FidoNet Deployments
Most FidoNet deployments were designed in a modular fashion. A typical deployment would involve several applications that would communicate through shared files and directories, and switch between each other through carefully designed scripts or batch files. However, monolithic software that encompassed all required functions in one package is available, such as D'Bridge. Such software eliminated the need for custom batch files and is tightly integrated in operation. The preference of deployment was that of the operator and there were both pros and cons of running in either fashion.
Arguably the most important piece of software on a DOS-based Fido system was the FOSSIL driver, which was a small device driver which provided a standard way for the Fido software to talk to the modem. This driver needed to be loaded before any Fido software would work. An efficient FOSSIL driver meant faster, more reliable connections.
Mailer software was responsible for transferring files and messages between systems, as well as passing control to other applications, such as the BBS software, at appropriate times. The mailer would initially answer the phone and, if necessary, deal with incoming mail via FidoNet transfer protocols. If the mailer answered the phone and a human caller was detected rather than other mailer software, the mailer would exit, and pass control to the BBS software, which would then initialise for interaction with the user. When outgoing mail was waiting on the local system, the mailer software would attempt to send it from time to time by dialing and connecting to other systems who would accept and route the mail further. Due to the costs of toll calls which often varied between peak and off-peak times, mailer software would usually allow its operator to configure the optimal times in which to attempt to send mail to other systems.
BBS software was used to interact with human callers to the system. BBS software would allow dial-in users to use the system's message bases and write mail to others, locally or on other BBSes. Mail directed to other BBSes would later be routed and sent by the mailer, usually after the user had finished using the system. Many BBSes also allowed users to exchange files, play games, and interact with other users in a variety of ways (i.e.: node to node chat).
A scanner/tosser application, such as FastEcho, FMail, TosScan and Squish, would normally be invoked when a BBS user had entered a new FidoNet message that needed to be sent, or when a mailer had received new mail to be imported into the local messages bases. This application would be responsible for handling the packaging of incoming and outgoing mail, moving it between the local system's message bases and the mailer's inbound and outbound directories. The scanner/tosser application would generally be responsible for basic routing information, determining which systems to forward mail to.
In later times, message readers or editors that were independent of BBS software were also developed. Often the System Operator of a particular BBS would use a devoted message reader, rather than the BBS software itself, to read and write FidoNet and related messages. One of the most popular editors in 2008 was GoldED+. In some cases FidoNet nodes, or more often FidoNet points, had no public bulletin board attached, and existed only for the transfer of mail for the benefit of the node's operator. Most nodes in 2009 had no BBS access, but only points, if anything.
The original Fido BBS software, and some other FidoNet-supporting software from the 1980s, is no longer functional on modern systems. This is for several reasons, including problems related to the Y2K bug. In some cases, the original authors have left the BBS or shareware community, and the software, much of which was closed source, has been rendered abandonware.
Several DOS based legacy FidoNet Mailers such as FrontDoor, Intermail, MainDoor and D'Bridge from the early 1990s can still be run today under Windows without a modem, by using the freeware NetFoss Telnet FOSSIL driver, and by using a Virtual Modem such as NetSerial. This allows the mailer to "Dial" an IP address or hostname via Telnet, rather than dialing a real POTS phone number. There are similar solutions for Linux such as MODEMU (modem emulator) which has limited success when combined with DOSEMU (DOS emulator). Mail Tossers such as FastEcho and FMail are still used today under both Windows and Linux/DOSEMU.
There are several modern Windows based FidoNet Mailers available today with source code, including Argus, Radius, and Taurus. MainDoor is another Windows based Fidonet mailer, which also can be run using either a modem or directly over TCP/IP. Two popular free and open source software FidoNet mailers for Unix-like systems are the binkd (cross-platform, IP-only, uses the binkp protocol) and qico (supports modem communication as well as the IP protocol of ifcico and binkp).
On the hardware side, Fido systems were usually well-equipped machines, for their day, with quick CPUs, high-speed modems and 16550 UARTs, which were at the time an upgrade. As a Fidonet system was usually a BBS, it needed to quickly process any new mail events before returning to its 'waiting for call' state. In addition, the BBS itself usually necessitated lots of storage space. Finally, a FidoNet system usually had at least one dedicated phoneline. Consequently, operating a Fidonet system often required significant financial investment, a cost usually met by the owner of the system.
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