Linux
The original version of this document resides at
http://stommel.tamu.edu/~baum/programming.html.
"The DNS directory service consists of DNS data, DNS servers, and Internet protocols for fetching data from the servers. The billions of resource records in the DNS directory are split into millions of files called zones. Zones are kept on authoritative servers distributed all over the Internet, which answer queries according to the DNS network protocols. In contrast, caching servers simply query the authoritative servers and cache any replies. Most servers are authoritative for some zones and perform a caching function for all other DNS information. Most DNS servers are authoritative for just a few zones, but larger servers are authoritative for tens of thousands of zones." - What is DNS?
" The term Ethernet refers to the family of local-area network (LAN) products covered by the IEEE 802.3 standard that defines what is commonly known as the CSMA/CD protocol."
" The original Ethernet was developed as an experimental coaxial cable network in the 1970s by Xerox Corporation to operate with a data rate of 3 Mbps using a carrierxi sense multiple access collision detect (CSMA/CD) protocol for LANs with sporadic butxi occasionally heavy traffic requirements. Success with that project attracted early attentionxi and led to the 1980 joint development of the 10-Mbps Ethernet Version 1.0 specificationxi by the three-company consortium: Digital Equipment Corporation, Intel Corporation,xi and Xerox Corporation." - Internetworking Technology Handbook: Ethernet
Netfilter is the system compiled into the kernel which provides hooks into the IP stack which loadable modules (e.g. iptables) can use to perform operations on packets. IPTables consists of two parts: user-space tools and kernel-space modules. The latter are distributed with the kernel, and include the main ip_tables module as well as modules for NAT, logging, connection tracking, etc. The former takes the form of the iptables binary, distributed separately from the kernel and used to add, remove or edit rules for the various modules.
The netfilter/iptables project is the Linux 2.4.x / 2.5.x firewalling subsystem. It delivers you the functionality of packet filtering (stateless or stateful), all different kinds of NAT (Network Address Translation) and packet mangling.
" Internet Protocol (IP) multicast is a bandwidth-conserving technology that reduces traffic by simultaneously delivering a single stream of information to thousands of corporate recipients and homes. Applications that take advantage of multicast include videoconferencing, corporate communications, distance learning, and distribution of software, stock quotes, and news." - Internet Protocol Multicast
"Short for Point-to-Point Tunneling Protocol, a new technology for creating Virtual Private Networks (VPNs) , developed jointly by Microsoft Corporation, U.S. Robotics, and several remote access vendor companies, known collectively as the PPTP Forum. A VPN is a private network of computers that uses the public Internet to connect some nodes. Because the Internet is essentially an open network, the Point-to-Point Tunneling Protocol (PPTP) is used to ensure that messages transmitted from one VPN node to another are secure. With PPTP, users can dial in to their corporate network via the Internet." - Webopedia
"Short for Unix-to-Unix Copy, a Unix utility and protocol that enables one computer to send files to another computer over a direct serial connection or via modems and the telephone system. For most file transfer applications, UUCP has been superseded by other protocols, such as FTP, SMTP and NNTP." - Webopedia
"A private data network that makes use of the public telecommunication infrastructure, maintaining privacy through the use of a tunneling protocol and security procedures." - VPNC Glossary
UNIX/Linux Software
The original version of this document resides at
http://stommel.tamu.edu/~baum/programming.html.
"Why is AWK so important? It is an excellent filter and report writer. Many UNIX utilities generates rows and columns of information. AWK is an excellent tool for processing these rows and columns, and is easier to use AWK than most conventional programming languages. It can be considered to be a pseudo-C interpretor, as it understands the same arithmatic operators as C. AWK also has string manipulation functions, so it can search for particular strings and modify the output. AWK also has associative arrays, which are incredible useful, and is a feature most computing languages lack. Associative arrays can make a complex problem a trivial exercise." - Bruce Barnett (from Awk)
CSS stands for Cascading Style Sheets and is a simple styling language which allows attaching style to HTML elements. Every element type as well as every occurance of a specific element within that type can be declared an unique style, e.g. margins, positioning, color or size.
