Super Dimension Fortress (abbreviated as ''SDF'', also known as freeshell.org) is a

non-profit A nonprofit organization (NPO), also known as a nonbusiness entity, nonprofit institution, not-for-profit organization, or simply a nonprofit, is a non-governmental (private) legal entity organized and operated for a collective, public, or so ...

public access

UNIX Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

shell provider on the

Internet The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...

. It has been in continual operation since 1987 as a non-profit

social club A social club or social organization may be a group of people or the place where they meet, generally formed around a common interest, occupation or activity with in an organizational association known as a Club (organization), club. Exampl ...

. The name is derived from the Japanese

anime is a Traditional animation, hand-drawn and computer animation, computer-generated animation originating from Japan. Outside Japan and in English, ''anime'' refers specifically to animation produced in Japan. However, , in Japan and in Ja ...

series ''

Super Dimension Fortress Macross is a Japanese science fiction anime television series. It is the first part of the ''Super Dimension'' trilogy and the ''Macross'' franchise. The series aired in Japan from October 1982 to June 1983. According to story creator Shoji Kawam ...

''; the original SDF server was a

Bulletin board system A bulletin board system (BBS), also called a computer bulletin board service (CBBS), is a computer server running list of BBS software, software that allows users to connect to the system using a terminal program. Once logged in, the user perfor ...

created by Ted Uhlemann for fellow Japanese anime fans. From its BBS roots, which have been well documented as part of the '' BBS: The Documentary'' project, SDF has grown into a

feature-rich A feature is "a prominent or distinctive user-visible aspect, quality, or characteristic of a software system or systems", as defined by Kang et al. At the implementation level, "it is a structure that extends and modifies the structure of a give ...

provider serving members around the world.

Services

SDF provides free

Unix shell A Unix shell is a Command-line_interface#Command-line_interpreter, command-line interpreter or shell (computing), shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command languag ...

access,

web Web most often refers to: * Spider web, a silken structure created by the animal * World Wide Web or the Web, an Internet-based hypertext system Web, WEB, or the Web may also refer to: Computing * WEB, a literate programming system created by ...

hosting and many other features at the user membership level. Additional programs, capabilities and resources are available at "patron" and "sustaining" level memberships, which are granted with one-time or recurring dues in support of the SDF system. The SDF network of systems that serves its membership currently includes

NetBSD NetBSD is a free and open-source Unix-like operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was fork (software development), forked. It continues to ...

servers for regular use (running on

DEC Alpha Alpha (original name Alpha AXP) is a 64-bit reduced instruction set computer (RISC) instruction set architecture (ISA) developed by Digital Equipment Corporation (DEC). Alpha was designed to replace 32-bit VAX complex instruction set computers ( ...

- and

AMD Opteron Opteron is AMD's x86 former server and workstation processor line, and was the first processor which supported the AMD64 instruction set architecture (known generically as x86-64). It was released on April 22, 2003, with the ''SledgeHammer'' co ...

-powered hardware) as well as

retrocomputing Retrocomputing is the current use of Vintage computer, older computer hardware and software. Retrocomputing is usually classed as a hobby and recreation rather than a practical application of technology; enthusiasts often collect rare and valuabl ...

environments: a TWENEX system running the Panda Distribution TOPS-20 MONITOR 7.1 on two

XKL XKL, LLC is an American company that develops optical transport networking technologies. Founded in 1991 and based in Redmond, Washington, XKL is led by Cisco Systems co-founder Len Bosack. History of XKL In its earliest days XKL developed, an ...

TOAD-2 computers, a

Symbolics Symbolics, Inc., is a privately held American computer software maker that acquired the assets of the former manufacturing company of the identical name and continues to sell and maintain the Open Genera Lisp (programming language), Lisp sy ...

Genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

system, and an ITS system SDF also hosts its own instances of

social media Social media are interactive technologies that facilitate the Content creation, creation, information exchange, sharing and news aggregator, aggregation of Content (media), content (such as ideas, interests, and other forms of expression) amongs ...

websites from the

fediverse The Fediverse (commonly shortened to fedi) is a collection of social networking services that can communicate with each other (formally known as Federation (information technology), federation) using a common protocol. Users of different websites ...

