Category Archives: General

Is your computer now protected from Spectre and Meltdown security vulnerabilities? 

Steve Gibson of Gibson Research Corporation has provided a downloadable program that says whether or not your Windows PC has been updated with fixes for Spectre and Meltdown. The program also offers, if possible, options to disable the security protections (such as you find the updates cause your computer to run slower).

Go here to read about and download the utility program: GRC | InSpectre  

High level overview of compiling a program into executable instructions

A high level look at the concepts of compilers, interpreters, byte codes and Just-in-Time compilation, as ways of converting our programs into executable programs or machine instructions processed by the CPU.

The first video provided a high level look at computer system architecture.

The second video introduced the concepts of the CPU or processor.

This video introduces the conversion of our high level programs into machine executable code. Note that this video does not cover specifically how App Inventor blocks code is converted into an executable program.

The fourth video, relying on the information covered in the first 3 videos, will explain the ideas behind the SPECTRE exploit.

 

Intel updates performance impact of SPECTRE and MELTDOWN fixes

Intel is continuing to measure and evaluate the performance impact of their own firmware changes to address the SPECTRE and MELTDOWN exploits. Click on the chart to view the results in full size.

The chart shows Intel’s measurements for certain 6th, 7th and 8th generation Intel processors. The measurements are made using standard “benchmarket” tests that simulate specific usage scenarios. Consequently, these are measurements of performance impacts to these benchmark tests, which may not represent how we use our own computers.

Source: Intel Security Issue Update: Initial Performance Data Results for Client Systems

Separately, Google says they managed to upgrade their cloud servers with their own fixes that had negligible impacts.

While AMD processors appear to not be impacted by the MELTDOWN exploit, AMD did announce that one of the variants of SPECTRE does impact the AMD processors.

This suggests that over the weeks and months to come, future updates may appear that fix new variations of the exploits but also improve performance as better solutions are identified.

New drone quadcopter programmable using Scratch #AppInventor #STEM #Drones #CES2018

The ability to code is an important part of literacy and will enable kids to learn about creative problem solving and how to communicate their ideas. Engineers at Ryze have made Tello programmable with Scratch, an MIT-developed coding system that allows kids and teens to learn the basics of programming. Kids can program their Tello to string multiple flips into a single command or create their own flight patterns using MIT Media Lab’s easy-to-use block-based coding interface called Scratch.

Source: Ryze and DJI team to create Tello $99 drone – sUAS News – The Business of Drones

The Scratch programming system came before App Inventor and inspired the “blocks” programming model used in App Inventor.

The “Intel CPU” Exploit – does it affect App Inventor apps? #SPECTRE #MELTDOWN

Yes, but Android has already been updated to deal with it.

What is the “Intel CPU” Exploit? Well, its not just Intel, as first described. The SPECTRE exploit works on processors from many vendors. The MELTDOWN exploit might mostly impact Intel processor (but could affect some others).

What are these exploits and what do they do?

This first video is a high level overview. I hope to add another video going into more details – which means explaining a bit about what goes on inside your computer or smart phone processor and computing system.

There is a typo in a title in the slide set – about half way through the video the title says “What do this exploits actually do?” and of course, that should say, “”What do these exploits actually do?”

Ignore the type “doe” in the FB link below – that’s been fixed on the web site! But the typo in this tittle, in the middle of the video should say “What do THESE exploits actually do?

App Inventor to run on iPhones? Yes. How about Windows and Mac OS X? #AppInventor #Stem

MIT has announced that App Inventor will run on iPhones and iPads, hopefully by spring of 2018. You can help make that happen by making a donation to their effort – go to http://appinventor.mit.edu and follow the links to make a donation!

Did you know that you can run App Inventor Android apps on Windows and Mac OS X? Sure can!

All you need is to install an Android simulator for Windows or Mac and then install your App Inventor .apk app into the simulator. This way you can run your apps on Windows or Mac!

