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#94 Application Error

Posted by mroots1 on 04 February 2012 - 12:57 PM

When I select an availlable update ( I currently show 2: CloneDVD 2.9.3.0 and Glary Uitilities 2.41.0.1358 ) I get:

An error occurred

Application error

(See attachment)

I am running Soft32 Updater Version 1.0.2.0 on Windows 7 64 bit.

Thanks,

Michael

Attached Thumbnails

  • Soft32 Capture.JPG



#80 NAT (Network Address Translation)

Posted by Stefan Rusu on 26 August 2011 - 01:29 PM

In computer networking, the process of network address translation (NAT, also known as network masquerading or IP-masquerading) involves re-writing the source and/or destination addresses of IP packets as they pass through a router or firewall. Most systems using NAT do so in order to enable multiple hosts on a private network to access the Internet using a single public IP address. According to specifications, routers should not act in this way, but many network administrators find NAT a convenient technique and use it widely. Nonetheless, NAT can introduce complications in communication between hosts.

Overview

NAT first became popular as a way to deal with the IPv4 address shortage and to avoid the difficulty of reserving IP addresses. Use of NAT has proven particularly popular in countries other than the United States, which (for historical reasons) have fewer address-blocks allocated per capita. It has become a standard feature in routers for home and small-office Internet connections, where the price of extra IP addresses would often outweigh the benefits.

In a typical configuration, a local network uses one of the designated "private" IP address subnets (the RFC 1918 Private Network Addresses are 192.168.x.x, 172.16.x.x through 172.31.x.x, and 10.x.x.x), and a router on that network has a private address (such as 192.168.0.1) in that address space. The router is also connected to the Internet with a single "public" address (known as "overloaded" NAT) or multiple "public" addresses assigned by an ISP. As traffic passes from the local network to the Internet, the source address in each packet is translated on the fly from the private addresses to the public address(es). The router tracks basic data about each active connection (particularly the destination address and port). When a reply returns to the router, it uses the connection tracking data it stored during the outbound phase to determine where on the internal network to forward the reply; the TCP or UDP client port numbers are used to demultiplex the packets in the case of overloaded NAT, or IP address and port number when multiple public addresses are available, on packet return. To a system on the Internet, the router itself appears to be the source/destination for this traffic.

Drawbacks

Hosts behind a NAT-enabled router do not have true end-to-end connectivity and cannot participate in some Internet protocols. Services that require the initiation of TCP connections from the outside network, or stateless protocols such as those using UDP, can be disrupted. Unless the NAT router makes a specific effort to support such protocols, incoming packets cannot reach their destination. Some protocols can accommodate one instance of NAT between participating hosts ("passive mode" FTP, for example), sometimes with the assistance of an Application Layer Gateway (see below), but fail when both systems are separated from the internet by NAT. Use of NAT also complicates security protocols such as IPsec.

End-to-end connectivity has been a core principle of the Internet, supported for example by the Internet Architecture Board. Some people thus regard NAT as a detriment to the Public Internet. Some internet service providers (ISPs) only provide their customers with "local" IP addresses. Thus, these customers must access services external to the ISP's network through NAT. As a result, some may argue that such companies do not properly provide "Internet" service.

Depending on one's point of view, another drawback of NAT is that it greatly slowed the acceptance of IPv6, relegating it to research networks and limited public use.

Benefits

In addition to the convenience and low cost of NAT, the lack of full bidirectional connectivity can be regarded in some situations as a "feature", rather than a "limitation". To the extent that NAT depends on a machine on the local network to initiate any connection to hosts on the other side of the router, it prevents malicious activity initiated by outside hosts from reaching those local hosts. This can enhance the reliability of local systems by stopping worms and enhance privacy by discouraging scans. Many NAT-enabled firewalls use this as the core of the protection they provide.

The greatest benefit of NAT is that it is a practical solution to the impending exhaustion of IPv4 address space. Networks that previously required a Class B IP range or a block of Class C network addresses can now be connected to the Internet with as little as a single IP address (many home networks are set up this way). The more common arrangement is having machines that require true bidirectional and unfettered connectivity supplied with a 'real' IP addresses, while having machines that do not provide services to outside users (e.g. a secretary's computer) tucked away behind NAT with only a few IP addresses used to enable Internet access.

Basic NAT vs port number translation

Two kinds of network address translation exist. The type often popularly called simply "NAT" (also sometimes named "Network Address Port Translation" or "NAPT") refers to network address translation involving the mapping of port numbers, allowing multiple machines to share a single IP address. The other, technically simpler, form - also called NAT or "one-to-one NAT" or "basic NAT" or "static NAT" - involves only address translation, not port mapping. This requires an external IP address for each simultaneous connection. Broadband routers often use this feature, sometimes labelled "DMZ host", to allow a designated computer to accept all external connections even when the router itself uses the only available external IP address.

NAT with port-translation comes in two sub-types: source address translation (source NAT), which re-writes the IP address of the computer which initiated the connection; and its counterpart, destination address translation (destination NAT). In practice, both are usually used together in coordination for two-way communication.

Applications affected by NAT

Some higher-layer protocols (such as FTP and SIP) send network layer address information inside application payloads. FTP in active mode, for example, uses separate connections for control traffic (commands) and for data traffic (file contents). When requesting a file transfer, the host making the request identifies the corresponding data connection by its layer 3 and layer 4 addresses. If the host making the request lies behind a simple NAT firewall, the translation of the IP address and/or TCP port number makes the information received by the server invalid.

