Northstar Advantage floppys

[Manuel Teira]

Hello,

I've finally been able to mostly bring back my Nortstar Advantage to
life. It has a Shugart floppy drive unit that seems to work (I've
tested it on a PC controller), but unfortunately I have no working
hard-sectored 5.25 floppy disks.

Do you have some advice to give me, regarding such disks. I've seen
somebody commented time ago about a punching tool, but I've also found
references about the unreliability of such mechanical tools.
Furthermore, how could I write an image to such a disk, in case I could
get them?

Any other posibility to load some real program on the advantage? Maybe
using the serial port?

Do you know if there's any Nortstar Advantage simulator available?

Thanks a lot for your time and best regards!
Manuel

[David Jones]

Well this week I'm working on a serial loading utility that uses the serial port in slot 1. It is based on the Northstar loader from deramp.com. Mostly just a matter of changing it to init the port, set the baud rate, etc and move the address it loads things to where the Advantage has memory mapped on boot. I haven't had a chance to test it but it looks good. Next I plan on trying to get the Deramp.com PC2Flop modified to work on the advantage. If it helps, I've dumped the boot ROM, disassembled it, and have partially commented it.

Also, I have a punch jigg that can be printed with a 3d printer. I think it works but haven't tested it. Sort of a chicken and eggs thing. Need something working so I can test the other.

A simulator would be really nice. So far I haven't found one.

Let me know if anyone wants any of this.

David

[Manuel Teira]

Really interesting David! Looking forward to hear about how it turns out. :-)

I've also tried some dissassembly of the Advantage boot ROM. It was
useful for me to find that the video RAM was not working (due to a
failing flip-flop in charge of generating the Write Enable signal) by
comparing the dissassembly with the address bus timeline in an
analyzer. In case it can be useful:

https://github.com/teiram/northstar-advantage-boot/blob/master/src/boot_eprom.asm


I was also wondering if one of those Gotek floppy emulators could work
with the enhanced HxC firmware. I've seen that there was some
discussion in its support forum about making it work with CP/M based
computers. I don't know if it emulates hard-sectores floppies, but
maybe it can be combined with the deramp.com VSG solution to simulate
sector pulses.

When you talk about the PC2Flop from deramp.com are you talking about
the Virtual Sector Generator? Why does it need to be modified to work
on the Advantage?
I have a PIC somewhere and would like to experiment with this kind of
solution too. :-)


Best regards,
Manuel

[David Jones]

Thanks for the assembly file. I'll compare it to what I've got so far. At first glance, it looks like what I've done will complement yours, at least some.

The deramp.com program I was talking about was for the Sol-20 with a Northstar floppy controller, which I also have but is giving me problems. The thing is the Sol-20 has a different memory map from the Advantage. So the program will need to be modified for that and buffering location changed as well.

http://deramp.com/downloads/index.php?dir=processor_technology%2Fsol-20%2Fsoftware%2Fnorthstar_dd_controller%2Fdisk_image_transfer%2F

I'll set up a repository for what I've done and let you know once I get things set up and uploaded.

David

[David Jones]

Ok. I've put things up in a git repository.
https://github.com/djones60/North-Star-Advantage

[David Jones]

I forgot to mention. I didn't see any copyright notices on those programs I mentioned from deramp.com. Please let me know if he doesn't want us modifying his programs.

[Manuel Teira]

Great! If you don't mind, and as soon as I get some free time, I would
like to merge both efforts, of course mentioning your contribution.
I think it would be nice to have a complete dissassembly of the boot ROM.

[Manuel Teira]

The point is that... I think that my Advantage is a bit different. I
already found some differences between my mainboard layout and the one
in the Service Manual. Additionally, it has a 4K boot PROM (Fujitsu
MBM2732A). The memory layout also seems to be different, whereas the
Service manual talks about 20Kb of Video RAM, my board has two rows of
16Kb each. I thought that maybe my Advantage is a later revision, for
which I was not able to find any information. Most of what is stated in
the Service Manual apply though.

