The Acorn Emulation Page

Die Speccy

Graham Nelson reviews the ZX Spectrum package from Warm Silence Software

Warm Silence Software has a well-deserved reputation for its utilities. Some companies produce the kind of tools you could make yourself if you could be bothered to - backdrop changers, spare memory meters and so on. Warm Silence also writes the other kind - its main products are viewers for Quicktime, AVI and other movie formats, and two emulators. This is a review of its Z80Em - really a ZX Spectrum emulator - and its optional extra, a CD of Spectrum games programs. I hope to cover 6502Em - for the BBC Micro in its various forms - in a future issue.

As I sit here, my head grown slightly bald, I gave been trying to remember when I first saw a ZX Spectrum. The Sinclair ZX81 had been popular - computers under £100, a miracle! - but bever quite felt genuine. People squeezed astonishing programs into its 1K of memory. It was even persuaded to play chess, though its game was modestly described as 'not illegal'. But that physique never inspired confidence - the tiny pressure-pad keyboard, the wobbly RAM pack connection and a printer which was like feeding medicated toilet paper into a supermarket till.

Upmarket, the rival was the Acorn Atom, a solid machine with a high-brow pitch: it had an assembler built in and a manual full of mathematical virtue. But it cost twice as much. The pattern was repeated with the ZX Spectrum and the BBC Micro: the BBC Micro was 'serious' and had a real keyboard, one that would survive cups of coffee beimg poured through it. The Spectrum was turned out as cheaply as possible, with clammy rubberised keys which didn't so much click as squirm under the finger.

It sold and it deserved to sell. Crucially, it was just within Christmas present range for teenage boys. I was jealously trying to write games for a BBC Micro instead and couldn't help envying the Spectrum design: 48K of memory, of which only 8K went on the screen. It had both the full colour range - which is to say, all eight - and a decent horizontal resolution. Compare that with the BBC Micro's 32K, from which all the screen modes were horrid compromises - to have full colour you lost 20K at once, and then only had 20 characters resolution across. It left about 6K for code and images.

The Emulator

This must now be a nightmare to emulate, because where a Spectrum program could turn a shape red with only one instruction cycle of the Z80, an emulator has to alter flocks of pixels. Quite apart from that, the ordinary operation of the Z80 chip has to be imitated. The ARM has a good 14 or so free registers but the emulator has to use some of them for book-keeping so the Z80's numerous registers can't fit into what's left. However it's done, one Z80 cycle can't be achieved in only one ARM cycle so an emulator always runs at a disadvantage. On the other hand, it has 15 years of technology on its side not to mention hardware costing up to 10 times as much.

In the case of Warm Silence's Z80Em, the emulator easily wins the race and has configuration settings to run up to twice as fast as original Spectrum speed. On my Risc PC, which has StrongARM fitted, yet higher speeds seem to be possible.

This is an exceptionally efficient and impressive program. I have been unable to find any respect in which it is incorrect as an emulator, and every game I've tried has worked perfectly - or at least, only as badly as it once did on the real thing. Z80Em is easy to install and reads 'snapshots' of the Spectrum memory in any of the three standard Internet formats. It occupies only 300K of Acorn memory and can be configured to imitate each different Spectrum model. Sound effects are convincingly reproduced - it used to be said that the Spectrum didn't so much have a sound system as a mouse living inside which would scratch the case from time to time. But it can sound fairly tuneful, if monophonic.

What Z80Em doesn't do is run in a desktop window: it is single-tasking, unlike some previous and cruder Spectrum emulators. However, pressing F12 returns instantly to the desktop while freezing the state of whatever is running. This can then be resumed, or not - useful both as a magic 'pause' key and to run away from any game which has used up its patience.

A slight nuisance is that it can be tricky to work out the keys to use. The configuration of keys is different on a modern keyboard anyway - sometimes the shape is awkward, particularly with cross-shapes for movement in four directions.

3000+ Spielen...

