[CS] Computer Science Part1 Day-86

How many bytes does a string take?

In English, each letter occupies one byte. Every programming language has different bytes in a string. So, when you understand the bytes by the data type, you can give an answer.

What is Unicode?

Industry standard designed to provide a consistent representation and handling of global characters on computers. It contains character sets, encodings, databases, algorithms for manipulating characters.

What is encoding?

It is to turn a character or symbol into a signal that the computer can use. For復号、入力、復号は、標準ルールに従って実行する必要があります.
The standard for encoding and decoding is called a character set.

Difference between UTF-8 and UTF-16

It means the difference in the encoding method. Numbers after UTF mean bits.

Difference between PNG image and SVG image

PNG is pixel-based. Not suitable for magnification, but suitable for images with different color combinations.

jpg, gjf, png

SVG is based on mathematically calculated Shapes. Suitable for product images such as logos and illustrations. It can be enlarged to any size without loss of quality

svg

operating system

Makes the hardware work. (Owner of hardware)

system resource management

Applications cannot run without an operating system. Applications are intended to perform various tasks using the computer.
The CPU is responsible for configuring hardware, RAM to store data, and the operating system is responsible for managing system resources.

process management

memory management

I/O Management

Application: Making the computer do work through the operating system

Order for an application to do something to computer, through the operating system, Application granted permission by operating system. to manipulate the computer.

Process

An application running in the operating system is called a process.
When a user runs an application, the necessary memory is allocated from the operating system and the application is executed.
If you run two Chrome, two processes are created.

Thread

When you run one task, it lists the task sequence. (リスト順)
When one thread runs, the other threads wait.

Multi-Thread

Process two or more tasks together. It allocates CPU and memory resources appropriately to run multiple tasks together.

Advantages of Multi-Thread

Multiple tasks can be performed at the same time, and system throughput is improved.

The problem of Multi-Thread

If two different threads affect one data at the same time, it will produce invalid data. So, when over two threads affect one data, you need to control the order in which operation process first and control access to the share data.