If you're interested, I have some photos of the board in my Google
Drive, like this one:

https://drive.google.com/uc?id=0B1IyxkqPHp2BdUt0NTc4bmpyNEk

[Manuel Teira]

Neither I did. Maybe we could ask him...

[David Jones]

From the pictures, yours must be a newer one. Mine has two rows of 4116 by 8 bit for video memory and four rows of them with parity for main memory. Mine also doesn't have the extra connector on slot three. I'd be interested in seeing your 4k ROM. Mine is supposed to support that and has a jumper for it. I just wonder what is does in the extra space. It might be interesting to burn a copy of it and see if it works in my Advantage.

Sure go ahead and merge what I have with yours. FYI. I just sent him an email asking if we could use his programs as a starting point for an Advantage version.

David

[David Jones]

I should have said connector by slot four. Miss counted :(

[Manuel Teira]

My 4K ROM is also available in my Git repository:

https://github.com/teiram/northstar-advantage-boot/tree/master/bin

In that directory you can find both the boot EPROM dump (what I
disassembled) and the keyboard EPROM.

Manuel

[Manuel Teira]

No worries, I understood. Yes, in the service manual there's no trace
of that extra connector.

[David Jones]

I found the ROM dump after I posted that and am looking through your code for the last 2k. Here in bit, I'll try burning one and see what happens in my Advantage. I wonder if my ROM will work in yours? If so, we might be able to put some kind of loader in that last 2k.

David

[David Jones]

Well I just tried your ROM image in my Advantage and it worked, including a minimal CP/M. Unfortunately, this disk doesn't have the utilities needed to make copies.

David

[David Jones]

Also Mike Douglas at deramp.com is ok with us making a version of his loader and imaging software to work on the Advantage.

David

[Manuel Teira]

Yes, that would be an interesting experiment. Currently I have no
compatible chip to burn and replace the current ROM. I will try to buy
some.

Anyway, one can also make place in the current ROM to accomodate some
sort of loader, for instance, replacing the monitor or the serial boot
code. It would be harder, of course, and it would be always better to
have some empty space to play with.

Best regards,
Manuel

[Manuel Teira]

Good news!

[Manuel Teira]

Good to know. I think I have good chances to get some hard-sectored
floppies for the Advantage with some software preloaded. Anyway, I
would like to try the Virtual Sector Generator, to avoid depending on
such media.

It would be also interesting to find out if a Gotek simulator with the
HxC firmware would emulate hard-sectored media (I've asked in the
support forum, where somebody also asked before me) or even the
combination of the VSC and a Gotek just supporting typical CP/M disk
layouts.

Best regards,
Manuel

[David Jones]

Glad you are able to get a boot disk!

If you don't mind, I would still like to merge your source with mine. I still have some ideas on a custom boot ROM. Such as changing the serial boot to be an Intel Hex format loader. With the larger 4k ROM, there are all kinds of things we could do. Such as an disk image loader, maybe a tiny basic, etc. I was also thinking that it might be possible, with a little soldering, to build an adapter for a 16k ROM.

I'm still thinking it would be good to make a version of PC2Flop for the Advantage. People periodically post in the forums looking for someplace to get disks and this would be handy for them. Plus it would give me a good excuse to relearn Z80 programming :)

David

[Manuel Teira]

Of course, feel free to use my source. I hope it contains no errors.

And yes, it would be very nice to have a PC2Flop version for the
Advantage. If I can be of any help, just tell me.

Best regards,
Manuel

[Manuel]

Finally somebody was so kind to send me hard-sectored floppies with
preloaded Northstar Advantage software. He was able to write them using
his Northstar Horizon.

So, after some video RAM chip change, I have it working again!!

Here a video to the demonstration disk running:
https://www.youtube.com/watch?v=PVM0qTwyH7A

Sorry for crossposting here and to com.os.cpm, but I think it could be
of interest in both lists.

Best regards
Manuel

El 17/09/16 a las 21:05, Manuel Teira escribió:

[Happy Oyster]

On Tue, 4 Oct 2016 14:30:51 +0200, Manuel <manuel...@gmail.com>
wrote:

Congrats!

