15 Dec
2014
15 Dec
'14
1:07 p.m.
OK, so somewhat weekly questions.
Back in the days of high speed line printers there was a characteristic of
drum style printers that made the output print style quite distinct. What
was this characteristic?
I don't miss the noise of those devices and it seemed like no matter how
careful you were when changing the ribbon you would smudge your hands.
Doug Ingraham
15 Dec
15 Dec
1:21 p.m.
The characters would not be necessarily aligned perfectly horizontally
due to slight timing differences.
-Ian
On Mon, Dec 15, 2014 at 4:07 PM, Doug Ingraham
<dpi at dustyoldcomputers.com> wrote:
OK, so somewhat weekly questions.
Back in the days of high speed line printers there was a characteristic of
drum style printers that made the output print style quite distinct. What
was this characteristic?
I don't miss the noise of those devices and it seemed like no matter how
careful you were when changing the ribbon you would smudge your hands.
Doug Ingraham
1:31 p.m.
And yep, it was the "wavy" type style. I recall some Univac 1108
engineering manuals that were nearly impossible to read.
--Chuck
1:29 p.m.
On 12/15/2014 01:07 PM, Doug Ingraham wrote:
OK, so somewhat weekly questions.
Back in the days of high speed line printers there was a characteristic of
drum style printers that made the output print style quite distinct. What
was this characteristic?
Sounded like a machine gun, the CDC 501 did.
--Chuck
3:43 p.m.
Where I worked the un-even text was referred to as "Dancing Text" .....
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Doug
Ingraham
Sent: 15 December 2014 21:08
To: cctalk at classiccmp.org
Subject: Weekly Classic Computer Trivia Question (20141215)
OK, so somewhat weekly questions.
Back in the days of high speed line printers there was a characteristic of drum
style printers that made the output print style quite distinct. What was this
characteristic?
I don't miss the noise of those devices and it seemed like no matter how
careful you were when changing the ribbon you would smudge your hands.
Doug Ingraham
4:15 p.m.
The hammers pushed from the back of the paper, push in it into a sheet
ribbon and then into the rotating type drum.
On Dec 15, 2014 6:43 PM, "Dave G4UGM" <dave.g4ugm at gmail.com> wrote:
Where I worked the un-even text was referred to as
"Dancing Text" .....
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Doug
Ingraham
Sent: 15 December 2014 21:08
To: cctalk at classiccmp.org
Subject: Weekly Classic Computer Trivia Question (20141215)
OK, so somewhat weekly questions.
Back in the days of high speed line printers there was a characteristic
of drum
style printers that made the output print style
quite distinct. What
was this
characteristic?
I don't miss the noise of those devices and it seemed like no matter how
careful you were when changing the ribbon you would smudge your hands.
Doug Ingraham
4:28 p.m.
On 12/15/2014 03:43 PM, Dave G4UGM wrote:
Where I worked the un-even text was referred to as
"Dancing Text" .....
Heh. The CDC 501 printer had a switch inside the cabinet (but
accessible to operators) that was marked "high" and "low" speed.
Basically, it offered the choice of "Do you want your output readable or
do you want it fast?"
IIRC, the speeds were something like 500 LPM and 1000 LPM.
--Chuck
6:11 p.m.
On 12/15/2014 03:07 PM, Doug Ingraham wrote:
OK, so somewhat weekly questions.
Back in the days of high speed line printers there was a characteristic of
drum style printers that made the output print style quite distinct. What
was this characteristic?
Well, some people mentioned the wavy text. I had a HUGE
Honeywell drum
printer here that had VERY good alignment. That was 300 LPM.
I worked with a couple other units that also had pretty good
alignment,
and were rated for 600 LPM, but if you were only printing
numeric data,
it could do over 1000 LPM.
Jon
18 Dec
18 Dec
12:43 a.m.
Well, some people mentioned the wavy text. I had a
HUGE Honeywell drum
printer here that had VERY good alignment. That was 300 LPM.
I have a
"small" data products drum printer (2230) which makes quite
straight lines at 300 lines per minute. The timing can be adjusted..
Regards
Philipp :-)
22 Dec
22 Dec
9:31 a.m.
Thanks for playing everyone. The answer I was looking for was vertical
displacement of the letters or wavy text.
There are two reasons this happened. The primary reason is the critical
timing of the firing of the hammer. The other reason would affect all
types of impact printers and that is stopping the paper motion through the
printer. This was not usually a problem unless the weight of the paper was
very light which would allow the sprocket holes to elongate. This would
allow the paper to continue moving around while the drum was completing its
turn. The sprocket holes could also elongate if the paper tension was
increased too much.
None of this was of much concern on the slower 300 lpm printers but at 1000
lpm or faster timing would be more than three times as critical.
Chain, train, and band printers would tend to have mild misalignment in the
horizontal direction but could still have vertical alignment issues if the
paper continued to move around.
