 1957. Describing his early work on FORTRAN, Backus said:-

We did not know what we wanted and how to do it. It just sort of grew. The first struggle was over what the language would look like. Then how to parse expressions - it was a big problem and what we did looks astonishingly clumsy now....

In 1959 he invented what is now called the Backus Naur Form (BNF), a standard notation to describe the syntax of a high level programming language. (Peter Naur invented a similar scheme in 1960)

His third major contribution to computer science was to develop a functional programming language called FP, which advocates a mathematical approach to programming.


 

Books:

  1. J W Backus, The History of Fortran I, II and III, History of Programming Languages (New York, 1981).

Articles:

  1. D Shasha and C Lazere, John Backus, in Out of their minds : The lives and discoveries of 15 great computer scientists (New York, 1995), 1-4.

 




الجبر أحد الفروع الرئيسية في الرياضيات، حيث إن التمكن من الرياضيات يعتمد على الفهم السليم للجبر. ويستخدم المهندسون والعلماء الجبر يومياً، وتعول المشاريع التجارية والصناعية على الجبر لحل الكثير من المعضلات التي تتعرض لها. ونظراً لأهمية الجبر في الحياة العصرية فإنه يدرّس في المدارس والجامعات في جميع أنحاء العالم. ويُعجب الكثير من الدارسين للجبر بقدرته وفائدته الكبيرتين، إذ باستخدام الجبر يمكن للمرء أن يحل كثيرًا من المسائل التي يتعذر حلها باستخدام الحساب فقط.وجاء اسمه من كتاب عالم الرياضيات والفلك والرحالة محمد بن موسى الخورازمي.


يعتبر علم المثلثات Trigonometry علماً عربياً ، فرياضيو العرب فضلوا علم المثلثات عن علم الفلك كأنهما علمين متداخلين ، ونظموه تنظيماً فيه لكثير من الدقة ، وقد كان اليونان يستعملون وتر CORDE ضعف القوسي قياس الزوايا ، فاستعاض رياضيو العرب عن الوتر بالجيب SINUS فأنت هذه الاستعاضة إلى تسهيل كثير من الاعمال الرياضية.

تعتبر المعادلات التفاضلية خير وسيلة لوصف معظم المـسائل الهندسـية والرياضـية والعلمية على حد سواء، إذ يتضح ذلك جليا في وصف عمليات انتقال الحرارة، جريان الموائـع، الحركة الموجية، الدوائر الإلكترونية فضلاً عن استخدامها في مسائل الهياكل الإنشائية والوصف الرياضي للتفاعلات الكيميائية.
ففي في الرياضيات, يطلق اسم المعادلات التفاضلية على المعادلات التي تحوي مشتقات و تفاضلات لبعض الدوال الرياضية و تظهر فيها بشكل متغيرات المعادلة . و يكون الهدف من حل هذه المعادلات هو إيجاد هذه الدوال الرياضية التي تحقق مشتقات هذه المعادلات.