miracle systems ExpanderRAM

[Simon_Carr]

Hello All!

I've just received a 512k ExpanderRAM (a rare eBay bargain at £12)... But before I get carried away, I thought I'd ask if there is anything I need to do, as there is no manual or instructions, and I don't want to simply plug it in without considering what is necessary.

I take it that the card simply slots into the expander-slot on the LHS of the QL, but just by looking at that, I can see it will project out a good inch or so beyond the case of the QL. This explains the black metal top cover that slides along the edge of the memory card, but it looks like that cover will project well beyond the card itself, and will not slide under the edge of the QL to make a tidy fit. Is this correct? Just seems a bit strange...

Also, I received a microdrive cartridge with the RAMA labelled RAM DISC v2... It looks in good condition with a seemingly perfect condition felt tab, but can anyone explain what this cartridge is for?

Normally I would just plug everything in and try and work it out as I go along, but the QL is a bit more special, so I don't want to bugger it up!

Cheers,

Simon

[dilwyn]

If you are just using the expandaram, no need to use the black cover, but keep it for when you add a floppy disk interface.

You'll notice that the Expandaram has a through connector, to let you plug in a disk interface (the expandaram plugs into the QL, then the disk interface plugs into the expandaram). This leaves the electronics of the disk interface exposed, so you can use the cover to partly cover the exposed part of the disk interface (which is exposed because when it's plugged directly into a QL, the exposed electronics are inside the QL case).

You can safely use the Expandaram without this cover. Just power down the QL first of course before plugging in or unplugging the expandaram

The ramdisk software is entirely optional. What it does is to set up something called a ramdisk, which is a bit like a "temporary" floppy disk but in the computer's memory only, so its content is lost when you switch off. Very handy for when you need to make a temporary copy of files which you know you will not need after switch off. Can be very useful for copying files from a Microdrive, for example. You can save, load, copy etc files to/from a ramdisk just like a Microdrive or floppy disk, but much faster.

If you've never come across ramdisks before, there's a couple of articles about them on my website at http://www.dilwyn.me.uk/docs/articles/index.html

Hopefully this picture of a CST QDisc disk interface (which I admit I stole from QL Wiki, the best source of info on things like this, crawl, crawl) will show what I mean.

cstqdisc.png

[Simon_Carr]

That's fantastic help Dilwyn, very much appreciated. I wanted to make sure that I would not do any damage to the QL, and it is useful to know about the value of the RAM disc program (I will be making use of that very soon, I think!).

One final question: I have now installed the new RAM, and as I expected, the startup process on the QL is much slower, as the computer works out how much memory it has. Is there a quick SuperBasic command I can use to check the memory size? I recall there being something in ZX BASIC for the Spectrum, but I have never has need to use it.

[RWAP]

Just be careful if using the ExpandeRAM without the cover as I found that this could cause interference on the TV output - however, you may find that it works fine without it.

Hmm without Toolkit II there is a PEEK command to find the amount of free memory / available memory - when I get chance, I will look it up!

[ppe]

Is there a quick SuperBasic command I can use to check the memory size? I recall there being something in ZX BASIC for the Spectrum, but I have never has need to use it.

print peek_l(163872)

[dilwyn]

Is there a quick SuperBasic command I can use to check the memory size? I recall there being something in ZX BASIC for the Spectrum, but I have never has need to use it.

print peek_l(163872)

If you want to be a little bit more accurate than this, bearing in mind that RAM does not really start until you run into the screen start address, you could go a stage further:

print peek_l(163872)-131072

131072 being the start address of the screen memory on a standard QL. You can even get a reply in K by diving by 1024:

print (peek_l(163872)-131072)/1024;'KB'

Explanation: The system variable at 163872 (or you can refer to it as system variable at 32 from start of system variables at 163840) keeps a note of the address of the top of RAM.

[Simon_Carr]

Marvellous, I knew I needed to PEEK somewhere, but thanks for confirming I have 640k of throbbing QL power at my fingertips!

It just amazes me how much fun I can have with a 30 year old computer which has 51200 times less memory than the iMac I am writing this post on! Now, that is progress....

[dilwyn]

Marvellous, I knew I needed to PEEK somewhere, but thanks for confirming I have 640k of throbbing QL power at my fingertips!
It just amazes me how much fun I can have with a 30 year old computer which has 51200 times less memory than the iMac I am writing this post on! Now, that is progress....

Absolutely! That's the enduring appeal of a QL - despite being a 30 year old machine, you can still have fun tinkering with it!