Editing UNIVAC I (section)

===Input/output===
Besides the operator's console, the only [[input/output|I/O]] devices connected to the UNIVAC I were up to 10 [[UNISERVO]] tape drives, a [[Remington Standard]] [[electric typewriter]] <!-- Maint. Man. page 1-29. I maintained Univac I's for 13 years. --> and a [[Tektronix]] [[oscilloscope]]. The UNISERVO was the first commercial computer tape drive commercially sold. It used data density 128 bits per inch (with real transfer rate 7,200 characters per second) on magnetically plated phosphor bronze tapes. The UNISERVO could also read and write UNITYPER created tapes at 20 bits per inch. The [[UNITYPER]] was an offline typewriter to tape device, used by programmers and for minor data editing. Backward and forward tape read and write operations were possible on the UNIVAC and were fully overlapped with instruction execution, permitting high system throughput in typical sort/merge data processing applications. Large volumes of data could be submitted as input via magnetic tapes created on offline card to tape system and made as output via a separate offline tape to printer system. The operators console had three columns of decimal coded switches that allowed any of the 1000 memory locations to be displayed on the oscilloscope. Since the mercury delay-line memory stored bits in a serial format, a programmer or operator could monitor any memory location continuously and with sufficient patience, decode its contents as displayed on the scope. The on-line typewriter was typically used for announcing program breakpoints, checkpoints, and for memory dumps.{{citation needed|date=July 2022}}