--
Homöopathie ist nichts als Hütchenspielerbetrug und organisierte Kriminalität
http://ariplex.com/folia/archives/565.htm http://ariplex.com/folia/archives/570.htm
http://ariplex.com/folia/archives/585.htm http://ariplex.com/folia/archives/643.htm
http://ariplex.com/folia/archives/647.htm

[jackst...@gmail.com]

On Friday, September 16, 2016 at 7:02:22 AM UTC+10, Manuel Teira wrote:


> Do you know if there's any Nortstar Advantage simulator available?
>

Hi Manuel, I'm working on one using Linux X11 graphics. I have several disk-images with what seems to be a complete GHDOS. But I haven't got any disk-images which can do the initial hard-disk initialisation and setup for the Advantage. Do you have any?

I can do all that for my North Star Horizon Emulation. HDOS requires a file called TRANSIENT on the hard drive to replace the CLI interface after the termination of each HDOS command. I assume that the Advantage also does that, but I don't know what the file is called, and where I can find it.

Regards,

Jack Strangio

[ingmar...@gmail.com]

G'day folks,

I'm in Australia and I've recently been given an Advantage but so far no disks. I've also gone through the process of disassembling the 2k boot rom and transferring Z80 code over the serial port from my PC laptop. Nice old machines and no doubt much more fun once I get some disks running.

Cheers,
Ingmar

[David Jones]

The newest version of the HxC software on the GoTek floppy emulator will work in the NS Advantage. The HxC emulator software will also convert the .NSI images you can find online into something their drive software understands. I was able to use to to create some boot and app disks.

Also if you look on Thingiverse, I put up a template for creating hard sector disks. Of course, you will need a 3d printer and something to punch the holes. I used a laser to burn them but not everyone has one strong enough.

David

[ingmar...@gmail.com]

Great thanks for the pointers David, I had been reading the 18 pages of hardsector stuff on the HXC forum but obviously missed the bit where they got it working. I used my CO2 laser to modify a disk the other night. I was about to write disk formatting and writing code from scratch but the gotek will save the day. I actually bought the hxc firmware a few weeks ago for something else, doh..
Cheers
Ingmar

[ka3...@gmail.com]

I have an Advantage that I got years ago, but no floppy's. I used the
monitor to enter some code and made dots on the screen. Found the monitor when
I pushed the button on the back. Is there somewhere I can get a list of commands and info for it? This unit has a floppy and HDD.

[Robert Stek]

Contact me privately - I have a bootable copy of GDOS and GBASIC for the Advantage.

[David Jones]

On Tuesday, November 26, 2019 at 6:12:53 PM UTC-5, ka3...@gmail.com wrote:

Google for advtech.pdf or email me for a copy. It has all kinds of information on the system including how to get into the monitor and how to use it.

[ka3...@gmail.com]

Thanks for the info. I saw where you could load system from 2nd drive.
I wonder if there is a chance the HDD could have the system on it. Not sure when I'll get a chance to check it out.

73,
Dave
KA3JGG

[wcbr...@gmail.com]

> The newest version of the HxC software on the GoTek floppy emulator will work in the NS Advantage. The HxC emulator software will also convert the .NSI images you can find online into something their drive software understands. I was able to use to to create some boot and app disks.
>
> Also if you look on Thingiverse, I put up a template for creating hard sector disks. Of course, you will need a 3d printer and something to punch the holes. I used a laser to burn them but not everyone has one strong enough.
>
> David

I have been restoring a North Star Advantage, actually a GBC System 9, and I need some help. The drives have been destroyed by a mouse. I would like to learn more about using a GoTek, particularly as a boot drive. I am also having trouble with the motherboard and ROMs. Any help would be greatly appreciated.

Bill

[David Jones]

Here is a link to the ROM's
https://github.com/djones60/North-Star-Advantage

I also have a dump of the keyboard controller ROM.

For using the GoTek, here is some information
http://torlus.com/floppy/forum/viewtopic.php?f=19&t=1777&sid=c05b1655b09181acaaa15982121cf1e6&start=270

I can't remember if it can boot directly off the hard drive or not. But if I remember right, there is the option for it in the ROM. So I am guessing it can.

David