TRS-80.org » Operating Systems

NEWDOS 2.1

Matthew Reed — Wed, 29 Jun 2011 12:30:00 +0000

NEWDOS 2.1, also known as NEWDOS, NEWDOS/21, and NEWDOS+, was the first alternative disk operating system for the TRS-80 Model I. Introduced in March 1979 by Apparat, Inc. of Denver, Colorado, NEWDOS jump started the entire third-party TRS-80 disk operating system market. NEWDOS was considered by many to be an essential program for the Model I; it is quite possible that NEWDOS was more widely used than Model I TRSDOS itself.

MULTIDOS

Matthew Reed — Thu, 13 May 2010 13:10:00 +0000

MULTIDOS was one of the major TRS-80 operating systems, described in advertisements as “the most compatible, user friendly operating system on the market.” It was written by Vernon Hester, the author of ULTRADOS, and was in some ways a continuation of that operating system. MULTIDOS was the least expensive TRS-80 operating system and also the one with the most recent update (MULTIDOS 5.1 in 2005). It was also the only TRS-80 operating system to offer software compatible versions for the TRS-80 Model I, Model III, Model 4, and the Lobo MAX-80.

ULTRADOS was an earlier TRS-80 operating system for the Model I that was sold by Level IV Products. After Vernon Hester parted ways with Level IV Products in 1981, he began writing a completely new operating system. This operating system, which was briefly advertised as ULTRA-II, soon became known as MULTIDOS. Vernon Hester originally sold MULTIDOS through his company, Cosmopolitan Electronics Corporation. The Model I version of MULTIDOS was released in late 1981 and the Model III version was released in January 1982. The price started out at $79.95 but soon increased to $99.95. Later on, MAX-80 MULTIDOS was released in late 1983 and Model 4 MULTIDOS (originally known as MULTIDOS 80/64) in 1985.

DOSPLUS

Matthew Reed — Mon, 08 Jun 2009 13:22:05 +0000

DOSPLUS was one of the most popular of the disk operating systems available for the TRS-80. Sold by Micro-Systems Software based in Hollywood (later Boca Raton), Florida, there were eventually versions of DOSPLUS for the TRS-80 Model I, Model III, Model II, and Model 4.

The people behind Micro-Systems Software were Larry Studdard, Mark Lautenschlager, Steve Pagliarulo, and later Todd Tolhurst. According to a 1981 interview in 80-U.S. Journal, DOSPLUS came about indirectly when they were writing software for Larry Studdard’s sheet metal business. Steve Pagliarulo developed a number of patches to TRSDOS to deal with bugs they had encountered. That experience led Pagliarulo to write his own TRSDOS-compatible replacement operating system, which became the first version of DOSPLUS. That original version was never publicly released and was used only with their business software.

In 1980, Micro-Systems Software introduced DOSPLUS 3.0, the first publicly available version of DOSPLUS, for $99.95. The name “DOSPLUS” presumably identified it as an improvement to the Radio Shack DOS or as “DOS Plus.” Although not actually the third version, it used a 3.0 version number to show that it followed TRSDOS 2.3. Advertisements described it as “the fastest, most reliable, and easy-to-use operating system available.”

VTOS

Matthew Reed — Wed, 11 Mar 2009 14:45:46 +0000

VTOS (which stood for “Virtual Technology’s Operating System”) was the second TRS-80 Model I operating system created by Randy Cook, the author of Model I TRSDOS. VTOS was released in 1979 and sold through Randy Cook’s company, Virtual Technology Inc. The original price was $49.95 for VTOS version 3.0. That was increased to $99.95 for version 4.0, or $125.00 for VTOS plus Operator’s Guide and Master Reference manual. There doesn’t appear to have been a Model III version of VTOS.

ULTRADOS

Matthew Reed — Thu, 29 Jan 2009 19:55:51 +0000

ULTRADOS was the first TRS-80 operating system written by Vernon Hester. Introduced in September 1980, ULTRADOS was sold by Level IV Products, a software and hardware retailer based in Michigan. The regular price for ULTRADOS was $119.95 but the introductory price of $89.95 lasted for several months. ULTRADOS was for the Model I only; there never was a Model III version.

Originally called Level IV DOS, ULTRADOS began life as a heavily patched version of Model I TRSDOS. However, Vernon Hester made so many modifications that ULTRADOS bore little resemblance to TRSDOS. ULTRADOS was a very stable operating system with the bugs of TRSDOS corrected.

MICRODOS

Matthew Reed — Mon, 06 Oct 2008 16:53:11 +0000

MICRODOS, later known as OS-80, was the only TRS-80 disk operating system that made no attempt at TRSDOS compatibility. It was written by James W. Stutsman and released by Percom in 1979. Rather than using a command shell like Model I TRSDOS, MICRODOS used extensions to BASIC. It implemented most of the Disk BASIC commands added by TRSDOS. Also unlike the other operating systems, MICRODOS had no file system. All disk accesses were made using the starting sector and length. As stated in the manual:

Model I TRSDOS Versions

Matthew Reed — Fri, 12 Sep 2008 19:21:11 +0000

TRSDOS 2.0 was the first version of Model I TRSDOS to be released to the public. All earlier versions had been used for testing within Radio Shack only. It came with a preliminary instruction manual, with a final manual promised for the near future. Not many people used TRSDOS 2.0 because it was replaced by TRSDOS 2.1 after only a short time.

Model I TRSDOS Disk BASIC Commands

Matthew Reed — Wed, 06 Aug 2008 23:52:06 +0000

Model I TRSDOS Disk BASIC contained a number of extra commands and enhancements to Level II BASIC, not all related to disk. The commands were documented in the TRSDOS 2.3 Reference Manual. All other TRS-80 operating systems with a Disk BASIC supported these commands, although often CMD and NAME used different syntax.

Model I TRSDOS Commands

Matthew Reed — Wed, 06 Aug 2008 23:51:56 +0000

The Model I TRSDOS command shell supported a number of internal commands, as documented by the TRSDOS 2.3 Reference Manual. Most of the commands were also supported by other TRS-80 operating systems, although they usually added extra features beyond the TRSDOS versions.

TRSDOS for the Model I

Matthew Reed — Wed, 06 Aug 2008 23:51:22 +0000

TRSDOS, referred to as DOS in some early references, was Radio Shack's official disk operating system for the Model I. The name stood for Tandy Radio Shack Disk Operating System. It was bundled with Radio Shack's floppy disk upgrade, but it could also be purchased separately.