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Please switch off your mobile phones
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WELCOME To ESC101NFundamentals of Computing

• Instructor Mainak Chaudhuri
• mainakc_at_cse.iitk.ac.in

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Agenda

• Administrivia
• What this course is not about
• Anatomy of a computer
• This weeks lab

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Administrivia

• Lecture hours
• Monday, Wednesday, Thursday 8-9am, L7
• Come to class in time we will start with
  announcements
  
• Labs
• 10am-1pm, 12 lab sessions
• Monday B5-B6, Tuesday B7-B8, Wednesday B9-B10,
  Thursday B1-B2, Friday B3-B4
  
• There will be lab this week
• Tutorial
• Tuesday 8-9am, Tutorial Block 101-110
• No tutorial this week

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Administrivia

• Grading this is the sad part
• Exam 151530
• One compulsory lab test 10
• Project or another lab test (your choice) 20
• Weekly lab sessions 10
• Surprise quizzes 10 (this is extra)
• Held in tutorial sessions
• You should be able to prove that these do not
  remain a matter of surprise any more once I have
  made this announcement
  

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Administrivia

• There will be a course web page with all info
• Temporarily www.cse.iitk.ac.in/mainakc/esc101/no
  tes.html
  
• Text book
• Nothing specific your choice
• Suggestion Java Elements Principles of
  Programming in Java by Bailey and Bailey
  
• More references are on the webpage
• Visit past course sites www.iitk.ac.in/esc101

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What this course is not about

• This is not a course on programming
• You will learn how to solve problems with
  computers especially the ones that you cannot
  solve with paper and pencil quickly
  
• The greater part of the lectures will be devoted
  to the concepts involved in developing a computer
  algorithm
  
• Sequence of steps that solve a problem
• Java will be used as a vehicle to demonstrate the
  concepts
  
• Do not expect to become an expert in Java after
  taking this course

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Anatomy of a computer

• What you see
• A monitor, a keyboard, a mouse, a printer
• Input/Output devices
• Through these you ask the computer to do
  something and the computer tells you the results
  
• Need a way to convey your commands to the
  computer (it is really a stupid device which
  cannot do anything on its own)
  
• Internally
• A central processing unit and a scratchpad (often
  called main memory) accomplish the job

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Anatomy of a computer

• Central processing unit does not understand
  English, not even Java
  
• It only understands two symbols 0 and 1
• These are called bits (short for binary digits)
• You encode your algorithm into a high-level
  language called Java
  
• This is called a program
• This is harder to understand than English, but
  easier to understand than a 0-1 encoding
  
• How do I encode a program in 0-1? This is used
  only for storing the program in main memory

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Anatomy of a computer

• A friend of yours called compiler translates the
  program into a binary encoding called an object
  program
  
• This is almost understandable to the central
  processing unit (often called a microprocessor)
  
• Another friend of yours called a linker adds
  something more to an object program to convert it
  to an executable
  
• This is understandable to the CPU
• But somehow it needs to get started executing

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Anatomy of a computer

• A big boss called operating system loads the
  executable in main memory and hands over the
  control to the CPU
  
• Now the CPU starts executing your program
  (essentially the binary executable)
  
• Once in a while it prints something on the
  monitor and you appreciate that
  
• Notice that it is not doing anything on its own,
  only doing whatever you have asked it to do
  
• At some point the CPU completes the execution and
  you have all the results

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A simple program

• Lets write a program in English (almost)
• Want to add five numbers a, b, c, d, e and print
  the result on monitor
  
• print (monitor, abcde)
• print is used as a function which takes two
  arguments where to print and what to print
  
• A binary translation of this could convert each
  character i.e. p, r, i, n, t, (, m, into a
  binary string e.g., p is the 16th alphabet, so
  represent it as 16 zeros put a 1 to mark the end
  of a character
• Now I can design a CPU which can understand this
  translation and execute my program (caution this
  is just an example)

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This weeks lab

• Learn to use the UNIX environment
• How to create a file (this where you store your
  programs)
  
• How to create and navigate through directory
  (this where you store your files)
  
• How to copy files from one directory to another
• And more www.iitk.ac.in/esc101/linux.pdf
• Lab is upstairs in CC I will be present at the
  front door to lead you