Simple example of SSH tunneling

SSH tunneling is a technique to transfer arbitrary networking data using an encrypted SSH connection. It can be used to add encryption to not secure protocols such as HTTP and to bypassing firewalls. It is also named as port forwarding, there is a post related to C# implementation of SSH port forwarding. Here is presented… Read More »

MSDOS debugger

If you are not familiar how to enable old legacy MSDOS application capabilities on modern Windows OS, it is good to start with “WoW. 16-bit supplication on 32-bit Windows” article. The MS-DOS debugger is portable command line-oriented debugger in operating systems such as MS-DOS and OS/2, Windows (16-bit/32-bit versions only). It is started by DEBUG… Read More »

WoW. 16-bit application on 32-bit Windows.

There was time when PC used 16-bit microprocessors such as 8086 and 80286. The first 32-bit Windows NT operating system had NTVDM (NT Vistual DOS Machine) component that allowed execution of 16-bit Windows and 16-bit / 32-bit DOS applications. The latest 32-bit Windows operating systems does not support NTVDM by default, it should be enabled.… Read More »

VirtualBix bidirectional clipboard between host and guest

After installation virtual machine in Oracle VirtualBox clipboard between host and guest machines does not work. It is necessary to do some manipulation to start Copy and Paste operation working. Below is example how organize bidirectional clipboard between Windows host and CentOS guest. In Oracle VM VirtualBox Manager right click on your VM, select Setting,… Read More »

snmpget in C#

SNMP (simple network management protocol) is the way to discover information about remote device or to monitor such device using agentless technique. The agentless approach means that no additional custom spy software is installed on target device. Anyware snmp or WMI are detective features, but usually they are part of operating system. Here is example… Read More »

Linux C error handling, errno and perror

If you have Java or .Net programming background you used to be familiar with exception which generated in runtime if something is going wrong with code execution. Linux C does not provide direct support to runtime error handling or exception handling. Usually code developer has to check return values from the functions. Generally C function… Read More »

Bash script for xml parsing

Usually XML processing is already implemented in programming languages. Several of them have numerous API for that. However some of these API are awkward and cumbersome. Recently it was necessary to parse xml file from bash script so I create my own parser. Basically what I create it is not inversion but small and it… Read More »

sizeof in c code, compilation and runtime

What is sizeof? In C sizeof is not a function, it is the unary operator sizeof which is measured in the number of byte-sized storage units required for the type. Usually it is calculated during compilation but some compilers could create code which computes sizeof in runtime. Now small quiz related to sizeof. Possible that… Read More »

No mountable file systems or something about Mac kernel extensions

Something happened with Macintosh device, the DMG file which was mounted before without problem cannot be mounted anymore. Several day ago it was OK, I installed several updates, rebooted my Mac couple of times and now something that worked before was rejected. The same result “no mountable file systems” I got when I double clicked… Read More »

View Mac OSX File System details from terminal

Mac OSX storage have 4 different concepts: disk, formatting, partition and volume. Disk are the physical devices where data are kept. Disk may be divided on several areas or partitions, every partition may contain own and be data partition as well. OSX may support up to 16 partitions per disk. OSX supports 2 main partition… Read More »