1. 1. Glitches, Bugs and ImportanceGlitches, Bugs and Importance of good programmingof good programming Sridhar Pandurangiah Director Engineering sridhar@sastratechnologies.in Sastra Technologies
2. 2. Bug :Fund House (The Cause) AMC Code in URL Number of rows in URL File support for DBF
3. 3. Bug :Fund House (The Effect) Bank has to generate more than 20 files instead of one; hogging bandwidth on the internet No way of passing number of rows in URL Bank doesnt use FoxPro or Access, bandwidth hogging, requires the process to be off-line Delayed implementation by one year
4. 4. Bug : Loan Processing (The Cause) Loan processing software Accepted 2 decimal places for Amount Accepted First, middle and last name
5. 5. Bug : Loan Processing (The Effect) Implemented in Sultanate of Oman Rial is made of 1000 baisa calling for 3 decimal places! Omanis have 4 names! (so do the spanish) Increased effort of more than 3000 person hours (not including downline activities) translating to an increased cost of more than Rs. 8 lakhs
6. 6. Bug : Portfolio Management (The Cause) Portfolio management software accepted alphabets for distinctive numbers
7. 7. Bug : Portfolio Management (The Effect) Directly affects the common investor No way to determine the number of shares in an investors portfolio Project Shelved
8. 8. Bug : Loan Origination (The Cause) Loan origination software development environment was different
9. 9. Bug : Loan Origination(The Effect) Unable to login!
10. 10. Glitch : Hubble Telescope(The Cause) Spherical aberration, an optical distortion caused by an incorrectly shaped mirror Perkin-Elmer could have corrected the error before it was too late, the optical team managed to dismiss the warning signs
11. 11. Glitch: Hubble Telescope(The Effect) Light collected by the mirror was spread over a larger area in a fuzzy halo. Images of objects such as stars, planets and galaxies were blurred $2.2 billion at launch! Not including corrections like COSTAR
12. 12. Bug : Ariane Rocket (The Cause) Software error in the inertial reference system 64 bit floating point number relating to the horizontal velocity of the rocket with respect to the platform was converted to a 16 bit signed integer The number was larger than 32,767, the largest integer storeable in a 16 bit signed integer, and thus the conversion failed.
13. 13. Bug : Ariane Rocket (The Effect) $ 7 billion development costs $500 million rocket and cargo
14. 14. Bug : Denver Baggage (The Cause) Laser scanners read barcodes on baggage tags Photocells tracked telecars movement 300 computers controlled the baggage system
15. 15. Bug : Denver Baggage(The Effect) Telecars crashed against walls Baggage lost or misplaced Airport couldnt open Loss of 1.1 Million per Day Cost $ 4.2 billion Additional $88 million spent on rectification One airline used it!
16. 16. Bug : Tax Demand(The Cause) Round off calculation errors
17. 17. Bug : Tax Demand(The Effect) Salaried individuals in Mumbai receive demand notice for Re. 1! Some cases refund order for Re 1. Cost of cheques, cost of processing, clearing Interest and penalty will be computed on Re 1 Spend more to pay less
18. 18. Bug : Internet Explorer(The Cause) Flaw fixed six years ago in Internet Explorer 3.0 and 4.0 that has resurfaced in versions 5.01, 5.5 and 6 does not properly validate source of redirected frame
19. 19. Bug : Internet Explorer(The Effect) keystroke-logging Trojan horses - capture IDs, passwords, and credit card information users dont suspect there's anything wrong
20. 20. Bug : BlueTooth(The Cause) Phones in visible mode after exchanging information with someone
21. 21. Bug : BlueTooth(The Effect) Attacker can remotely download information - contact address, calendar appointments, text messages Attacker can install a gateway on victim's phone to reroute phone calls through his own phone
22. 22. Bug : Mars Orbiter(The Cause) One team used English units (e.g., inches, feet and pounds) while the other used metric units for a key spacecraft operation
23. 23. Bug : Mars Orbiter(The Effect) Loss of the Mars Climate Orbiter (in Mars)
24. 24. Is everything Hunky Dory? NO
25. 25. NASA's Mars Rover Hardware is extremely limited Software development began before the vehicle was built Uses 25Mhz processor and has only 387MB of RAM Bulk of the available weight goes to cameras, scientific instruments, batteries, solar panels, and locomotion equipment.
26. 26. NASA's Mars Rover Survives in a high dust build-up environment Survives in very low night temperatures Exceeded the projected 90-Martian-day lifespan
27. 27. Some More
28. 28. Remember Today software is assuming the status of Infrastructure Its important to develop Industrial Strength Software Its more important to be honest and responsible
29. 29. The Reason We stop learning the day we stop studying Ego Shortcuts and disdainful of processes Know all attitude Boss is meant to sit in a cabin. Not work! We dont measure Undue importance to price at the cost of quality
30. 30. Prevention is better (and a lot cheaper!) than cure
31. 31. Preventing Bugs Be aware of the hriar limit Use an iterative development model Plan well and document assumptions Gather requirements in the language of the domain Design before development Dont be a coding drone understand what your are programming Test thoroughly
32. 32. Preventing bugs Release early and release often Dont sit back and relax
33. 33. Most importantly Continue learning, long after youve stopped studying
34. 34. Thank You