, including a

Mastodon A mastodon, from Ancient Greek μαστός (''mastós''), meaning "breast", and ὀδούς (''odoús'') "tooth", is a member of the genus ''Mammut'' (German for 'mammoth'), which was endemic to North America and lived from the late Miocene to ...

microblogging service, a

Pixelfed Pixelfed is a free and open-source image sharing social network service. The platform uses a decentralized architecture which is roughly comparable to e-mail providers, meaning user data is not stored on one central server. It uses the ActivityP ...

image sharing service, and a

Lemmy Ian Fraser Kilmister (24 December 1945 – 28 December 2015), better known as Lemmy Kilmister or simply Lemmy, was a British musician. He was the founder, lead vocalist, bassist and primary songwriter of the metal band Motörhead, of which he ...

link aggregator with discussion. In addition, SDF hosts a

Matrix Matrix (: matrices or matrixes) or MATRIX may refer to: Science and mathematics * Matrix (mathematics), a rectangular array of numbers, symbols or expressions * Matrix (logic), part of a formula in prenex normal form * Matrix (biology), the m ...

chat server.

Free Membership Services

SDF provides free Unix shell access and web hosting to its users. In addition, SDF provides increasingly rare services such as

dial-up internet access Dial-up Internet access is a form of Internet access that uses the facilities of the public switched telephone network (PSTN) to establish a connection to an Internet service provider (ISP) by dialing a telephone number on a conventional telepho ...

, and

Gopher Pocket gophers, commonly referred to simply as gophers, are burrowing rodents of the family Geomyidae. The roughly 41 speciesSearch results for "Geomyidae" on thASM Mammal Diversity Database are all endemic to North and Central America. They ar ...

hosting. SDF is one of very few organizations in the world still actively promoting the gopher protocol, an alternate protocol that existed at the introduction of the modern World Wide Web. The system contains thousands of programs and utilities, including a

command-line A command-line interface (CLI) is a means of interacting with software via commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user-friendly alternativ ...

BBS called BBOARD, a chat program called COMMODE, email programs, webmail, social networking programs, developer tools and games. Most of the applications hosted at SDF are accessed via the command-line, and SDF provides K-12 and college classrooms the free use of computing resources for Unix education. SDF also supports multiple retrocomputing experiences, including free user accounts on

TOPS-20 The TOPS-20 operating system by Digital Equipment Corporation (DEC) is a proprietary OS used on some of DEC's 36-bit mainframe computers. The Hardware Reference Manual was described as for "DECsystem-10/DECSYSTEM-20 Processor" (meaning the DEC PDP ...

and Symbolics Genera operating systems that are running live and accessible via the internet.

Dues-paying membership services

There are additional services that are made available on SDF systems to users who apply to be "patrons" and pay one-time dues of US$36 for "Lifetime Membership", and still more services available for at US$9/quarter "sustaining membership", including services such as

NextCloud Nextcloud is a suite of Client–server model, client-server software for creating and using file hosting services. It can integrate with the Collabora Online and OnlyOffice office suites. It can be hosted in the Cloud computing, cloud or On-pre ...

, and access to a large disc-array server. At the sustaining membership level, members are authorized to validate new users to SDF's free User level of membership (otherwise, new members may submit US$1 to be validated). There are also specialized privileges which patron and sustaining level users can obtain to gain access to particular technologies, including

mailing lists A mailing list is a collection of names and addresses used by an individual or an organization to send material to multiple recipients. Mailing lists are often rented or sold. If rented, the renter agrees to use the mailing list only at contra ...

Voice-over-IP Voice over Internet Protocol (VoIP), also known as IP telephony, is a set of technologies used primarily for voice communication sessions over Internet Protocol (IP) networks, such as the Internet. VoIP enables voice calls to be transmitted as ...

Database In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and a ...

s, Virtual Private Network (VPN), and

Domain registration Domain registration is the process of acquiring a domain name from a domain name Domain name registrar, registrar. History In 1993 the U.S. Department of Commerce, in conjunction with several public and private entities, created InterNIC to mai ...

History

In 1987, Ted Uhlemann started SDF on an

Apple IIe The Apple IIe (styled as Apple //e) is the third model in the Apple II series of personal computers produced by Apple Inc., Apple Computer. It was released in January 1983 as the successor to the Apple II Plus. The ''e'' in the name stands for ...

microcomputer A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (P ...

running "Magic City Micro-BBS" under

ProDOS ProDOS is the name of two similar operating systems for the Apple II of personal computer. The original ProDOS, renamed ProDOS 8 in version 1.2, is the last official operating system usable by all 8-bit Apple II computers, and was distributed ...

. The system was run as a "Japanese Anime SIG" known as the SDF-1. In 1989, Uhlemann and Stephen Jones operated SDF very briefly as a DragCit Citadel BBS before attempting to use an Intel x86 UNIX clone called

Coherent Coherence is, in general, a state or situation in which all the parts or ideas fit together well so that they form a united whole. More specifically, coherence, coherency, or coherent may refer to the following: Physics * Coherence (physics ...

