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  Today in history : Steve Wozniak invented Apple I in 1975

The original Apple Computer, also known retroactively as the Apple I, or Apple-1, is a personal computer invented by Steve Wozniak ion 29th June, 1975. Wozniak's friend Steve Jobs had the idea of selling the computer. Features:CPU : MCStek 6502CPU Speed : 1MHzBus Speed : 1MHzMemory : 8KbResolution : 60.05 Hz, 40*24 charactersPower : 58WPrice : $666.66The Apple I went on sale in July 1976 at a price of US$666.66, because Wozniak "liked repeating digits" and because they originally sold it to a lo...

   Apple I,History,Steve Wozniak     2012-06-29 06:00:08

  How many bytes a boolean value takes in Java?

Have you ever wondered how many bytes a boolean value takes in Java? One byte, this might be the answer comes out of your mind right away. But is it? Let's dig in more. Per Oracle documentation on boolean value definition, there is below statement: boolean: The boolean data type has only two possible values: true and false. Use this data type for simple flags that track true/false conditions. This data type represents one bit of information, but its "size" isn't something that's precisely defin...

   JAVA,INTERVIEW,SIZE,BOOLEAN     2020-02-29 02:49:18

  Understanding JavaScript closure and where it can be used

Closure The official definition of closure is: an expression (usually a function) that has many variables and is bound to an environment that includes those variables. In JavaScript, closure refers to the ability of a function to access the lexical scope in which it was defined, even after the function has been executed and left that scope. This ability is due to the fact that when a function is created, it generates a closure that includes a reference to the definition environment of the curr...

   CLOSURE,JAVASCRIPT,USAGE     2023-03-05 02:17:08

  Some laws of interactive design

The well known quote from Alan Cooper is   Conforming to the standard unless there is a better choice. There are some best practices in interaction design. How many do you know? 1. Fitts' Law The time from one start point to target point is determined by two parameters: The distance to the target and the size of the target. )D and W in above picture), the formula is : T=a+blog2(D/W+1). It was first proposed by Paul Fitts, it is mathematical model used to predict the time from any poin...

   interaction design, laws, Fitts' law     2012-11-16 11:25:24

  Learning Python as your first programming language

Python is a widely used general-purpose, high-level programming language Its design philosophy emphasizes code readability, and its syntax allows programmers to express concepts in fewer lines of code than would be possible in languages such as C. Python now becomes more and more popular and is now being used the first teaching language in some universities. Why would you like to learn Python as your first programming language? Below are the reasons. Python is a high-level language with dynami...

   Python,Advantage     2014-04-07 05:36:04

  How big is sizeof structure?

First let's see the codes of a structure: struct node{ int a; int b; }; Question : What's sizeof(node)? The answer is very simple, on a 32 bit machine, an int will take 4 bytes and two ints will take 8 bytes. So sizeof(node) is 8. The answer for the above codes is 8, then how about the following structure: struct node{ char a; int b; }; Question : Then what's sizeof(node) now? int takes 4 bytes, char takes 1 bytes, is the answer 5? Now the answer may not be 5, on some mac...

   Data structure alignment, pack     2012-10-29 12:13:37

  Python and PLC Communication

This article provides detailed steps on how to use Python to communicate with Schneider M221 and Siemens S7-1200 PLCs via Ethernet. Additionally, we offer a packaged Python PLC client library, enabling you to easily build your own SCADA control programs, such as Human-Machine Interfaces (HMI). The system overview is shown below: To check the project detail please refer to Python Physical PLC Communication Clients # Created: 2024/06/29 # Version: v0.1.3 # Copyright: Copyright (c) 2024 ...

   PYTHON,PLC,COMMUNICATION     2024-06-30 02:21:17

  Which one has a worse reputation, JavaScript or PHP?

There has a been a lot of criticism of PHP over being a badly designed programming language. JavaScript seems quite a similar language with loose-typing and flexible array declarations/memory management, but is widely adopted by industry leaders such as Google. Google even has a JavaScript style guide. Many people think that PHP has a worse reputation than JavaScript. Carlos Ribeiro gave his analysis on a high level which doesn't touch the language syntax. Attributing JavaScript success to it be...

   JavaScript,PHP,reputation,comparison     2014-05-03 06:26:10

  Hey, you may be happy to know these mottos about programming languages

Different programming are similar in helping people build staff work as people want them to. But they all have their own features which differentiate them from other programming languages. The language type may be different, for example Java is OOP, some may have different syntax. A programming motto usually can best describe the characteristic of the programming language. For example, "Write once Run everywhere" for Java. But today we are going to take a look at "unofficial mottos" about some p...

   motto,programming language     2014-04-05 20:02:13

  Generate certificate in Java -- Self signed certificate

This is the first post in this series which I will show you how to generate SSL certificate in Java programmatically. Certificates are frequently used in SSL communication which requires the authentication of server to client. This is to make the client to trust that the server is actually the one it claims. Certificates are really important on the Internet. All HTTPS communications on the Internet need the server side to present their certificates signed by trusted CAs. The basic flow of a requ...

   Java,Certificate,X509     2014-07-30 07:42:18

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