|
Process Control Daemon
Process Control Daemon (PCD) is an open source, light-weight system level process manager/controller for Embedded Linux based projects (such as consumer electronics and network devices). This tool provides a complementary service for any Embedded Linux driven product and is specialized for the needs of embedded products. PCD was created because Embedded Linux distributions did not provide such a tool. Other similar tools which are available are not suited for embedded products in terms of compatibility, performance and limited hardware resources. Background The PCD project was designed and implemented by Hai Shalom, senior software engineer at Texas Instruments Israel at the time, as part of his M.Sc. degree in Computer Science. The project was initiated due to a true need in one of Texas Instruments’ broadband solutions ( ARM1176 Running MV-Linux Pro-5.00). The system was originally started with shell scripts, where the init process started the ''rcS'' script, and it started s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Source
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized software development model that encourages open collaboration. A main principle of open-source software development is peer production, with products such as source code, blueprints, and documentation freely available to the public. The open-source movement in software began as a response to the limitations of proprietary code. The model is used for projects such as in open-source appropriate technology, and open-source drug discovery. Open source promotes universal access via an open-source or free license to a product's design or blueprint, and universal redistribution of that design or blueprint. Before the phrase ''open source'' became widely adopted, developers and producers have used a variety of other terms. ''Open source'' gai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix Domain Socket
A Unix domain socket aka UDS or IPC socket ( inter-process communication socket) is a data communications endpoint for exchanging data between processes executing on the same host operating system. It is also referred to by its address family AF_UNIX. Valid socket types in the UNIX domain are: * SOCK_STREAM (compare to TCP) – for a stream-oriented socket * SOCK_DGRAM (compare to UDP) – for a datagram-oriented socket that preserves message boundaries (as on most UNIX implementations, UNIX domain datagram sockets are always reliable and don't reorder datagrams) * SOCK_SEQPACKET (compare to SCTP) – for a sequenced-packet socket that is connection-oriented, preserves message boundaries, and delivers messages in the order that they were sent The Unix domain socket facility is a standard component of POSIX operating systems. The API for Unix domain sockets is similar to that of an Internet socket, but rather than using an underlying network protocol, all communication occurs ent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LGPL
The GNU Lesser General Public License (LGPL) is a free-software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate a software component released under the LGPL into their own (even proprietary) software without being required by the terms of a strong copyleft license to release the source code of their own components. However, any developer who modifies an LGPL-covered component is required to make their modified version available under the same LGPL license. For proprietary software, code under the LGPL is usually used in the form of a shared library, so that there is a clear separation between the proprietary and LGPL components. The LGPL is primarily used for software libraries, although it is also used by some stand-alone applications. The LGPL was developed as a compromise between the strong copyleft of the GNU General Public License (GPL) and more permissive licenses such as the BSD licenses and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNU Lesser General Public License
The GNU Lesser General Public License (LGPL) is a free-software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate a software component released under the LGPL into their own (even proprietary) software without being required by the terms of a strong copyleft license to release the source code of their own components. However, any developer who modifies an LGPL-covered component is required to make their modified version available under the same LGPL license. For proprietary software, code under the LGPL is usually used in the form of a shared library, so that there is a clear separation between the proprietary and LGPL components. The LGPL is primarily used for software libraries, although it is also used by some stand-alone applications. The LGPL was developed as a compromise between the strong copyleft of the GNU General Public License (GPL) and more permissive licenses such as the BSD licenses and the M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bus Error
In computing, a bus error is a fault raised by hardware, notifying an operating system (OS) that a process is trying to access memory that the CPU cannot physically address: an invalid address for the address bus, hence the name. In modern use on most architectures these are much rarer than segmentation faults, which occur primarily due to memory access violations: problems in the ''logical'' address or permissions. On POSIX-compliant platforms, bus errors usually result in the SIGBUS signal being sent to the process that caused the error. SIGBUS can also be caused by any general device fault that the computer detects, though a bus error rarely means that the computer hardware is physically broken—it is normally caused by a bug in software. Bus errors may also be raised for certain other paging errors; see below. Causes There are at least three main causes of bus errors: Non-existent address Software instructs the CPU to read or write a specific physical memory address. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Segmentation Fault
In computing, a segmentation fault (often shortened to segfault) or access violation is a fault, or failure condition, raised by hardware with memory protection, notifying an operating system (OS) the software has attempted to access a restricted area of memory (a memory access violation). On standard x86 computers, this is a form of general protection fault. The operating system kernel will, in response, usually perform some corrective action, generally passing the fault on to the offending process by sending the process a signal. Processes can in some cases install a custom signal handler, allowing them to recover on their own,''Expert C programming: deep C secrets'' By Peter Van der Linden, page 188 but otherwise the OS default signal handler is used, generally causing abnormal termination of the process (a program crash), and sometimes a core dump. Segmentation faults are a common class of error in programs written in languages like C that provide low-level memory acce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gdbserver
gdbserver is a computer program that makes it possible to remotely debug other programs. Running on the same system as the program to be debugged, it allows the GNU Debugger to connect from another system; that is, only the executable to be debugged needs to be resident on the target system ("target"), while the source code and a copy of the binary file to be debugged reside on the developer's local computer ("host"). The connection can be either TCP or a serial line. How it works # gdbserver is launched on the target system, with the arguments: #* Either a device name (to use a serial line) or a TCP hostname and port number, and #* The path and filename of the executable to be debugged #:It then waits passively for the host gdb to communicate with it. # gdb is run on the host, with the arguments: #* The path and filename of the executable (and any sources) on the host, and #* A device name (for a serial line) or the IP address and port number needed for connection to the target s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daemon (computer Software)
In multitasking computer operating systems, a daemon ( or ) is a computer program that runs as a background process, rather than being under the direct control of an interactive user. Traditionally, the process names of a daemon end with the letter ''d'', for clarification that the process is in fact a daemon, and for differentiation between a daemon and a normal computer program. For example, is a daemon that implements system logging facility, and is a daemon that serves incoming SSH connections. In a Unix environment, the parent process of a daemon is often, but not always, the init process. A daemon is usually created either by a process forking a child process and then immediately exiting, thus causing init to adopt the child process, or by the init process directly launching the daemon. In addition, a daemon launched by forking and exiting typically must perform other operations, such as dissociating the process from any controlling terminal (tty). Such procedures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Process Management (computing)
A process is a program in execution, and an integral part of any modern-day operating system (OS). The OS must allocate resources to processes, enable processes to share and exchange information, protect the resources of each process from other processes and enable synchronization among processes. To meet these requirements, the OS must maintain a data structure for each process, which describes the state and resource ownership of that process, and which enables the OS to exert control over each process. Multiprogramming In any modern operating system there can be more than one instance of a program loaded in memory at the same time. For example, more than one user could be executing the same program, each user having separate copies of the program loaded into memory. With some programs, it is possible to have one copy loaded into memory, while several users have shared access to it so that they each can execute the same program-code. Such a program is said to be Reentrant (subro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
