6502 Emulator Version 1.50 
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                        Reviewed by Martin Wilson (4WL)

Acorn's original BBC emulator !65Host is very restrictive and it has to be
said not that compatible with games. Speedwise its acceptable but only just
with an Arm250 computer. This new BBC emulator vastly improves
compatibility, adds a lot more features and is a bit faster too. However its
still quite slow. At best its about 80% BBC speed and at worst about 10% of
the speed. Of course this speed problem goes away with a faster Archimedes.
An Arm3 computer should actually surpass BBC speed at times and I'm sure a
Risc PC will really zap along.

Actual configuration isn't too difficult. It will make use of the BBC B ROM
image from 65Host and so its quickly BBC compatible. You can also obtain ROM
images from the Electron, Compact and Master using a supplied util and then
emulate these computers too. Although the Compact and Masters processor
isn't fully emulated it says. It will still run Master 128 Elite though. The
emulator does seem optimised for the BBC B emulation as even the Electron
seems slower. The Compact seems slowest of all. As you toggle between the
different emulated models the graphics on the icon bar change to represent
images of the different models. A nice touch. 

Sideways and Shadow Ram are supported with the two Master computers and
paged ROMs are supported for all models. Certainly a big step up from
65Host. The keyboard is not remapped so you find that certain symbols are
now on different keys which can be a bit awkward. Presumably they've done
this to make the emulation more successful. Two great features are the
facility to snapshot games once you've loaded them in via floppy disk and
also save the screen image as a normal Risc OS sprite. These two features
can be used at any time. Double clicking a snapshot will load up the
emulator if it hasn't been loaded already and you can easily save a snapshot
back on itself to play a game a screen at a time without having to ever
restart it which makes many games much more playable. Two things I've
noticed really slow down the emulator. One is sound especially music and the
other is horizontal scrolling. Games without much music that don't
horizontally scroll perform best of all. There is a scroll hack feature
meant to improve horizontal scrolling but it just doesn't seem to work for
me and ruins the display. F12 is used to get out of the emulator to use the
different options. Clicking the 6502em icon returns you to the emulation.

You'll be pleased to know the 8bit issues seem to work 100% and the mode 7
bits are not quite as slow to scroll. 

You use a separate DFS util for loading DFS disks and this can be
temperamental. It seems to take a dislike to disk titles and sometimes its
necessary to delete the title of a DFS disk to see the actual directory.
I've managed to convert about 20 games so far and this doesn't take that
long. I reckon I'd managed to convert about 5 games in about  5 minutes.
Thats including a quick play to see if they work. Space Pilot a game I could
never get working with the Master has no problems with the emulator. To be
perfectly frank the emulator is at least as compatible with BBC B games as
the Master series and a definite improvement on the Electron. Disc
protection can be a problem to converting games to run on the emulator. I've
managed to run the standard BBC B disk Elite but have so far failed to get
the Master 128 or Compact Elites to run. I believe this is solely due to the
protection. I'm pretty sure though that you can get all versions of Elite
working on this emulator except for the Tube version. Theres no support for
the 2nd processor. The BBC B disk version is the only version that
continuously loads from disk so that couldn't be snapshotted as far as I can
tell but it may be possible to move the main files onto the hard drive. The
Electron and BBC tape versions plus the two Master versions will all
probably work as snapshots. 

The emulator does away with the normal DFS and ADFS roms and uses its own
filer called Virtual DFS. This acts as a go between the emulator and the
host Risc computer. This method is more effective than 65Host and incredibly
more flexible. To read DFS disks you need a normal risc DFS reader. For some
reason I could never get 65Host to work with these but 6502em does.

This is an incredible flexible emulator but really needs an Arm3 or above
for normal BBC speed. To be honest to emulate the Master series you'd
probably need an Arm710 based computer or a clocked A5000i. I do believe
that the emulator could be optimised to go a lot faster as I feel an Arm250
computer should be enough for the job but I imagine its probably compiled C
based and not true assembler although I don't know for sure.

Speed 5/10

Emulation 8/10

Features 9/10

Ease of installation 6/10

Ease of use 7/10

Well I'm off for another game of Mined Out (upto about level 6 or 7 so far)

4WL