[GEM Development] Video mode - bitplane vs packed pixels

John Elliott jce at seasip.info
Tue Feb 6 16:23:48 PST 2024


This article
<http://cd.textfiles.com/crawlycrypt1/program/books/progem/gemdos.15>
describes the early history of GEMDOS. I've also seen it described as
starting as a private project of the original developer (Jason Loveman)
which Digital Research picked up and ran with when they needed an OS to
support GEM on the 68000 processor (rather than building something based
on CP/M-68K).

--
John Elliott

Cyprian Konador wrote:
> On Tue, 6 Feb 2024 at 22:30, John Elliott  wrote:
>
>     Michael Bernstein wrote:
>     > GEMDOS was a little bit like MS DOS. Bur i am not aware, that GEMDOS
>     > is used as a base for other DOS operating systems. And the BIOS and
>     > XBIOS are hardware specific.
>
>     As far as I know, GEMDOS doesn't share any DNA with DOS Plus, though
>     they may have superficial similarities (being operating systems by
>     Digital Research that implement the MSDOS 2.x API). DOS Plus is, under
>     the covers, an MS-DOS emulator running on top of a multitasking
>     CP/M-86
>     kernel, while GEMDOS isn't.
>
>
>
> There you can find by quick comparison GEMDOS, MS DOS 1.x/2.x and
> CM/P 2.2/3.0
> I see that GEMDOS shares some function with CP/M:
> https://docs.google.com/spreadsheets/d/12XHJ6YHRDfvNhtnlzEINBjRRXZPKvDQgI7AI424oTws/edit?usp=sharing
>
> If I remember correctly Digital Research had a few similar OSes in the
> same time frame:
> CP/M, Concurrent DOS, DOS Plus and DR DOS (a bit later).
> I'm wondering about the history of GEMDOS. How it was related to
> mentioned OSes and how DR chose the API function for it.
>
> Regards
> Cyprian
>
>
>
>
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