[Coco] NitrOS-9 on a 128k Coco-3

[Bill Pierce]

Kandur, you don't count tracks on both sides, that would be an 5.25 80 trk DSHD drive.... a 720k drive. They hold the same as a 3.5 720k drive but are "double stepped", meaning the tracks are double the density of the 5.25 360k disks though the disks are the same size. The tracks are half as wide as the tracks on 360k disks, therefore the drive head step is half the distance hence the "double step". 
Another thing to remember, is to use only the HD disks in that drive. Normal Coco compatible DSDD disks will probably not be reliable.

Gene can probably verify the dmode settings for one of those, but I think it's:
dmode /dx typ=20 dns=3 cyl=50 sid=52


As for the software disk timers, I've found every one that I've tested, and I have about 4 or 5 for RSDOS and one for OS9 and they all seem to be pretty accurate. There's a percentage margin for error anyway, they don't need to be "dead on" 300 rpm.
 

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

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-----Original Message-----
From: Kandur <k at qdv.pw>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Thu, Jun 19, 2014 11:47 am
Subject: Re: [Coco] NitrOS-9 on a 128k Coco-3


Have done this, but don't know if the drive is spinning REALLY at 300 rpm.
Anyway, my 28 backup disks are marked as:
"OS-9, 160T, 96TPI 89-1-9"
How would you dmode this drive?
Don't think a 720k setup would work with it.
Am I wrong?


Kandur

Thursday, June 19, 2014, 12:47:20 AM, you wrote:
> On Wednesday 18 June 2014 23:12:36 Kandur did opine
> And Gene did reply:
>> Thanks Gene,
>> I got the service manual and the jumper settings for that drive.
>> I think, I found the speed select jumper.
>> http://qdv.pw/coco/blog/2014/06/19/panasonic-ju-475-4-5-14-fd/

> The jumper on PH, move it to 1M.  You have it
> right if you can dmode the 
> descripter for 50 cyl's, 2 sid, and format it
> ok. It will then be a 720k 
> disk drive on the coco.


>> First I couldn?t boot OS-9 from a 3.5" drive, because it's drive select
>> was soldered to /d1, took it apart and managed to change it to /d0.
>> http://qdv.pw/coco/blog/2014/06/19/changed-a-3-5-drives-drive-select-t
>> o-d0-from-d1/

> I've also done that, but some drives are even
> simpler and stuck as /d1.

> [...]

> Cheers, Gene Heskett
> -- 
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page
> <http://geneslinuxbox.net:6309/gene>
> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS

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