An Application Layer Gateway (ALG) can fix this problem. An ALG software module running on a NAT firewall device updates any payload data made invalid by address translation. ALGs obviously need to understand the higher-layer protocol that they need to fix, and so each protocol with this problem requires a separate ALG.

Another possible solution to this problem is to use NAT traversal techniques using protocols such as STUN or ICE or proprietary approaches in a session border controller. NAT traversal is possible in both TCP- and UDP-based applications, but the UDP-based technique is simpler, more widely understood, and more compatible with legacy NATs. In either case, the high level protocol must be designed with NAT traversal in mind, and it does not work reliably across symmetric NATs or other poorly-behaved legacy NATs.

Yet another possibility is UPnP (Universal Plug and Play) or Bonjour but this requires the cooperation of the NAT device.

Most traditional client-server protocols (FTP being the main exception), however, do not send layer 3 contact information and therefore do not require any special treatment by NATs. In fact, avoiding NAT complications is practically a requirement when designing new higher-layer protocols today.

NATs can also cause problems where IPsec encryption is applied and in cases where multiple devices such as SIP phones are located behind a NAT. Phones which encrypt their signalling with IPsec encapsulate the port information within the IPsec packet meaning that NA(P)T devices cannot access and translate the port. In these cases the NA(P)T devices revert to simple NAT operation. This means that all traffic returning to the NAT will be mapped onto one client causing the service to fail. There are a couple of solutions to this problem, one is to use TLS which operates at level 4 in the OSI Reference Model and therefore does not mask the port number, or to Encapsulate the IPsec within UDP - the latter being the solution chosen by TISPAN to achieve secure NAT traversal.

Different types of NAT

Applications that deal with NAT sometimes need to characterize NAT by type. The STUN protocol proposed to characterize Network address translation as Full cone NAT, restricted cone NAT, port restricted cone NAT or symmetric NAT. Note that it is indeed called "cone" and not possibly a type of "clone".

With full cone NAT, also known as one-to-one NAT, all requests from the same internal IP address and port are mapped to the same external IP address and port. An external host can send a packet to the internal host, by sending a packet to the mapped external address.

With restricted cone NAT, all requests from the same internal IP address and port are mapped to the same external IP address and port. Unlike a full cone NAT, an external host can send a packet to the internal host only if the internal host had previously sent a packet to it.

Port restricted cone NAT or symmetric NAT is like a restricted cone NAT, but the restriction includes port numbers. Specifically, an external host can send a packet to a particular port on the internal host only if the internal host had previously sent a packet from that port to the external host.

With symmetric NAT all requests from the same internal IP address and port to a specific destination IP address and port are mapped to a unique external source IP address and port. If the same internal host sends a packet with the same source address and port to a different destination, a different mapping is used. Only an external host that receives a packet can send a UDP packet back to the internal host.

This classification is now abandoned, because many NAT implementations oscillate between the various types. For example, many NAT follow a port preservation design. For most communications, they will use the same values as internal and external port numbers. However, if two internal hosts attempt to communicate with the same external hosts using the same port number, the external port number used by the second host will be chosen at random. Such NAT will be sometimes perceived as restricted cone NAT and other times as symmetric NAT.

Other examples of use

  • Load Balancing: Destination NAT can redirect connections pointed at some server to randomly selected servers.
  • Fail over: Destination NAT can be used to set up a service requiring high availability. If a system involves a critical server accessed through a router, and if the router detects that that server has gone down, it could use destination NAT to transparently re-route a connection to arrive on a backup server.
  • Transparent proxying: NAT can redirect HTTP connections targeted at the Internet to a special HTTP proxy which can cache content and filter requests. Some internet service providers use this technique to reduce bandwidth usage without requiring their clients to configure their web browser for proxy support.



#79 UPnP (Universal Plug-and-Play)

Posted by Stefan Rusu on 26 August 2011 - 01:26 PM

Universal Plug and Play (UPnP) is a set of computer network protocols promulgated by the UPnP Forum. The goals of UPnP are to allow devices to connect seamlessly and to simplify the implementation of networks in the home (data sharing, communications, and entertainment) and corporate environments. UPnP achieves this by defining and publishing UPnP device control protocols built upon open, Internet-based communication standards.

The term UPnP is derived from Plug-and-play, a technology for dynamically attaching devices to a computer directly.

Overview

The UPnP architecture offers pervasive peer-to-peer network connectivity of PCs, intelligent appliances, and wireless devices. The UPnP architecture is a distributed, open networking architecture that uses TCP/IP and HTTP to enable seamless proximity networking in addition to control and data transfer among networked devices in the home, office, and everywhere in between.

It enables data communication between any two devices under the command of any control device on the network.

  • Media and device independence. UPnP technology can run on any medium including phone lines, power lines (PLC), Ethernet, IR (IrDA), RF (Wi-Fi, Bluetooth), and FireWire. No device drivers are used; common protocols are used instead.
  • Common base protocols. Base protocol sets are used, on a per-device basis.
  • User interface (UI) Control. UPnP architecture enables vendor control over device user interface and interaction using the web browser.
  • Operating system and programming language independence. Any operating system and any programming language can be used to build UPnP products. UPnP does not specify or constrain the design of an API for applications running on control points; OS vendors may create APIs that suit their customer's needs. UPnP enables vendor control over device UI and interaction using the browser as well as conventional application programmatic control.
  • Internet-based technologies. UPnP technology is built upon IP, TCP, UDP, HTTP, and XML, among others.
  • Programmatic control. UPnP architecture also enables conventional application programmatic control.
  • Extendable. Each UPnP product can have value-added services layered on top of the basic device architecture by the individual manufacturers.

