Another discussion re PETSCII

Den Sat, 06 Apr 2019 12:07:25 +0200 skrev Rhialto <rhialto_at_falu.nl>:
> On April 5, 2019 6:08:01 PM GMT+02:00, Francesco Messineo
> <francesco.messineo_at_gmail.com> wrote:
> 
> >https://en.wikipedia.org/wiki/PETSCII
> 
> Note that that page contains a lot of nonsense regarding which
> characters are valid. See the discussion page. Someone should really
> correct it now.

Side track:
Are/were the terms "shifted" and "unshifted" really a thing, or is it
something that were invented by whoever wrote that parts of the
Wikipedia article?

Re correct the page: Where to start? It's kind of a mess that would
benefit from a more or less complete rewrite.

A few things spring to mind: It states that the VIC 20 font is the same
as the PET font, even though the pound sign replaced another char. The
talk page incorrectly states that this change happend with the C64.

Re the disussion of why Commodore did chose upper-lower case as they
did needs some more background.

Noteable is that PET is the only one of the three "1977 computers" to
have lower case at all. APPLE II and TRS-80 only had upper case! (Well,
Apple II had a hires mode so you could roll your own lower case but
then the display would be rather slow).

Lower case weren't that common at the time. Digitals VT50 terminal
(july 1974) only had upper case. The VT52 added lower case (september
1975).

Btw the physical layout of the PET business keyboard is the same as the
Digital "Decscope" VT50/VT52 terminals.

https://en.wikipedia.org/wiki/VT52

According to the "DECscope Users' Manual" the VT52 has both a
upper+lower case mode (default) and a upper case + graphics mode, much
like Commodore did. It seems like this was done the same way as in the
first PET, with upper case staying at the same positions and lower case
being replaced with graphics chars.

http://bitsavers.trailing-edge.com/pdf/dec/terminal/vt52/EK-VT5X-OP-001_DECscope_Users_Manual_Mar77.pdf

One notable computer manufacturer at the time, IBM, used their
completely different EBCDIC encoding.

What other computers did use lower case at the time?

A terminal that seems to have been common for hobbyists back in the
days were the ASR-33, a teletype which used ASCII. According to
Wikipedia it were upper case only.

https://en.wikipedia.org/wiki/Teletype_Model_33

It seems like the TV Typewriter only did upper case, but in 1977 an
updated version also did lower case
https://en.wikipedia.org/wiki/TV_Typewriter

The VDM-1, the first video display card for S100 computers, did both
lower and upper case. It seems like it had upper case and lower case as
in usual ASCII.
http://www.s100computers.com/Hardware%20Folder/Processor%20Technology/VDM-1/VDM-1.htm


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