The Sinclair QL Forum

Mine arrived today, and I'm about to open up my QL to insert it! Looks like a nice bit of electronics, so well done Peter and Paul for realising the concept!

Looks like time to update your sig from "JS ROM" to "Minerva 1.98!"

Minerva is quite a bit faster than JS...

And it WORKS! Straight away! I found a rather neat way of keeping both microdrives and retaining access to the SD card, by feeding the daughter board though the slot where my SuperQBoard plugs in. Snug fit, but not tight, and doesn't pinch the ribbon cable.

Now I just have to work out how to use it, but that will be a beer and a few hours this weekend...

Dave wrote:Looks like time to update your sig from "JS ROM" to "Minerva 1.98!"

Minerva is quite a bit faster than JS...

No, I kept old fashioned with the JS ROM version of the QL-SD, rather than upgrade to Minerva. I have Qemulator on my iMac if I want to get fancy, my QL is to stay the real deal!

I noticed that on one of the JS ROMS I removed (the left hand IC without a transistor behind it) had a leg removed (far right hand corner); The other one is intact. Just curious, but can anyone provide a brief explanation why there are a: two ROM chips, and b: why one had a missing leg?

The JS ROMs all have the missing one leg on one of the chips - no idea why - earlier ROMs had all the pins (but that missing one was never used - maybe it was only for the EPROM version ?)

As to why there are two chips? Who knows - probably 32K ROMs were cheaper than 48K ROMs ?

Thanks for that Rich, I'm glad that there is no definitive logic behind the number of ROMs and the missing leg. we can just put it down to the penny pinching genius that is Sir Clive...

Do you want a simple reply, or a more complex reply?

Simple:

First, the OS and BASIC were larger than expected. So instead of fitting on one 32k byte chip (or two 16k byte chips), an extra 16k byte chip was needed as a total 48k was needed. So you will find that the chips you removed comprised of one 32k byte chip and one 16k byte chip.

For that particular configuration in your machine, the connection was not needed

More complex: At various times, for various different "ROM" issues, for all PCBs except the last production runs, either EPROMs or ROMs could be fitted. If EPROMs are fitted, they require slightly different connections. Where as mask programmed ROM chips can have more than one chip select pin and the logic level (active low or active high) can be programmed.

Even more complex: no, you don't really want to know...

Mark

BTW, what issue board is yours?

Mark

Oh, and I got my QL SD system yesterday

Mark

1024MAK wrote: First, the OS and BASIC were larger than expected. So instead of fitting on one 32k byte chip (or two 16k byte chips), an extra 16k byte chip was needed as a total 48k was needed.

I am never really convinced about this - Tony Tebby also suggests that the Kludge was really an invention by Sinclair to explain away the need for a recall on the basis of a 'software update' rather than an issue with the hardware.

After all, both ROM sockets can happily accept 48K (hence how Minerva fits) and even 64K, which suggests that it was always envisaged that the operating system might be larger than 32K.