Waht does a Sirius (Vixtor 9000) or an HP150 have to offer that a 'bow doesn't? The 'bow graphics card had a limited vertical resolution (200 pixels?) but apart from that it was pretty good. It had a 7220 graphics chip on it, it had a colour lookup table. Darn it, it had colour (the HP150 and the Sirius seem to be monochrome only). The 'bow also has the Z80 processor and can run CP/M 80 programs IIRC. -tony

Eh? Out of the HP150, Sirius and Rainbow, the last was the only one to have colour graphics, I think. I usspect one of the best 'IBM Incomatibles' for colour graphics was the Sharp MZ5600 (I think that's the number). It has a couple of ASICs on the videao board and according to the manual it has hardware support for 4 windows. Yes, but most of the 'IBM incompatibles' had 1 bit per pixel, just on/off monochrome grpahics. The 'Bow had a CLUT and up to 4 bits per pixel I think. For a suitable definition of 'nice'. Actually I don't much care for it, as it's can't read or write a 'standard' (FM or MFM) disk. The ability to exchange disks with the rest of the world is something I put very high up my list of desirable features. As yuo doubtless know the data encoder/decoder is a similar circuit to that in, say, a CBM8050. The drive spindle motor is controlled by a microcontroller, etc, on the controller card and the disk spins at different speeds dependin on which cylinder the head is on (the CBM drives kept the spindle speed constant and varied the data clock rate, which is roughly equivalent, both methods maintain a more even linear bit density on different cylinders). I have one. I also have a home-made schemaitc of the machine, keyboard and monitor. Let me know which section seems to be emiting magic smoke (PSU, monitor, CPU board, disk controlelr board) and I'll see if I can figure it out. For the record, I have the official techref for the HP150 and 150-II (including schematics) and a homemade schematic for the 'bow. -tony

Hi, No, that's right. The standard disc controller in the Sirius couldn't handle FM or MFM discs at all. I used to collect Sirii and Apricots, as I recall at some point *very* late in the life of the machine the manufacturers produced a floppy controller board which could read/write standard IBM 5.25' floppies. I don't know whether this board supported both IBM and "Sirius" formats or which IBM format (360K/1.2MB), but they did exist and were rarer than hen's teeth even back in 1990 - I knew two people who had them, despite never being able to find one myself. TTFN - Pete.