"IEEE 754-1985 governs binary floating-point arithmetic. It specifies number formats, basic operations, conversions, and exceptional conditions. The related standard IEEE 854-1987 generalizes 754 to cover decimal arithmetic as well as binary." - IEEE 754 Group
"The Inter-Language Unification system (ILU) is a multi-language object interface system. The object interfaces provided by ILU hide implementation distinctions between different languages, between different address spaces, and between operating system types. ILU can be used to build multi-lingual object-oriented libraries ("class libraries") with well-specified language-independent interfaces. It can also be used to implement distributed systems. It can also be used to define and document interfaces between the modules of non-distributed programs. ILU interfaces can be specified in either the OMG's CORBA Interface Definition Language (OMG IDL), or ILU's Interface Specification Language (ISL). - Inter-Language Unification Page
"The IPC interface in BSD-like versions of Unix is implemented as a layer over the network TCP and UDP protocols. Message destinations are specified as socket addresses; each socket address is a communication identifier that consists of a port number and an Internet address.
The IPC operations are based on socket pairs, one belonging to a communication process. IPC is done by exchanging some data through transmitting that data in a message between a socket in one process and another socket in another process. When messages are sent, the messages are queued at the sending socket until the underlying network protocol has transmitted them. When they arrive, the messages are queued at the receiving socket until the receiving process makes the necessary calls to receive them." - Sockets Programming in Java
"Sed is the ultimate stream editor. If that sounds strange, picture a stream flowing through a pipe. Okay, you can't see a stream if it's inside a pipe. That's what I get for attempting a flowing analogy. You want literature, read James Joyce. Anyhow, sed is a marvelous utility. Unfortunately, most people never learn its real power. The language is very simple, but the documentation is terrible. The on-line manual pages for sed are five pages long, and two of those pages describe the 34 different errors you can get. A program that spends as much space documenting the errors that it does documenting the language has a serious learning curve." - Bruce Barnett (from Sed)
"What is a shell, anyway? It's simple, really. The UNIX operating system is a complex collection of files and programs. UNIX does not require any single method or interface. Many different techniques can be used. The oldest interface, which sits between the user and the software, is the shell. Twenty five years ago many users didn't even have a video terminal. Some only had a noisy, large, slow hard-copy terminal. The shell was the interface to the operating system. Shell, layer, interface, these words all describe the same concept. By convention, a shell is a user program that is ASCII based, that allows the user to specify operations in a certain sequence.
There are four important concepts in a UNIX shell:
"A set of library routines that enable C programmers to describe arbitrary data structures in a machine-independent way." - External Data Representation: Technical Notes
XML is the Extensible Markup Language. It is designed to improve the functionality of the Web by providing more flexible and adaptable information identification. It is called extensible because it is not a fixed format like HTML (a single, predefined markup language). Instead, XML is actually a `metalanguage' - a language for describing other languages - hich lets you design your own customized markup languages for limitless different types of documents. XML can do this because it's written in SGML, the international standard metalanguage for text markup systems (ISO 8879). - XML FAQ
MathML is a low-level specification for describing mathematics as a basis for machine to machine communication.
SVG is a language for describing two-dimensional graphics and graphical applications in XML.
X3D is a powerful and extensible open file format standard for 3D visual effects, behavioral modelling and interaction. It provides an XML-encoded scene graph and a language-neutral Scene Authoring Interface (SAI). The XML encoding enables 3D to be incorporated into web services architectures and distributed environments, and facilitates moving 3D data between applications. The Scene Authoring Interface allows real time 3D content and controls to be easily integrated into a broad range of web and non-web applications.
XSL is a family of recommendations for defining XML document
transformation and presentation. It consists of three parts:
The XML User Interface Language (XUL) is a markup language for describing user interfaces.