This short video shows you how to do that – take a look!

 

There are several Android simulators for both Windows and Mac OS X.

This video demonstrates using BlueStacks for Windows (also available for Mac OS X) and Nox App Player for Mac OS X.

New web address Learn2c.org

To make accessing this web page easier, I created a new web address for my App Inventor “how to” web site:

The name is short for “Learn to Code”. A short URL makes it easy to visit the web site!

I duplicated the old web site at the new address and everything looks the same. The new web site is “live” now although I will still be posting here for a bit.

I will keep you updated on the switch over, perhaps later in the week. But go ahead – check out the new web site – it is up and running now!

By creating a new web site, the two older web sites will remain online. All links from Facebook, Twitter, Google+, Tumblr and personal pages will still work and point back to the original articles from when they were first posted.

Interesting questions :)

I am back after having been traveling for over 2 weeks (and some travel before that too); during most of that time, I had no Internet or cell phone access.

While I was away, readers sent me questions about how to do various things in App Inventor and I will start working on creating tutorials to answer their questions. I think others will find their questions and possible solutions to solve the problems of interest!

Another reader indicates their’s been a change to the Google Fusion tables API and I will try to look into that and see what’s up.

Brief update

I’ve been busy with other projects, traveling for work, and other tasks, that have cut into my App Inventor posts. Sorry about that!

One task I have been busy with is a project from AV8 Designer LLC to create an aircraft wing tip protection system. The system places proximity sensors on the tips of aircraft wings to detect – and help prevent – collisions with obstacles during aircraft ground movement operations. Aircraft are pushed and pulled around on the ground during all times of the day and night, and during all types of weather. They are frequently squeezed into aircraft hangers and parked extremely close to other aircraft. Unfortunately, this leads to occasional wing tip collisions that are expensive to repair.

The wing tip sensors provide audio and visual alerts of potential collisions and status (with audio and visual display) on Android tablets or smart phones carried by ground crew. The Android app is simple to use but incorporates complex programming to wirelessly communicate with all wing tip sensors. The app and the wireless communication links were implemented using App Inventor, rather than the Android Java SDK.

We took a risk in choosing to use App Inventor. While preliminary experiments were done to verify the concept, we did not know if we could develop the full application in App Inventor. Well, we took the risk and everything worked out great. Using App Inventor we were able to quickly develop – and demonstrate – the user interface and functionality. In doing this project, we proved App Inventor is capable of creating powerful and complex industrial applications. App Inventor can do much more than only educational and gaming applications!

Appy Builder – an alternative to MIT App Inventor, with more features

AppyBuilder is a commercial version of MIT App Inventor that, for a monthly subscription fee, provides access to many additional components and features. Some of these features include monetization services that work with advertising networks to display ads with your apps, plus unique features like SQL Lite and the Android Material Design user interface.  You can also add in-app purchases.

There is also a free version that operates similar to MIT App Inventor. You can set up your free account at the Appy Builder web site or sign up for a subscription account with added features.

AppyBuilder is based on MIT App Inventor – if you know how to use App Inventor, you’ll find AppyBuilder very easy to use. The company behind AppBuilder also does custom app development and mobile web site development.

Click on their “Tell me more” button, and then page down to see the description of features and services, and subscription options.

I’ve played a bit with the “free” version but I could see buying a monthly subscription to access several of their enhanced features. Their lead architect also has a blog including this tutorial on how to use their components to access the web, camera and upload photos to a server using App Builder.

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Since I moved the web site from my own server over to the WordPress platform, you will often see posts authored by “Coldstreams”, or sometimes “AppinventorPlus”, rather than my name, EdwardM, that appeared on the old web site. I have 4 separate accounts on WordPress and set them up so that my Coldstreams account can update any of the blogs, including this one. Most of my posts will likely appear with the “Coldstreams” name, but it is still just me 🙂 … EdwardM