• Please review our updated Terms and Rules here

Lo-Tech IDE Harddisk Interface for the Model II

H

Hans01

Experienced Member
Joined
Feb 17, 2014
Messages
459
Location
Netherlands
After working many weeks in my spare free time, I succeeded in interfacing the Lo-Tech IDE interface to the Model II family.

It is running very good with the performance of a model 4P.
It needs NO Tandy harddisk controller.
It runs at the moment on LSDos 6.3.1.a without any problems
Auto boot not (yet) possible.
Tested with a DOM module for the moment as a very good option.
It needs a small interface between the Model II and the Lo-Tech controller.
A smal modification on the Lo-Tech must be done.

I'am running four partitions of 6364 K. and the system can be moved from drive :4 to drive :0
I can tell you that it runs like a modern computer now.

As a few pictures tells more than a thousend words, here they are.

HPIM0221.jpg

HPIM0224.jpg

HPIM0225.jpg

HPIM0228.jpg

HPIM0229.jpg
 
Hans, this is great! Please can you post details of the mod and interface, as possibly the interface could be run along side this product :)
 
Hans, great work! I look forward to the details. You may have help save the Model II line from vintage computing oblivion.
 
Hans01 said:
After working many weeks in my spare free time, I succeeded in interfacing the Lo-Tech IDE interface to the Model II family.
Click to expand...

This is excellent. There would be enough space in the card cage for your interface card plus the lo-tech, and obtaining power from the backplane, I would think. Very nice work.
 
Thank you all for the kind replies.

At the moment I'am investigating the possibilities together with James to build a PCB for this
interface.

If every body who is interrested in this, please send me a PM, so I can see if there are enough
TRS users who like this project.



HPIM0223.jpg HPIM0226.jpg
 
lowen said:
Hans,

Are you using the same driver on the Model II with the lo-tech and LS-DOS 6.3.1a as you use with the Model 4/4P LS-DOS?
Click to expand...

Yes, the last version as for the autoboot version for the Model 4.

I'am checking if they are usable for Tdos 2.0a too.
It is not easy to get the drivers on a TRS dos bootable formatted disk.
 
Question... Do you think this would be also addressable using Xenix with the 68000/memory card combos, outside of regular LSDOS boot?

Myles
 
k0d3g3ar said:
Question... Do you think this would be also addressable using Xenix with the 68000/memory card combos, outside of regular LSDOS boot?

Myles
Click to expand...

I'am very glad with the results until now. If I have some time in the future I'll try to make it usable with TDOS v. 2.0
I have no experiance with Xenix and 68000/memory. I think that it technical possible is, but surely not for me.
May be a challenge for some users to search for a solution.
 
k0d3g3ar said:
Question... Do you think this would be also addressable using Xenix with the 68000/memory card combos, outside of regular LSDOS boot?

Myles
Click to expand...

It would require patching the driver in the z80ctl and diskutil for Xenix. If that driver uses interrupts, then you need something to properly feed a Mode 2 vector onto the bus; that's what the Z80 CTC on the Tandy Hard Disk Interface is for. Hmmm, let me see..... yep, according to Frank Durda IV, who maintained the z80ctl code and knew it better than anyone:
Hard disk transfers could go directly from hardware to 68000 memory because
the hard disk controller contained a full sector buffer, and wouldn't
generate an interrupt until it had completely finished the sector read
command and was ready to transfer all of the sector to the host CPU.
The floppy controller had a one byte buffer.
Click to expand...
Meaning that the hard disk driver in z80ctl is expecting Mode 2 interrupts.
 
It received some questions about the things you need to setup the harddisk.


An empty slot in the cardbox.
My interface.
A Lo-Tech IDE controller (with one chip replaced)
A 50 wires flatcable to connect the IDE interface to my interface.
A SD card adapter or a DOM (128 Mb.)
I got very good results with a DOM
The LSDOS drivers

The state of the project so far:

The interface is tested and working oke.
James is drawing the PCB
 
What wizardry is this??

I turn my back for eerm, a week? and suddenly there it is, a cost effective HDD solution for my Model II!

Bravo, Hans!

And now for my question: what about CP/M drivers? :)

Edit: now I am going to have to recondition the keyboard. I was putting that job off....
 
Last edited:
JonB said:
What wizardry is this??

I turn my back for eerm, a week? and suddenly there it is, a cost effective HDD solution for my Model II!

Bravo, Hans!

And now for my question: what about CP/M drivers? :)
Click to expand...

JonB, thank you for the kind words.

Just to be clear. I started this project to prove to some people that it was possible to get the Lo-Tech
IDE controller working on a Model II. As I got accustomed with LSDos 6, I used this operating
system to make it usable.

The harddisk interface depends on the driver(s) for the Lo-Tech interface.
I have seen many questions about, will it runs with NewDos, DoubleDos, CP/M, etc.
I have never had the intention to check this, as I have no time for this and a lack of knowledge
about all the existing operating systems makes it impossible to do.

There are 3 drivers (including CP/M) in the Lo-Tech package to have a good starting point.

Let every specilist in an operating system take a chance and prove that it can be done and make
the results available to all the VCF users.

B.t.w. I'am working on the TDos version, as it is very close to LSDos, but don't expect more.
 
Hans01 said:
JonB, thank you for the kind words.

Just to be clear. I started this project to prove to some people that it was possible to get the Lo-Tech
IDE controller working on a Model II. As I got accustomed with LSDos 6, I used this operating
system to make it usable.

The harddisk interface depends on the driver(s) for the Lo-Tech interface.
Click to expand...

I would think that the LS-DOS 6.3.1a drivers for the FreHD would work with your backplane interface as well. This is a double confirmation, actually, in that it shows how similar at the HDD level the two machines are.

And your results are excellent, great work.

B.t.w. I'am working on the TDos version, as it is very close to LSDos, but don't expect more.
Click to expand...

This will be very interesting to see, since if the TRSDOS 2.0 code is that similar to the LS-DOS code, it would seem that Tandy didn't do very much in the way of changes for the Model II TRSDOS from the Model I TRSDOS, which shares a codebase with LS-DOS to a degree by virtue of both being derived from Randy Cook's work. Although I think the concept of the SVC is from the Model II TRSDOS line, but I reserve the right to be wrong. Beyond that, I know very little about the Model II TRSDOS, so have fun and let us know how it goes.....
 
You must log in or register to reply here.
Back
Top