<The accompanying lab workbook for the _The Art of Electronics_ is <worth obtaining for getting the "Write-Only Memory" datasheet, too. <My favorite graph on the data sheet is "Number of pins remaining <vs. number of socket insertions". (Wasn't this originally published <in an April 1 issue of _Electronics_ in the 70's?) I got my copy of that data sheet as an official looking Signetics data sheet along with the data books circa 1972. It was the EIA/IEEE spec'd spigot in the lower right side of the device logical drawing. IT went well with the ISO bit bucket. ;) Allison