Scor­pio News


July–September 1987 – Volume 1. Issue 3.

Page 54 of 67

6MHz,1 wait state5.7
6MHz,0 wait states7.0
8MHz,1 wait state7.7
8MHz,0 wait states9.2
10MHz,1 wait state10.2
10MHz,0 wait states11.5

A program supplied with the system, SPEED, was used to switch between these. You can also switch clock speeds directly from the keyboard, but not wait states. The default power-on state is set via SETUP, which stores your choice into battery backed memory.

In general I can see of no reason why you should want to switch clock speeds, and normally leave the system at 10MHz. However, a few of the programs that I have are games, and these are far too fast at 6MHz, let alone at 10! It is in fact interesting to note that some of the genes don’t seen to alter, even when you change the clock speed. Presumably they are using one of the programmable timers that are a standard part of the AT spec.? As far as I am aware the only time you HAVE to change clock speed is with some clever formatting and backup programs that drive various chips directly, and have very specific and critical timing loops in the code. As I don’t seem to have any of these programs this doesn’t worry me.

I tried a variety of software on the system, and it all ran without problem, with the exception of BASIC! By trial and error I discovered that BASIC was fine at all speeds except 10MHz, 0 wait states. I started to wonder if BASIC was one of these programs that falls over at high speeds – I couldn’t understand how it could be for a moment, but that was how it looked. What would happen was that a BASIC program that would run fine at 10MHz, 1 wait state (from now on 10/1, etc), would give various syntax errors at 10/0. I went with my system to see Dave Hunt. These funny programs ran at 10/0 on his system – aha, a hardware fault on mine! I then said “Look how they fall over on mine”. They didn’t! Hmmm! Then several minutes later, at 10/0, they started to fail. A temperature dependent fault, temporarily cured by a cold spell in the car? OK, let’s leave the system on for a bit longer. Lo and behold, the same problem at 10/1.

Back to Elonex

I took the system back to Elonex, and they disappeared into a back room. When they reappeared they said “changed some chips – try that”. I did, leaving it on for some time with no problem. Then, running Norton, I noticed that it was back at 10/1 again – they’d reset the link! I queried this, and was told that all the initial systems that they had had had run at 10/0 OK. But then they had started to get problems, so they were all now sold set to 1 wait state.

I pointed out that the advert said 0 wait states, and was told “yes it will run with 0 wait states, but not at 10 MHz. We don’t say it will do both at the same time”. For some reason I let this pass, but have subsequently decided that I may raise this again. After all, the SETUP program allows 10/0 to be set as a default, and the manual makes various references to it. In fact, I have subsequently met someone else who has recently bought an Elonex system and he has noticed a Norton of only 10.3, yet his SETUP, AS DELIVERED, shows it is set to 10/0. Obviously the system is supposed to be capable of it, but I expect you’ll see Elonex’s adverts changed in the near future.

At the time of writing, I don’t think you’ll find another 10MHz systems at the same price, in fact I’m not aware of even an 8MHz system that’s within £100, and so I suppose it can be argued that one shouldn’t quibble about the lack of this last bit of possible performance. If you are looking for a system with that extra edge, do check carefully. Some suppliers make no comment at all about wait states, and more often than not this means that the system has then permanently set. Of course, if you’re wealthy, there’s always the 12MHz systems which have recently become available, and if you’re absolutely stinking rich you can get an 80386 based system!

Page 54 of 67