[sebhc] Re: Great Idea for IDE MORE!! STATUS -- More Ideas ..

Lee Hart leeahart at earthlink.net
Fri Sep 22 13:20:46 CDT 2006

bill malcolm wrote:
> Here is a link for TRS-80  IDE   it has Z80 Like  H-89
> http://www.qsl.net/zl1wjq/trside1.htm
> I am thinking of using this as a add on for my H-67 Card

This is another simplified 8-bit interface to an IDE drive. It depends 
on the IDE drive to support 8-bit mode to work. My understanding is that 
most drives do not support this, and there's no way to know except trial 
and error (keep trying them until you find one that works).

But the hardware is the easy part -- it's the software that's going to 
drive you nuts! H89s and H8s never had anything like an IDE hard drive, 
so you'll have to start from scratch. And, I suspect it will be 
difficult to find any software specs on the particular hard drive you 
want to interface -- you'll have to rely on vague generic specs for the 
PC (which will assume 16-bit mode), and find out by trial and error if 
they work on your particular IDE drive.

If you *have* an H67 card, you already have a SCSI host adapter. 
Therefore, you may have an easier time interfacing a SCSI hard drive in 
place of the old 8" H67 drive. These were widely used in Macs, and so 
almost as easy to find as PC IDE drives.

And, the software for SCSI hard drives was already written and provided 
by Heath. The stock Heath software assumed a 10 meg drive, and they made 
no provisions to change it. But they did provide source code, and 
documented the command set; so it should be easier to modify the old 
code than to start over from scratch.

Another possibility:

Here's another idea I'm toying with. I have a dead H47 that will 
probably never be fixed. There's a LOT of room in that case! So, how 
about putting a complete PC clone in that box? Use the PC's floppy disk 
controller to talk to a pair of generic 8" drives (they interface like 
3.5" 1.44meg drives as far as the PC is concerned). Also include a hard 
drive (IDE, almost certainly). Use the PC's parallel port and software 
on the PC to *emulate* the H89's H47 or H67 interface; that way, the H89 
remains completely stock, both hardware and software.

Or, if you don't have the H8 or H89 host adapter cards for the H47 or 
H67, then interface it serially to one of the RS-232 ports. Now you'll 
have to write software, or find an existing software package that does 
the job. For example, I have Woolfe Software's "MOVE-IT" program, which 
installs on the H89 to make the drives in a remote serially-connected 
computer behave like local disk drives. You preceed disk drive names 
with "R" to signify remote; for example

PIP A:=RB:filename.txt

will copy filename.txt from the remote computer's B: drive to the H89's 
A: drive.

Yes, it's kind of a "killing cockroaches with a hammer" solution. But we 
have so many old hammers (useless PCs) lying around...
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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