Working with a newly hired advertising agency, Infocom created the first feelies for this game: extra items that gave more information than could be included within the digital game itself.

In addition, Zork was written on the PDP-10, and Infocom used several PDP-10s for game development and testing.

The Z-machine is a virtual machine that was developed by Joel Berez and Marc Blank in 1979 and used by Infocom for its text adventure games.

The compiler ( called Zilch ) which Infocom used to produce its story files, has never been released, although documentation of the language used ( called ZIL, for Zork Implementation Language ) still exists and an open-source replacement ( called ZILF ) has been written.

* Zork Implementation Language, the language which Infocom used to produce their works of interactive fiction

* Infocom used the Z-machine to make its software applications more portable.

It was also the first of the " Interactive Fiction Plus " line, meaning that AMFV had greater memory requirements, unlike earlier Infocom games that used a less advanced version of the company's Z-machine interpreter.

The number 69, 105 was used as an in-joke at the United States computer game manufacturer Infocom.

* A software compiler used by Infocom to create Z-machine games.

Infocom borrowed heavily and used a sole source of venture capital.

Infocom used the term feelie to refer to the extra content included with the boxed versions of their interactive fiction computer games.

The Infocom game Planetfall is a sort of sequel, since the technology gained in " Starcross " is used in the spaceships of that game, set somewhat further in the future.

Infocom had used these concepts before only in a rather limited way in Zork I and III.

Previous games by Infocom used a parser evolved from the one in Zork I, but for Zork Zero, they designed a new LALR parser from scratch.

Besides the high quality of their interactive fiction games, Infocom was also known for feelies: extra items included in each game package related to the story, and sometimes used as copy protection.

The feelies pioneered by text adventure company Infocom include many examples, such as blueprints, maps, documents, and publications designed within the context of each game's fictional setting.

Infocom was a software company, based in Cambridge, Massachusetts, that produced numerous works of interactive fiction.

Infocom was founded on June 22, 1979 by MIT staff and students led by Dave Lebling, Marc Blank, Albert Vezza, and Joel Berez and lasted as an independent company until 1986 when it was bought by Activision.

Activision finally shut down the Infocom division in 1989, although they released some titles in the 1990s under the Infocom Zork brand.

Activision abandoned the Infocom trademark in 2002.

The Infocom trademark is currently held by Pete Hottelet's Omni Consumer Products, who registered the name around the same time as Klaeffling in 2007.

Infocom games are text adventures where users direct the action by entering short strings of words to give commands when prompted.

Infocom games were written using a roughly LISP-like programming language called ZIL ( Zork Implementation Language or Zork Interactive Language — it was referred to as both ) that compiled into a byte code able to run on a standardized virtual machine called the Z-machine.

With the Z-machine, Infocom was able to release most of their games for most popular home computers of the day simultaneously — the Apple II family, Atari 800, IBM PC compatibles, Amstrad CPC / PCW ( one disc worked on both machines ), Commodore 64, Commodore Plus / 4, Commodore 128, Kaypro CP / M, Texas Instruments TI-99 / 4A, the Mac, Atari ST, the Commodore Amiga and the Radio Shack TRS-80.

Inspired by Colossal Cave, Marc Blank and Dave Lebling created what was to become the first Infocom game, Zork, in 1977 at MIT's Laboratory for Computer Science.

Whereas most computer games of the era would achieve initial success and then suffer a significant drop-off in sales, Infocom titles continued to sell for years and years.

Whereas most game developers sold their games mainly in software stores, Infocom also distributed their games via bookstores.

Since their games were text-based, patrons of bookstores were drawn to the Infocom games as they were already interested in reading.

Unlike most computer software, Infocom titles were distributed under a no-returns policy, which allowed them to make money from a single game for a longer period of time.

Next, Infocom titles featured strong storytelling and rich descriptions, eschewing the day's primitive graphic capabilities, allowing users to use their own imaginations for the lavish and exotic locations the games described.

Sometimes, though, Infocom threw in puzzles just for the humor of it — if the user never ran into these, they could still finish the game just fine.

Although Infocom started out with Zork, and although the Zork world was the centerpiece of their product line throughout the Zork and Enchanter series, the company quickly branched out into a wide variety of story lines: fantasy, science-fiction, mystery, horror, historical adventure, children's stories, and others that defied categories.

In an attempt to reach out to females, Infocom also produced Plundered Hearts, which required the gamer to take the part of a heroine in a swashbuckling adventure on the high seas, and which required the heroine to use more feminine tactics to win the game, since hacking-and-slashing was not a very ladylike way to behave.

And to compete with the Leisure Suit Larry style games that were also appearing, Infocom also came out with Leather Goddesses of Phobos in 1986, which featured " tame ", " suggestive ", and " lewd " playing modes, and that was notable for including among its " feelies " a " scratch-and-sniff " card with six odors that corresponded to six cues during the game.

Infocom also released a small number of " interactive fiction paperbacks " ( gamebooks ), which were based on the games and featured the ability to choose a different path through the story.

In 1984 Infocom started putting resources into a new division to produce business products.

Reviewers were also consistently disappointed that Infocom — noted for the natural language syntax of their games — did not include a natural language query ability, which was the most expected feature for this database.

And a final disappointment was that Cornerstone was available only for IBM PCs and not any of the other platforms that Infocom supported for their games ; while Cornerstone had been programmed with its own virtual machine for maximum portability, that feature had become essentially irrelevant.

Infocom had sunk much of the money from games sales into Cornerstone ; this, in addition to a slump in computer game sales, left the company in a very precarious financial position.

* Description of ZIP ( PDF ) the Z-Language Interpreter Program ( Infocom Internal Document ), dated 3 / 23 / 89.

There are currently at least four Infocom sampler and demos available from the IF Archive as Z-machine story files which require a Z-machine interpreter to play.

Infocom compiled game code to files containing Z-machine instructions ( called story files, or Z-code files ), and could therefore port all its text adventures to a new platform simply by writing a Z-machine implementation for that platform.

Infocom produced six versions of the Z-machine.

During the 1990s, Graham Nelson drew up a Z-machine standard, based on detailed studies of the existing Infocom files.

Such virtual machines exist for several platforms, and in this respect, TADS closely follows the example of the original Infocom Z-machine, as well as modern languages such as Java and C #.

Like most Infocom games, thanks to the portable Z-machine, it was released for several platforms simultaneously.

Since all Z-machine games were produced by Infocom, there was also no chance that resources would be shipped in a format which a user's interpreter program could not handle.

This allows authors of modern games to ship one file containing everything needed to play the game, while also allowing the creation of resource files for classic Infocom games without running the risk of copyright infringement by distributing Infocom's Z-machine executable code.

This marked one of the few major additions to the Z-machine with the exception of graphics ; traditionally, Infocom had eschewed such changes in favor of expanding the parser capacity and overall size of game files.