Thanks Jos, I hadn't realized how similar the DP1100 is.
This brochure has a great image of the font right on the front page (80x12
text):
http://www.bitsavers.org/pdf/datapoint/1100/Dataform_1100_Brochure_1974.pdf
And it's probably a safe bet that it's the same font as in the 1972
models. Would be neat to see the entire character set. In the photo, the
screen looks fairly inset -- like maybe an inch? That's good for keeping
glare off the screen.
I see there was a Cassette 1100 and Disk 1100 (by '75):
http://www.bitsavers.org/pdf/datapoint/1100/60259_1100_Brochure_1975.pdf
Then I came across a DP2200 emulator, except -- it was apparently made in
1973 and ran on a DP2200! (ACM link, but click the PDF, it's freely
available)
https://dl.acm.org/doi/10.1145/800192.805722
What a neat system. In an old IBM 5110, I replaced its power supply with
modern components. From the DP2200 manual, it looks like it needs -5
-12 +5 +12 and +24V? There is a "trick" in the modern buck-boost voltage
converters to get negative voltage (the IBM PSU needs -5 -12 +5 +12
and +8.5V). I put notes about it here:
https://voidstar.blog/ibm-5100-power-supply/
Maybe something similar can be done for the old DP's? I understand for
authentic/historical perspective all original components is prefered, but
using a substitute PSU is reasonable for checking out the rest of the
system.
Were there any contemporary complaints about the DP PSU in the mid-1970s?
Like was it noisy, ran hot, cause any fires? I recall a talk from one of
the early 1980s Commodore engineer, where he was amazed ANY C64 was still
running since the components were truly not designed to last more than a
few years.
What an amazing system those Datapoints were, for their time. The
chicken-farm story in the DP2200 book is really fun - these farmers being
savvy enough to code up what they needed, and the systems compact enough to
fit in the farms and using modems even to sync up data (pre-1975).
The IBM 5100: 64x16 screen (instead of 80x12 used in DP), and a slightly
larger "box"(case) that had a "horn" inside for better airflow over
all the
components (not an audible horn, but a thing that channel air from the PSU
fan to distribute over all the electronic cards and display circuits).
Plus the 5100 supported the external BNC video (I'm not sure if any of the
DP systems had an external video connector? I didn't see it mentioned in
the DP2200 manual) - I've put 3x extra CRT's chained up to the IBM 5100, in
the manual I think it says it can go up to 16 (not sure what the limiting
factor of that signal is). I'm not sure if quality-wise the IBM PSU was
"better" (it takes about 3/4th of the back half of the case, the other
1/4th for the fan) - other than to say quite a few 5100's are still running
in the world. Maybe all that altogether makes it (the 5100) a more
"portable" system (construction sites, forward edge battlespace, etc --
i.e. being more robust to handle outside heat). Also it had a minimum of
8K. The APL stuff made the 5100 expensive, but the base BASIC model was
~$9K (I think even with the single QIC tape for 207KB storage; but that
price didn't include async/comm cards). Weren't base DPs $5K-$7K (all
throughout 72-75) ?
But, in extracting the data on those TTLs, it seems like a modern replica
of a DP2200 would be possible. Can't say the same for the 5100 because
apparently nobody left on the planet understands those MOSFET silver cans
(and how to extract the 6KB of content from them).
Sorry for the tangent:) I really was just curious about the DP2200 font,
and possibly seeing where it came from (just based on its style). The DP
has a better "0" (zero) font than the 5100 :) (IMO)
-Steve
On Sun, Nov 13, 2022 at 3:45 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