[Coco] OS-9 RAM disk with "rdisk" command? And /md descriptor?

[Bill Pierce]

I have a program that will edit modules in memory while running... as well as any memory locations.
It works just like ded with the same interface, it called "med" and I've used it for years to edit system modules before cobblering a bootdisk.
I noticed it's on one of Brother Jeremy's "Update Disks" but I had it long before those disks ever surfaced.
 

Bill Pierce
"Today is a good day... I woke up" - Ritchie Havens
 

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-----Original Message-----
From: Allen Huffman <alsplace at pobox.com>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Sat, Jan 31, 2015 11:02 pm
Subject: Re: [Coco] OS-9 RAM disk with "rdisk" command? And /md descriptor?


> On Jan 31, 2015, at 9:39 PM, Gene Heskett <gheskett at wdtv.com> wrote:
> 
> Probably because you were out of the os9 neighborhood when I wrote that.  
> md is the descriptor that goes with myram, an automatic ramdisk I wrote 
> quite a while back.

Nope, this is the one Curtis is talking about. It allows you to dEd through 
memory. As soon as he said that, I remembered it. I don’t remember where it came 
from, though.

>  If it (md.dd) and myram (myram.dr) are in your 
> bootfile, and you issue a dir /md, there will be a slight pause, 200 
> milliseconds maybe, while it allocates the ram it needs and formats (does 
> not use the format command for this) a ramdisk whose size is determined by 
> one var in the descriptor, cyl. The dir command is held in sleep till this 
> is done, and then it wakes and dutifully reports an empty disk. The number 
> of cyl's is the number of 8192 byte blocks of ram it allocates.  None of 
> the other placeholder vars in the descriptor are used.

Clever — that’s a nice improvement over the “iniz / format” approach of most 
others.

> Any access, even it the first access is a write, is held until the 
> automatic formatting has been done, and then the write will be done as you 
> requested.

That’s cool The Microware official RAM disk (non-6809) was like that… iniz would 
set it up. In fact, format wouldn’t even work on that.

I didn’t like RBF devices that didn’t act like normal RBF devices, so while I 
was working for Microware, I actually wrote my own RAM disk driver called VDISK. 
It honored ALL the settings in the descriptor (not just the ones Microware’s 
did) so I could dmode it to match a floppy disk and to a “backup /d0 /r0” — 
something most RAM disks didn’t allow.

> The myram.README on my web page uses /r0 for the descriptors name, but 
> that clashed with the rammer/ro kit, so when it was added to the repo, the 
> descriptor was renamed to make it distinct from rammer.  Tested at up to 
> about 1.7 megabytes of usable ramdisk on my 2 meg machine.  I intended for 
> it to Just Work(TM) and I believe it does.
> 
> And when you are done, a simple deiniz /md returns every byte it used to 
> the free memory pool.  Restarting it after changing the cyl to some other 
> value does not recover what was there when it was deiniz’d.


I would expect no less from any RAM disk. Was this a problem with others? I 
noticed some devices I have under my NitrOS-9 boot disk CRASH if you deiniz 
them. That sounds like a poorly written driver to me, since you’d think the 
driver would just return an error in the deinit routine if it couldn’t do that.

> Enjoy Allen, I think you will like it.

I may look in to it if the one I am used to won’t work under current NitrOS-9. I 
liked being able to change the size with one command. I suppose if I booted with 
yours, and it was set to some size, in order to change it I would have to:

deiniz /md
dmode /md new settings

…then the first use would set it back up. I guess that’s not too much more than 
the rdisk approach but man, rdisk spoiled me.
--
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