I thought this was worth discussing separately but in the JAM
Assembler conversation earlier today Andrew Gillan provided a link to
http://sam.speccy.cz/ , on which one of the documents is
http://sam.speccy.cz/coding/hardware_scroll.txt — which alleges that
changing the border rapidly between black and white can affect the
position of the pixel area within the television frame by a row. Sadly
it doesn't bother to explain what aspect of the hardware it thinks is
responsible or to provide any real timing information, preferring to
talk at great length about how a single pixel hardware scroll would
buy you two frames to update the display rather than one if you wanted
a scrolling area. It's also weirdly specific to a particular monitor
in one place, and I notice that whatever effect it thinks it is
relying on doesn't work in Sim Coupe.

Can anyone comment on whether the article documents a real Sam
hardware effect rather than merely a perceived effect specific to a
particular monitor?

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