Concurrent and Parallel Systems CS-160 Assignment 1 Prof B. D. Fleisch

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1 Concurrent and Parallel Systems CS-160 Assignment 1 Prof B. D. Fleisch Due: October 20, :59:59 (turnin method will be announceed) You have asked write a database for a national auto dealer. The database keeps track of its sales information. The auto dealer has one branch in each state. The project in CS160 will begin focusing on the California dealership but will eventually use multiple database one for each state of the country. The project is divided into three smaller assignments. In the first assignment, you will write a simple database object, a command shell, and an object for managing all of your threads. This first assignment will lead to the second, which in turn will lead to the third. So, it would be good to write flexible and maintainable code that can be used as the basis for future work. This first assignment is to be done independently. Collaboration is not allowed. Overview You will need to maintain information about several databases (one for each state in the country). However, in Assignment 1, assume only one database will be tested (for the database located in California for example). A command shell (like a UNIX shell) allows interactive operations to be performed on the database. Table 1 shows the operations permitted. Objects We ask that you break the project up into several different modules: a database object, a job object, a command shell, and worker threads to handle each of the assigned tasks, and the thread manager to keep track of all the threads. Each module can then be implemented using C++ classes and, with the exception of the database object, which runs in its own thread. Implementing each module with C++ classes makes changing modules easier in later projects. And, remember that the later assignments are dependent on the earlier assignments. Database Object The database must support four generic types of operations: insertions, modifications, queries, and deletions. Eventually, the database will also support transactions. Each entry in the database contains sales code (the Key) of the car, its manufacturer, its brand, the year in which it is made, quantity in the database. The database is maintained in memory, and written to disk and preserved when the program exits or when the user types in the save command. This is not a database class, so the database object can be implemented any way that you see fit. Keep in mind that the database will be extended in the future assignments and you have a limited amount of time to do the assignment. If you plan to use STL observe

2 that STL may not be thread safe and may misbehave in strange ways that my manifest themselves in Assignment 2 and Assignment 3 when more concurrency is added. Research into this matter would be prudent. Thread safety will be discussed further in lab and in the class. Worker Threads The worker threads carry out all operations against the database. Each command will be performed in a separate thread. Only one thread at a time is allowed to modify the database in the first assignment this simplifies thread synchronization. However, thread output to the screen must be synchronized so that no interleaving of output from different threads does not occur. Synchronization of work threads will be covered in later assignment. Thread Manager You should have an object that controls all aspects of thread management. This object should be responsible for creating threads and assigning tasks to them as well as keeping track of currently running threads and killing threads. Each running thread should have a unique programmer-defined number to identify it as well as a short description of what task the thread performs.. Command shell The command shell allows a user to interact with the database and to control the threads. The command shell should run its own thread and call the Thread Manager to create worker threads to handle the commands. The command shell is test based and contains the following commands. Command list create DATABASE load DATABASE save DATABASE insert KEY delete KEY Purpose provides a list of threads and what each thread is doing kills all threads and ends the program. All objects associated with the program are destroyed. create a database reads the sales records from a database file named DATABASE. writes the sales records from memory to the file named DATABASE. inserts the tuple into the database if not already there based on KEY. If already there, simply discard the command but report this to the error log. The initialization value for the quantity is 0. delete the entry in the DATABASE that match the KEY.

3 buy KEY QUANTITY sell KEY QUANTITY printi DATABASE printo KEYWORD increase the value associated with the KEY by QUANTITY decrease the value associated with the KEY by QUANTITY display all the entries in that DATABASE display all entries that match KEYWORD Other commands may be added at a later time. The following are descriptions of the terms used above. THREAD_ID DATABASE KEY KEYWORD VALUE Database Format Some sort of id created by you A string that names the database by US states abbreviation. For example, CA refers to the database located at California. (Refer to Appendix for the abbreviation) A string that is composed of code of state, manufacturer, and model. For example, code refers to California, Toyota, Camry. (Refer to Appendix for the code table) A string that can be compose of (state code), (state code and manufacturer code), or (state code, manufacturer code and model code) An integer that describes the current quantity of that entry in the database. State : Manufacturer : Model : Quantity (For example: : California : Toyota : Camry : 535) Here is an example of a set of legal commands to the database shell and its corresponding result: Command create CA load CA Corresponding result Create a file named CA Load the content in the CA database into memory (data structure) insert : California : Toyota : Camry : 0 insert : California : Toyota : Camry : : California : Ford : CrownVictoria : 0 insert : California : Toyota : Camry : : California : Ford : CrownVictoria : 0 buy : California : Toyota : Camry : : California : Ford : CrownVictoria buy : California : Toyota : Camry : : California : Ford : CrownVictoria : 300 sell : California : Toyota : Camry : 400

