Did Sam Coupe had Zx Spectrum ROM?

[Ralf]

My knowledge is very poor when it comes to Sam Coupe and I decided to improve it a bit today

Sam Coupe could run Zx Spectrum games and other programs, right? So did it have a copy of Spectrum ROM?

I guess that without ROM memory a lot of programs would crash.

If so, how did they deal with copyrights?

[mjwilson]

I found some info here if it's any use: https://www.worldofsam.org/products/spectrum-emulator

The original emulation was via a 'skeleton' ROM image (not containing any copyrighted code) that was not 100% compatible leading to many problems with software that made extensive ROM routine calls or utilised undocumented calls or features.

[8BitAG]

No, but what we all ended up doing was basically saving a copy of the ROM from a Spectrum and loading that into one of the later emulators; which gave the SAM a lot better compatibility with Spectrum games than the initial "emulator", based on non-copyrighted code, that MGT supplied with the machine. The SAM was my main "ZX Spectrum" for years.

[Stefan]

SAM's Z80 memory space consists of four 16K banks: A, B, C and D.

Bank A and B are controlled by the low memory page register (LMPR = port 250).
Bank C and D are controlled by the high memory page register (HMPR = port 251).

Since there are only two memory page registers, you /can/ select a 16K page, but the next bank is paged in with page + 1. While useful when crossing page boundaries, it is otherwise rather annoying since it is too coarse grained.

SAM's internal ROM0 can be paged into Page A and ROM1 into page D by setting bits on LMPR.
Page A can also be RAM, another bit on LMPR sets this RAM to read only, which is useful in protecting, for example, a Spectrum ROM that happens to reside here.

[Timmy]

In SU someone sent in a Letter to explain how to copy your Spectrum ROM to your Sam Coupe.

https://spectrumcomputing.co.uk/page.ph ... 98&page=38

(no clue if that's how it worked, I don't have one).

[flatduckrecords]

In SU someone sent in a Letter to explain how to copy your Spectrum ROM to your Sam Coupe.

https://spectrumcomputing.co.uk/page.ph ... 98&page=38

(no clue if that's how it worked, I don't have one).

Yes, that would work. I’ve seen similar listings published in other magazines too. (Format and Outlet, I think). SAM is more well-known for using disks but it also supports loading from tape. (In fact the first SAMs shipped with no drives at all so the early software came on tape). And of course once the emulator is running you can LOAD your (48k) Speccy tapes.

MGT (Miles Gordon Technology) also made the PlusD and Disciple disk interfaces for Spectrum so the disks are somewhat compatible with SAM—so that’s another way you could save out the Spectrum ROM and load it into SAM. Some of the emulators could even import the Spectrum “magic button” snapshot files.

More recently @Quazar has developed a “ZX-ecutor” interface for SAM that allows you to load any 16k ROM, including the original cartridge games released for ZX Interface 2, or indeed the Spectrum ROM itself (and other variants of it).

[8BitAG]

We used to include licensed ZX Spectrum games on our Sam Adventure Club disks, together with a suitable emulator. All the readers had to do was supply their own copy of the Spectrum ROM... but "everyone" had a copy of the Spectrum ROM by then, even if they hadn't extracted it themselves.

[Timmy]

So if you don't have a disk drive, then one would have to load the 16K ROM from tape into the Sam Coupe every time?

[flatduckrecords]

So if you don't have a disk drive, then one would have to load the 16K ROM from tape into the Sam Coupe every time?

Yes, that's right. As well as supporting standard Spectrum loading speed, SAM could also save data at a faster speed - so you could in principle save the ROM from Spectrum onto a tape, load that into SAM as a DATA block, then re-save it from SAM as a high-speed data block so that future loading would be a bit quicker.

Whether it works reliably depends on the fidelity of your cassette and recorder. A range of speeds are supported; slower being more reliable.

There was also The Messenger which could transfer the ROM and snapshots over a MIDI/network connection (but you'd need a SAM disk drive to load the associated software)

[Ralf]

Thanks for explanations. I'll try to sum it up.

SAM creators didn't secure any copyrights for ZX Spectrum ROM code so you had to use a bit dirty workarounds.

SAM has built in some "skeleton ROM" which in theory could replace Spectrum ROM without using original copyrighted code but
in practice it very often failed to do its job.

So you had to save Spectrum ROM to tape and load it from tape each time when you wanted to have reliable Spectrum emulation.

Well, it's a bit lame for a computer that claimed to be "Super Spectrum"

And please remember that Sam wasn't cheap. I remember reading it costed as much as second hand Atari ST. Maybe if they
managed to sell in in more numbers, they would be able to go down with the price but as we know it never happened.

[Stefan]

SAM creators didn't secure any copyrights for ZX Spectrum ROM code so you had to use a bit dirty workarounds.

No relevant commercial titles as of 1989, and probably much earlier even going back to 1986, needed the ROM.

SAM has built in some "skeleton ROM" which in theory could replace Spectrum ROM without using original copyrighted code but
in practice it very often failed to do its job.

The skeleton ROM was not built in. It's just some basic code containing some often used ROM stubs loaded into a RAM page that is at address 0 with write protect enabled.

