Scor­pio News

prototype? It certainly looks old and dirty enough. You should be ashamed, and so should Gemini who sold it for the full price.

Help Wanted

Having mentioned Gemini, there is also their retail arm, Quantum, and I have something to say about them too. While I cannot complain about their standard of service, I must point out that I pay a lot for it. In spite of transferring five-figure sums to their bank account I still have to pay retail prices. Is there any dealer who’d like to take over this business in exchange for 30-day credit and a modest trade discount? This year I’ve got “loads-a-money” to spend and I’m totally corrupt.

New Pluto Review-ette

The new Plutos have arrived at last! The first thing I noticed is that the user manual is dated 1986, and the cards have “1988” etched into the metal. I expect that’s why they have so many undocumented links and features. Still, they work; a process of elimination revealed that the extra six pins on the TTL video connector carry only the new brightness line, and can be ignored in my application. It’s a good job I never used the 50-pin header because it’s gone without trace.

A very nice board, altogether. It has no less than five layers of metal and ninety(!) ICs including for the first time a serial interface (undocumented) and space for a palette DAC. The silk screen now carries the legend “gemini computer systems ltd.” as well as the IO Research trademark, and joy of joys! a full set of 78 edge fingers. So at last I can have a “Ready” interrupt, once I figure out where to patch it on the board. But wait! what is this link marked “INT” connected to bus pin 22? I don’t know, because it is not mentioned anywhere in the manual. Neither is the DIL switch, though fortunately here the silk screen gives some help. It apparently selects serial baud rates, a diagnostic mode, palette on or off and the polarity of the sync signals. A reset push button has been fitted, though the board still doesn’t reset from the bus, doubtless for very good reasons. Resetting the Pluto has always given me problems. If the host system is turned off and on again quickly, Pluto hangs up. My customers can’t understand this, and I don’t think they should have to, as it could be cured by the addition of a single diode.

There’s an extra 64k of memory on board, which implements the brightness attribute as a fourth colour plane. This means you can have sixteen colours without a palette, instead of the eight formerly available. Personally I don’t find it that much of an advantage, and I think most serious users will want the palette, but it’s there if needed. Tests with a stop-watch show that this extra plane slows things up, but not by as much as expected. I am a bit mystified as to why the board is stuffed up with 64k RAM chips in these days of megabits, but I suspect it has to do-with availability. So long as I get my cards on time I’m not going to complain. The ROM has taken a