LING 408/508: Programming for
Linguists
Lecture 1
August 24th
Administrivia
1. Syllabus
2. Introduction
3. Quickie Homework 1
– due Wednesday night by midnight in my e-mailbox
• I will assume everyone has a laptop…
Syllabus
• Details
– Instructor: Sandiway Fong
Depts. Linguistics and Computer Science
– Email: sandiway@email.arizona.edu (homeworks go here)
– Office: Douglass 311
– Hours: by appt. or walk-in, after class
– Meet: Shantz 338, Mondays/Wednesdays 3:15-4:30pm
– No class on:
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Monday September 7th (Labor Day)
Wednesday November 11th (Veterans Day)
Week after September 11th (out of town), plus Monday 21st
Monday October 12th
– My academic webpage:
• dingo.sbs.arizona.edu/~sandiway/ or just Google me
Syllabus
• dingo.sbs.arizona.edu/~sandiway/
– Lecture slides will be available online (.pptx and pdf
formats) just before class
• look for updates/corrections afterwards
– Lectures will be recorded using the panopto system (video,
laptop screen, synchronized slides, keyword search)
Syllabus
• Pre-requisites:
– none!
• Course Objectives:
– Introduction to programming
• data types, different programming styles, thinking algorithmically
…
– and fundamental computer concepts
• computer organization: underlying hardware, and operating
systems (processes, shell, filesystem etc.)
– Operating System:
• Ubuntu (Linux)
– Programming Languages:
• selected examples: Bash shell, Python, Javascript, Perl, Tcl/Tk,
HTML/CSS, MySQL, cgi-bin etc.
Syllabus
• Expected learning outcomes:
– familiarity with the underlying technology,
terminology and programming concepts
– acquire the ability to think algorithmically
– acquire the ability to write short programs
– build a graphical user interface
– build a web application (with a relational database)
– be equipped to take classes in the Human Language
Technology (HLT) program and related classes
Syllabus
• Grading
– 408: homeworks (80%), term programming project (20%)
– 508: homeworks (65%), term programming project (35%)
– Note: requirement – you must submit all homeworks
• Homework submissions:
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email only to me
See homework 1 for the required format …
homeworks will be introduced in class
due date:
• almost one week (typically)
• example: homework presented in class on Monday (resp. Wednesday), due
Sunday (resp. Tuesday) night by 11:59pm in my mailbox
– all homeworks will be reviewed in class
Syllabus
• Homeworks
– you may discuss questions with other students
– however, you must program/write it up yourself (in your
own words/code)
– cite (web) references and your classmates (in the case of
discussion)
– Student Code of Academic Integrity: plagiarism etc.
• http://deanofstudents.arizona.edu/codeofacademicintegrity
• Revisions to the syllabus
– “the information contained in the course syllabus, other
than the grade and absence policies, may be subject to
change with reasonable advance notice, as deemed
appropriate by the instructor.”
Syllabus
• Absences
– tell me ahead of time so we can make special
arrangements, e.g. homeworks
– I expect you to attend lectures (though attendance
will not be taken)
Introduction
• Computers
– Memory
• Programs and data
– CPU
• Interprets machine instructions
– I/O
• keyboard, mouse, touchpad, screen, touch sensitive
screen, printer, usb port, etc.
