UniDOS on the +D (Plus D) disk system

[equinox]

I don't know how many people had an MGT +D (Plus D) floppy disk system. This plugged into yer backside and gave you proper high-speed mass storage, on 3.5" floppies, not the dodgy "mass-storage" lie of the microdrive. However of course it came somewhat later, and had no official approval. I got mine in 1994 (haha, very late indeed) -- when MGT had become (or been purchased by?) Datel, and I had got sick of swapping cassette tapes in the post with the remaining Speccy sceners.

Before the +D there was the Disciple (disk... I pull?? GET IT?? god knows) -- which was largely compatible. The +D also had some interesting half-finished bits and pieces and error messages (in its little ROM) that seemed to support a network, but there you go, it didn't work.

You had to boot up DOS before you could use the disk commands in BASIC. This could be done in various ways, like the very first time, you would use the supplied cassette, and after that, you could (I think) just write RUN, with no program in memory, and it would somehow fall back on some NMI routine? or RST 8? and -- I don't know, I'm too stupid to understand these things. But it would then load DOS off the current floppy. You could put a DOS file on disk by naming it "+sys".

But there were several DOSes. The out-of-the-box +D DOS was "G+DOS" (I believe the G stood for Gordon, MGT being Miles Gordon Technologies, named after the two guys behind the affair), and it was workmanlike, but had some bugs and limitations. The COOL DOS that we all in fact used was "BetaDOS" (I sadly never had any idea who made it), which was mostly compatible, and just faster and better or mumble...something... it did support the excellent SQUASH.X (X being an "executable file", which was resident in the +D RAM): like the Multiface, the +D had its own little RAM (was it 8K?) and a snapshot button, and SQUASH would compress the snapshots and fit more on a single disk. I still can't believe that I got through The Addams Family (even with an infy lives poke) but SQUASH kept me slightly more sane.

FINALLY TO THE POINT: there was a third DOS that you'd always hear about (in zines, or from your swapper friends), called UniDOS. I gather there was also a UniDOS on the Disciple but it can't have been quite the same thing. I was told that it was totally incompatible, and writing a UniDOS disk with G+ or BetaDOS (or vice versa) would trash it. And I swapped a lot in those days, in the 90s, but I only ever heard about UniDOS and never saw it.

My question (if there are enough Disciple/+D users here) is: WHO EVER USED UNIDOS? And what was it like?

I know it was real because I have found this archive entry:
https://spectrumcomputing.co.uk/entry/1 ... um/Uni-Dos
It says: "Came with a required ROM chip to replace GDOS as well." Ouch! And note the complete absence of manual and instructions.
Who can tell the story?

[Stefan]

Reading through all Format issues could provide more insight. SD Software was advertising in pretty much every issue.

[equinox]

Reading through all Format issues could provide more insight. SD Software was advertising in pretty much every issue.

Oh I had totally forgotten about Format... I remember it existing as a paid subscription, and I remember Mr Bob Brenchley (didn't they end up being more of a Sam Coupé affair?), but I don't believe I ever read an issue. SC archive seems to have them so maybe I'll have a look just for fun, UniDOS or not.

If anyone else is curious, here's what to bookmark: https://spectrumcomputing.co.uk/magazine/75/Format

[8BitAG]

Nev Young mentions UNIDOS in his entry at World of SAM

Wrote a couple of simple utilities for my own benefit and was persuaded by Bob Brenchley to start SD Software (he thought of the name) to sell them. Later wrote the help page for Format for a couple of years. Nearly went bankrupt after funding the production of UNIDOS, written by Steve Warr, for the disciple and PlusD when a major flaw was found with the first shipping that required almost all ROMs to be replaced, free of charge, when a fix had been applied. SD Software supported several independent coders, on a royalty per sale basis, until it folded due to lack of sales, when it was sold to Format, who ran it until its demise.

[equinox]

Nev Young mentions UNIDOS in his entry at World of SAM

side comment, not about disks or DOS:
Perhaps I am cynical but did Brenchley suggest "you should do a royalty-based independent-coder software house" (= the house takes care of the coder for the gradual development, and pays them repeatedly thereafter), perhaps knowing that this would fail, and then casually snapped up the results (it's cheaper to buy a product than a process) afterwards.
Anyone who thought royalties was a reasonable way to approach the Sam Coupé must have been insane.

I wonder what the big boys like Ocean were thinking about the Sam at the time. Did they have a meeting, discuss it, and bin it? Apparently.