Protocol

Discovery

Given an IP address, the first step in UPnP networking is discovery. When a device is added to the network, the UPnP discovery protocol allows that device to advertise its services to control points on the network. Similarly, when a control point is added to the network, the UPnP discovery protocol allows that control point to search for devices of interest on the network. The fundamental exchange in both cases is a discovery message containing a few, essential specifics about the device or one of its services, for example, its type, identifier, and a pointer to more detailed information. The UPnP discovery protocol is based on the Simple Service Discovery Protocol (SSDP).

Description

The next step in UPnP networking is description. After a control point has discovered a device, the control point still knows very little about the device. For the control point to learn more about the device and its capabilities, or to interact with the device, the control point must retrieve the device's description from the URL provided by the device in the discovery message. The UPnP description for a device is expressed in XML and includes vendor-specific, manufacturer information like the model name and number, serial number, manufacturer name, URLs to vendor-specific web sites, etc. The description also includes a list of any embedded devices or services, as well as URLs for control, eventing, and presentation. For each service, the description includes a list of the commands, or actions, to which the service responds, and parameters, or arguments, for each action; the description for a service also includes a list of variables; these variables model the state of the service at run time, and are described in terms of their data type, range, and event characteristics.

Control

The next step in UPnP networking is control. After a control point has retrieved a description of the device, the control point can send actions to a device's service. To do this, a control point sends a suitable control message to the control URL for the service (provided in the device description). Control messages are also expressed in XML using the Simple Object Access Protocol (SOAP). Like function calls, in response to the control message, the service returns any action-specific values. The effects of the action, if any, are modeled by changes in the variables that describe the run-time state of the service.

Event Notification

The next step in UPnP networking is event notification, or "eventing". A UPnP description for a service includes a list of actions the service responds to and a list of variables that model the state of the service at run time. The service publishes updates when these variables change, and a control point may subscribe to receive this information. The service publishes updates by sending event messages. Event messages contain the names of one or more state variables and the current value of those variables. These messages are also expressed in XML and formatted using the General Event Notification Architecture (GENA). A special initial event message is sent when a control point first subscribes; this event message contains the names and values for all evented variables and allows the subscriber to initialize its model of the state of the service. To support scenarios with multiple control points, eventing is designed to keep all control points equally informed about the effects of any action. Therefore, all subscribers are sent all event messages, subscribers receive event messages for all "evented" variables that have changed, and event messages are sent no matter why the state variable changed (either in response to a requested action or because the state the service is modeling changed).

Presentation

The final step in UPnP networking is presentation. If a device has a URL for presentation, then the control point can retrieve a page from this URL, load the page into a web browser, and depending on the capabilities of the page, allow a user to control the device and/or view device status. The degree to which each of these can be accomplished depends on the specific capabilities of the presentation page and device.

UPnP AV (Audio and Video) standards

UPnP AV stands for UPnP Audio and Video, and is a grouping within the UPnP standards supervised by the DLNA (Digital Living Network Alliance), (formely: Digital Home Working Group), which is a forum of vendors and manufacturers who work in the home entertainment industry, and offer a "DLNA CERTIFIEDâ„¢" branding for those products which follow their Networked Device Interoperability Guidelines. The DLNA forum members "share a vision of a wired and wireless interoperable network of Personal Computers (PC), Consumer Electronics (CE) and mobile devices in the home enabling a seamless environment for sharing and growing new digital media and content services", and is "DLNA is focused on delivering an interoperability framework of design guidelines based on open industry standards to complete the cross-industry digital convergence". On the 12th of July 2006 the UPnP Forum announced the release of 'Enhanced AV Specifications', this release was version 2 of the UPnP Audio and Video specifications (UPnP AV v2), with new MediaServer version 2.0 and MediaRenderer version 2.0 classes. These enhancements are created by adding capabilities to the UPnP AV MediaServer and MediaRenderer device classes that allow a higher level of interoperability between MediaServers and MediaRenderers from different manufacturers.

UPnP AV components:

  • UPnP MediaServer DCP - which is the UPnP-server (a 'slave' device) that share/stream media-data (like audio/video/picture/files) to UPnP-clients on the network).
  • UPnP MediaServer ControlPoint - which is the UPnP-client (a 'master' device) that can auto-detect UPnP-servers on the network to browse and stream media/data-files from them.
  • UPnP Remote User Interface (RUI) client/server - which sends/receives control-commands between the UPnP-client and UPnP-server over network, (like record, schedule, play, pause, stop, etc.).
  • UPnP MediaRenderer DCP - which is a 'slave' device that can render content.
  • UPnP RenderingControl DCP - control MediaRenderer settings; volume, brightness, RGB, sharpness, and more).

NAT traversal

UPnP comes with a solution for Network Address Translation (NAT) traversal: Internet Gateway Device (IGD) protocol.

Problems with UPnP

  • UPnP uses HTTP over UDP (known as HTTPU and HTTPMU for unicast and multicast), even though this is not standardized and is specified only in an Internet-Draft that expired in 2001.
  • UPnP does not have a lightweight authentication protocol, while the available security protocols are complex. As a result, many UPnP devices ship with UPnP turned off by default as a security measure.



#75 RSS/Atom

Posted by Stefan Rusu on 26 August 2011 - 12:03 PM

RSS is a family of web feed formats. The initialism "RSS" is variously used to refer to the following standards:

  • Really Simple Syndication (RSS 2.0)
  • Rich Site Summary (RSS 0.91, RSS 1.0)
  • RDF Site Summary (RSS 0.9 and 1.0), where RDF means Resource Description Framework.

