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On 14/05/2014 10.50, Tim Hill wrote:
Pretty much .. though it’s paper tape not punched cards .. a “hole” was a 1, non-hole a 0, so the only way to erase a character was to punch out ALL the holes, hence 127 (the 8th bit was nominally a parity bit). In fact, DEL is really “IGNORE” since when reading the tape and 127 codes were usually silently skipped by the computer or reader.
Very interesting, thanks for the information!(my first 6502 assembler for the KIM-1 was on punched tape; the tape had a spurious hole and we had to find and fix the wrong byte in memory to avoid waiting for a replacement)
-- Enrico