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

Bill Pierce ooogalapasooo at aol.com
Tue Aug 23 09:42:25 EDT 2016

 Mark, why the toolshed source for hdbdos is set for 198 disk images I'll never know... but You can change the source to 256 images (0-255) which is the standard in HDBDOS.
Once you have the OS9 size offset, the value goes into $d938, $d939, & $d93a. Which when just looking at a raw rom image from a PC hex editor, it would be $1938, $1939, & $193a. It's easy to find as it's one of the only rom locations that contain three "0" bytes in a row. You also must remember, this value is in "sectors" not bytes (256 bytes per sector). I can't remember if this value changes to half when using LBA mode since LBA uses 512 byte sectors.
If you want more than one OS9 partition, then you must add ALL the values of each partition to create the offset, or you can create additional os9 partitions after the rsdos partition and reflect their offsets in the os9 drive descriptors :-)
Also, the os9 partition size limit is about 128meg using a cluster size of 1. Anything larger (up to 4gig) uses larger cluster sizes. Most of which is explained here:


I have some other documentation that's not posted if you need it.


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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