“Choosy“ software shouldn‘t be a problem: when our data-recorders
were split-new they had tight mechanisms, round pinch rollers and central
capstans; the heads were perfectly aligned and the motors all ran at
exactly the same speed. Under these conditions just about anything would
work with one machine if it would work on another. Sadly, nothing lasts
forever and some data-recorders will now be approaching their eighth
birthdays... how healthy is the car cassette player that you bought
in 1982? You can do something about head
alignment, if you are adventurous you can even strip down the data-recorder
and adjust its speed
( there‘s a pot on the control board ) but I doubt it will do much
good; however, when the belts get slack, when the springs cease to be
springy, when the capstan becomes eccentric and the pinch roller wears
down to a sad oval shape it‘s time to put the old girl out of her
misery. ( sounds like the wife, sub-ed ) Not only so old data-recorders
become idiosyncratic - so that your machine can only swap software with
a limited numbers of others - but they lose consistency. The signal
that goes to your data-recorder is not reproduced faithfully on playback:
in hifi terms, you are getting too much wow and flutter. At £9.00
( from M&B ) replacement data-recorders have never been so cheap,
and I doubt if they‘ll ever be so freely available again. Even
if your recorder is healthy now, I count £9.00 as pretty cheap
insurance for the future. It is, infact, possible to adapt a 700 and
an “ordinary“ cassette player so that you can have motor sense
/ control. When recorders were £50 a shot I did it for one of
my machines, but the built-in data-recorder is infinitely more convenient.
So, Paul asked, in an earlier issue, why he was getting check sum
errors with his QD BASIC and not with S-BASIC. I have similar problems
and did a bit of experimenting: Firstly, from what I can gather with
my disassembler, S-BASIC uses a slightly different set of tape routines
from those in the ROM monitor. ( BASIC has to worry about paging in
the RAM from $D000 to $FFFF: the monitor doesn‘t ). QD BASIC uses
a third set, different from the other two, and slightly less forgiving.
One tape I was trying to TRANS was a commercial adventure that had obviously
been recorded as an audio copy: a buzzing noise was audible with the
tape eavesdropping switch ( see earlier issue ). I loaded this to S-BASIC
and then saved it to the B side of the cassette: QD BASIC then accepted
it quite happily, so that's one thing to try. This also ties up with
Paul‘s own solution. ( I have no need for any other - sub-ed ).
|