Editing UNIVAC I (section)

===Main memory details===
[[Image:Mercury memory.jpg|300px|right|thumb|Mercury delay-line memory of UNIVAC&nbsp;I]]
The main memory consisted of 1000&nbsp;[[Word (data type)|words]] of 12&nbsp;characters each. When representing numbers, they were written as 11 [[decimal]] digits plus [[signed number representations|sign]]. The 1000&nbsp;words of memory consisted of 100&nbsp;channels of 10-word [[delay-line memory|mercury delay-line]] [[register (computing)|registers]]. The [[input/output]] buffers were 60&nbsp;words each, consisting of 12&nbsp;channels of 10-word mercury delay-line registers. There are six channels of 10-word mercury delay-line registers as spares. With modified circuitry, seven more channels control the temperature of the seven mercury tanks, and one more channel is used for the 10-word "Y" register. The total of 126 mercury channels is contained in the seven mercury tanks mounted on the backs of sections MT, MV, MX, NT, NV, NX, and GV. Each mercury tank is divided into 18 mercury channels.{{citation needed|date=July 2022}}

Each 10-word mercury delay-line channel is made up of three sections:
# A channel in a column of mercury, with receiving and transmitting [[quartz]] piezo-electric [[crystal]]s mounted at opposite ends.
# An intermediate frequency chassis, connected to the receiving crystal, containing amplifiers, detector, and compensating delay, mounted on the shell of the mercury tank.
# A recirculation chassis, containing cathode follower, pulse former and retimer, modulator, which drives the transmitting crystal, and input, clear, and memory-switch gates, mounted in the sections adjacent to the mercury tanks.{{citation needed|date=July 2022}}

[[File:UNIVAC 1 Recirculation Chassis Board (1951).jpg|thumb|UNIVAC 1 recirculation chassis board]]