• bluetooth, ethernet, wifi, cellular …
Introduction
• Memory
– CPU registers invisible to
programmers
– L1/L2 cache
– RAM
– SSD/hard drive
– blu ray/dvd/cd drive
open file
read/write
fast
slow
Introduction
• Memory Representation
0
array
a[23]
– binary: zeros and ones (1 bit)
– organized into bytes (8 bits)
• memory is byte-addressable
– word (32 bits)
• e.g. integer
• (64 bits: floating point number)
– big-endian/little-endian
addressable
Memory
(RAM)
your Intel and
ARM CPUs
• most significant byte first or least
significant byte
• communication …
FFFFFFFF
Introduction
• A typical notebook computer
– Example: a 2013 Macbook Air
– CPU: Core i5-4250U
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1.3 billion transistors
built-in GPU
TDP: 15W (1.3 GHz)
Dual core (Turbo: 2.6 GHz)
Hyper-Threaded (4 logical CPUs, 2 physical)
64 bit
64 KB (32 KB Instruction + 32 KB Data) L1 cache
256 KB L2 cache per core
12MB L3 cache shared
16GB max RAM
Increased
address space
and 64-bit
registers
Introduction
A 4 core machine: 8 virtual
anandtech.com
Introduction
• Machine Language
– A CPU understands only one language: machine language
• all other languages must be translated into machine language
– Primitive instructions include:
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MOV
PUSH
POP
ADD / SUB
INC / DEC
IMUL / IDIV
AND / OR / XOR / NOT
NEG
SHL / SHR
JMP
CMP
JE / JNE / JZ / JG / JGE / JL / JLE
CALL / RET
Assembly Language: (this notation)
by definition, nothing built on it is more powerful
http://www.cs.virginia.edu/~evans/cs216/guides/x86.html
Introduction
• Not all the machine instructions are conceptually
necessary
– many provided for speed/efficiency
• Theoretical Computer Science
– All mechanical computation can be carried out using a
TURING MACHINE
– Finite state table + (infinite) tape
– Tape instructions:
• at the tape head: Erase, Write, Move (Left/Right/NoMove)
– Finite state table:
• Current state x Tape symbol --> new state x New Tape
symbol x Move
Introduction
• Storage:
– based on digital logic
– binary (base 2) – everything is a power of 2
– Byte: 8 bits
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01011011
= 26+24+23+21+20
= 64 + 16 + 8 + 2 + 1
= 91 (in decimal)
– Hexadecimal (base 16)
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0-9,A,B,C,D,E,F (need 4 bits)
5B (= 1 byte)
= 5*161 + 11
161 160
= 80 + 11
5
B
= 91
27
26
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23
22
21
20
0
1
0
1
1
0
1
1
23
22
21
20
23
22
21
20
0
1
0
1
1
0
1
1
5
B
Introduction: data types
• Integers
– In one byte (= 8 bits), what’s the largest and smallest
number, we can represent?
– 00000000 = 0
– 01111111 = 127
– 10000000 = -128
– 11111111 = -1
00000000
0
…
11111111
127 -128
-127
2’s complement representation
-1
Introduction: data types
• Integers
– In one byte, what’s the largest and smallest number, we can
represent?
– Answer: -128 .. 0 .. 127 using the 2’s complement representation
– Why? super-convenient for arithmetic operations
– “to convert a positive integer X to its negative counterpart, flip all the
bits, and add 1”
– Example:
– 00001010 = 23 + 21 = 10 (decimal)
– 11110101 + 1 = 11110110 = -10 (decimal)
– 11110110 flip + 1 = 00001001 + 1 = 00001010
Addition:
-10 + 10
= 11110110
+ 00001010 = 0 (ignore overflow)
Introduction: data types
• Typically 32 bits (4 bytes) are used to store an integer
– range: -2,147,483,648 (2(31-1) -1) to 2,147,483,647 (2(32-1) -1)
231 230 229 228 227 226 225 224 …
byte 3
byte 2
…
byte 1
27
26
25
24
23
22
byte 0
21
20
C:
int
• what if you want to store even larger numbers?
– Binary Coded Decimal (BCD)
– code each decimal digit separately, use a string (sequence)
of decimal digits …
Introduction: data types
• what if you want to store even larger numbers?
– Binary Coded Decimal (BCD)
– 1 byte can code two digits (0-9 requires 4 bits)
– 1 nibble (4 bits) codes the sign (+/-), e.g. hex C/D
23
22
21
20
0
0
0
0
23
22
21
20
0
0
0
1
23
22
21
20
1
0
0
1
2
0
0
1
4
2 bytes (= 4 nibbles)
1
+
2
0
1
4
2.5 bytes (= 5 nibbles)
9
23
1
credit (+)
22 21
1
0
20
0
C
23
debit (-)
22 21 20
1
1
0
1
D