[Info-vax] OT: Computing Experience, What brought you to VMS?

[Johnny Billquist]

On 2014-02-06 12:34, Roger Ivie wrote:
> On 2014-02-06, Johnny Billquist <bqt at softjar.se> wrote:
>> Rainbow was a IBM-PC sortof-compatible machine.
>
> Rainbow was not compatible. It ran MS-DOS, but did not have the
> ROM BIOS and hardware that software began to expect from a PC.

As it could run MS-DOS, it was compatible with the IBM-PC on that level. 
The problem was that back in that day, many programs didn't use the 
system calls to invoke system functions. Since there was no memory 
protection, and people knew at what address a specific routine sat, they 
called the routines directly. And the Rainbow did not have the same 
memory layout as an IBM-PC. Oh well. Code written by the same people who 
used loops to waste and measure time. Code which then totally failed 
when you got a faster CPU.

> I gave up on the 'Bow when I bought Turbo C 1.5 and discovered
> the *command line* version of the compiler could not run on the
> 'Bow because it was using IBM PC ROM BIOS functions to see whether
> you punched ^C while it was compiling.
>
> I also thought it was a pretty mediocre CP/M machine; it was
> an ungodly mixture of 8088 and Z80 and didn't handle some Z80
> stuff how I expected (IIRC, the IOBYTE didn't work). I much
> preferred the DECmate II with Z80 APU for CP/M.

I touched a Rainbow a few times, but since I was not into either CP/M, 
nor MS-DOS, it totally did not interest me.

People did eventually manage to run Windows on Rainbows, and I remember 
that things got much better at that point, since by that time, fewer 
programs actually just called random addresses and expected services to 
just sit there...

	Johnny