[Coco] deciding to code for OS/9

Bill Pierce ooogalapasooo at aol.com
Fri May 20 08:26:51 EDT 2016

Randy, you are right. In RSDOS, you only have a limited, few rom calls and they're pretty obscure. Other than that, you're on your own. RSDOS is still in the very same state it was in 1986 (never bug fixed or updated).
In OS9, almost everything is done.. disk I/O, display, serial I/o etc. You just make simple system calls and you can interface to anything that has a driver. Memory can be allocate/deallocated, mapped in/out of the workspace, programs can be forked or chained, the possibilities are almost endless. The only tradeoff being the system interrupts. Since OS9 is multitasking, the system cycles all processes in a queue. Blocking interrupts is generally a no-no, but is done when necessary, such as when playing sounds.

Two good books to get started with (other than the manuals) are:




The first will introduce you to OS9 through OS9 Level 1, the second will follow into the workings of OS9 Level 2 (preferred and Coco 3 only).

As a note, OS9 has been morphed into "NitrOS9" through the years and is kept current with all the new hardware being developed. We maintain a repository of the sources where you can build your own flavor or choose from ready-made disks for several "standard" I/O systems (hard drives, Drivewire4, CocoSDC, floppies etc) as well as different machines (Coco 1, 2, & 3, Dragon 64 etc).
Here is the repository:


The disk library:


and the NitrOS9 wiki:


Then there's DriveWire4 which connects your Coco to your PC (serial cable) allowing you to mount "virtual disks" and load files from disk images on your PC you've downloaded from the internet as well as virtual terminals on the PC, DriveWire MIDI using virtual synths on your PC (no hardware needed), and internet connection through telnet:


Also, there are emulators allowing you to run a Coco on your PC with the advantages of overclocking. I use emulators for development as it makes things flow faster. There's (of course) Mess, which introduces new bugs with every version, or my personal favorite; Vcc:


You can live in 1986 with RSDOS, or you can move your Coco into the future with NitrOS9 :-)


Bill Pierce
"Charlie stole the handle, and the train it won't stop going, no way to slow down!" - Ian Anderson - Jethro Tull


My Music from the Tandy/Radio Shack Color Computer 2 & 3
Co-Contributor, Co-Editor for CocoPedia
Global Moderator for TRS-80/Tandy Color Computer Forums

E-Mail: ooogalapasooo at aol.com



-----Original Message-----
From: emceesquared <emceesquared at gmail.com>
To: 'CoCoList for Color Computer Enthusiasts' <coco at maltedmedia.com>
Sent: Fri, May 20, 2016 6:14 am
Subject: [Coco] deciding to code for OS/9

I understand OS/9 is not a language but I’m assuming os/9 provides an environment you could take advantage of that would have sone benefits like memory management and multi threading?  Maybe some IO functionality?My question is… what’s the trade off?  Raw power?  When u compile for rs-dos .. it’s just you and the machine right?  Like dos vs windows I guess? Sent from my Windows 10 phone-- Coco mailing listCoco at maltedmedia.comhttps://pairlist5.pair.net/mailman/listinfo/coco

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