Nox is an android emulator designed originally for Windows and Mac to help users emulate the android operating system and run android apps on their computer.
A flaw in the Windows kernel could stop antivirus programs from recognizing malware, but Microsoft believes it’s not a security risk. Security researchers believe that this bug could allow hackers to perform malicious actions by tricking AV software that blindly rely on a particular Windows API.
I wasn’t aware we can mount a folder as a drive in Windows. Was experimenting the same and found the below item. I created a virtual drive today. Use the below URI to understand more.
Yesterday I was working with my laptop connected with a remote monitor. I realised the screen in my laptop looks upside down. Not sure I did pressed any key combination or a bug with windows. Searched for the screen turning around and found this good tip. This is with windows 10. May work for other versions also.
Tips for turning the screen around:
If you want to turn the screen upside down, press “Ctrl + Alt + down arrow”.
To turn the screen back to the default position, press “Ctrl + Alt + up arrow”.
To turn the screen on to the side, press “Ctrl + Alt + left/right arrow”.
sort will sort the file contents concatenates to the standard output and uniq will filter the adjacent matching lines, -d option of uniq will print the duplicate lines.
What is a Toolchain?
Its a set of tools linked together by specific stages which can be used to run on a specific machine.
It contains tools for compiling, debugging , binary file manipulation and analysis.
There are pre-built toolchain available in internet. We can build our own using automated tool chain build tools or from scratch.
What are the types of Toolchain available?
Tool chains are run on 3 machine types
Build – The machine where the tool chain is first built.
Host – The machine where the tool chain is used to generate the target binary.
Target – The machine where the target binary is run.
Based on the above below are the Toolchain types
Native – The build, host and target are the same architecture. E.G:- The GCC compiler coming with RedHat x86 version
Cross Compiled – The build and host are same architecture, but the target is different. E.G:- Using x86 GCC creating a cross compiled GCC which generates binary to run on an ARM processor.
Cross Native – The host and target are of the same architecture. E.G;- Using x86 GCC create a cross native arm GCC, which can be used in an ARM Linux OS to generate binary which runs on ARM processor.
Canadian Build – The architecture for all the build, host and target differs. E.G:- Using X86 GCC create an ARM GCC which generates binary to run on a PPC machine. In this case build and target can be same architecture.
What are the Toolchain components?
The main components are
Binutils – as,ld,readelf etc
Compiler – gcc,g++ etc
C library – glibc, uclibc etc
Debugger – gdb
Kernel – headers
What are the stages in building a Toolchain?
1. Download sources for the components
2. Set the environment variables for the Toolchain build. e.g:- setting the build, host, target architecture and intermediate installation directories.
3. Build first the binutils
4. Build the bootstrap gcc with options –with-gnu-as –with-gnu-ld to instruct the compiler to use binutils assembler and linker than native assembler and linker.
5. Build glibc
6. Build gcc again with newly build glibc with options –with-gnu-as –with-gnu-ld to instruct the compiler to use binutils assembler and linker than native
7. Build gcc again with newly build glibc with options –with-gnu-as –with-gnu-ld to instruct the compiler to use binutils assembler and linker than native. This is to compare the binaries and make sure you are getting the same output and no compiler bug.
8. Use the Toolchain to build your application.
9. Run your application on the target machine.
What are the options for building a Toolchain?
Option 1: Build your own
Option 2: Prebuilt Toolchain. e.g:- CodeSourcery, Linoro(ARM) etc
Option 3: Automated Toolchain build systems. e.g:- Buildroot, Open ADK, crosstool-NG
Note:- The option 2 and 3 helps in quick development as the dependencies between the Toolchain components will be taken care by the maintainers of the Toolchain build systems.
Good article on C++ atomic template, how it uses memory fencing and the x86 instructions (compare and swap, fetch and add) and uses hardware level lock and reference counting. Read more…