13 Nov
2022
13 Nov
'22
2:13 p.m.
I assume the Datapoint 3300 terminal's electronics beam characters to the
crt differently. If they're the same, or close enough from the font
perspective, I have a 3300 that works that could be used. Same goes for
power supply, I have a spare of one of the 3300"s power supplies should it
be used to modified to be used in a 2200. I.assume it's a long shot.. I
did not look it up to see for sure.
Anyone have a 3300 that needs a power supply? The 3300 has multiple power
supplies, I have a working spare of the supply that attaches to the back
behind the.crt.
Bill
On Sun, Nov 13, 2022, 4:45 AM jos via cctalk <cctalk(a)classiccmp.org> wrote:
On 13.11.22 07:13, Steve Lewis via cctalk wrote:
I've been looking for a video or image that
shows what font the original
Datapoint 2200 used.
It's not shown in the manual. There is one vintage image with the
office
lady and the DP2200 on the desk- but the font
isn't very clear in that.
In any modern video about the DP2200, none of them seem to power it on --
which is certainly understandable. From what I've read, the power
supply
of that system is prone to failure. Also, the
system is hard-coded to
load
from Tape 1 -- which means both the tape drive,
and tape media, still
needs
to be in good working order (which would be
pretty rare after this time).
In "the" DP2200 book, it only briefly mentions that the original tape
software was developed "on an HP system" (without any elaboration that I
could tell on which HP system that was).
Nothing in the manual suggests the original DP2200 could "program itself"
(i.e. no built in machine code monitor -- those TTL chips had one strict
boot up sequence: load from tape 1). If there was a read error or no
tape
available, I'm curious if any message showed
on the CRT.
So, I was just wondering if there was any known pre-1973 Datapoint 2200's
that are still working? (and/or if any HD video of them powered on and
legible font can be seen) Or any other more current system that we know
for sure used the same font?
Thanks!
-Steve
Not only is the powersupply prone to failure, it is also the most
dangerous I have ever seen, and I am hesitant on working it. Primary and
secondary sides not separated, isolation between the two almost
nonexistant, many primary nodes exposed. Would never pass modern safety
checks.
But here is a picture of my DP1100, a DP2200 derivative, while it was
running a memory selftest, for a short time in 2021, before the powersupply
blew again :
https://forum.vcfed.org/index.php?threads/its-alive-my-datapoint-2200-1100.…
While the DP2200 is hardcoded to start from tape, the DP1100, otherwise
identical, boots from a ROM. This ROM also contains a minimal machinecode
monitor. I recovered & disasembled the ROM and Gordon Peterson, from
Datapoint, commented it out :
http://www.bitsavers.org/pdf/datapoint/1100/DisketteBootDisassemblyGEP2.txt
Note that there are multiple videoboard options : the later DP2200, my
DP1100, and the DP5500 share the same videoboard. This relies on a
programmable characterset. In the disassembly mentioned above above,
starting at line 3660 you will see a load of gobldecook, these are actually
fondsets to be loaded into the machine.
The fontset has a very particular "look" to it. How much is due to
fontdefinition, and how much is due to the diddlescan, that I dont know.
Diddlescan is where they scan each character in full, before proceding to
the next.
Note that a ROM based bootboard for a DP2200 would be a trivial
undertaking, and only involve changing the cassette reader board for the
ROM board.
Jos