12 Apr
2021
12 Apr
'21
10:47 p.m.
Part 2
I wrote conditional macros to allow me to run the ?OS? under RT-11 as an application. This
was the fastest way to debug logic errors. It didn?t do much for the hardware interfaces
but it was better than debugging on the actual HW platform.
-Steve Davidson
SF:iP1
On Apr 12, 2021, at 16:43, Steve Davidson <steve at
davidson.net> wrote:
?When I was a DEC OEM we used RT-11 and LDA format to load our custom ?OS?. It was my
first real project as a system developer. Made good money in those days... ?
-Steve Davidson
SF:iP1
> On Apr 12, 2021, at 16:17, Paul Koning <paulkoning at comcast.net> wrote:
>
> ?
>
>>> On Apr 12, 2021, at 4:09 PM, Johnny Billquist <bqt at softjar.se>
wrote:
>>
>> Right.
>> When someone talks about the paper tape system, and absolute loader format, it is
without any operating system underneath. It's just bare metal. And the absolute loader
is just a simple format that can be read by a small program that you have in memory.
It's only purpose is to read in a paper tape with the binary on it, and start that.
>>
>> So there are no system dependecies, there are no addressing issues. It's just
actual bytes that will be written to specific addresses in memory, and then a jump to an
address, and off it goes.
>>
>> Johnny
>
> BTW, SimH can load abs loader format files directly (with the "load"
command). So you don't even need to feed it the abs loader to execute such programs.
>
> paul
>
>