Билет 8

A system is a collection of elements or components that are organized for a common purpose.A computer system consists of hardware components that have been carefully chosen so that they work well together and software components or programs that run in the computer.The main software component is itself an operating system that manages and provides services to other programs that can be run in the computer.A filing system is a group of files organized with a plan (for example, alphabetical by customer).All of nature and the universe can be said to be a system. We've coined a word, ecosystem, for the systems on Earth that affect life systems.The term can be very useful because so many things can be described as systems. It can also be very unuseful when a more specific term is needed.

Билет 9

We should consider the general concept of abstraction in robotics a bit before moving on to more specific topics. Abstraction comes up a lot in computer science and programming, so I think people in that field are exposed to it early and often. Just about any program will have at least some user-made abstractions in it, be it a data structure or a subroutine, so programmers tend to be aware that the abstractions are just whatever they choose to make them and that they are not necessarily statements of absolute fact. In other introductory engineering contexts, at least in my experience, there is less of an explicit acknowledgment of the abstractions being used. There’s all kinds of talk of models and approximations, and there are probably disclaimers at the beginning of the classes or texts that warn students of the limitations of the models. Perhaps those disclaimers come so early that by the time students learn the models, they have forgotten that they are just simplifications. It’s also possible that the people I am thinking of have not had any formal engineering education, but whatever their backgrounds, I have seen many customers thoroughly confused when an abstraction is violated.

Билет 10

Context Database Designer

Context Database Designer is a great tool for designing and managing database schemas. It provides the full cycle of database schema design and maintenance, including: creating of tables, relations views and stored procedures; drawing of sophisticated and professional looking diagrams; maintaining the history of changes made to the database schema; allows to compare any two versions of any two schemas, view the difference and instantly build upgrade SQL script for any given database engine.Context Database Designer does what very few professional and very expensive tools can - it is able to automatically generate create/alter/drop DDL scripts for virtually any database engine. Moreover, it also is able to import SQL DDL scripts for any database engine, which is accomplished by highly customizable SQL generator/parser - a unique piece of software, developed by Contexts Software. The only thing required in order to support another database engine is to create a simple text profile (see them stored under 'dbdefs' folder), defining a way to input and output SQL scripts for that particular type of database.