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To improve "authenticity" of a mainframe simulator and for an additional nostalgic effect, I'd like to add sounds of a line printer to it. They should be similar enough to the original sounds for people to recognize familiar cadences of standard headers and/or footers of printouts. Before I attempt to write my own, I'd like to try and find an existing one; I'm unlikely the first person who'd want something like that.

Unfortunately, searches for "line printer sound simulator" return nothing of relevance; a few printer sound effects in the form of MP3 files at best.

Does anyone know of an open source mainframe simulator with line printer sound? I have a drum printer in mind, but a chain printer sound simulator would do as well.

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    You'll need a good amp and speakers to make it truly authentic. Chain printers were loud! Nice question, by the way. – Wayne Conrad Dec 11 '18 at 21:48
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    @WayneConrad That's granted; but first I'd like to be able to get the right frequencies and timings. – Leo B. Dec 11 '18 at 22:01
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    @Dougie If I'm to write a simulator (which I'd like to avoid doing from scratch, hence my question), I'll need a sample of exactly one hammer firing. A generic sound of a printer printing something won't do. – Leo B. Dec 11 '18 at 23:47
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    Go and ask the folks at the Californian Computer Museum. They've got a working 1403. computerhistory.org – Dougie Dec 11 '18 at 23:58
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    @Raffzahn some where quite loud my NL printer had guaranteed 95dB noise from the manufactor ... It was nearly impossible to stay in the same room during printing ... – Spektre Dec 12 '18 at 9:09
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Well, having a separate sound file will be a challenge. beside the fact, that you'll always get the way louder base level of a computer room with it, it also depends a lot on the type and model of line printer. Equally important, the sound isn't much impressive as long as the cover is closed - yes, it did make a huge difference.

Maybe try this video The IBM 1401 mainframe runs "Edith".

Beside several printouts (sorry, always covered) including two very similar spaced but with different amount of characters printed, which is relevant for the specific noise, it also gives impression of basic sound level as well as card readers and keypunch in 'DUP' mode

Here are more, this time showing the printer without cover, but different cameras and different loudness setting. Not the basic noise the chain i making when the printer is in ready to print.

I think it would be a good idea to take a look at the 1403 printer manuals as they not only provide basic estimations about printing time for a line, but also take form advance according to form control into account - plus describing the allowed processing time for the CPU to feed the next line. A perfect line printer emulation would also have to include this part. This includes as well the I/O load on a given channel - don't we all remember printers having hiccups on machines with too many devices on a channel, just because the owner didn't want to buy more?

  • That'll be hard as the souds aren't that simple. Frequency mix changes a lot between cover closed and open, even depending on the side you stand. Also hammer cadence is not only different depending on the text printed, but more so on the chain used and within that the sequence of links on the chain - keep in mind, companies rarely used standard chains. They Chains where fited to support the main documents printed. Like having only a single set of lettrs anall the rest filled with repeated numbers when they usually printed more numbers than letters and so on. – Raffzahn Dec 11 '18 at 22:18
  • @manassehkatz LINE PRINTERS? The real ones, chain or drum or bar? Serious? – Raffzahn Dec 11 '18 at 23:02
  • There were terminal rooms scattered around campus. 1/2 were from the CS department in the hard sciences (CS, Math, Physics, Chemistry, etc.) and the other 1/2 were under jurisdiction of the Behavioral and Social Sciences division. I was a first aider for that group (even though I was a CS major - they were happy to have me and it was convenient to other parts of campus where I spent the rest of my time (except for CS classes)). I definitely remember two rooms (one was Architecture, the other I can't remember) with line printers. It was a big deal when they got an IBM continuous feed laser... – manassehkatz Dec 11 '18 at 23:16
  • Well, then I'm not sure what they were. But they were not dot-matrix (I used a Printronix dot-matrix-line-printer in a summer internship - another interesting story - but these were definitely fully formed characters). Probably 2 - 3 feet on a side, 3 - 4 feet tall. Big but not huge. – manassehkatz Dec 12 '18 at 1:35
  • Hmm, during the 80s several companies offered band printers. They are muh like chain printers, but instead of a chain a flexible metal band with types moved along and like with chain printers hammer did push paper against the band. They where usually slower than chain printers and thus comparably quiet - smaler ones would quite well fit your size description - like the Dataproducts B600 (also sold under many names as OEM). – Raffzahn Dec 12 '18 at 2:10
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Not a simulator as such, but the BBC has just released an archive of its sound effects library which contains a couple of "line printer" recordings.

Explore http://bbcsfx.acropolis.org.uk/?q=printer

Try the two tracks labeled "General computer room atmosphere with printer in foreground" - one on the first page of the list, the other on the second.

To quote from the web page, "The Sound Effects are BBC copyright, but they may be used for personal, educational or research purposes..."

  • Generic recorded sound effects are definitely NOT what I'm looking for. If you think that it is not obvious from the wording of the question, please suggest an edit. – Leo B. Dec 13 '18 at 0:12
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    When you have failed to find one and need to write your own, some professional quality recordings would be a better place to start than the average crappy mp3 file. But feel free to ignore it if you think I'm not functionally literate enough to understand your questions. – alephzero Dec 13 '18 at 2:02
  • @LeoB. I guess for a reasonably close sound experience, you will need at least some real samples to start from. – tofro Dec 13 '18 at 8:07
  • @tofro Real samples would be needed not to start from, but close to the end of the project; and only very specific ones, like one hammer striking, a few hammers striking, a dozen hammers striking, etc. so that I'll be able to create waveforms by combining them. The sound of some arbitrary printer printing arbitrary something would be of no use. – Leo B. Dec 14 '18 at 1:41
  • @LeoB. With today's sound editing software, it's pretty easy to extract "one hammer striking" from "arbitrary printer sound". – tofro Dec 14 '18 at 7:25
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The dominant sound from a line printer is likely to be that of hammers firing. If one has something close to the sound of a single hammer firing, and plays that sound with the proper timing, that would probably give a pretty good overall impression of the printer's sound. To determine when hammers fire, identify the spacing of characters around the chain, figure out where the chain will be when the paper arrives in position to print a line, figure out which character on the chain will be the next one eligible for printing each column, and then figure out how far that character will have to move to get into position. Once one determines the maximum time required for a character to get into position, that will indicate when the carriage mechanism can start advancing to the next line. Based upon the character control character (distance to advance) one can figure out how much further the chain will move while the paper is advancing and where the chain will be when it gets there.

Getting a clean recording of a hammer-strike sounds might be a little tough, but perhaps not too bad if it would be possible to temporarily disconnect a hammer from its associated electronics and operate it directly from a charged capacitor while everything else was switched off. Alternatively, one may be able to find something that sounds close and tweak the sound suitably. Depending upon what the simulator is for, the cadence of the hammers may be more important than the exact impulse response of each hammer strike.

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