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

Mark J. Blair nf6x at nf6x.net
Tue Aug 23 14:29:27 EDT 2016

> On Aug 23, 2016, at 11:18 , Bill Pierce via Coco <coco at maltedmedia.com> wrote:
> Mark, 256 disks (35trk ssdd) is (I think) only about 40meg (correct me if I'm wrong).

I was under the impression that HDB-DOS only uses the first 256 bytes of each 512 byte block for a 256 byte DECB sector, so 256 disks would require 256 disks * 35 tracks * 18 sectors * 512 bytes = 82,575,360 bytes. My 64M CF card would thus support (64 * 1024 * 1024) / (35 * 18 * 512) = 208 disk images. I presume that my card is reporting a block count smaller than 64M for some reason, but 198 is in the right ball park.

> You just wouldn't have room for any other partitions for OS9. 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'll probably dig up a larger card; the 64M is just what I've been testing with so far.

> 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 crads 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.

A CF to IDE adapter isn't much more than a simple connector adapter. CF cards have an ATA/IDE mode, in which they just act like a plain old IDE hard drive. That makes them pretty easy to substitute for IDE drives in vintage computers most of the time.

Mark J. Blair, NF6X <nf6x at nf6x.net>

More information about the Coco mailing list