[Coco] Formatting L.R. Tech Hard Drive in OS9 Level II

[Mark J. Blair]

> On Jan 10, 2016, at 17:40, Steven Hirsch <snhirsch at gmail.com> wrote:
> 
> Sorry if this is obvious, but I don't see where you low-level formatted the disk.  Very doubtful that issuing the OS-9 format command will do that.

Aw, bummer. I don't have any instructions for doing that, and I don't know if I have any software for doing so on the floppies that came with the system. There is a program called "init" on the LRTECH disk; I don't know what it does, but it could be a low-level formatter? The readme on the disks stated that it doesn't work under Level II, and I haven't figured out how to do anything with it under Level I so far. I have no detailed instructions other than the "LII.addendum" and "read.me" text files on the LRTECH floppy.


> It's fairly easy to talk to the S1410 controller if you're able to issue arbitrary SCSI commands.  Have you been able to find the 1410 documentation?

I have this manual for the S1410:

https://github.com/NF6X/CoCoHardDrive/blob/master/manuals/104524C_S1410Man_Aug83.pdf

However, I do not yet know how to issue arbitrary commands to it. I have zero documentation for the SASI interface cartridge that came with the system, which is in a plain white painted metal box with no markings. I don't even know whether the included software knows how to "magically" find it in slot 3 of the MPI... I just plain wildly guessed that installing it in slot 3 and the FDC in slot 4 is a correct configuration. But maybe it was intended to be hooked up with a Y cable and the drivers don't expect to find it in an MPI slot?


> IIRC, the 1410 must either have the hard disk geometry hard-coded into the EPROM on the controller (there were many, many OEM versions for that purpose) - OR, something needs to make a SASI call to set drive parameters after each power-up.

I hope that this hard drive actually is matched to the system and it was simply reformatted for use in an Epson PC after the owner got tired of the CoCo, as opposed to being a mis-matched hard drive that the Xebec controller might not know how to talk to.

Hmm, I'll try digging around online to see if I might find any documentation about the SASI cartridge. I suppose I could reverse engineer it since it looks like nothing but 7400 logic, but that would take a bunch of gumption. The only things looking like any sort of identification on its PCB are the text "LRT" and "HDI", presumably making it an LR Tech hard disk interface.

I'll also play with it under Level I some more to see if I can figure out how to load up drivers and try out that "init" program.

> Years ago I did considerable hacking on 1410s connected to an Apple 2. Probably still have a bunch of 6502 code for speaking to the drive.

I don't think that would help me much without having a SASI controller that I could plug into my IIe to format the drive. If I can figure out enough about the SASI cartridge then maybe I can write some CoCo program to send the commands to do a low level format.

-- 
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/