DEC Rainbows ...

From: Mark Tapley <mtapley_at_swri.edu>
Date: Mon Feb 18 20:18:41 2002

Sorry all, I'm delayed (on digest and backlogged anyway). But:

RB100B == RB100+ except that the + included the HD and HD controller card.

RB100A has 64kB on-board, can accept 3 256kB banks of RAM (with the right
adaptor card and memory card) for a max. of 832kB, or 3 64kB banks with
just a memory card for 192 kB total.
RB100B/+ has 128kB on-board, doesn't need an adaptor to go to 896 kB with
the memory card.

In addition to the boot-from-Winchester option being present in the later
models, there are some other differences in the ROM, enough that the dvorak
keyboard remapper I have won't work on my 100A, though it's reported to
work on the 100B or 100+. (Project #1 for when I get sufficient spare time.)

B and + support the "Compose Character" key on the LK-201 (?) to generate
overstrike characters.

Here's how the Graphics option works (colors or monochrome intensities
displayed before the slash, all available after the slash):

                             +---------------+---------------+
                             |Med. Resolution|High Resolution|
          +----------+-------+-------+-------+-------+-------+
          | Config. | Model | Color | Mono. | Color | Mono. |
          +----------+-------+-------+-------+-------+-------+
          |Monochrome| 100-A | N/A | 4/4 | N/A | 4/4 |
          | Monitor +-------+-------+-------+-------+-------+
          | Only | 100-B | N/A | 16/16 | N/A | 4/16 |
          +----------+-------+-------+-------+-------+-------+
          | Color | 100-A |16/1024| N/A | 4/1024| N/A |
          | Monitor +-------+-------+-------+-------+-------+
          | Only | 100-B |16/4096| N/A | 4/4096| N/A |
          +----------+-------+-------+-------+-------+-------+
          | Dual | 100-A |16/4096| 4/4 | 4/4096| 4/4 |
          | +-------+-------+-------+-------+-------+
          | Monitors | 100-B |16/4096| 16/16 | 4/4096| 4/16 |
          +----------+-------+-------+-------+-------+-------+

Tony Duell has published on this list a good description of how to make a
cable to allow dual (VR-201 and e.g. VR-241) monitors. It should be in the
archives, but I have a copy and can email if desired.

My 100A has a DEC 8087 coprocessor board which also serves as a memory
adaptor, and is stuffed up to 832k. It has an upgraded (100B or 100+) power
supply and a HD controller with an ST-225 as the hard disk. BTW, I have not
seen a 100A power supply, but they are referred to in multiple reasonably
believable places.

Rainbow MS-DOS was different from PC-DOS. The last version, MS-DOS 3.11b,
was a third-party (Suitable Solutions, who also did the ClickClock and
TurBow) effort that also supported "Code Blue" (from the same vendor),
which I guess was an attempt to patch the incompatibilities. It was
supposed to have done pretty well but not perfectly.

                                                - Mark
Received on Mon Feb 18 2002 - 20:18:41 GMT