4 : California : Ford : CrownVictoria : 300 sell : California : Toyota : Camry : : California : Ford : CrownVictoria : 133 list List current thread (note for assignment 1, you should see only two threads: Thread Manager and Shell) printi CA : California : Toyota : Camry : : California : Ford : CrownVictoria : 133 printo : California : Toyota : Camry : 400 printo : California : Toyota : Camry : 400 printo : California : Ford : CrownVictoria : 133 load CA Save the content of the data structure into database CA file and the program (including shell) Load database CA, if the database of that name has already been loaded and has not been saved warn the user before overwriting the database with new values sell : California : Toyota : Camry : : California : Ford : CrownVictoria : 99 save CA Save database CA Instruction Specific Problems The printo command should display all records whose key values match the key values in the command. For example, the command Printo 05 should display all the entries in the CA database. Printo 0502 should display all the entries whose manufacturer is TOYOTA in the CA database Printo should display the entry whose model CAMRY, manufacturer is TOYOTA in the CA database. Error Handling (Error log) An error log file (error_log) to keep track the system information is required. The content of the file contains: thread (THREAD_ID) created, thread (THREAD_ID) exit status (normal or abnormal and its reason), failures that the thread encountered, and out of storage warning information. Failures can be one of the following situations: If you try to modify a database that doesn t exist in any way (ie adding an item to a non-existent database) then the command should report a failure. If there are no matches to the key value in the storage then the operation should report a failure. After each of these instances the program should continue but each of threads that failed should exit. Warning information issues in the following situation: If after the sell, the quantity becomes negative, which means the left over is not enough to complete the transaction. In this case, set the quantity to 0 and write warning information to the error log.

5 A sample error_log is as following: [Normal] Thread 234 created; [Normal] Thread 234 exits; [Abnormal] Thread 234 exits: Segment Fault [Failure] Thread 234 exits when it attempts to write to database OO. [Warning] The California Toyota Camry is out of storage. Important Information C++ should be used for this project. You do not have to use classes or any other special features of C++, but those features will make your life easier. Also, makefiles are required. The grader will not accept any project that does not have a makefile. Programs that do not compile will not receive credit regardless of the effort you invested in programming. The purpose of the first assignment is to create a framework for future assignments that to introduce you to basic pthreads. Keep the first program simple and make it maintainable so that you can easily extend it in future assignments. A README file should also be included explaining any initial steps that need to be taken (for example if some file needs to be in place before running your program). The README should also explain what has been implemented in your assignment and what is missing. All programs will be carefully cheat checked and any plagiarism found will result in a failing grade in the course. There is a 25 percent per day lateness penalty. After four days late the assignments is worth 0 points. To clarify this more precisely, a project that would have scored an 80 on-time that is 3 days late will score 20 (rather that a 5). Suggestions Begin work ASAP! I would suggest that you start with the Thread manager and get ht creation of threads working first. Second, work on one instruction and a time getting each instruction working. Keep adding instructions and debugging until the assignment is completed. Do not try to debug the assignment after you write everything. Develop and test the code incrementally. Appendix I US States Abbreviation 01 ALABAMA AL 26 MISSOURI MO 02 ALASKA AK 27 MONTANA MT 03 ARIZONA AZ 28 NEBRASKA NE 04 ARKANSAS AR 29 NEVADA NV 05 CALIFORNIA CA 30 NEW HAMPSHIRE NH 06 COLORADO CO 31 NEW JERSEY NJ 07 CONNECTICUT CT 32 NEW MEXICO NM 08 DELAWARE DE 33 NEW YORK NY 09 DISTRICT OF COLUMBIA DC 34 NORTH CAROLINA NC 10 FLORIDA FL 35 NORTH DAKOTA ND 11 GEORGIA GA 36 OHIO OH

6 12 HAWAII HI 37 OKLAHOMA OK 13 IDAHO ID 38 OREGON OR 14 ILLINOIS IL 39 PENNSYLVANIA PA 15 INDIANA IN 40 RHODE ISLAND RI 16 IOWA IA 41 SOUTH CAROLINA SC 17 KANSAS KS 42 SOUTH DAKOTA SD 18 KENTUCKY KY 43 TENNESSEE TN 19 LOUISIANA LA 44 TEXAS TX 20 MAINE ME 45 UTAH UT 21 MARYLAND MD 46 VERMONT VT 22 MASSACHUSETTS MA 47 VIRGINIA VA 23 MICHIGAN MI 48 WASHINGTON WA 24 MINNESOTA MN 49 WEST VIRGINIA WV 25 MISSISSIPPI MS 50 WISCONSIN WI 51 WYOMING WY Appendix II Manufacturer and Model Code Ford 01 Toyota02 Honda03 Dodge04 Chrysler05 Buick06 Mazda07 01 Aspire 4Runner Accord Avenger Cirrus Century Contour Avalon Civic Colt Concorde GrandNational CrownVictoria Camry CR-V Daytona Imperial LeSabre Escort Celica Odyssey Durango Laser ParkAvenue Miata 05 Festiva Corolla Passport Dynasty Lebaron Reqal Millenia 06 Mustanq Corona Prelude Intrepid New Yorker Riviera MX-3 07 Probe Cressida Lancer Sebring Roadmaster MX-6 08 Taurus LandCruiser Neon Town and Country Skylark Navajo 09 Tempo MR2 Omni Proteqe 10 Thunderbird Paseo Shadow RX-4 11 Previa Spirit RX-7 12 RAV4 Stealth 13 Supra Stratus 14 Tacoma 15 Tercel