RSS formats are specified in XML (a generic specification for data formats). RSS delivers its information as an XML file called an "RSS feed", "webfeed", "RSS stream", or "RSS channel".

Usage

RSS is a simple XML-based system that allows users to subscribe to their favorite websites. Using RSS, a webmaster can put their content into a standardized format, which can be viewed and organized through a RSS-aware software.

A program known as a feed reader or aggregator can check a list of feeds on behalf of a user and display any updated articles that it finds. It is common to find web feeds on major websites and many smaller ones. Some websites let people choose between RSS or Atom formatted web feeds; others offer only RSS or only Atom.

RSS-aware programs are available for various operating systems. Client-side readers and aggregators are typically constructed as standalone programs or extensions to existing programs such as web browsers. Many browsers have integrated support for RSS feeds. There also are other applications that can convert a RSS feed into several usenet articles, viewable through the major newsreader software such as Mozilla Thunderbird or Forté Agent: an example of such applications are nntp//rss, a Java coded program, or RSS Feed Converter a script for the popular mail-newsserver Hamster.

Web-based feed readers and news aggregators such as YourLiveWire require no software installation and make the user's "feeds" available on any computer with Web access. Some aggregators combine existing web feeds into new feeds, e.g., taking all football related items from several sports feeds and providing a new football feed. There are also search engines for content published via web feeds like Feedster or Blogdigger.

On Web pages, web feeds (RSS or Atom) are typically linked with the word "Subscribe", an orange rectangle, a feed icon, or with the letters XML or RSS. Many news aggregators such as My Yahoo! publish subscription buttons for use on Web pages to simplify the process of adding news feeds.

RSS is also beginning to be used as the delivery system of choice for sending desktop alerts.

Incompatibilities

As noted above, there are several different versions of RSS, falling into two major branches (RDF and 2.*). The RDF, or RSS 1.* branch includes the following versions:

1) RSS 0.90 was the original Netscape RSS version. This RSS was called RDF Site Summary, but was based on an early working draft of the RDF standard, and was not compatible with the final RDF Recommendation.

2) RSS 1.0 is an open format by the RSS-DEV Working Group, again standing for RDF Site Summary. RSS 1.0 is an RDF format like RSS 0.90, but not fully compatible with it, since 1.0 is based on the final RDF 1.0 Recommendation.

3) RSS 1.1 is also an open format and is intended to update and replace RSS 1.0. The specification is an independent draft not supported or endorsed in any way by the RSS-Dev Working Group or any other organization.

The RSS 2.* branch (initially UserLand, now Harvard) includes the following versions:

1) RSS 0.91 is the simplified RSS version released by Netscape, and also the version number of the simplified version championed by Dave Winer from Userland Software. The Netscape version was now called Rich Site Summary, this was no longer an RDF format, but was relatively easy to use. It remains the most common RSS variant.

2) RSS 0.92 through 0.94 are expansions of the RSS 0.91 format, which are mostly compatible with each other and with Winer's version of RSS 0.91, but are not compatible with RSS 0.90. In all Userland RSS 0.9x specifications, RSS was no longer an acronym.

3) RSS 2.0.1 has the internal version number 2.0. RSS 2.0.1 was proclaimed to be "frozen", but still updated shortly after release without changing the version number. RSS now stood for Really Simple Syndication. The major change in this version is an explicit extension mechanism using XML Namespaces.

For the most part, later versions in each branch are backward-compatible with earlier versions (aside from non-conformant RDF syntax in 0.90), and both versions include properly documented extension mechanisms using XML Namespaces, either directly (in the 2.* branch) or through RDF (in the 1.* branch). Most syndication software supports both branches. Mark Pilgrim's article "The Myth of RSS Compatibility" discusses RSS version compatibility in more detail.

The extension mechanisms make it possible for each branch to track innovations in the other. For example, the RSS 2.* branch was the first to support enclosures, making it the current leading choice for podcasting, and as of mid-2005 is the format supported for that use by iTunes and other podcasting software; however, an enclosure extension is now available for the RSS 1.* branch, mod_enclosure. Likewise, the RSS 2.* core specification does not support providing full-text in addition to a synopsis, but the RSS 1.* markup can be (and often is) used as an extension. There are also several common outside extension packages available, including a new proposal from Microsoft for use in Internet Explorer 7.

The most serious compatibility problem is with HTML markup. Userland's RSS reader—generally considered as the reference implementation—did not originally filter out HTML markup from feeds. As a result, publishers began placing HTML markup into the titles and descriptions of items in their RSS feeds. This behaviour has become widely expected of readers, to the point of becoming a de facto standard, though there is still some inconsistency in how software handles this markup, particularly in titles. The RSS 2.0 specification was later updated to include examples of entity-encoded HTML, however all prior plain text usages remain valid.

Atom

In reaction to recognized issues with RSS (and because RSS 2.0 is frozen), a third group began a new syndication specification, Atom, in June 2003, and their work was later adopted by Internet Engineering Task Force (IETF) leading to the publication of a specification (RFC 4287) for the Atom Format in 2005. Work on the Atom Publishing Protocol, a standards-based protocol for posting to publishing tools is ongoing.

The relative benefits of Atom in comparison to the two RSS branches are a matter of debate within the Web-syndication community. Supporters of Atom claim that it improves on RSS by relying on standard XML features, by specifying a payload container that can handle many different kinds of content unambiguously, and by having a specification maintained by a recognized standards organization. Critics claim that Atom unnecessarily introduces a third branch of syndication specifications, further confusing the marketplace.

