Shortly after IBM announced their Personal Computer in August 1981, Tecmar became one of the first third-party manufacturers to release expansion cards for the system.

[4]: 37  Alpert operated Tecmar as a private business until summer 1986, when he sold it to Rexon, Inc., of Culver City, California, for less than US$2.3 million.

The Stepping Stone was released to address the PS/2's lack of a 5.25-inch floppy drive (IBM had adopted the newer 3.5-inch standard, developed by Sony Corporation, for the PS/2).

This opened the PS/2 to a larger back-catalog of IBM PC software; the installers of some contemporary applications on 5.25-inch disks, like Lotus 1-2-3, required being run from the A: floppy drive, as a form of copy protection.

For the Model 50, this meant that that system could possess more RAM than IBM's prescribed upper limit of 7 MB, while leaving one of its three expansion slots open.

[8]: 143  Computer Reseller News wrote that Cumulus was the first American expansion board maker to harness the 1 μm process of semiconductor fabrication with the CuRAM in August 1987.

[32] Cumulus won Sears as a reseller of the GLC line, the latter company marketing the computer inside their Office Center store-within-a-store.

[33] The GLC/SBS (Good Little Computer/Small Business System), introduced in November 1990 and featuring a built-in combination fax modem–answering machine unit,[34] intended to compete with IBM's PS/1 of personal computers for the home.

Its motherboard featured the SCAT chipset by Chips and Technologies, and the computer shipped with a Paradise (Western Digital) SVGA graphics card.

[43] In July 1992, Cumulus introduced the GLC/MC line, a desktop computer with a Micro Channel bus directly competing with IBM's PS/2.

[47]: 248  That same summer, Cumulus announced their intent to work on the design for a cellular phone, in a corporate refocus toward mobile computing.

[15] In anticipation of their stock launch, Bill Lowe—the former president of IBM's Entry Systems Division—joined Cumulus' board of directors and was named vice chairman.

[50] Despite keeping appearances of a thriving company, Cumulus was crumbling internally under poor cash flow and externally from the fierce price war in the desktop computer market in the early 1990s, in which bigger players in the market lowered the prices of their systems far below what smaller firms like Cumulus could afford to compete against.

[15] This, combined with computer companies under-performing in the stock market in 1992, compelled Cumulus to rescind their initial public offering.

[1] This had the effect of exacerbating their cash flow dilemma,[15] and with the planned retirement of their growing debt to lenders and suppliers foiled by the lack of liquidity that their IPO would have offered, Cumulus quickly became insolvent.

[1] Over the summer of 1992, the company canceled plans to move into a larger 165,000-square-foot office in Solon, Ohio, and in September 1992, Cumulus furloughed 170 workers in production and management[15]—laying them off entirely the following week.

[52] Interconnect Technical Services, an executive recruiting firm out of Toledo, sought $18,750 in payment for arranging an employee to work for Cumulus.

[55] Cumulus, erstwhile under ownership of Star Banc as "crisis managers",[57] moved its headquarters to a much smaller office in Beachwood, across the street from their former 37,500-square-foot building, in October 1992.

Following these suits, Cumulus plead to the Cuyahoga County Common Pleas Court to appoint a receiver to liquidate the company.