No definitions found for 'IBM 1800'
Perhaps one of these:
ibneiah,
ibm 701,
ibm 1620,
ibm 1403,
iwbni,
ibm 801,
ibm 7090,
ibm 3720,
ibn,
ifiom,
ibfn,
ibm 7094,
ibm 7040,
ibm 2741,
ibm 705,
i-beam,
iban,
ivm,
ipm,
ibm 704,
ibm 650,
ibm 370,
ippm,
ifna,
ibm390,
ivanhoe,
ipn,
ibm,
iwfm,
ipomoea,
ipmi,
ivan,
ibm 1710,
ibm 360,
ibm 1130,
ibm 709,
ivan iii,
ibm 3270