25 Jun
2014
25 Jun
'14
12:24 p.m.
For one thing, you need more pixels for lower case.
Early dot matrix
printers had, I think, 5x7 matrix for the uppercase only model, but
You can get a sort-of lower case font out of a 5*7 character generator,
but it doesn't look nice. To get an apporxiamtion to descenders, you have
a baseline that is higher for such characters. Readable, but...
Omewhere I have a portable thermal printing terminal which prints lower
case as small capitals. Odd.
I also have an old video terminal (old enough that it uses shfit
regiusters for the video memroy) where the dispaly section could handle
lower cases (I suspect without true descenders, but it's been a long time
since I used it) but hhe keyboard was upper case only. The service
manualk gave 2 modfiications to the keyboard to let it generate lower
case Of course I hacked mine . IIRCL it involved wiring up a couple of
TTL chips and patchign them into the keyboard encoder circuit.
needed at least 7x9 for lowercase. (Then there were
printers with
something like 16x16 matrix, for printing Japanese text.
There were also printers that did multiple passes with the position of the
head relative to the paper moced. The DEC LA100 has a solenoid mechanism
to moce the head up and dowbn. The Sanders 12/7 and 700 series move the
paper in fractional-dot icrements -- I think at least one font uses 8
pases and thus has an effective vertical resolution of 56 dots (7 pin
head).
-tony