1990 Era computer room
jws at jwsss.com
Wed Jun 24 13:40:11 CDT 2015
On 6/24/2015 9:33 AM, J. David Bryan wrote:
> On Tuesday, June 23, 2015 at 22:14, jwsmobile wrote:
>> Also I don't recall the Data Products ever scaling as fast by
>> restricting columns. At least our 2230, 2260 and 2290 UC only and 96
>> character set printers didn't. Got the same speed regardless of the
>> columns on those Data Products printers.
> The HP 2767A service manual (02767-90002, available from Bitsavers) is a
> reprint of the Data Products 2310 service manual. Page 1-17 says:
The Data Products 2310 isn't a 2230, 2260, or 2290. Those are later
models than the one
that is being discussed here. When you fired all the same characters on
these printers, however
the printer almost seemed like it wanted to move with a 64 character
model. It was possible to get
it to do that if you studied how to get the right pattern of characters.
> "The printer receives data from the user system and stores up to 20
> characters in the buffer memory. [...] A full line of data is
> printed in four zones, each zone having 20 consecutive print
> positions. In this manner, the printer's 20 hammer drivers can be
> time-shared among the 80 print positions."
> ...and the spec on page 1-5 says the print rate for the 64-character drum
> is 356 lines per minute for 80 columns, 460 lpm for 60 columns, 650 lpm for
> 40 columns, and 1110 lpm for 20 columns.
> I tested a 2767A as a customer of the HP Rockville, MD office in the early
> 1970s. As I recall, the character set wasn't staggered on the drum, and
> the hammer force was constant, regardless of glyph area. The result of
> printing a line of hyphens -- or worse, a line of periods -- was a very
> loud bang and a neatly perfed page.
> -- Dave
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