OMG A4!

I’ve been working on my Risc PC today with the RISC OS 5 ROM. First problem is there was no USB, so the mouse didn’t work. I hunted around and failed to find the quadrature mouse that normally belongs with it. So I ended up dragging out one of my A4s to steal the trackerball.

A certain period of hacking later, I found I needed to turn on debugging dprintf(()) in the IOMD ROM (HAL.IOMD.hdr.Debug in case anyone was wondering). This outputs debug to the serial port.

Ah, but I don’t have anything to plug it into. Linux box is a serial-port free zone and so is the Pi, Beagle is at work, and I don’t have a USB/serial gadget to hand.

Ah, but there’s an A4 sitting on the table and that has a screen and a serial port… I don’t think I’ve turned it on in 10 years and I thought it was dead (blown power supply diodes). OK, let’s power it up.

Lights on, hard drive rattle, it’s alive. No screen. What’s the keypress to pick between the LCD and VGA? Oh, there isn’t one. Twiddle contrast/brightness, no joy, backlight off. Blind-type F12, *Con. MonitorType 5. Backlight on! *Conf. Mode 27, garbled stippled background showing data abort. Ah, CMOS must be flat. Power-on Delete – we have RISC OS booting!

OK, where’s the touchpad. Oh, there isn’t one – that’s what the trackerball was for, but it’s on the RPC. But I can use FN-cursors plus FN-Q/W/E for buttons. At this point I head back to the RPC and format a floppy (at least I still have some!) and put !Connector and !SerialDev on it.

Floppy into A4, click on disc, floppy whirrs, filer window appears. It turns out that !Connector doesn’t seem to work (RISC OS 3.1, without boot sequence) and !SerialDev is a shell pointing to BootResources: (which I don’t have).

Hmm, the HDD is now making some worrying rattling noises. And I forgot to even look at it. Try to configure IDEDiscs 1, it works but drive is inaccessible. Ah well, probably dead. But the machine is siezing up when it’s making its rattle (potentially the elusive A4-freeze bug I saw long ago).

Dig around RPC HDD, find a program called !ZAnsi which seems to be a serial terminal. Put that on the A4 floppy, Some worrying grinding noises. How else to get storage into this thing – can’t I just use a USB sti—- nope!

Hmm, I can run !Zansi most of the time, but I’m getting random freezes. Not sure what’s up there – still the dying HDD?

Pick another floppy. That one says ‘Pipedream 4 backup’ and (the disc itself) dates from 1987. And it’s readable! But still freezing, often mid floppy read. Power supply?

The battery went from ‘0%-charging’ to ‘full’, but provides zero seconds of power, of course.

Pulling the power out of it (rather than merely turning off) seems to have done it some good – power brick troubles? It’ll now run Pipedream fine. Looks like !Zansi doesn’t work on RISC OS 3.1

Try ArcTerm 3.11 (from 1989). Runs, but doesn’t respond to keypresses. Maybe it’s not RISC OS 3 compatible?!?

Try Grapevine (1991). I seem to have data from A4 to RPC, but not RPC to A4. Simple hardware fix: swap the plugs around. Success!

But now I need to rebuild my RPC ROM to output at 19200 baud (Grapevine only goes that fast). HAL.IOMD.s.Debug. Build in RPCemu – I’m using three RISC OS machines to acheive this!

Copy across ROM, softload on RPC. We have log messages!

Ah, but it’s now bedtime and I failed to actually get any useful coding done. Oops.

Ah, but it’s now bedtime and I failed to actually get any usefulcoding done. Oops.

Sweet dreams!

Ah, the joy of trying to get new and old kit to talk to each other. For decades we could at least fall back to serial. Sucks so hard that there isn’t even a three wire implementation on modern machines; though I wonder how many of the internal chips are actually capable in the same way the SoCs are?

OMG – ZAnsi. There’s a blast from the past! Shame it didn’t start or you could remind me how spectacularly ugly it was. I had my copy working on 3.1 but it took some patches to the executable…and yes, its limitations are what pushed me in the direction of Hearsay. Still, for your purposes it would have sufficed…

Good luck, then, for tomorrow!