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Please switch off your
mobile phones
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Prolog: The Initiation
ET: Hey Alice! What is this on your desk?
Alice: That’s a digital computer.
ET: Digital what? Looks pretty unsocial.
Doesn’t even greet me!
Alice: It helped us discover you and your
solar system.
ET: Wow! That sounds cool. How do you use
it? Does it talk?
Alice: It can solve hard problems. You have
to program it to do that.
ET: Will you teach me do that?
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WELCOME To ESC101N:
Fundamentals of Computing
Instructor: Mainak Chaudhuri
[email protected]
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Agenda
• Administrivia
• What this course is not about
• Anatomy of a computer
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Administrivia
• Lecture hours
– Monday, Wednesday, Thursday: 9-10am, L17
– Please come to class in time
• Labs
– 2pm-5pm, 11 lab sessions
– Monday: B5-B6, Tuesday: B1-B2, Wednesday:
B9-B10, Thursday: B7-B8, Friday: B3-B4
– No lab this week
• Tutorial
– Tuesday 9-10am, Tutorial Block 101-110
– No tutorial this week
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Administrivia
• Grading [this is the sad part]
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–
–
–
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Exam: 15+15+30
One compulsory lab test: 10
Project or another lab test (your choice): 20
Weekly lab sessions: 10
Two surprise quizzes: 10 (this is extra)
• Held in tutorial sessions
• No make up for surprise quizzes (so come to
tutorial regularly)
– Project proposal submission deadline: any
time before 1st October
• Can get started even today if you know Java
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Administrivia
• There will be a course web page with all
info
– Temporarily:
www.cse.iitk.ac.in/~mainakc/esc101notes.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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For Visitors and Wanderers
• Also known as audit students
• In case you want to experience the
“excitements” of the tutorials and labs
– Send your section preference to me so that
we can be prepared to accommodate you
– But not allowed to sit in the lab tests
– Can do a project, but will not be graded
– Can write quizzes, but will not be graded
– Not allowed to take the exams
• In case there are too many visitors, we
will not allow anyone in the tutorials and
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labs
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
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called main memory) accomplish the job
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 memory11
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
• Let’s write a program in English (almost)
– Want to add five numbers a, b, c, d, e and
print the result on monitor
print (monitor, a+b+c+d+e)
– 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 14my
program (caution: this is just an example)
“The Computing Stack”
Problem
ESC101N
Central in CS
Algorithm
HLL=Java
Program (HLLs)
Hardware/ HLL Compiler/Linker
Executable binary
software
interface
Operating System
Microarchitecture
Circuits
Hardware
Transistors
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Next week’s lab
• Learn to use the UNIX environment
– How to create a file (this is where you store
your programs)
– How to create and navigate through
directory (this is 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: TAs will be present at
the front door to lead you
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