BitTorrent and RSS

The peer-to-peer application BitTorrent has also announced support for RSS. Such feeds (also known as Torrent/RSS-es) will allow client applications to download files automatically (also known as Broadcatching). Most common BitTorrent clients already offer RSS support.


#73 Open Source Software (OSS)

Posted by Stefan Rusu on 26 August 2011 - 12:00 PM

Open source describes the principles and methodologies to promote open access to the production and design process for various goods, products, resources and technical conclusions or advice. The term is most commonly applied to the source code of software that is made available to the general public with either relaxed or non-existent intellectual property restrictions. This allows users to create user-generated software content through either incremental individual effort, or collaboration.

Some consider open source as one of various possible design approaches, while others consider it a critical strategic element of their operations. Before open source became widely adopted, developers and producers used a variety of phrases to describe the concept; the term open source gained popularity with the rise of the Internet and its enabling of diverse production models, communication paths, and interactive communities. Subsequently, open source software became the most prominent face of open source practices.

Open-source software is computer software whose source code is available under a license (or arrangement such as the public domain) that permits users to study, change, and improve the software, and to redistribute it in modified or unmodified form. It is often developed in a public, collaborative manner. It is the most prominent example of open source development and often compared to user generated content.

The Open Source Definition, notably, presents an open-source philosophy, and further defines a boundary on the usage, modification and redistribution of open-source software. Software licenses grant rights to users which would otherwise be prohibited by copyright. These include rights on usage, modification and redistribution. Several open-source software licenses have qualified within the boundary of the Open Source Definition. The most prominent example is the popular GNU General Public License (GPL). While open source presents a way to broadly make the sources of a product publicly accessible, the open-source licenses allow the authors to fine tune such access.


#67 DHT (Distributed Hash Table)

Posted by Stefan Rusu on 26 August 2011 - 11:41 AM

Distributed hash tables (DHTs) are a class of decentralized distributed systems that partition ownership of a set of keys among participating nodes, and can efficiently route messages to the unique owner of any given key. Each node is analogous to an array slot in a hash table. DHTs are typically designed to scale to large numbers of nodes and to handle continual node arrivals and failures. This infrastructure can be used to build more complex services, such as distributed file systems, peer-to-peer file sharing systems, cooperative web caching, multicast, anycast, domain name services, and instant messaging.

Background

DHT research was originally motivated, in part, by peer-to-peer systems such as Napster, Gnutella, and Freenet, which took advantage of resources distributed across the Internet to provide a single useful application. In particular, they took advantage of increased bandwidth and hard disk capacity to provide a file sharing service.

These systems differed in how they found the data their peers contained. Napster had a central index server: each node, upon joining, would send a list of locally held files to the server, which would perform searches and refer the querier to the nodes that held the results. This central component left the system vulnerable to attacks and lawsuits. Gnutella and similar networks moved to a flooding query model — in essence, each search would result in a message being broadcast to every other machine in the network. While avoiding a single point of failure, this method was significantly less efficient than Napster. Finally, Freenet was also fully distributed, but employed a heuristic key based routing in which each file was associated with a key, and files with similar keys tended to cluster on a similar set of nodes. Queries were likely to be routed through the network to such a cluster without needing to visit many peers. However, Freenet did not guarantee that data would be found.

Distributed hash tables use a more structured key based routing in order to attain both the decentralization of Gnutella and Freenet, and the efficiency and guaranteed results of Napster. One drawback is that, like Freenet, DHTs only directly support exact-match search, rather than keyword search, although that functionality can be layered on top of a DHT.

The first four DHTs—CAN, Chord, Pastry, and Tapestry—were introduced about the same time in 2001. Since then this area of research has been quite active. Outside academia, DHT technology has been adopted as a component of BitTorrent and in the Coral Content Distribution Network

Properties

DHTs characteristically emphasize the following properties:

  • Decentralisation: the nodes collectively form the system without any central coordination.
  • Scalability: the system should function efficiently even with thousands or millions of nodes.
  • Fault tolerance: the system should be reliable (in some sense) even with nodes continuously joining, leaving, and failing.

A key technique used to achieve these goals is that any one node needs to coordinate with only a few other nodes in the system -- most commonly, Θ(logn) of the n participants (see below) -- so that only a limited amount of work needs to be done for each change in membership.

Some DHT designs seek to be secure against malicious participants and to allow participants to remain anonymous, though this is less common than in many other peer-to-peer (especially file sharing) systems; see anonymous P2P.

Finally, DHTs must deal with more traditional distributed systems issues such as load balance, data integrity, and performance (in particular, ensuring that operations such as routing and data storage or retrieval complete quickly).

Structure

A DHT is built around an abstract keyspace, such as the set of 160-bit strings. Ownership of the keyspace is split among the participating nodes according to a keyspace partitioning scheme. The overlay network connects the nodes, allowing them to find the owner of any given key in the keyspace. (This design decomposition has been suggested in (Naor and Wieder, 2003) and (Manku, 2004).)

Once these components are in place, a typical use of the DHT for storage and retrieval might proceed as follows. Suppose the keyspace is the set of 160-bit strings. To store a file with given filename and data in the DHT, the SHA1 hash of filename is found, producing a 160-bit key k. Thereafter, a message put(k,data) may be sent to any node participating in the DHT. The message is forwarded from node to node through the overlay network until it reaches the single node responsible for key k as specified by the keyspace partitioning, where the pair (k,data) is stored. Any other client can then retrieve the contents of the file by again hashing filename to produce k and asking any DHT node to find the data associated with k with a message get(k). The message will again be routed through the overlay to the node responsible for k, which will reply with the stored data.


