Psion and ROM cartridges

[Wicksy]

I read on the special launch issue of QL User magazine, page 54 that Psion were looking at putting the 4 business packages on to ROM cartridges. It said it would free up RAM in the process.
Could they have overwritten some of the system ROM as happens when using a cartridge on the Spectrum to overcome the 16k limit, if needed?

Finally, has anyone tried it? It would be a nice back ROM on clones / emulators and plugin on the real thing. Even the larger Xchange.

[Wicksy]

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[Derek_Stewart]

Hi,

I read the FB QL group discussion about this.

I think, Psion were trying to move their application suite into a ROM format, so that the application like Quill was loaded instantly, without using the QL RAM.

Bear in mind the QL only had Microdrive storage, of 100Kb on the Microdrive Cartridge, and loading slow compared to loading from ROM.

These days we have access to SD Cards, IDE Hard Drives, Floppy Disk drives, holding more data than Microdrives.

The Q68, QIMSI Gold loads its operating system from SD Card, and can load the executable programme from QLWA container file.

What do you mean a bigger Xchange?

[Wicksy]

Am interested how they would have achieved getting an individual Psion file of around 60k, when only 16k ROM is on offer.

Is the emulated back rom space of Q68 limited to 16k?
I mentioned Xchange due to its' larger file size.

[Derek_Stewart]

Hi,

I am not sure what you mean by Back ROM on the Q68.

The Back ROM comes from Q-emulator, where a Rom image file is loaded into $C000 hex or the QL Rom port area, which I assume it called this as it is the Rom at the Back of the machine.

Minerva4Q68 allows a 16K ROM file, like Toolkit 2 to added on to the end of the Minerva ROM file that is loaded from the SD Card on power up.

But on SMSQ/E a ROM file can not be added to $C000 Hex. as I think thzt the SMSQ/E whould link the Rom code into the operating system.

ROM image files can be loaded into an SMSQ/E system with the EPROM_LOAD command.

Maybe Psion thought they could have a ROM loader at $C0000

The is no facility on th Q68 to load a ROM from the 16x16K ROM slots starting at $C0000 Hex. and allocate 16K Rom slots to make the space required for the application required. But you would have to write the ROM loader code.

Executing Quill, Abacus, Archive, Easel or Xchange is very quick on the Q68 from SD Card, so Roms ard not required.

I find the Qspread is a better spreadsheet than Abacus, but that is personal opinion.

[Wicksy]

I used back rom to mean the eprom command on Q68, just seemed better to use the same term when talking about it and Qemulator in the same question.

Qemulator has scope to run a back rom and expand rom.

[Derek_Stewart]

I used back rom to mean the eprom command on Q68, just seemed better to use the same term when talking about it and Qemulator in the same question.

Not sure what you mean, there is a standard SMSQ/E command to load ROMS: EPROM_LOAD. But nothing specfic to the Q68.

The Q68 can load a ROM file that is a maximum size of 96K, which allows systems like Minerva4 Q68 and Toolkit 2 to be loaded similiar to a standard QL.

Qemulator has scope to run 2 16k roms at the same time, ie back rom and expand rom, set out in the manual.

Qemulator, loads at memory location:

Back Rom: $C000
Exp Rom: $C0000

The QL can have 16 x 16Kb ROMs at $C0000, with a Rom at $C000
Qemulator as you said only allows 1 ROM at $C0000

Anice enhancement would be to have a wai of populating thd QL Expaned ROM slots. But very difficult to do.

[dilwyn]

I wonder if what Derek says about the availability of addressing above the $C0000 range hints at what Sinclair were planning to do with a QL successor or what CST were doing with the Thor machines? Rather than the standard 16K EPROM slot on a QL, they may have used addressing above the design limit of 640K total RAM for a ROM expansion to hold the Psion software? That is, where Miracle put extra RAM so that a Trump Card could take the total memory to 896K rather than the previous maximum of 640K total, or where hardware add-on card driver ROMs may have gone?

No idea if there's any truth in this, I'm just speculating.

[tofro]

I wonder if what Derek says about the availability of addressing above the $C0000 range hints at what Sinclair were planning to do with a QL successor or what CST were doing with the Thor machines? Rather than the standard 16K EPROM slot on a QL, they may have used addressing above the design limit of 640K total RAM for a ROM expansion to hold the Psion software? That is, where Miracle put extra RAM so that a Trump Card could take the total memory to 896K rather than the previous maximum of 640K total, or where hardware add-on card driver ROMs may have gone?

No idea if there's any truth in this, I'm just speculating.

When the Bill Gates quote "640 kBytes of RAM should be enough for everyone" is true, Sir Sinclair should probably be assigned the same quote. The "official" QL memory map (QL Technical Guide, Chapter 10) doesn't show more. And, in my opinion, it also shows they weren't really thinking about upcoming 68k successor CPUs (because there is really not an easy way to hold on to this architecture with more than 1MByte address space - just like the IBM PC).

The top 128kBytes have been reserved for "Add-on ROM", something I think hasn't ever been implemented by an add-on card. Beyond this scarce description, there's also no hint on what this ROM was supposed to be good for. (Maybe they were thinking about office software in ROM? Then it was not enough, would maybe have been good for one or two of the Psion 4)

Another 128 kBytes below that have been reserved for peripheral cards and their ROMs (just like the IBM PC) - something that - at least to the extent of 8 cards) wasn't really possible with the hardware we know and would have required a complex expansion box or a PC-like, completely new slot-oriented hardware architecture (The provisions on card identification and automatic address space assignment for peripheral cards give, however, a strong hint that they were thinking about a slot architecture)

The Trump card did the right thing and simply filled all of these areas with RAM, improved the QLs original on-board hardware decoding and put its registers there without polluting the upper address space. Later Miracle developments completely ignored that as well (and had to - Gold and SuperGold cards had grown beyond this original Sinclair memory architecture)

[Derek_Stewart]

Hi,

I just read the the QL Technical Manual, QL Service Manual, QDOS Companion, all indicate the QL has 128K Ram expandable to 640K Ram, with 16 x 16k Eproms slots startint at $C0000 as well ax the Rom Slot at $0C000.

The Trump Card logic took the Rom slot addresses allowing extra 256K Ram to be added to the 640K QL memory, giving, 896K ram.

The only free space being Rom Slot: $0C000, for add on 16K ROM.

But the Toolkit 2 ROM on the Trump Card was located at $10000, see attached Appendix A from "QL Advanced User Guide"