Assembly Coder's Zenith (ACZ)

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Site URL


Dux Gregis (?)
Clement Vasseur (?)

Founding Date

November 1998

Years Active


Programmed For

TI-83+, TI-86, TI-89, TI-92+


Assembly, Flash, C/C++




83+ Asm Central
86 Asm Central
89 Asm Central

Assembly Coder's Zenith, Inc. (ACZ) was one of the best programming groups that the TI community has ever seen. While they were active, they released many programs and games that were both high-quality and innovative. They were also one of the first programming groups to branch out into making computer applications to make assembly development easier for the TI community.

Group Content

Group Staff

Group Significance

ACZ was responsible for writing many assembly programs and games for the TI-83+, TI-86, and TI-89 graphing calculators, as well as porting several assembly programs and games written by others in the TI community.

They released three commercial-quality computer applications, including the first completed calculator emulator available in the TI community called Virtual TI (coded by Rusty Wagner); a complete assembly development environment to make programming assembly on the computer easier coded by Jeremy Goetsch called Assembly Studio 8x; and a graphics development environment to make the process of developing graphics easier (coded by Rusty Wagner and Corey Taylor).

They also created assembly information repositories for the TI-83+, TI-86, and TI-89 respectively called <calculator> Central. Each site was quite comprehensive in its collection of programming information, featuring tutorials, TI-OS information, game programming, sourcecode, a FAQ, and a live chat feature.

Group Milestones

Group History


ACZ originally started out as individual webpages by various people. In particular, Matt Johnson had his own websites in 1998 called TI-86 Central (URL:, where he hosted a repository of assembly programming information for the TI-86. The ROM/RAM portion of the site (ROM/RAM Central as it was called) was taken down by the request of TI due to copyright infringement, while the TI-86 Central site was handed over to David Phillips. Matt Johnson later added the programming information on TI-86 Central to Jimi Malcolm's The Guide, located at Dux Gregis, Clement Vasseur and Brett Barwick likewise had their own programming information sites, so it was a natural progression to combine their efforts and become a group.

In November 1998, the Assembly Coder's Zenith programming group was started by Dux Gregis (?) and Clement Vasseur (?), and its membership consisted of CLEM, Dux Gregis, Brett Barwick, David Phillips, and Dave Scheltema (see November 1998 newsletter). More members joined the group over time, including Matt Johnson, James Rubingh, Rusty Wagner, Corey Taylor, and Scott Noveck. Likewise, the group products and focus expanded from providing documentation and programs and games to making commercial-quality software applications for the computer (i.e., Virtual TI, Assembly Studio, and Graphics Studio).

Group Mission Statement

(Taken from ACZ home page)

Assembly Coder's Zenith (ACZ), composed in sum of especially skilled young programmers, is a new kind of company. We strive chiefly for quality, for innovation and to provide such information and software products that can raise standards in the areas of our proficiency. Our talents in a broad range of computer-related fields enable the efficiency and cohesion that all successful Internet software companies must share, and we believe that our work in these domains resolutely embodies a prized measure of corporate professionalism. At present our attention is centered principally around select Game Boy, TI Calculator and PC platforms, although we nonetheless may accept membership from qualified persons from nearly every relevant ability.

Site URLs

The original precursor to ACZ site was hosted on Geocities(?) (URL: <insert URL>). Once the programming group started adding members and creating new programs, the ACZ programming group was officially formed and the more professional URL was adopted (i.e.,

Because Matt Johnson worked for a web development company, he had ample server space available for ACZ. Subsequently, each member was given their own third-level domain on the ACZ server, as well as each of their computer application products:

  • ACZ Frontpage —
  • 83+ Asm Central —
  • 86 Asm Central —
  • 89 Asm Central —
  • Virtual TI Emulator —
  • Assembly Studio —
  • Graphics Studio —
  • Brett's Homepage —
  • Corey's Homepage —
  • David's Homepage —
  • Dux's Homepage —
  • James' Homepage —
  • Jeremy's Homepage —
  • Matt's Homepage —
  • Rusty's Homepage —
  • Scott's Homepage —

Site Screenshots

(Screenshot of 86 Central circa 2000)
(Screenshot of ACZ homepage circa 2000)


Matt Johnson started his own site in February 1998 with assembly programming tutorials and information. The site was originally called Optic2000's TI-86 Asm Site, but he changed the name to TI-86 Central later that month. At the end of February, he decided to start a new section of the site called Rom and Ram Central. It consisted of a CGI-based database that allowed people to add and view ROM/RAM calls, as well as making available a commented version of the ROM image for download. The ROM image was provided as a useful service for those people that wanted to program for the TI-86, but didn't own a TI-graphlink cable (it cost $40-$50 at the time).

Because the ROM image was (and still is) owned and copyrighted by TI, he tried to implement a security check to prevent those people who don't own the actual TI-86 calculator from downloading it. Unfortunately, he was never really able to figure out a full-proof method to prevent people from illegally downloading the ROM image, and Texas Instruments eventually emailed him to tell him to remove the ROM image from the site.

Rusty Wagner and Corey Taylor were contracted by Texas Instruments in the Summer of 2000 to create a Probability Simulation Flash concept application for the TI-83+ graphing calculator. TI contracted several other developers from the TI community from 2000 to 2002 including Michael Vincent, Jonah Cohen, Kouri Rosenberg, Joel Seligstein, to name a few.