So you had to save Spectrum ROM to tape and load it from tape each time when you wanted to have reliable Spectrum emulation.

When you buy a Super Spectrum you would have been a bit mad (or cheap) IMHO if you did not also get at least one disk drive.

I had had a DISCiPLE disk interface for years before upgrading to the SAM Coupe, no way was I getting a SAM without a disk drive. I also got the SAM disk interface, which allowed me to use one of the 5.25" drives that was connected to my Spectrum. In hindsight I should have copied all my Spectrum disks over to 3.5" disks, but I did not since I did not care about the old Spectrum stuff.

[Ralf]

No relevant commercial titles as of 1989, and probably much earlier even going back to 1986, needed the ROM.

Really? How do you imagine a program in Basic running without the ROM? How do you imagine a program using default font
running without the ROM?

[Stefan]

Really? How do you imagine a program in Basic running without the ROM? How do you imagine a program using default font
running without the ROM?

Hmm... very good point.

If the "skeleton" ROM needed to be able to execute Spectrum basic, then it is more of a fully clothed human than a skeleton.

Thank you for giving me something to investigate.

[AndyC]

Really? How do you imagine a program in Basic running without the ROM? How do you imagine a program using default font
running without the ROM?

How many commercial titles after 1989 do you imagine we're written in BASIC or used the system font?

And the system font issue could probably be circumvented by just copying the SAM ROM font into the relevant addresses in the skeleton ROM (which I presume it did).

[Stefan]

How many commercial titles after 1989 do you imagine we're written in BASIC or used the system font?

The loaders are all basic. Theoretically the skeleton ROM could just have picked out the LOAD and USR tokens and continued from there.

[bob_fossil]

The loaders are all basic. Theoretically the skeleton ROM could just have picked out the LOAD and USR tokens and continued from there.

The loaders may be BASIC but the commercial protection systems and custom loading schemes did some odd things with BASIC. Some loaders like the Lenslok on the original release of Elite also used sections of the ROM to decrypt the game code.

I remember looking at the OpenZX replacement ROM a while ago and while it could load and run a lot of commercial tapes, there were quite a few titles that refused to get past the first basic loader block due to issues with the BASIC implementation or unimplemented ROM calls.

[1024MAK]

I don’t know a great deal about the Sam, but at the very least, it had to have at least some ROM paged in at power-up or reset.
Did it have it’s own build-in BASIC? I presume it also had it’s own font.

Mark

[flatduckrecords]

I don’t know a great deal about the Sam, but at the very least, it had to have at least some ROM paged in at power-up or reset.

Yes, there were a couple of revisions over the machine’s life to correct bugs.

Did it have it’s own build-in BASIC? I presume it also had it’s own font.

A very good one! It was a follow-on by Dr Andy Wright of his Beta BASIC for Spectrum.

[1024MAK]

That’s what I thought. Thank you for answering.

So presumably, Sam BASIC could handle generic BASIC programs, and it was only when commercial software or software written in machine code (or BASIC) specifically for a ZX Spectrum directly accessed where it expected ROM data or machine code to be, that there would be a problem.

Mark

[flatduckrecords]

Spectrum CODE blocks can be loaded but not other types, including BASIC. On the MGT introductory tape/disk there is a Sinclair BASIC translator for converting those to SAM BASIC.

[dvduk]

One of these days would love to have a bash converting Football Manager to SAM Basic

Maybe when I clear some of my work backlog.....

[HEXdidnt]

Well, it's a bit lame for a computer that claimed to be "Super Spectrum"

Bit late to the game on this topic, but the nobody involved with making the SAM claimed it was a "Super Spectrum". If anything, MGT tried very hard to break away from that description. It was lazy shorthand, used by the computer press at the time.

[Alessandro]

My knowledge is very poor when it comes to Sam Coupe and I decided to improve it a bit today

Sam Coupe could run Zx Spectrum games and other programs, right? So did it have a copy of Spectrum ROM?

I guess that without ROM memory a lot of programs would crash.

If so, how did they deal with copyrights?

Sorry, I am late to the question too. Just wanted to add that you can find all of the answers to the above, and much more, in the Spectrumpedia, Volume 1, pages 474-483 (Chapter 4 in Volume 2 adds sources and further reference)

Shortly answered: 1) through an external device called The Messenger; 2) no.

Bit late to the game on this topic, but the nobody involved with making the SAM claimed it was a "Super Spectrum". If anything, MGT tried very hard to break away from that description. It was lazy shorthand, used by the computer press at the time.

This "super-Spectrum" hype was an awkward marketing move and damaged the potential diffusion of the SAM Coupé in fact. When the computer appeared on the market, its intended user target had been heavily exposed for a year to the expectations of journalists and MGT propaganda presenting the SAM Coupé, first of all, as a sort of advanced Spectrum, so it was very difficult for them, if not impossible, to understand the computer’s authentic potential. Moreover, all of this took place in a historical moment when software houses were slowly deserting the 8-bit range.

[g0blinish]

Some games published in Fred e-mag contain ROM 48k