Design Systems, Inc.

ph. (314) 546-1425

Background Information

Design Systems began its start in 1975 becoming incorporated in the State of Missouri with a stated purpose of producing microcomputer based applications that could serve multiple users. Networking was not even in the picture, but several multi-user operating systems were being introduced that centralized data (on floppy disks) for small businesses with shared access. DSI chose to base its applications on OASIS, which was an 8-bit multi-user operating system based on the Zilog Z-80 instruction set - an enhanced chip that incorporated the instructions from Intel 8080.

Our original applications were designed to extract maximum performance from the 64K memory and access the floppy disks no more than necessary to be able to provide good response to a serial display terminal at 300 bps. This proved to be a good choice, since as memory, storage and CPU speeds increased, application performance has soared. Current PC based THEOS systems, using our applications, have un-paralleled performance!

While this discussion is somewhat technical, computer engineers will recognize that the OASIS Operating System was years ahead of its time. It featured shared memory with caching, Multi-user operations, a Macro assembler, sophisticated BASIC Library, a Linkage Editor, a Spooler Que for optimized printing, a top-level EXEC Language, and compiled code. All developed for 8-bit micros that were just being created in many garages around the country. Note the publishing date on the manuals (listed below). All of this preceded, by years, the commercial release of the single-user MS-DOS PC which was totally limited to being merely a word processor and a calculator (or used for entertainment).

The fact that the OASIS Operating System was shipped with detail Operating System manuals and essentially ran without any serious bugs was a huge accomplishment for the Company. Design Systems was able to make good use of the base system and build its application base specifically for the Manufacturing, Inventory and Wholesale Distribution industry.

In 1983, the OASIS system, developed by Tim Williams at Phase One Systems, became the THEOS Operating System and Tim established his own Company - Theos Software. Now almost 30 years later, the THEOS Operating system, in its latest distribution as Corona, is almost entirely backward compatible to applications that were created then. Enhancements have provided many add-ons that bring the Corona OS up to par with any other OS that runs on Intel chipsets. None can touch it for performance. Theos Software Corporation is headquartered in Oakland, California. Design Systems is a Nevada Corporation with offices near St. Louis, Missouri.

THEOS continues to maintain its technical lead in performance and reliability and still retains its ease of use. The OS is now in use around the world. And allows Design Systems to deliver cost effective IT solutions to the small business owner.

From a technical viewpoint, it is interesting to view the original Operating system as it was developed in 1978 to the current Corona system. The original line-based commands that remain applicable to today's IT environment are still in use. The system has been enhanced with windowing and mouse control, and migrated from an 8-bit chip to the current crop of 64 bit chips, but basically, the core presentation has endured. Before discarding some of the original OASIS Manuals that have been gathering dust all these years, I scanned them to PDF. See below for links to each one of the Original Manuals and a list of Z-80 instructions that were used in the original OS.

OASIS Manuals

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Last update 09/17/15