One of my friends reminded me of the most unusual uses of the 1000 LPM
printer on the CDC 3400 that South Dakota School of Mines and Technology
had in the 1970's and that was as a bass drum when the computer played the
Stars and Stripes forever. I only saw this run a handful of times and it
is probably one of those things lost forever. Even if someone had a copy
of the program no simulator would be accurate enough to run it and I am
pretty sure there is no running hardware.
Doug Ingraham
On Mon, Dec 15, 2014 at 2:07 PM, Doug Ingraham <dpi at dustyoldcomputers.com>
wrote:
OK, so somewhat weekly questions.
Back in the days of high speed line printers there was a characteristic of
drum style printers that made the output print style quite distinct. What
was this characteristic?
I don't miss the noise of those devices and it seemed like no matter how
careful you were when changing the ribbon you would smudge your hands.
Doug Ingraham
10:57 a.m.
On 12/22/2014 09:31 AM, Doug Ingraham wrote:
One of my friends reminded me of the most unusual uses
of the 1000 LPM
printer on the CDC 3400 that South Dakota School of Mines and Technology
had in the 1970's and that was as a bass drum when the computer played the
Stars and Stripes forever. I only saw this run a handful of times and it
is probably one of those things lost forever. Even if someone had a copy
of the program no simulator would be accurate enough to run it and I am
pretty sure there is no running hardware.
"Anchors Aweigh" was also another favorite when the Navy brass showed
up--and the Navy was usually a very good customer in those days. It was
said that CDC would have an order as soon as a new machine was
announced. Perhaps not true, but pretty nearly.
One aspect of hammer issues (and this also was a problem in later train
printers) was contamination from the ribbon and paper dust. Eventually
a hammer would become sluggish and its characters vertically
displaced--train printers had characters horizontally displaced.
Character wear was also a problem. In programming shops where lots of
core dumps were taken, the "fuzzy zero" was a common artifact.
Here's a photo of a 501:
http://commons.wikimedia.org/wiki/File:LCM_-_CDC_501_printer_and_other_equi…
It's the bug box in the middle next to the card punch.
Interesting tidbit is that the 501 drum printer took the same ribbon as
the 512 train printer. Each ribbon came with a pair of poly gloves for
handling the filthy thing.
--Chuck
11:51 a.m.
On 12/22/2014 10:57 AM, Chuck Guzis wrote:
"Anchors Aweigh" was also another favorite
when the Navy brass showed
up--and the Navy was usually a very good customer in those days. It was
said that CDC would have an order as soon as a new machine was
announced. Perhaps not true, but pretty nearly.
I should also add that the 60x (and probably 65x) 7-track tape drives
were used to good effect. Reading (and writing) short records caused
the voice-coil valves switching the vacuum capstan flows made quite a
loud (with recognizable pitch) sound. The usual custom was to leave the
tape door down to better hear it. From memory, said noise was also
quite audible when running some of the Navy Audit COBOL tests even with
the door closed--so much so, that people on the other side of a room
packed with noisy equipment could hear it quite distinctly.
--Chuck
11:08 a.m.
On Mon, 22 Dec 2014, Doug Ingraham wrote:
One of my friends reminded me of the most unusual uses
of the 1000 LPM
printer on the CDC 3400 that South Dakota School of Mines and Technology
had in the 1970's and that was as a bass drum when the computer played the
Stars and Stripes forever. I only saw this run a handful of times and it
is probably one of those things lost forever. Even if someone had a copy
Back about 35 years ago, a friend told me that he was once a student at
Red Deer College in Alberta, Canada where he programmed his batch jobs so
that the printer made a distictive noise when his output was printed.
Apparantly the printer could be heard pretty much any place where he was
likely to be.
In unrelated news, I maintained two Data Printer Corporation "Chain Train"
line printers at that time and once had a problem where the left and right
edges of the output became wavey. After a moderate amount of scrutiny, the
problem was traced to a marginal capacitor in the main power supply (it is
still on my desk and it is a... hmm... General Electric 3042181 86F570MA
40,000 uF 50VDC unit). There were two identical capacitors and it took a
long time to dig that far into the machine so I replaced both of them.
--
Richard Loken VE6BSV, Unix System Administrator : "Anybody can be a father
Athabasca University : but you have to earn
Athabasca, Alberta Canada : the title of 'daddy'"
** richardlo at admin.athabascau.ca ** : - Lynn Johnston
3652
days inactive
3659
days old
12 comments
8 participants
participants (8)
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cclist＠sydex.com -
dave.g4ugm＠gmail.com -
dpi＠dustyoldcomputers.com -
elson＠pico-systems.com -
hachti＠hachti.de -
ian.primus.ccmp＠gmail.com -
richardlo＠admin.athabascau.ca -
rrissell＠gmail.com