In the early 1980s, the Rainbow was a major contendor in the struggle for the 16-bit PC market, and it had a lot of advantages over the IBM PC:
On the other hand:
Of course IBM won, and soon all the non-IBM-compatible MS-DOS PCs (the Rainbow, the Victor 9000, the Texas Instruments Professional, the HP-110 and HP-150, the NEC APC, the Grid Compass, the Japanese NEC PC9801, the Wang PC, the Heath/Zenith-100) eventually vanished from the scene. And then IBM did too for all practical purposes, as the marketplace became dominated by PC clone makers such as Compaq, Gateway, and Dell.
Photo: Frank da Cruz. This mint-condition Rainbow 100 happens to be in the Kermit production area in the Penthouse of Watson Lab, serving as the system console to a VAXstation just below (not visible) whose monitor died; the VMS 5.5-2 console log is barely visible on the screen. Peeking out from behind the left side of the keyboard is the VAX's external TK50 tape cartridge drive.
In December 2004 - Feb 2005, Carl Bowman of Bridgewater University commented:
The Rainbow drives were not "totally incompatible" with any other MSDOS PC" as you state. They could actually read and write to disks that had been formatted on an IBM PC using a single-sided parameter in the format command. This may seem trivial, but it wasn't to DEC Rainbow users, because it allowed them to transfer data back and forth between Rainbows and IBM PC's using the RX50 drives.
Both the Rainbow monochrome and color monitors had an excellent high resolution graphics mode. I'm not sure why you say that there were "no graphics and no color" when in fact there were both.
- The Rainbow could directly address 896 k of RAM, while the IBM PC and all other MS.DOS machines of that era could directly address only 640 k RAM.
- The RX-50 drives wrote to single-sided quad density disks, which was something of an accomplishment at that time. This method enabled the Rainbow to store 400k on a single sided floppy, while an IBM PC could store only 396 on a double sided floppy.
The hi-res graphics were standard, but you had to have programs written expressly for the Rainbow to access them. Thus a fair number of MS-DOS programs would not go into graphics mode on the Rainbow. Programs like Multiplan, Lotus 123, etc. that had custom-Rainbow versions, on the other hand, did nice high-res charts on the Rainbow. I have a full set of manuals and even a software guide for the Rainbow that clearly document this. As a matter of fact, I have an early version of MS Windows running on my Rainbow without ever having added a graphics card.