[8BitAG]

Anyone who thought royalties was a reasonable way to approach the Sam Coupé must have been insane.

It's a perfectly reasonable approach for software produced by enthusiastic amateurs as a hobby. The author would get a little bit of income if it was popular and sold and Nev would be taking on most of the risk and hassle of selling it.

[equinox]

It's a perfectly reasonable approach for software produced by enthusiastic amateurs as a hobby. The author would get a little bit of income if it was popular and sold and Nev would be taking on most of the risk and hassle of selling it.

It's a perfectly reasonable approach given a minimum figure of sales... Sammy didn't hit that.
I watched that Lemmings docu recently (and finally learned how to pronounce Psygnosis -- not as Ancient Greek as you think). One of the developers had made it his mission to collect all the various versions of Lemmings (all kinds of demo disks, and Japanese, etc.) -- oh yeah, -- never mind -- wrong thread. Another time.

[flatduckrecords]

when MGT had become (or been purchased by?) Datel

I believe they sold the PlusD to concentrate on launching SAM Coupé (and raise a bit of cash, and get away from support, repairs etc. to focus on the new machine).

Before the +D there was the Disciple (disk... I pull?? GET IT?? god knows) -- which was largely compatible. The +D also had some interesting half-finished bits and pieces and error messages (in its little ROM) that seemed to support a network, but there you go, it didn't work.

The Disciple networking was compatible with Interface 1, but it was dropped when they simplified (cost-reduced?) the design for the PlusD.

You had to boot up DOS before you could use the disk commands in BASIC. This could be done in various ways, like the very first time, you would use the supplied cassette, and after that, you could (I think) just write RUN, with no program in memory, and it would somehow fall back on some NMI routine? or RST 8? and -- I don't know, I'm too stupid to understand these things. But it would then load DOS off the current floppy. You could put a DOS file on disk by naming it "+sys".

Yeah, SAM works in the same way, but SAM BASIC has a dedicated BOOT command. The filename is important but it also needs to be the first file on the disk.

The COOL DOS that we all in fact used was "BetaDOS" (I sadly never had any idea who made it), which was mostly compatible, and just faster and better or mumble...something... it did support the excellent SQUASH.X (X being an "executable file", which was resident in the +D RAM): like the Multiface, the +D had its own little RAM (was it 8K?) and a snapshot button, and SQUASH would compress the snapshots and fit more on a single disk. I still can't believe that I got through The Addams Family (even with an infy lives poke) but SQUASH kept me slightly more sane.

That would be Dr Andy Wright who also wrote Beta BASIC, and went on to write the ROM for SAM (including re-implementing Nine Tiles floating point calculator (I think the Spectrum one was too expensive for MGT to license?) Yeah there's 8K of RAM and 8K of ROM. G+DOS supports execute files as well though, that's not exclusive to Beta DOS.

FINALLY TO THE POINT: there was a third DOS that you'd always hear about (in zines, or from your swapper friends), called UniDOS. I gather there was also a UniDOS on the Disciple but it can't have been quite the same thing. I was told that it was totally incompatible, and writing a UniDOS disk with G+ or BetaDOS (or vice versa) would trash it. And I swapped a lot in those days, in the 90s, but I only ever heard about UniDOS and never saw it.

I think the "Uni" in the name refers to the fact that it's the same DOS on Disciple and PlusD (some of the adverts play on that).

My question (if there are enough Disciple/+D users here) is: WHO EVER USED UNIDOS? And what was it like?

I haven't really put it through it's paces, but I've got it on my PlusD clone interface but since it's not compatible with PlusD disks I haven't made the commitment to really using it for anything yet.

You can try it out in Fuse. Swap out plusd.rom for the Uni-DOS ROM (rename it plusd.rom) before enabling the PlusD in the peripherals menu. Use the Uni-DOS.img file as a boot disk (utilities etc are on that disk as well so you can try it out) and use RUN to boot as usual.

[equinox]

Very informative -- thank you!

And Dr Andy Wright was definitely for me the name that I knew when I heard it -- yes -- everyone knew Beta BASIC was excellent but it's tough to introduce a new standard. (I truly think Sam BASIC is the best consumer BASIC ever made. It's stunning.)

[PeterJ]

I think I've posted this guide to SAM BASIC previously. I found it very useful:

https://sam.speccy.cz/basic/sam-basic_c ... _guide.pdf