Page 1 of 1

Writing System 80 Disks

PostPosted: Sat Dec 19, 2015 7:33 pm
by 3pcedev
Hi all,

I managed to find myself a System 80 expansion unit complete with two disk drives and a printer. I will be picking it up soon and no doubt I will be eager to try it out....

My question now is what is the best way to create some disks to try out on the system? I see Terry and a number of other sites have a lot of DSK images which are ready to go. Looking at the format I see that they are 80 track single sided, single density.

I have a heap of 5.25" DD and HD disks here (used on my older PC's and also my Apple IIE). Will these be suitable for use on the System 80? If so what is the best software to write the images? I have a number of 5.25" PC drives, from 360k right up to 1.2MB running on a number of PC's from DOS 3.3 up to Windows 98. Any advice on which is suitable / best / whatever is appreciated.


Re: Writing System 80 Disks

PostPosted: Mon Dec 21, 2015 2:26 pm
by tezza
H Matthew,

ok, this can be someone what complicated. First, does your expansion unit have a doubler so that disks are written in double density? Or is it without a doubler, which means the disks are single density. Just how you approach this largely depends on that one thing. The doubler will be a small daughterboard plugged into the socket where the disk controller chip would largely be.

If it DOES have a doubler, then it's easy enough to write disks using an old PC. You can use the same software I've mentioned in this article. ... -trs80.htm

You'd be best not to use my System 80 images directly however if you are going to use a PC to write the disks. You'd be best to use a TRS-80 Model 1 emulator to make some 40 track, double density disk images (a DOS disk of some type and some blanks) then using Matthew Reed's TRSTools (Google it), copy the programs from my images to these new images. These new 40 track images can then be used by the PC program and a 360k drive to make disks which should work on the System 80. If you don't want to go to this bother, I have a collection of favourites in 40 track, double density disk images. Email me and I'll share with you.

If the expansion unit only read single density, then it's a whole new ballgame. There are some old '90s computers that write single density disks but they seem to be the exception rather than the rule.

Re: Writing System 80 Disks

PostPosted: Wed Dec 23, 2015 12:31 am
by 3pcedev
Hi Terry,

Unfortunately I don't have a double but I did "partially" manage to write an 80 track single density disk...

By partially I managed to format a disk using my Laser 286 clone (with 1.2mb 5.25" drive) running Matthew Reeds TRS-80 emulator. It got to sector 420 and then had errors; so I aborted. I tried the same thing on a P3 machine with the same make of drive and it didn't work at all (errors from track 0 onwards).

If I then copy the NEWDOS/80 boot disk (virtual disk) to the real 'sort of formatted' disk it will boot on the physical Dick Smith System 80. I think this is because it is not writing past sector 420 as NEWDOS is only around 20k or something like that. As expected when I try to copy a disk that is almost full it will also fail at sector 420 and thus not work.

I have no idea why it works up to sector 420 but if anyone has one please let me know. I was planning to try the same trick with my old XT (with a 360k drive) but I then realised that it will only work up to 40 tracks; not 80....

Re: Writing System 80 Disks

PostPosted: Wed Dec 23, 2015 9:18 am
by tezza
3pcedev wrote:.. I was planning to try the same trick with my old XT (with a 360k drive) but I then realised that it will only work up to 40 tracks; not 80....

If you do have a PC disk controller that can write single density, my advice would be to use the 80 track images and TRStools to make 40 track single density images, then use that 360k drive to write them out onto disk. Make them single sided. This avoids most of the complicating factors, as I'm assuming the System 80 drives are 40 track single sided?

You can hook other drives up the the system 80 (single sided, double sided, 40 track and 80 track) but they all need to be running at 300rmp. A 1.2 MB PC drive normally runs at 360. Some have jumpers to step down the speed. Not all TRS/80 DOSes support 80 track drives. NewDos 80/v2 does, but it needs configuring to recognise them.

Hope this helps.

Re: Writing System 80 Disks

PostPosted: Fri Jan 01, 2016 10:46 am
by 3pcedev
Just for the record I did manage to write single density disks on an PC.

I used an ACER IDE/Floppy disk controller combo board. It has very little information printed on it but it is 16 bit ISA and it was found in Acer 486/66 PC's. The heart of the controller is a small ASIC in the centre of the board with ACER written on it. This was teamed up either a Chinon 360k 5.25" drive or a Chinon 1.2Mb 5.25" drive to successfully write single density FM disks.

Strangely though it's not 100% - while it can read / write disks on the PC it can't read anything written on the System 80 (System 80 can read disks from the PC, but not vice versa). At first I thought it was a drive alignment problem but I realigned everything and I am convinced it is not.