> My tests were done on a W$-Vista with Q-emuLator 2.5 and 3.1., with JS and
> both the old DATA_bin and latest 2.13.
> Only 3.1 & JS produces the errors, the DATA_bin version makes no
> difference.
> I looks like something changed between Q-emuLator 2.5 & 3.1 to stop DBAS
> from working.
>
> Bob
I've looked into this and there is a change in behaviour in version 3.0 which
causes this issue. The change was for compatibility reasons to allow some old
games to run. DATA_BIN is patching the directory device drivers to be able to
intercept a special new I/O command. On a (JS) QL, I think this would _not_
work for the MDV driver as the device driver definition is in ROM and can't be
patched (actually, it could still be patched, but only by using a different
method). But it works for other device drivers like FLP that are defined in
RAM. Up to version 2.5, the additional Q-emuLator device driver definitions
(additional definitions are necessary as a JS ROM doesn't know about 'FLP' and
'TCP', for example) were in RAM and DATA_BIN used to work fine, but later I
changed the definitions to be in ROM and DATA_BIN is not able to patch the
drivers anymore. The reason for the change is that the RAM definitions were
causing incompatibilities with some old software that expected to
find some QDOS data structures at fixed addresses in the QL memory, but the
extra memory used by Q-emuLator's device drivers was causing these addresses to
be off by a few bytes. Finally, I only activated this change for Sinclair ROMs,
as those old QL programs wouldn't work on Minerva anyways, and this explains
why DATA_BIN still runs fine under Q-emuLator 3 when using a Minerva ROM or
SMSQ/E. I'll think about ways of mantaining compatibilities with both DATA_BIN
and the old software that doesn't like extra drivers to be in RAM. In the
meantime, the workaround on Q-emuLator version 3 is to use the Minerva ROM.
Daniele
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