Russia 10 класс Informatics (advanced)
Chapters: 4
1. Digital literacy
Computer architecture · Software and file systems · Networks · Information security and cryptography
- Computers and Computing: Evolution, Parts and I/O Devices – A computer is an electronic machine that takes input, processes it under the control of a program, stores data and gives output. Computing devices grew from the abacus to smartphones. Every computer has an input unit, a CPU, memory and an output unit, joined by buses and ports.
- Software: System and Application, Generic and Specific – Software is a set of programs. System software (operating system, device drivers, utilities, language translators) runs and looks after the computer. Application software does a user's task. Application software can be generic (general-purpose, ready-made for many users) or specific-purpose (customised for one organisation's need).
- Computer Networks: Types, Devices and Topologies – A computer network is a group of devices connected to share data and resources. By area, networks are PAN, LAN, MAN and WAN. Devices do different jobs: a modem converts digital and analog signals, a repeater boosts a weak signal, a hub sends data to all ports, a switch sends it only to the right device, a router joins networks and chooses a path, and a gateway joins networks that use different protocols. Topology is the layout of connections: star, bus, tree and mesh, each with its own strengths and weaknesses.
- Cryptography: How Secret Messages Keep Data Safe – Cryptography is the science of keeping messages secret and trustworthy. A normal message (plaintext) is mixed with a key to make a secret message (ciphertext); this is encryption. Turning it back with the right key is decryption. Old ciphers like the Caesar cipher shift letters. Modern systems use symmetric encryption (one shared key) and asymmetric or public-key encryption (a public key to lock, a private key to unlock). Hashing makes a fixed-length fingerprint of data to check it was not changed, and digital signatures prove who sent a message. Your phone uses all of these every time you open a website with https or send a chat message.
2. Theoretical foundations
Coding · Number systems · Algebra of logic · Number representation
- Data Representation: How Computers Store Numbers, Text, Images and Sound – Data is raw facts; information is data given meaning; knowledge is information we can use. A computer stores all data as bits (0 or 1). 8 bits make a byte, and 1 kB = 1000 bytes, 1 MB = 1000 kB, 1 GB = 1000 MB, 1 TB = 1000 GB. Numbers are stored in binary, where place values double: 1, 2, 4, 8 and so on. Text uses a character set: in ASCII 'A' is 65; Unicode covers every script. A bitmap image is a grid of pixels; size = width × height × colour depth. Sound is sampled: size = sample rate × bit depth × seconds. Vector images store shapes instead of pixels. Compression makes files smaller: lossless keeps every bit, lossy throws some detail away.
- Number Systems and Encoding – A number system is a way to write numbers using a set of digits and a base. Decimal (base 10) uses 0–9, binary (base 2) uses 0 and 1, octal (base 8) uses 0–7, and hexadecimal (base 16) uses 0–9 and A–F. To go from decimal to any base, divide repeatedly by the base and read remainders bottom to top; for fractions, multiply by the base and read the integer parts top to bottom. To go to decimal, multiply each digit by its place value and add. Binary ↔ octal uses groups of 3 bits, binary ↔ hex groups of 4. Text is stored with encoding schemes: ASCII (7-bit, 128 characters), ISCII (8-bit, Indian scripts) and Unicode (every script), stored as UTF-8 (1–4 bytes) or UTF-32 (4 bytes).
- Boolean Logic – Boolean logic works with only two values: 1 (true) and 0 (false). Logic gates act on them: NOT flips a value; AND gives 1 only if all inputs are 1; OR gives 1 if any input is 1; NAND and NOR are the opposites of AND and OR; XOR gives 1 when inputs differ. A truth table lists the output for every input combination (2ⁿ rows for n inputs). De Morgan's laws: (A·B)' = A' + B' and (A + B)' = A'·B'. Gates joined together form logic circuits that match Boolean expressions.
3. Algorithms and programming
Development tools · Number algorithms · Files · Subprograms and recursion · Numerical methods · Strings · Arrays and sorting
- Python Basics: Modes, Variables, Data Types and Operators – Python runs in interactive mode (one line at a time) or script mode (a saved .py file). Blocks are shown by indentation. Variables are names tied to values; every value has a data type, and some types are mutable. Operators build expressions that Python works out by precedence. input() reads text, int()/float()/str() convert types, and debugging fixes syntax, runtime and logical errors.
- Introduction to Problem Solving – Problem solving on a computer has stages: analyse the problem (inputs, outputs, rules), develop an algorithm (a finite, clear, ordered set of steps), code it in a programming language, test it with different inputs, and debug (find and remove errors). An algorithm can be shown as a flowchart (oval = start/stop, parallelogram = input/output, rectangle = process, diamond = decision, arrows = flow) or as pseudocode (structured plain English). Decomposition breaks a big problem into smaller sub-problems that are solved separately and then joined.
- File Handling in Python: Save Data That Lasts – Variables vanish when a program ends; files keep data on the disk. A text file stores characters in lines, a binary file stores raw bytes (such as pickled Python objects), and a CSV file stores table rows with commas. You open a file with open(path, mode), using an absolute or relative path and a mode such as r, w, a, r+, rb or wb. The with statement closes the file for you. Text files use write, writelines, read, readline and readlines. seek moves the file pointer and tell reports where it is. pickle.dump and pickle.load save and load objects in binary files, letting you search, append and update records. The csv module's writer (writerow, writerows) and reader handle CSV files.
- Functions in Python: Build Your Own Machines – A function is a named block of code that does one job. Python has built-in functions (print, len), functions inside modules (math.sqrt, random.randint) and user-defined functions you write with def. Values sent in a call are arguments; the names that receive them are parameters. Arguments can be positional, keyword or use default values. return sends a value back. Python runs code top to bottom, jumps into a function when it is called and comes back after it. Names made inside a function are local; names made outside are global.
- Strings in Python – A string is an immutable sequence of characters written in single, double or triple quotes. Each character has a positive index (0 from the left) and a negative index (−1 from the right). Operations: + (concatenation), * (repetition), in / not in (membership) and slicing s[start:stop:step], which takes characters from start up to but not including stop. Traversal means visiting each character with a for or while loop. Built-in methods like len(), upper(), lower(), title(), capitalize(), count(), find(), index(), replace(), split(), join(), strip(), startswith(), endswith(), isalpha(), isdigit(), isalnum(), islower(), isupper() and isspace() return new values without changing the original string.
- Lists in Python: Create, Traverse, Change and List Methods – A list is an ordered, changeable collection written in square brackets, like [10, 20, 30]. Items are reached by index (from 0, or negative from the end) and slices. We traverse a list with a for loop, change items in place because lists are mutable, and use functions (len, max, min, sum, sorted, list) and methods (append, insert, extend, remove, pop, sort, reverse, count, index, clear) to work with it.
4. Information technologies
Documents and data analysis
- Data Analysis – Data analysis means turning raw data into answers. It follows a cycle: ask a question, collect data, clean it (remove errors, repeats and blanks), organise and transform it, analyse it with summaries such as mean, median, range and patterns, show it with a good chart, and draw a careful conclusion. Watch for outliers, small samples and bias, and remember that a correlation between two things does not prove that one causes the other. Data must also be stored safely and used with permission.