#65 Bonjour

Posted by Stefan Rusu on 26 August 2011 - 11:32 AM

Bonjour, formerly Rendezvous, is Apple's trade name for its implementation of the Zeroconf specification framework, a computer network technology used in Apple's Mac OS X from version 10.2 onwards. It uses standard DNS packets in a new way. Thus it is a new service, but it is using a technology that is relatively old, DNS over IP.

Bonjour is a general method to discover services on a local area network. This technology is widely used throughout Mac OS X and allows users to set up a network without any configuration. Currently it is used by Mac OS X and on other operating systems to find printers and file sharing servers. It is also used by iTunes to find shared music, iPhoto to find shared photos, iChat, Adium, Fire, Skype and the Gizmo Project to find other users on the local network, TiVo Desktop to find digital video recorders, SubEthaEdit to find document collaborators, and OD4Contact to find and share contacts information. Additionally it is used by Safari to find local web servers and configuration pages for local devices, and by Asterisk to advertise telephone services along with configuration parameters to VoIP phones and dialers. Without special DNS configuration, Bonjour only works on a single subnet, which is usually a small area.

Bonjour is sometimes misunderstood to make services on a personal computer (for instance, file sharing) available to the public Internet, which could be considered a security risk. In fact, Bonjour does not provide any extra access to services, even on the same local area network (LAN); it merely announces ("advertises") their existence. For example, a user can browse a list of nearby computers which share files Bonjour on these computers has told the user that the service is available but he or she must still provide a password to access any protected files on these machines. Additionally, Bonjour works only in a close range; by default, its messages only reach users of the same subnet. Thus, the only security impact of Bonjour is that advertised services are no longer protected by security through obscurity within the local subnet. If the services are protected through a means other than obscurity, they will remain protected.

Bonjour was formerly named Rendezvous prior to the release of Mac OS X v10.4, but the name was changed due to a 2004 trademark settlement between Apple and Tibco Software Inc. Tibco had marketed a product with the name Rendezvous before Apple released the technology. It was widely rumored in 2004 that the new name would be OpenTalk, but this name was not picked (possibly due to the similarities to LocalTalk and PowerTalk).

Bonjour services are implemented at the application level largely using standard TCP/IP calls, rather than in the operating system. Although Mac OS X provides various Bonjour services, Bonjour works on other operating systems. Apple has made the source code of the Bonjour multicast DNS responder, the core component of service discovery, available as a Darwin open source project. The project provides source code to build the responder daemon for a wide range of platforms, including Mac OS 9, Mac OS X, Linux, *BSD, Solaris, VxWorks, and Windows. In addition, Apple provides a user-installable set of services called Bonjour for Windows as well as Java libraries. To date, however, only a small number of non-Apple programs, such as Cerulean Studios' Trillian Pro 3 and e, a collaborative text editor for Microsoft Windows, use Bonjour on non-Macintosh platforms.


#64 ADS (Alternate Data Streams)

Posted by Stefan Rusu on 26 August 2011 - 11:10 AM

Alternate data streams allows files to be associated with more than one data stream. For example, a file such as text.txt can have an ADS with the name of text.txt:secret.txt (of form filename:ads) that can only be accessed by knowing the ADS name or by specialized directory browsing programs. Alternate streams are not detectable in the original file's size but are lost when the original file (i.e. text.txt) is deleted with a RemoveFile or RemoveFileTransacted call (or a call that uses those calls), or when the file is copied or moved to a partition that doesn't support ADS (e.g. a FAT partition, a floppy disk, or a network share). While ADS is a useful feature, it can also easily eat up hard disk space if unknown either through being forgotten or not being detected.


#58 Soft32 Updater 1.0.1.2 available

Posted by Soft32 Admin on 22 August 2011 - 12:43 PM

  • New features and improvements
    • Improved program identification accuracy
    • Improved program detection algorithms - Soft32 Updater now builds a more comprehensive list of your installed programs
    • 100% availability for all setup prerequisites
  • Bug fixes
    • You will never need to restart your computer to finish Soft32 Updater installation
    • Fixed 'The application has encountered a connection problem!

Latest version can be download from here: http://updater.soft32.com/download



#33 How to uninstall the Soft32 Toolbar

Posted by Adrian on 08 March 2011 - 12:35 PM

How to uninstall the Soft32 Toolbar from your Computer

1. Click Windows Start.

2. Select Control Panel.

uninstall1.png

3. View the list of programs.

If you're using Windows XP, click the Add or Remove Programs link.
If you're using Windows Vista/7, under Programs, click the Uninstall a program link.

uninstall2.png

It may take a while for this page to open, but when it does, you’ll see a list of your installed programs.

4. Locate and select Soft32 Toolbar in the list of installed programs.

5. Start the removal.

If you're using Windows XP, to the right of the program name, click the Remove button.
If you're using Windows Vista/7, above the list of programs, click the Uninstall button.

uninstall3.png

6. When prompted, confirm the removal of Soft32 Toolbar by clicking Yes.


How to uninstall the Soft32 Toolbar from Mozilla Firefox

The first step for uninstalling the Soft32 Toolbar from Firefox (all versions) is to go to the 'Tools' section of the menu (as seen in the picture below). Next, you need to go to the 'Add-ons' management section.

Image 1.png

Here, you will find listed the Soft32 Toolbar among other add-ons. To remove the Soft32 Toolbar, click 'uninstall', and a confirmation window will pop-up prompting for the Soft32 Community Toolbar removal.

