Yes, the rules for ssdi are that must have in 40 quarters if you are over
30 of paying full time, meaning $900 a year or more, or if you are 30, you
must have half the quarters paid since you were 21. The rules for ssdi are
a bit complex, but it is definitely part of the OASDI insurance system,
while ssi is called an entitlement program, the only qualification
necessary is low income...or no income.