Developed by Palmtop Software, The Sinclair Spectrum Emulator - Version 4.0 (to give it its' full name) runs on EPOC32 machines and 16bit Psions. I'm sure there are versions for other handhelds, but I can't be certain (to be honest, I've not checked).

As you would expect with EPOC software, the installation and running of IV is extremely straightforward You can choose which disk you install it to as well (I tend to save as many programs to my D: drive as possible). It's also very system friendly - ie if you select another program whilst IV is running, it will automatically pause the program you are emulating. Handy if you're playing a game. It has a reasonably small footprint; it will eat up approx 600-700k when running. This makes it easy to run that and multitask with other programs with no fear of immediately running out of memory.

As said, IV runs on EPOC32, which includes Series 5 machines and upwards. It runs in greyscale and full colour, depending on which Psion you own (and you only need one version for this). I have only tried IV on my Series 7, so I can't determine if there are any differences on the S5 etc.

IV is configurable, to a degree. The main options include whether to have the toolbar visible or not, have the display in colour or black and white or to increase or decrease the emulated Spectrums' running speed. Although to be honest, it's not often that you want to increase the speed as it runs more than fast enough! (More on this later)

IV accepts 48K and 128K .sna, .z80 and .tap files, although it can be a bit picky which .tap games it loads. It likes HeroQuest and Fiendish Freddy, but not Chip's Challenge. That said, it's nowhere near as choosy as Mac Spectacle is. When it loads games, there's the option of running the emulator in 48 or 128K mode. Sometimes this is useful, most of the time I'd prefer IV to auto select the machine type before the game has loaded. Perhaps I'm being lazy....

There's a useful set of faster/slower buttons, but I'm assuming that they're more useful on a Revo/Series 5, as even on the slowest setting, IV runs about 120percent speed of a real Speccy. This means that IV runs action games a bit too fast (at least for my reflexes!), and with the type of display IV has, it gets a bit blurry. I prefer to play strategy/adventure games on my S7, which don't rely on fast reactions. For a bit of amusement, load STUN Runner into IV and crank the speed up; you get a feel of how it was supposed to be like! Try this only once, as the game's rubbish and there are plenty more worthy games to play.

Controls are either via keys in the normal Speccy sense or by using the Psion cursor keys as a Kempston interface. I find the latter almost unusable, so prefer to have 'regular' keyboard control. As there's no real joystick you can plug into a Psion, the directions are emulated through the cursor keys, with a choice of using the space bar or tab key as the fire button. You can also use the stylus pen as a controller, but I've not found this practical.

There is also an 'Enter POKE' menu option which enables you to cheat yourself silly at a variety of games. Interestingly, there's a Recorder facility too. Now this is possible on a real Spectrum, but I thought this would be quite a redundant (and space-hogging) feature. To test this out, I played a Chaos 7-wizard battle. The actual recording came to just over 900 bytes (the status bar at the bottom of the screen tells you) and this turned into a 3798-byte .zrc file. Not a huge file by any standards. The game length was about half an hour, so in actual fact it's pretty damn tiny. Of course, you need to use the IV emulator to run the .zrc file....

Apart from running a tad faster than a real Speccy, the only 'fault' I've found with IV is the complete lack of sound of any kind. I have a feeling this is only an issue with the Series7, but as I haven't tested IV with any other Psion, this is just conjecture. The Help file does mention sound parameters, but the option is ghosted out on the menus.

I decided to investigate this a bit further. I found a version of Spectrum Emulator III, which was designed for the Series 5, and installed it. The screen is displayed in a variety of grayscales, but it only occupies just over half of the Series 7 screen. There is sound!!! However, the sound makes the emulator almost unplayable. Zounds, the irony. The slowness of the emulator may lessen if III was optimised for the more powerful S7/netbook (etc), but perhaps that's what IV is. Maybe the programmers decided that sound emulation was too much for the machines.

Ah well......