[Coco] ROM Options for Glenside IDE, and a 3D-Printed Case

[Gene Heskett]

On Tuesday 23 August 2016 14:18:57 Bill Pierce via Coco wrote:

> Mark, 256 disks (35trk ssdd) is (I think) only about 40meg (correct me
> if I'm wrong). You just wouldn't have room for any other partitions
> for OS9.

Huh?  Well, not on that teeny a card.  You would have used it all up.

However, given large enough media, the os9 device descriptor's offset 
values can just as easily be set to be started at the next sector after 
the end of a 256 disk basic usage area.

Other than an overflow in those 3 bytes that address the first sector of 
an os9 image, there is absolutely no reason it can't be done. I believe 
that "overflow" would occurr, and wrap back to sector zero at anytime 
your offset into an os9 image + this basic offset value totalled more 
than 4,294,967,040 bytes. In 131 meg hunks, using it all for os9 will 
need more descriptors than os9 can load. So I have one of my 2 1Gb scsi 
drives, using a cluster size of 4, which gives me just under 500 megs, 
with a 256 disk rsdos image stacked on top of that, so I could, but 
haven't done it permanently, put a second os9 partition at the end of 
the rsdos area, and have another partition and backup copy of the first 
one there.

OTOH if the drive fails, the images are both gone, so the 2nd of those 
1Gb drives is fully formatted for os9, and is using a cluster size of 
$10, or 16 in decimal.  And I dsave the first drive to the second about 
monthly when its up and running.  And reverse the dsave occasionally 
just for practice.

> Even with 198 disk images, your OS9 partition will be very 
> small, you may want to go down to 128 disk images if you plan to use
> OS9. I haven't ever messed with the CF card adapter, so I don't really
> know that much of how it's used (I use a real IDE drive). I would
> assume larger cards would allow larger partitions. I'm used to doing
> all this with the DW4 version of hdbdos and using 256 disk images, but
> I would think it all works the same.

Get bigger cf cards... I have several, the smallest of which is 256 megs 
& there are some 512 meggers in that box too. I haven't a clue how big 
you can get them now as the appliance they were used in here failed 
several years back so I've not actively looked to see how big they are 
today.
>
> Bill Pierce
> "Charlie stole the handle, and the train it won't stop going, no way
> to slow down!" - Ian Anderson - Jethro Tull
>
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Cheers, Gene Heskett
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