Image 2.png

Click 'Uninstall' again and a yellow bar will show up on the 'Add-ons' management section prompting you to restart Firefox in order that the changes would be complete.

Image 4.png

Image 5.png

Optionally, the session restore confirmation dialog window will pop-up before restarting Firefox. Click 'Restart'.

Image 6.png

When Firefox restarts, a webpage will be opened confirming the removal of the Soft32 Toolbar.

Image 7.png

How to uninstall the Soft32 Toolbar from Internet Explorer

In case you are an Internet Explorer user, you can remove the Soft 32 toolbar only by following the control panel procedure.

If you don't want to definitely erase the toolbar and keep it for later usage, you can disable its components from the Add-on Manager included in the Tools section of Internet Explorer. See the image below:

removesoft32.png

It's enough to disable a single component, and the browser will be able to automatically detect and disable the rest of them.

removesoft3201.png

After a manual restart the Soft32 toolbar will disappear from Internet Explorer interface but can be re-activated anytime from the Add-on Manager.


#29 How to download from Soft32.com using: Safari

Posted by Volvosan on 22 November 2010 - 10:52 AM

Here's how to download a program or a file from Soft32.com using Safari. Search for the desired file, click the download button and wait as the download process should start automatically. If it doesn't start, you have to click the download link button.

Note: The download might start automatically so if it does, choose "Save File" and jump to step 3.

1.Click on the download link for the program you want to download. You might find multiple download links to the same program but you only need to choose one of these links.

safari download link.jpg

2.You'll be asked if you want to save the file or run it from its current location - click "Save" and the downloader manager will appear.

dialog box safari.jpg

3.Select the folder where you want to save the program or file. In case you have chosen to push "Open", the program will be automatically downloaded in a default location chosen by Safari and the installer of the application will be activated.

4.When the download is complete, the file will appear in Safari's download manager. Right click on the file you've just downloaded and click the "Open" button to run the program. Or just double click it.

safari download manager.jpg

5.What happens next will depend on the type of file you downloaded. But in most cases the program installer will be run.

The Download is not working?

There might be several reasons why a download cannot be made:

- the download link is broken (the publisher or the developer of the software has removed, moved or re-named the file on their servers). If this is the case, please report us the error and we will try to provide an accessible download link as soon as possible
- the download site is not available or offline for various reasons (technical problems, maintenance, etc)
- you cannot connect to the download site for various reasons (your internet provider has technical problems, maintenance, etc. or your network admin has blocked access to the site or to all downloads, your firewall is blocking the access to the site, etc.)


#27 How to download from Soft32.com using: Google Chrome

Posted by Adrian on 19 November 2010 - 03:31 PM

How can I download my file from Soft32.com using Chrome?

Using Google Chrome to download files should be a simple task: here's a couple of guidelines how to download files from soft32.com using Chrome.

1. Select the download link of the program you wish to download and click it.

Chrome_click_download_link.png

2. On the bottom of your Chrome window, you'll notice a dialog prompting you to save or discard the file. In case you wish to download the selected file, click 'save' and the file will be downloaded on to your computer.

Chrome_confirmation_save_file.png

3. When the download is complete, you can execute the downloaded file or you can view the file in the folder where it has been downloaded.

Chrome_file_saved.png
Chrome_file_open__show_in_folder.png

Where did my download go?

One of the biggest problems with downloading files is figuring out where they go once they're on your hard drive. Creating and using a download folder eliminates that problem. Right-click your desktop and hover your mouse pointer over New until a menu pops up. Select Folder from that menu to create a new folder on your desktop. When the folder appears, its name, New Folder, should be highlighted already, so you can just type your name for it, such as Downloads. Though you don't need to leave this folder on your desktop, make sure you remember where you put it.

In order to set your folder used by Chrome for downloads, you need to go to the 'Options' menu and there select the 'Under the hood' tab. Scroll down to the 'Download' settings and select your favorite download folder, so you can always find your downloaded files.

Chrome_options.png
Chrome_download_folder.png

Download still not working?

There might be several reasons why a download cannot be made:
- the download link is broken (the publisher or the developer of the software has removed, moved or re-named the file on their servers). If this is the case, please report us the error and we will try to provide an accessible download link as soon as possible;
- the download site is not available or offline for various reasons (technical problems, maintenance, etc);
- you cannot connect to the download site for various reasons (your internet provider has technical problems, maintenance, etc. or your network admin has blocked access to the site or to all downloads, your firewall is blocking the access to the site, etc.)


#113 How to update my software or delete it?

Posted by NetBrain on 22 August 2012 - 03:37 AM

Hi,

I submitted a software to soft32 site. I want to update some info.
Does anybody know how to update the software?
Or how to delete it? Maybe I can firstly delete it and then submit an update one.

Thanks!


#72427 How to Play Blu-Ray Disc Movie with VLC in Windows 8 64-bit/32-bit

Posted by JerryEdison001 on 23 June 2013 - 11:18 AM

On some Windows 8 reviews, like many other publications that got their information from Microsoft, originally reported that the Media Center and Pro Pack contain codecs for both DVD and Blu-ray movie playback. This is false. They only facilitate DVD playback, not Blu-ray. The quote most sites are referencing comes from Microsoft's blog. And, like most of the official Windows 8 pre-release literature, it contains ambiguous language regarding what's actually included in Windows 8:

"Windows Media Player will continue to be available in all editions, but without DVD playback support. For optical discs playback on new Windows 8 devices, we are going to rely on the many quality solutions on the market, which provide great experiences for both DVD and Blu-ray."