Warm Silence Software is not the publisher of Die Speccy CD 1996 (3000+ Trefflich Spectrum Spielen), but it does sell copies with the emulator. The games are absurdly cheap at one half-penny each and at the very end of their commercial lives. Nobody is being depreived of any serious royalties - still, that ripping sound you hear is the Copyrights, Designs and Patents Act (1988) being torn up. At least this disc, or rather, the Internet archive it reproduces - has saved a whole sub-culture of games that could easily have been lost.

After the first few hours I had a better idea of what a very large number 3000 is. It would take about eight pages of Acorn User just to list them all in small type. At five minutes each, it would take 30 working days to test them.

The 'A' directory alone has 172 of them, from ACE (the Air Combat Simulator) and Academy: Tau Ceti II to Avenger. Where on earth to begin? The famous companies are all here - Firebird, Nomen Luni, etc. And so are the famous games - Matthew Smith's legendary Manic Miner, Jet Set Willy and two sequels, once more that I thought existed, Ant Attack, featuring a 3D Peruvian city in the mandibles of giant ants, Arcadia, a dumb but amusing soot-everything game, Melbourne House's The Hobbit, an ingenious adaptation of the book and adventures of Asterix.

And there's plenty of total rubbish. Tom Lehrer used to say that the reason folk songs are so awful is that they're written by the people. Still, some of the home-brew games here are a breath of fresh air, like Pimamia. The truly mediocre games are mostly commercial productions. My special un-favourites are three versions of Strip Poker, one of which reminds us just how old Samantha Fox must be getting, and the 'Olympic sports' events - triggered by Los Angeles in '84, I guess - where sprinting meant hammering the keyboard as fast as possible.

The complete works of Level 9 are here, in a variety of versions, some souped up. Thus you can play Adventure Quest either in the clunky Spectrum font or in a very pretty Lindisfarne one, like the Book of Kells and quite unreadable for more than 30 seconds. Plenty of other text adventure-game firms are here too: Scott Adams, Brian Howarth, Artic, Melbourne House.

...and some surprises

The CD holds more that just games. There are emulators for most machines - though the Acorn one supplied, MZX, runs only on older Archimedes models. There are images (mostly JPEGs) of adverts, magazine covers, buildings and programmers, pieces of hardware.

I'd forgotten what a bright, colourful design the Spectrum keyboard was until I found this directory. And the disc goes on: some instructions for the games; the original Sinclair manuals, typed in; guides to the Spectrum hardare and a disassembly of the ROM (commented in German, though). The disc is topped up with a huge and lame 'jokes' directory, some desultory music and a little clip-art.

I was afraid that Die Speccy would be like having to watch 3000 programmes of 1980's mid-morning TV, until my brains turned to rice pudding. Some of it is like that but there are also very nice surprises among the mediocrity, and it's safe to say that you'll never run out of brand-new games to play. Don't buy an emulator without it.

Product details

Product: Z80 Emulator
Supplier: Warm Silience Software
Tel: (0585) 487642
Fax: (01608) 737172
E-mail: [email protected]
WWW: http://www.wss.co.uk/ (includes a demo version)
Price: £15 + VAT or £25 + VAT if bought together with 6502 emulator
Pros: Reliable, Easy to use, Impressive and fast
Cons: Doesn't run in desktop, Keyboard may not match Spectrum

Product: Speccy Emulator '96 (CD-ROM)
Price: £15 + VAT if bought with the Z80 Emulator, £18 + VAT otherwise
Pros: Vast range, Cheap supply of classics, Interesting information
Cons: Cheap supply of rubbish too, Hard to guess what's worth trying

Product: Z80Em Support Pack (optional extra for disassembling code and altering some classic games)
Price: £12 + VAT or £15 + VAT if bought with 6502Em Support Pack

Product: Tape Support Pack (optional extra for reading BBC or Spectrum tapes)
Price: £5 + VAT including circuit diagram for interface. Interface ready-made at £15 + VAT

The Acorn Emulation Page - David Sharp