Introducing LokiOS. A brand new model of CP/M, written from Scratch, Suitable with CP/M2.2 Applications.
Thought I would stick this in it is personal thread as I progress, because it’s come up in lots of previous threads… So I have been writing ( written? ) a brand new CP/M for Z80 based mostly on CPM/2.2 in a lot the identical means as DOS was created – I started with the system calls and recreated it, then labored to construct compatability. It is just about like CP/M2.2, however does change a bit bit, and there is nonetheless bugs.
So I determine I would begin with what the Loki was.
In 1985, Sir Clive Sinclair ( who constructed the zx80, zx81, zx Spectrum, QL, and so forth ) was about to go bankrupt. Attempting to stave off his collectors, he proposed a brand new pc system that may outperform most and equal the perfect in the best way they have been the perfect. He supposed to steal all the good concepts and construct them into a brand new pc known as the Loki, after which promote it for round 10 to twenty% of what these computer systems price.
It had fascinating specs.
512 x 192 graphics, 64 colors per pixel, 4 pixel planes, and inbuilt Bit Blit as seen on the Amiga 1000
Synthesizer high quality sound ( assume Sound Blaster which got here out a lot later )
128K minimal of reminiscence, heading up in the direction of 512K.
ZX Spectrum Backwardly appropriate.
8MHz z80 or perhaps even a 12MHz z280
Modular design
And {Hardware} Vector Graphics.
Gentle Pen
All for 200 GBP.
It was stated to be unattainable on the time… nonetheless after analyzing the entire information, there have been some specs that made sense given the extent of {hardware} improvement of the ZX Spectrum on the time, and I imagine it was solely potential to attain the objective inside the expertise limitations in late 1985. All by actually stealing the very best concepts from each different pc, simply as Sir Clive stated he would.
We by no means acquired to see the Loki, and it has been a long run objective of mine to lastly construct it, utilizing solely the expertise of the period, and inside the value constraints of the period.
Oh, and in contrast to all of Sir Clive’s different computer systems, this one was going to run CP/M software program.
Appears he was lastly studying from his earlier misteps and realized the very best concepts are stolen from others… Or, because the grasp as soon as stated, Take in what is helpful, Discard what just isn’t and add one thing of your personal.
As a result of I have not had a lot time to work on the {hardware}, I started writing an assembler, then an emulator, and at last a brand new model of CP/M which I merely name LokiOS. It appears like CP/M, runs like CP/M, and up to now, appears to run CP/M software program OK. I have been testing it with numerous BASICs for CP/M up to now. Working in an emulator helped me speed up software program improvement, and has been a fantastic base for studying new abilities, in addition to higher understanding the each day abilities I would like for my day job.
The structure of this intends to intention for as much as 1Mb of reminiscence, in a really summary mannequin, that’s easy to make in {Hardware}, to attain the low price targets of the challenge. The reminiscence makes use of what I name Reminiscence As Disk, reusing CP/Ms disk dealing with routines to regulate and populate reminiscence administration tables, and permit applications to simply break the 64K restrict set by the default z80 structure, even when they do not know something about paging, or do not help it.
The fundamental structure of the reminiscence system appears one thing like this ( under ).
I’m nonetheless constructing it, eliminating the bugs, and even altering my thoughts at occasions. All ideas and feedback or questions welcomed 
Thanks
David