Further down, in the same blog post, are the actual contents of the Media Center and Pro Pack:
"...Media Center, including DVD playback (in Media Center, not in Media Player), broadcast TV recording and playback (DBV-T/S, ISDB-S/T, DMBH, and ATSC), and VOB file playback."
Again, the Media Center Pack does not include codecs for Blu-ray playback.

So you may look for a free way to play Blu-ray discs movie on Windows 8, so VLC media player will be the best way to play Blu-Ray in Windows 8 64-bit or Windows 8 32 bit for free.

To better support Blu-Ray playback in Windows 8, VideoLAN and the VLC development team present the fifth version of “Twoflower” which is VLC 2.0.4. The a major updated VLC 2.0.4 introduces an important number of fixes and improvements especially for Blu-Ray under Windows 8. However, for legal reasons, AACS and BD+ DRM libraries and keys still are not shipped.

This article will guide you to download and place the AACS and BD+ DRM libraries and keys in order to play Blu Ray on Windows 8 with VLC for Free.

Step 1: Install the latest nightly of VLC 2.0: Go to: VideoLan,then download the latest version for your system.

Step 2: Download the Blu-ray playback addon pack from: here, and install the Key file from addon pack – “KEYDB.cfg”

Windows 8 – [place in folder named "aacs" located in appdata directory]
* Open your user area (start->”your username”)
* Enable view hidden files and folders (Organise->Folder and Search Options->View{tab} and select “show hidden files…”->select ok)
* Open “AppData” directory
* Create a folder and name it “aacs” {no quotations}
* Place the KEYDB.cfg file in this folder directly from the unzipped Blu-ray playback addon pack.

Step 3: Download Install AACS dynamic library for VLC to use:

Windows 8 32bit: put that file in your VLC directory
Windows 8 64bit: put that file in your VLC directory


Windows 8 – [Place in VLC program directory]

* Open “Computer”
* Open “Local Disk (C:)”
* Open “Program Files” [Or "Program Files (x86)" if running 64bit]
* Navigate to “VLC” directory
* Move appropriate file from unzipped Blu-ray playback addon pack to this directory (file located in “aacs/windows 32″ directory in pack)

Now, you can easily play Blu-Ray disc with VLC on Windows 8 64-bit or Windows 8 32 bit for free. Note: VLC 2.0 still doesn’t have menu support yet.

Tip: If VLC still can't help you play Blu-ray disc movie on Windows 8, you could visit here to learn more
 

 




#72426 New Glary Utilities - vs the OLD

Posted by BobK on 15 June 2013 - 07:14 PM

I don't like the new Glary Utilities..  

 

The old one was straightforward,  I liked the startup fixerupper, and the disk cleaning..

This new version is NOT easy to understand compared to the old.  Yes,  I got used to

the old format, and yes I had drastic (& this was) change in appearance for change's sake..

 

I did what I thought was disk cleanup and only 1.6 Mb was found!!?  No way.. there is lots

more crap out there (shades of the old Crap Cleaner ;-) ..

 

Come on guys,  fix your interface - it is not as easy to understand as the old one  (to wit:

I NEVER had to come to your site to find out how to use it.. & here I am and STILL can't

fathom where the hell your old functions disappeared to.

 

---- edit add on.

Just reran the disk clean, and 0 Mb were found,  then ran CCleaner and *IT* found 6.8Mb more!

You didn't even look at cookies or adobe or windows explorer!   Those were loaded as was  

Windows MS Antimalware ..

 

--- 2nd edit add on..

This gets better..   I had ended the previous,  having found nothing on the second run, and ran

CCleaner - which found much more..  So I restarted Glary, and did a clean disk again to see

if it'd be negative (as so much more it missed was cleaned ;-)  .. AND THIS TIME - it finds

142 files  for 4.94 MB!! ..  WHAT?       & The old version gave me a 'file list'  the new one,  I  

have just found it hidden under a button click ..  your default exceeds the size of the window,

where the file list doesn't .. Why not leave file list as the default?   

THEN, when I had it clean this new 5MB found,  it reverted to the incomprehensible result,

and clicking File List again shows - nothing..   ..

sigh...




#72422 Printers\Samsung SCX-4x21 Series

Posted by lifeed on 11 April 2013 - 07:15 AM

Light printing in middle of page




#72418 Inventory Manager,

Posted by dsballew on 20 March 2013 - 09:03 PM

We downloaded the free trial and paid the $95 fee for Inventory Manager 3.2.  Once the free trial was over we did not receive a new activation code nor did the software continue to function.  What do we need to do to continue?

 

Thank you!




#72417 Iniciating Mhotspot error

Posted by progallo on 07 February 2013 - 02:11 PM

Hi Mhotspot was runnig perfectly i really liked it, but just yesterday it asked to make an upgrade otherwise the program wouldnt run, so i did download the new version and since then i cant use it, whe i click on "start hotspot" botton i t brings me  this error in the picture. I have 2indows 7 32 bits. what should i do? thanks

Attached Thumbnails

  • Mhotspot prob.jpg



#59 How we rate popularity

Posted by volvo_san on 25 August 2011 - 11:42 AM

When calculating popularity more factors are taken into consideration besides the number of downloads:

- last week downloads count
- user ratings (the more they are, the more they matter)


#172 Is supermario bros X legal to download?/

Posted by Super Mario Playa on 25 January 2013 - 12:33 PM

Is supermario bros X legal to download?  Nintendo has created a game by this name but im still curious did some make this version or is it an ilegal??