This is my attempt at faithfully re-setting Ken Thompson's Bell Labs memo, Users' Reference to B, while preserving its original formatting as closely as possible.
I grabbed the original PDF from Dannis Ritchie's website and removed previous OCR attempts. Using Adobe Acrobat Pro, one of the best commercial PDF editors available, I re-OCRed the document and exported the results to a text file.
Next, I converted the OCR output into ROFF by inserting control lines, though I made no attempt to replicate the style of the original ROFF sources. The ROFF files were processed using roff(1) from UNIX V2, with the output captured in kbman_text.
However, the resulting text didn't match the original due to hyphenation differences. These differences were caused by changes in the suffix table over time. I used the earliest available suffix table from 28 March 1972, but since the memo dates back to 7 January 1972, it was undoubtedly typeset using an even earlier version. I manually corrected the hyphenation in the roff(1) output to match the original text.
To ensure accuracy, I typeset the edited roff(1) output using my Teletype Model 37 PDF simulator in debug mode (red text) and compared it to the original PDF. Each page was layered in Adobe Photoshop, with the re-set version placed over the original at 50% opacity. I manually adjusted the text until both versions matched exactly, fixing all OCR errors (e.g., missing spaces, incorrect characters, 0 vs o, 1 vs l) in the process.
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Left - original
Middle - re-set
Right - combined
After completing the corrections, I generated the final PDF (kbman_re-set.pdf) in black text by disabling debug mode. The document was then cleaned up and optimised.