68K/OS "ROM" based disk attempt

[Pr0f]

So not being familiar with the 68K/OS other than to boot the 32K rom image on Qemulator, I take it it supports a ROM disk - do you know what size this can be? Are there any requirements for a ROM image such as header, location in the memory map, etc. ?

[t0nyt]

So not being familiar with the 68K/OS other than to boot the 32K rom image on Qemulator, I take it it supports a ROM disk - do you know what size this can be? Are there any requirements for a ROM image such as header, location in the memory map, etc. ?

Hi Pr0f,

Yes, a ROM Disk

It seems to be a choice of 16K or 32K. In q-emuLator it's set as the backup ROM (so I assume it must sit at $C000?)

On page 2 of this thread there's a PDF explaining the layout (that I've identified so far) of the ROM Disk image structure, along with the 32K version of my ROM disk image (just has more of the utility programs than the 16K)

You can't do anything that needs the Microdrives as Q-emuLator doesn't support the 68K/OS MD format yet (but I believe Daniele is working on that from a logic capture of my drive)

There is a floppy driver, untested, but it can't be put in the ROM disk image (due to being a text file) that I've been able to find. Can't try it on a real QL as with 68K/OS card fitted there's no where to plug the floppy controller in! But if Q-emuLator can eventually work with the 68K/OS MD format we'd be able to test the floppy driver I assume

Regards
Tony

[t0nyt]

On another look at them - yes all 27(x)128 - so 16K size.

I thought I'd spotted a 27256 in there - but just my dodgy eyes!

Looks like 4 of my eprom's aren't supported by the programmer (2 x Intel, 2 x Fairchild), but at least I now know what to look for when I want some more

I still have 4 to be getting on with though

Many thanks

[Pr0f]

Are there specific types your programmer will work with?

What programmer is it?

I have a lot of Eprom's - just in the process of moving my 'man cave' - but if I have the type you need - I am happy to post some to you.

[t0nyt]

Are there specific types your programmer will work with?

What programmer is it?

I have a lot of Eprom's - just in the process of moving my 'man cave' - but if I have the type you need - I am happy to post some to you.

It’s a GQ-4x4

Thanks for the offer, but I’ve got 6x16k & 4x32k on the way this week that should be compatible.

I don’t have a huge use for EPROMs so am probably covered for a long time

Many thanks

[t0nyt]

Are there specific types your programmer will work with?

What programmer is it?

I have a lot of Eprom's - just in the process of moving my 'man cave' - but if I have the type you need - I am happy to post some to you.

It’s a GQ-4x4

Thanks for the offer, but I’ve got 6x16k & 4x32k on the way this week that should be compatible.

I don’t have a huge use for EPROMs so am probably covered for a long time

Many thanks

After faffing around I discovered the 4 EPROMs I thought weren't supported actually are!

[t0nyt]

Well I loaded up the 32K ROM into EPROMs and fitted them to the 68K/OS board and again it works!

Useful to have the editor available I think

[t0nyt]

Does anyone have any thoughts on the following please?

I'd like to try an experiment with fitting a QL mobo with a copy of the 68K/OS ROM (in place of the JM/whatever Roms) on an issue 5 mobo

But I'd also like to be able to access the 32K Utility ROM

So the question is, what options, if any, do I have to be able to fit my own 32K ROM (the utility ROM) into the ROM expansion port on the back of the QL so it starts at $C000 please?

I know Chr$ ROM/TK2 board has the TK2 at $C000 internally, so could I even have both ROM's (OS & Utility) internal?

I don't know how the QL knows what ROM goes where in the address space, so am flailing around pretty blindly here!

EDIT: the eventual aim is to be able to test using the floppy disk driver. In reality I don't really need the Utility ROM as I have working MDV's with the software on them but it would be good to have the main programs in ROM rather than relying on the MD units

Many thanks

[Pr0f]

I believe the ROM port actually addresses 64K, so from 00000H to 0FFFFH - ROMOEH is an enable high for any address in the lowest 64K - ROM cartridges use a logic gate to decode the top 16K and use it with ROMOEH to enable the Eprom / ROM chip in the ROM expansion port.

So nothing to stop you doing 32K in that ROM port if you wanted, provided it's not being used internally.

Likewise the ROM sockets in the QL also carry all the address lines for 64K and both sockets are identical - so the PCB's with jumper on would provide either 48K or 64K of the EPROM for the QL to use - so nothing stopping you using all 64K and having 32K os and 32K utility/tools

[t0nyt]

I believe the ROM port actually addresses 64K, so from 00000H to 0FFFFH - ROMOEH is an enable high for any address in the lowest 64K - ROM cartridges use a logic gate to decode the top 16K and use it with ROMOEH to enable the Eprom / ROM chip in the ROM expansion port.

So nothing to stop you doing 32K in that ROM port if you wanted, provided it's not being used internally.

Likewise the ROM sockets in the QL also carry all the address lines for 64K and both sockets are identical - so the PCB's with jumper on would provide either 48K or 64K of the EPROM for the QL to use - so nothing stopping you using all 64K and having 32K os and 32K utility/tools

Thanks Pr0f, but I don’t really get it

If I fit 2 x 32k EPROM internally the first, I assume, would be $00000 to $07FFF meaning the next would start at $08000 rather than the $0C000 I believe I need?

Also, if the sockets are identical how would it know which is meant to be at $00000?

As I say, I’m completely in the dark as to how the QL addressing works

Many thanks