. Unhappy with the restrictive menu driven structure of existing BBS systems, Uhlemann, Jones and Daniel Finster created a

System V Unix System V (pronounced: "System Five") is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, an ...

BBS in 1990, initially running on an

i386 The Intel 386, originally released as the 80386 and later renamed i386, is the third-generation x86 architecture microprocessor from Intel. It was the first 32-bit processor in the line, making it a significant evolution in the x86 archite ...

system, which later became an AT&T 3B2/400 and 500, and joined the lonestar.org

UUCP UUCP (Unix-to-Unix Copy) is a suite of computer programs and communications protocol, protocols allowing remote execution of commands and transfer of computer file, files, email and netnews between computers. A command named is one of the prog ...

network. Three additional phone lines were installed in late 1991. In the fall of 1992, Uhlemann and Finster left SDF to start one of the first commercial

companies in Texas, Texas Metronet. SDF continued to grow, expanding to ten lines in 1993 along with a

SLIP Slip or The Slip may refer to: * Slip (clothing), an underdress or underskirt Music * The Slip (band), a rock band * ''Slip'' (album), a 1993 album by the band Quicksand * ''The Slip'' (album) (2008), a.k.a. Halo 27, the seventh studio al ...

connection provided by cirr.com. UUCP was still heavily relied upon for

Usenet Usenet (), a portmanteau of User's Network, is a worldwide distributed discussion system available on computers. It was developed from the general-purpose UUCP, Unix-to-Unix Copy (UUCP) dial-up network architecture. Tom Truscott and Jim Elli ...

news and email. In 1997, SDF (then with about 15,000 users) migrated to

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

. The migration to Linux marked a turning point, as the system started coming under attack like it never had before in its history. Jones calls the Linux period ''the dark age''. Bye-bye-leenox

In part due to the number of attacks undertaken by malicious users against SDF, the years 2000 and 2001 saw SDF migrate from Linux to

and from Intel

x86 x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel, based on the 8086 microprocessor and its 8-bit-external-bus variant, the 8088. Th ...

. This migration included relocation of the servers from

Lewisville, Texas Lewisville ( ) is a city in the U.S. state of Texas, located in Denton County with portions extending into Dallas County. As one of the Mid-Cities within the Dallas–Fort Worth metroplex, the 2020 census reported a population of 111,822. O ...

Seattle Seattle ( ) is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the 18th-most populous city in the United States. The city is the cou ...

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

. The Linux system was officially decommissioned on August 17, 2001. The occasion was captured in
COMMODE Log
preserved by one of SDF's users. (COMMODE is a DEC TOPS-20 chat system ported by Jones to

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

as an executable

KornShell KornShell (ksh) is a Unix shell which was developed by David Korn (computer scientist), David Korn at Bell Labs in the early 1980s and announced at USENIX Annual Technical Conference, USENIX on July 14, 1983. The initial development was base ...

script.) Although SDF Public Access UNIX System was registered as an operating business in 1993 according to the Dallas County Records Office, it wasn't until October 1, 2001, that the SDF Public Access UNIX System was formed as a

Delaware Delaware ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic and South Atlantic states, South Atlantic regions of the United States. It borders Maryland to its south and west, Pennsylvania to its north, New Jersey ...

not-for-profit corporation and subsequently granted

501(c)(7) A 501(c) organization is a nonprofit organization in the federal law of the United States according to Internal Revenue Code (26 U.S.C. § 501(c)). Such organizations are exempt from some federal income taxes. Sections 503 through 505 set ou ...

non-profit membership club status by the

IRS The Internal Revenue Service (IRS) is the revenue service for the Federal government of the United States, United States federal government, which is responsible for collecting Taxation in the United States, U.S. federal taxes and administerin ...

. SDF had operated under the auspice of the MALR corporation between 1995 and 2001. , SDF was composed of 47,572 users from around the world. SDF users include engineers, computer programmers, students, artists and professionals. SDF.org is a development site for

, and in 2018, SDF was the largest NetBSD installation in the world.

References

External links

*
@sdf_pubnix on twitter
*
2012 Feature Story on NPR, "In Noisy Digital Era, 'Elegant' Internet Still Thrives"BBS: The Documentary
at the

Internet Archive The Internet Archive is an American 501(c)(3) organization, non-profit organization founded in 1996 by Brewster Kahle that runs a digital library website, archive.org. It provides free access to collections of digitized media including web ...