Interactive Systems Corporation
| Company type | Private (before acquisition) |
|---|---|
| Industry | Software |
| Founded | 1977 |
| Founder | Peter G. Weiner |
| Fate | Acquired by Eastman Kodak Company in 1988; Unix business sold to Sun Microsystems in 1991; remaining assets sold to SHL Systemhouse Inc in 1993 |
| Headquarters | Santa Monica , United States |
Key people | Peter G. Weiner, Heinz Lycklama |
| Products | IS/1, IS/3, IS/5, PC/IX, 386/ix, INTERACTIVE UNIX System V/386, VM/IX, IX/370, AIX 1.0 |
Interactive Systems Corporation (commonly presented as INTERACTIVE Systems Corporation and abbreviated as ISC) was an American software company recognized as the first commercial supplier of the Unix operating system outside of AT&T. The company was headquartered in Santa Monica, California. Established in 1977 by Peter G. Weiner—formerly a researcher at RAND Corporation and founder of Yale University's computer science department—ISC's leadership also included Heinz Lycklama, an AT&T alumnus known for authoring a Version 6 Unix port tailored to the LSI-11 platform.
In 1988, ISC became a wholly owned subsidiary of the Eastman Kodak Company, operating within Kodak's Commercial Imaging Group. During its tenure under Kodak, ISC expanded its portfolio by acquiring Lachman Associates, a networking software firm, in 1989, and purchasing VP/ix—software enabling "DOS-under-UNIX" functionality—from Phoenix Technologies in 1991. Kodak divested ISC’s Unix operating system business to Sun Microsystems on September 26, 1991, while the remaining assets were sold to SHL Systemhouse Inc in 1993.
A number of ISC’s former employees went on to establish Segue Software, which collaborated with Lotus Development to create the Unix version of Lotus 1-2-3. Additionally, Segue partnered with Peter Norton Computing on the Unix adaptation of the Norton Utilities.
Products
ISC’s inaugural product from 1977, IS/1, was a customized variant of Version 6 Unix designed to support office automation on the PDP-11. Subsequent releases such as IS/3 and IS/5 represented more sophisticated iterations based on System III and System V, targeting both PDP-11 and VAX architectures. The company also engineered Unix ports for the IBM PC platform, including PC/IX (Personal Computer Interactive eXecutive)—a System III derivative developed under contract with IBM—which was later rebranded as 386/ix and ultimately evolved into INTERACTIVE UNIX System V/386 (built upon System V Release 3.2). ISC held the role of AT&T's designated "Principal Publisher" for System V.4 on Intel hardware. Beyond these efforts, ISC contributed to projects such as VM/IX, a Unix guest operating system running within VM/370, and enhancements to IX/370, a TSS/370-based Unix variant co-developed by IBM and AT&T around 1980. Furthermore, ISC developed AIX 1.0 for the IBM RT PC under IBM’s contract; however, later AIX iterations for PS/2 and AIX/370 were outsourced to Locus Computing Corporation.
PC/IX
PC/IX represented the pioneering Unix release for the IBM PC XT directly from IBM, contrary to earlier expectations that favored either Microsoft’s Xenix or AT&T’s offerings. Bob Blake noted that PC/IX aimed to provide a reliable System III Unix experience without extensive modifications by IBM. It followed earlier products like Venix/86—which was derived from Version 7 Unix but lacked several features standard in more recent Unix versions.
The distribution included ISC’s INed screen editor featuring multiple window support and context-sensitive help; however, it excluded components such as the System III FORTRAN compiler along with utilities like the BSD-originated vi or the C shell. These omissions were partly due to the XT architecture’s limitation of a maximum 64 kB RAM segment per process.
To enhance filesystem throughput, PC/IX accessed the XT hard disk directly without relying on BIOS calls, resulting in faster performance compared to MS-DOS but limiting compatibility with contemporary virtualization environments. Given the minimal memory protection capabilities of the 8086/8088 processors, IBM restricted PC/IX licenses to single-user use only.
PC/IX was distributed on nineteen floppy disks accompanied by an extensive manual spanning approximately 1,800 pages and required about 4.5 MB of disk space once installed. Despite its $900 price tag and lack of compatibility with MS-DOS applications limiting its market appeal, BYTE magazine in 1984 commended PC/IX as a comprehensive single-user Unix system that outperformed Venix running on PDP-11/23 hardware.
INTERACTIVE UNIX System
In 1985, 386/ix was introduced as the successor to PC/IX, built upon the System VR3 foundation. Subsequent iterations, known as INTERACTIVE UNIX System V/386, incorporated System V version 3.2 along with enhancements derived from BSD.
Following its acquisition of Interactive, Sun Microsystems continued to offer INTERACTIVE UNIX System as a budget-friendly option alongside its System V.4-based Solaris, even after Solaris was adapted for x86 desktop platforms. A review by PC Magazine highlighted this release for its reliability. The last version, titled "System V/386 Release 3.2 Version 4.1.1," was launched in July 1998, with official support concluding on July 23, 2006—five years subsequent to Sun ceasing its sales.
At first, INTERACTIVE UNIX System was limited to supporting only 16 MB of RAM until ISA 3.0.1; later updates expanded this capacity to 256 MB and introduced compatibility with the PCI bus. Versions designed for EISA consistently accommodated 256 MB of RAM.
See also
Further reading
- Provides coverage and comparison of PC/IX, Xenix, and Venix.
- Maurice J. Bach, The Design of the UNIX Operating System, , Prentice Hall, 1986.
- IBM has snubbed both Microsoft's multimillion dollar investment in Xenix and AT&T's determination to establish System V as the dominant version on Unix. (InfoWorld 20 Feb 1984)
- IBM's latest hot potato (PC Mag 20 Mar 1984)